this isnt strictly CPC related but i hope someone can help...
it looks like ive run into a strange issue trying to power a GBS-8200 (no mods) and CPC on the same power...
i have just setup a PC PSU with breakout board that breaks out 12v 5v 3.3v.. and fuses!
connected to 12v i have a buck converter at 5v showing current draw...to power the CPC..
i also have 12v connected to the GBS...
this is where problems start.. gbs' onscreen display is perfectly fine..but CPC output seems to jump and distort...its not just screen but it looks like the characters change a little..
i also tried powering the gbs from the a separate 5v rail... but it did the same thing...
...next i powered the gbs via a 12v wall wart..separate from the main PSU...and it works perfectly...
ive tried 3 different psus now..ranging from 160w to 250w and they all do the same..
its like theres some ground loop or something happening..
does anyone have any idea?.. one would think the 12 and 5v rails are separate on a PC PSU
thanks..
It's not a ground loop, it sounds like an offset ground, ie: certain mixtures of PSU's are causing the grounds of the different devices to be slightly off from each other.
Bryce.
the thing is bryce...the issue is only showing up with a single power supply and single rail.. it should be all at same ground potential level... its when i seperate the supplies that it works (where ya would think its more possible for the levels to be different!)
mains power comes into my box...
main is split to power LCD, and PSU...
PSU rail putting out 12v@10A.. (through 5A fuse!)
12v to directly to GBS...
same 12v to buck..down to 5v to power CPC (this is where the screen bounces)...
where is the ground level difference?! can the buck change the ground level?
if i power the GBS separately its fine... (totally separate supply..does the same if i use 5v PSU rail)
ive had this issue for a while trying to power the CPC and GBS off the same supply...doesnt matter if its wall wart or PC PSU..
edit:
it seems to be like looping through the video connector
i do notice something strange...
ok so ive got 12v rail... from that 2 sets of wires.. one goes off to the buck then to the CPC.. one straight to the GBS...
the buck has voltage and current output displays... with CPC switched off and video not plugged in...buck shows 5v and 0mA current...
then i plug in the video connector from the GBS to the CPC...and instantly see the current increase to 100mA...
turn on CPC.. it works fine.. but the screen is bouncy... (again..only CPC output.. GBS onscreen display is stable)
the bounciness changes depending on power supply used.. and even between CPC boards!..i have another one here where the bounce is very mininal..still there but its not as bad as my own board!
it looks like the bounce...is being generated by the CPC...(which cant be good for it!)
maybe i should do away with the buck.. and power the CPC directly from the 5v rail...(and through a 3A fuse!..i only really want the buck for the current display and extra level of current protection)
here a quick layout i drew up to make it a little more clear... black is power ground.. blue is vga's ground..its like theres leakage in this config.. (that 100mA i see on the buck with CPC switched off..if i pull the RGBs connection the amperage drops to zero)
setup.png
ok.. after some more playing around... powering the gbs from its own power..causes the amperage to drop whiles the cpc is running...
eg.. ill pull the video cable from the CPC while its running and the amps going into the CPC increases!...im seeing 680mA...pull it and increase to 1.1a (with usifac)..
should i disconnect the ground to the gbs from the CPC?
so for clarification..
with video cable plugged in..its pulling 100mA with CPC off.. and its pulling 600mA with it on..
pull the video cable and it drops to 0v with CPC off, and increase to 1.1A when CPC is on..
edit: on more playing around...
i pulled the monitor side vga cable while it was running and the voltage increased..
so ..seems like monitor is causing it?! WTF
@WacKEDmaN
Try it without the Buck I think the Buck is -ucking it up.
Keep Safe
Ray
Quote from: Audronic on 08:09, 25 December 22@WacKEDmaN
Try it without the Buck I think the Buck is -ucking it up.
Keep Safe
Ray
i just powered the cpc from a 5v wall wart.. and gbs from another 12v wall wart
defeats the purpose of running it from the PC PSU...
and cant see if theres any power draw with video connected and cpc off.. :/
Quote from: WacKEDmaN on 23:51, 24 December 22PSU rail putting out 12v@10A.. (through 5A fuse!)
PSU's don't "put out" anything. They "offer". In this case the PSU can offer up to 10A, but if the consumers (the devices attached) only pull 3A, then the 5A fuse is fine.
The issue seems to be the PC PSU messing the PSU inside the LCD. The GND in the LCD (which comes from its own internal PSU) is clashing with the GND of the PC PSU and because they are using differing ground references, the voltages are not aligned. By using the wall warts you have everything referenced from the LCD GND.
A possible solution would be to swap the live and neutral of the LCD if it's one of those two pin 240V plugs on the back of the monitor. This might solve the problem. Or does the LCD have an earth connection too?
A better solution (and best practice) is to not connect two separate switched mode supplies (LCD and PC PSU) to a single system.
Bryce.
..thanks Bryce.. merry xams!
...i know a psu offers up to 10A ..it only "pulls" whats needed...
..its strange..ive now powered the LCD from a seperate power board..(still with the wall warts)..
i think the problem still exists to some extent as the usifac seems to be like not getting full power (crashing and not connecting etc)
i will try adding the PSU and buck back into the mix tomorrow (eg power lcd and psu from seperate 240v wall sockets and the cpc and gbs with PSU)
thanks guys.. dont get too drunk (like me) for xmas! :)
could you take a picture or maybe even a video of how that looks like?
Quote from: Bryce on 11:24, 25 December 22A possible solution would be to swap the live and neutral of the LCD if it's one of those two pin 240V plugs on the back of the monitor. This might solve the problem. Or does the LCD have an earth connection too?
A better solution (and best practice) is to not connect two separate switched mode supplies (LCD and PC PSU) to a single system.
they are both 3 wire earthed "jug" cords.. and thats what im not getting...it should ALL be referenced back to mains ground....like both chassis of the PSU and monitor are connected to the same ground...
..'best practice to not connect two seperate switch modes PSUs'..??.... umm well then how the hell do PCs work?! like PSU in PC and PSU in this PC monitor (oh and ive run 2 PSUs in a PC fine!..thermaltake GPU power supply+standard pc PSU)..aslong as the grounds are the same it will be fine..
hmm maybe i should "bond" the 2 chassis to make sure both ground levels are at the same potential? (they already should be - through the ground wire)
im thinking i might just pull the ground connection between the GBS and CPC...might still work...ill give it a go!
today..powering the GBS from 5v rail on the PSU...and CPC through the buck on the 12v rail.. but CPC switched OFF.. theres 200mA current draw going through the CPC...(includes bounce when cpc is switched on!)
powering the GBS from seperate wall wart seems to be ok.. but.. i want it all on 1 power! thats the purpose of doing it all!...
@eto.. its not a pretty setup atm.. im just trying to get it all working right b4 hot glueing it all in place..
BTW: dont get hotglue on ya fingers!... it leaves a nasty burn!.. i found out the hard way on xmas eve! :picard:
heres a quick vid of the bounce... ..best i could do..my camera is a potato!
..every time it looks like the focus is changing..its bouncing!...
I do have pretty much the exact same set-up, except for that I also have the GBS control mod installed. I'll check when I am back in a few days, if I can see something similar.
I have seen something similar with some LCD TVs where the image was just not 100% sharp and steady but it was not as bad as this and I am not sure if that is in any way related.
Quote from: WacKEDmaN on 02:16, 26 December 22Quote from: Bryce on 11:24, 25 December 22A possible solution would be to swap the live and neutral of the LCD if it's one of those two pin 240V plugs on the back of the monitor. This might solve the problem. Or does the LCD have an earth connection too?
A better solution (and best practice) is to not connect two separate switched mode supplies (LCD and PC PSU) to a single system.
it should ALL be referenced back to mains ground....
Most SPMPSU's aren't ground referenced, which is what is most likely causing the issues that I've mentioned.
PC's have a massive amount of filtering. In particular for the type of high frequency noise created by SMPSU's. Retro computers have none of this as they were designed for linear power supplies.
Bryce.
Quote from: Bryce on 10:37, 26 December 22Quote from: WacKEDmaN on 02:16, 26 December 22Quote from: Bryce on 11:24, 25 December 22A possible solution would be to swap the live and neutral of the LCD if it's one of those two pin 240V plugs on the back of the monitor. This might solve the problem. Or does the LCD have an earth connection too?
A better solution (and best practice) is to not connect two separate switched mode supplies (LCD and PC PSU) to a single system.
it should ALL be referenced back to mains ground....
Most SPMPSU's aren't ground referenced, which is what is most likely causing the issues that I've mentioned.
PC's have a massive amount of filtering. In particular for the type of high frequency noise created by SMPSU's. Retro computers have none of this as they were designed for linear power supplies.
Bryce.
ok..i get that some psu's dont ref to mains ground..but i was under the impression that all PC/Monitors PSUs are all ref to mains...
and..it all works fine if i just power the GBS seperatly.. (CPC powered from PSU.. LCD off its own PSU..so theres still 2 in the mix and its fine)..its just adding the GBS where the issue shows up..(and only when the GBS is powered)
anyways...
would you suggest i try to tap power off the LCDs power supply to power the CPC and GBS off?
(it would be a nicer solution..just not sure it the LCD PSU can supply the extra current)
edit: actually thats gonna be a PITA..coz the monitor is glued to the box lid! gonna be a pain to get off! LOL
You could try that, but remember to add appropriate fusing on the new output and be extremely careful when poking around on the PSU board. There's usually around 400VDC across some of the capacitors that could really ruin your day.
Bryce.
Quote from: Bryce on 15:27, 26 December 22You could try that, but remember to add appropriate fusing on the new output and be extremely careful when poking around on the PSU board. There's usually around 400VDC across some of the capacitors that could really ruin your day.
Bryce.
..thats going to be an issue.. cant get the monitor off the box to take it apart! :P
looks like im just going to have to use 2 seperate supplies for the CPC and GBS n be done with it
...
what a waste of money n time that was... :picard:
@WacKEDmaN If you want small power supplies have a look here (They are in Australia)
https://www.ebay.com.au/itm/393010083064
Keep Safe
Happy new Year
Ray
Quote from: Audronic on 22:57, 26 December 22@WacKEDmaN
If you want small power supplies have a look here (They are in Australia)
https://www.ebay.com.au/itm/393010083064
Keep Safe
Happy new Year
Ray
i dont need a new psu... ive got like 20 PC PSUs here.....
and besides...it wont fix the issue at hand....it doesnt matter what power supply i use... i CANNOT power CPC and GBS with same power supply... as it causes the bouncys...aswell as that 100-200mA of current that seem to flow through the CPC and out the video connector while the CPC is switched OFF
Quote from: WacKEDmaN on 04:08, 27 December 22Quote from: Audronic on 22:57, 26 December 22@WacKEDmaN
If you want small power supplies have a look here (They are in Australia)
https://www.ebay.com.au/itm/393010083064
Keep Safe
Happy new Year
Ray
i dont need a new psu... ive got like 20 PC PSUs here.....
and besides...it wont fix the issue at hand....it doesnt matter what power supply i use... i CANNOT power CPC and GBS with same power supply... as it causes the bouncys...aswell as that 100-200mA of current that seem to flow through the CPC and out the video connector while the CPC is switched OFF
Current will definitely flow through the LUM pin if the monitor it's connected to is powered. Not sure about the other monitor pins, but any current on that connector (when the CPC is turned off) is coming from the monitor.
Bryce.
Quote from: Bryce on 11:29, 27 December 22Quote from: WacKEDmaN on 04:08, 27 December 22Quote from: Audronic on 22:57, 26 December 22@WacKEDmaN
If you want small power supplies have a look here (They are in Australia)
https://www.ebay.com.au/itm/393010083064
Keep Safe
Happy new Year
Ray
i dont need a new psu... ive got like 20 PC PSUs here.....
and besides...it wont fix the issue at hand....it doesnt matter what power supply i use... i CANNOT power CPC and GBS with same power supply... as it causes the bouncys...aswell as that 100-200mA of current that seem to flow through the CPC and out the video connector while the CPC is switched OFF
Current will definitely flow through the LUM pin if the monitor it's connected to is powered. Not sure about the other monitor pins, but any current on that connector (when the CPC is turned off) is coming from the monitor.
Bryce.
LUM is the only pin NOT connected to the GBS!! (its connected to GND on GBS side..but CPC side was never soldered to anything..its just floating around and not touching anything else)
...and i dont see any current flow when i use a separate supply for the GBS..its only when the GBS is on same power supply as CPC (the monitor doesnt matter at all.. i can try another monitor and there will be same results..and i am using a 4way power strip to power 3 different supplies aswell..so all the same mains ground)
pulling the VGA monitor cable from the GBS does stop the current flow, but it seems like its an internal switch in the GBS itself, nothing to do with the monitors ground..
....sorry Bryce.. you might be right about it being monitor..
today ive been running CPC and GBS powered from seperate wall warts (5v@2A for CPC 12v@2A for GBS)..
i dont have the buck in the mix so i cant see the current draw...
BUT... im getting a slight bit of bounce occasionally... and now.. usifac is playing up again (especially with esp32 connected).. like its not getting current again..and im getting hella crashes on some boots (like sync goes crazy)..and random reboots during gameplay...i guess it needs more current but all i got are 5v@2A max..
so its looking like this issue is bringing the current down on the CPC input some how..(as it does with the buck..)
this is really strange...
but... i have to send this GBS back to its owner today.. im waiting for one to arrive from china, but its looking like a 2 month wait :(
hopefully its just this version of the GBS and the new one acts better...i dont think i had these issues with my old GBS ..but i killed it by ripping off the clock pin while doing the CBS-C mod
ill hook up direct VGA to one of my PC monitors later and see if theres any current draw through the CPC with it off...
edit: so mate is lending me the GBS some more till i get mine...
well i pulled it all down.. and then reconnected everything...
now..PC PSU is powering CPC through the buck.. and GBS is powered by 12v wall wart...
there is no bounce... and NO current flow with CPC off....(if i use 5v or 12v rails from PC PSU to power GBS the bounces and current flow are back)
...this current setup WAS causing current draw before....
i also just notice this board is label "HD9600" ..so maybe slightly different to the GBS8200..altho they are being sold as the same thing...
TLDR; ..im going to just use this 12v wall wart to power the GBS..and use a PC PSU to power CPC and other things... (ESP32 could do with its an external supply..and i wanna put RGB LED strips in my box! eventually to be controlled from the CPC!)
so it seems im not the only one with this issue....
mate has the same bouncy screen with his other HD9800...he is also powering both from a the same supply..that has isolated outputs..
you can see here in this video clip...
https://youtube.com/clip/UgkxcPZgvmHbz_9v37zRzVvl2FXQrpyAFP5B
I have a GBS-8200 that I have been using for over 10 years. I use a 5v 4A double insulated wall plug type power supply, powering both the CPC and GBS.
The LCD has the 'kettle' type 240v power cord. So it's all nice and simple.
I don't have any issues.
Quote from: 00WReX on 03:46, 30 December 22I have a GBS-8200 that I have been using for over 10 years. I use a 5v 4A double insulated wall plug type power supply, powering both the CPC and GBS.
The LCD has the 'kettle' type 240v power cord. So it's all nice and simple.
I don't have any issues.
Quote from: WacKEDmaN on 05:44, 24 December 22this isnt strictly CPC related but i hope someone can help...
it looks like ive run into a strange issue trying to power a GBS-8200 (no mods) and CPC on the same power...
i have just setup a PC PSU with breakout board that breaks out 12v 5v 3.3v.. and fuses!
connected to 12v i have a buck converter at 5v showing current draw...to power the CPC..
i also have 12v connected to the GBS...
this is where problems start.. gbs' onscreen display is perfectly fine..but CPC output seems to jump and distort...its not just screen but it looks like the characters change a little..
i also tried powering the gbs from the a separate 5v rail... but it did the same thing...
...next i powered the gbs via a 12v wall wart..separate from the main PSU...and it works perfectly...
ive tried 3 different psus now..ranging from 160w to 250w and they all do the same..
its like theres some ground loop or something happening..
does anyone have any idea?.. one would think the 12 and 5v rails are separate on a PC PSU
thanks..
i dont think my GBS8200 had this issue either...this HD9800 version seems to be bad for it....
...we'll find out when i get my new GBS8200 i guess!
for the time being powering it from its own wall wart seems to be doing the trick...
i am noticing some current draw through the CPC when off with the GBS powered by a wall wart...but its nowhere near as bad (60mA) as with the PC PSU powering both (upto 200mA)... and theres no bounce...
What needs to be understood is that you are connecting an 80's (relatively) low frequency device with pretty much no filtering for modern SMPSU's together with a modern device that has filtering for itself, but may mess up the power rails with spikes both from itself, but also probably reflecting the spikes from the PSU back at the CPC. My suggestion would be to add adequate filtering (perhaps a 100uH inductor (in series), a hefty 470uf Capacitor and a 100nf ceramic capacitor (in parallel)) between the GBS and the CPC. This will most likely remove all issues.
Bryce.
Quote from: Bryce on 19:27, 30 December 22What needs to be understood is that you are connecting an 80's (relatively) low frequency device with pretty much no filtering for modern SMPSU's together with a modern device that has filtering for itself, but may mess up the power rails with spikes both from itself, but also probably reflecting the spikes from the PSU back at the CPC. My suggestion would be to add adequate filtering (perhaps a 100uH inductor (in series), a hefty 470uf Capacitor and a 100nf ceramic capacitor (in parallel)) between the GBS and the CPC. This will most likely remove all issues.
Bryce.
where exactly "between" the cpc and gbs? i mean theres only RGBS+GND out of the cpc to the gbs..
...and do you reckon i could maybe get away with another buck (that has chunky inductor and caps) on the gbs..that should provide some filtering, just as the buck on the cpc is...
Quote from: WacKEDmaN on 01:39, 30 December 22you can see here in this video clip...
https://youtube.com/clip/UgkxcPZgvmHbz_9v37zRzVvl2FXQrpyAFP5B
That one I experience too!
@Bryce could you maybe give more details about the filter? I'd love to try that out.
This: Hand drawn because someone recently said they wanted to see how shitty my hand drawn circuits look like :)
Bryce.
Quote from: Bryce on 13:56, 31 December 22This: Hand drawn because someone recently said they wanted to see how shitty my hand drawn circuits look like :)
Bryce.
not so shitty!...
..so i guess that on both cpc and gbs... like i said i thought the buck on the CPC would be providing some filtering.. ill have to give it a go with another buck (just with voltage display) on the gbs and see how it goes..
if i still have issues ill have to source some bits from old boards n make up a filter or 2...
i guess we really need to design a nice 5v and 12v power supply with the filtering built in... (but i would think a proper lab bench power supply from a reputable brand like siglent would already have adiqite filtering..yet we still see the issue)
Not only does a buck NOT filter, it introduces more noise due to its switching frequency.
Is the Siglent a switched mode PSU or linear?
Bryce.
not sure...id have to go through mates videos to find out... siglent or rigol.. one of the two!
Quote from: Bryce on 13:56, 31 December 22This: Hand drawn because someone recently said they wanted to see how shitty my hand drawn circuits look like :)
Thanks a lot. I just ordered the inductor and will give that a try once it arrives.
Would that then be a recommended set-up any time we are connecting the CPC to e.g. a PC power supply or only in those cases, when someone wants to connect a modern device like the GBS in parallel?
Yes, that's the bit that's missing in Retro hardware, that would make them more compatible with SMPSU's.
Bryce.
im gonna source some components off old boards tomorrow and build a couple of them up for both the 12v and 5v rails coming from the PC PSU...
hopefully that sorts the issue....
no offence Bryce (yeah yeah another silly idea!)...
but i dont see how a filter like this will stop the current flow through the CPC when its off.....sure it will smooth spikes or drops..but i dont see how it can stop that current flow....
can you please explain how Bryce?!... or link somewhere with some good (easy to comprehend!) articles plz....
It definitely won't stop current from flowing through the CPC, but that current isn't a problem it's a requirement for the monitor to work. Turn your PC monitor on and leave the PC off, you'll see current flowing too. The monitor needs to sense what's connected to it and that would be impossible with no current.
Bryce.
Quote from: Bryce on 12:38, 02 January 23It definitely won't stop current from flowing through the CPC, but that current isn't a problem it's a requirement for the monitor to work. Turn your PC monitor on and leave the PC off, you'll see current flowing too. The monitor needs to sense what's connected to it and that would be impossible with no current.
Bryce.
i didnt think it would be able to stop it!....
but....it SHOULD NOT be flowing through the CPC.... it should only be on the GBS that the monitor detect is on... i mean the input side (that the CPC is on) shouldnt matter, the GBS detects the sync... not the power....(eg pulling the CPC RGBS from the GBS still lets the monitor connected to it display)
looking at the CPC schematic.. i cant see how current can be flowing.. i see RGB is pulled up to 5v..but there should be no 5v with it off!... and it shouldnt be connected anywhere that will it flow.... can you see the path on the schematic Bryce? (remember..LUM is not connected!)
i might hook up my PC monitor that works direct from CPC again and check the current...im fairly sure i didnt see any when the CPC was off..
i dont see how current can be flowing on RGB+S pins.. they are all "logic".. so should have very little current, and the chips aint powered so there should be no current...
maybe all i really need to do is put the GBS power AFTER the CPC switch (and add the filtering).... so switching the CPC off also switches the GBS off and kills that current flow! (i really dont like the thought of current flowing through the GA when its off)..
...but then my buck/meter will show current draw of both CPC and GBS which i dont really want!
...or do away with the CPC switch and put in a switch via the CPCs incoming power rail...(so no current can flow into the CPC to begin with!)
EDIT: i wonder if i should break out the scope and have a probe around with the CPC off and see exactly where that current is flowing....
The GBS also needs to detect the inputs, so the RGB pins of the GBS would have some voltage present that could be flowing through the Gate Array.
Bryce.
thanks Bryce.. i know it seems like we going around in circles here... but im just trying to get my head around how its happening!.. again, really do appreciate the help! (and i know eto does too!)
bugga...im gonna have to wait till the weekend for the filter...
you think i can find any 'marked' inductors on any of my old boards n power supplies?!
and i dont have a LCR meter or function gen to test the values.. its too long winded, and too much setup to test them with a scope and or multimeter!..ill just have to wait! (coz im a lazy ass!)
do you know where id definitely find a 100uH on a board Bryce? (anythin like old mobos, network cards, PSUs etc etc)...does the 100uH matter? can it be say 220uH? (i think i found some marked 220...not entirely sure what they actually are tbh! they got a strange package..but marked with a coil on the board..then again...220...is probably 220H not uH)
i did find some nice inductors on the HOT side that look to be around 100uH (but i dont wanna use them without measuring or atleast looking up the component datasheet first!)...
also scavenged some nice X class caps aswell as a bunch of diodes and other bits like PTCs
i can get 100uH 3A jobbies at the local for like 5$ a pop...
EDIT: on a side note....im finding it very strange that both the bounce and the current flow issue hasnt been seen earlier (how longs the gbs been around and used on CPCs?!)
ok...another silly question coming at ya
@Bryce ! :P
...so which one of these would ya use if ya had to?! blindly without knowing its value?.. im thinking the one with the green core looks about the right size for 100uH.....
the 2 on the right side seem to be mains isolation transformers (4 terminals and 2 winding.. maybe i could use one side of them tho?!)
none are marked except for the 2nd from left (marked with 220 on the top)
inductors and caps really smash me for a 6!.. always have...i fully get how they work and what they do.. but can never put it into practice!
The two on the right are common mode chokes, not inductors. The two on the left look like very low current inductors. The third (blue?) one looks like a variable inductor from an audio filter. Only the yellow one looks suitable from a current perspective, but it's most likely a lot less than 100uH.
The exact inductor value really depends on the switching frequency of the SMPSU (or buck). Try the yellow one. The capacitors should be doing most of the work anyway.
Bryce.
thanks for the confirmation mate...
isnt what we're after, "common mode" filtering? (but i guess them common mode chokes are meant for AC and we're playing in the DC domain)
yeah i was thinking the right 2 are probably too low current...
the blue one is actually out of a power supply! (TV)..i dont think its tunable, just wrapped around a ferrite core....i have seen ones with a tunable slug tho
i was thinking the exact value of the inductor shouldnt really matter (aslong as it can handle the current)...it'll just smooth any spikes.. where the 2x caps are doing the actual filtering across the power...
and yes... i AM colourblind! ...i gave up reading resistor values along time ago.. now i just measure em with the multimeter!
Common mode is only for AC and mainly removes noise that got picked up by transmission cables (the house cabling).
Bryce.
Quote from: Bryce on 12:42, 03 January 23Common mode is only for AC and mainly removes noise that got picked up by transmission cables (the house cabling).
Bryce.
thank you Sir!.. as i thought....
on another side note....ive got a bunch of linear regulators here...(LM317T in TO-220).. would a linear supply do away with all these issues?
sure the linear is gonna still need filtering on the input side..coz id still be powering the linear via the PC PSU or wall wart... but output should be solid DC.. no switch mode BS!
1.5Amp rating on the linear "should" be alright too yes? (ill whack a chunky heat sink on it!)...i mean ive never seen the CPC go above 1.1A...even with expansions
ive even got the right value resistors to set the adjustable linear to 5.03v (33k and 100k!)
Yeah, linear would be a better solution. The heat produced by the LM317T is dependent on the difference between the input and output voltage, so try to keep the input voltage around 3V higher than the desired output voltage. Below 3V it may stop regulating properly and anything above will lower the efficiency and cause the chip to heat up.
Bryce.
Quote from: Bryce on 13:41, 03 January 23Yeah, linear would be a better solution. The heat produced by the LM317T is dependent on the difference between the input and output voltage, so try to keep the input voltage around 3V higher than the desired output voltage. Below 3V it may stop regulating properly and anything above will lower the efficiency and cause the chip to heat up.
Bryce.
awesome!... ill get to building something up tomorrow....input filtering and linear reg on a single board..
thanks again Bryce
heres my back of an envelope hand drawn circuit!...yours is far from shitty Bryce!
WacKEDmaN I already sent you these in your messages but thought it might help someone else if they have this issue in the future.
I tried to replicate the issue using a 5v 2.5a cheap wall wart power supply connected to both the GBS8200 and the CPC through a splitter. I also tested the current draw of the GBS with the CPC powered off but still in circuit on the RGB connector and the DC power jack. I connected a bench supply through a multimeter and used the ground and +5v solder joints on the CPC barrel connector to inject the voltage while checking the current draw of the GBS.
I could not reproduce the bounce, and the GBS does seem to draw around 300 milliamp.
Video trying to reproduce the bounce
https://drive.google.com/file/d/1dtFQr8thFjTCv8nIHGRFaAL2i4sBzmm9/view?usp=sharing
Video of the ammeter test of GBS from the CPC barrel jack while CPC is powered off
https://drive.google.com/file/d/1e7R8Cpk1ZKHlRad3ifgSWQb3S-WXhs1h/view?usp=sharing
Pic of my GBS8200 board
https://drive.google.com/file/d/1eNlulzDnA-aafDRmm5SH5CopeUr6KrzX/view?usp=sharing
thanks mate.... strange ya not seeing the bounce... i wonder if its something with 60hz vs 50hz mains....
i found my bucks run at 52hz.....
but im still finding it really strange there is power flowing through the CPC and GA when its off... ...and that the current going into the CPC INCREASES if ya pull the video connector from the back while its powered on...
gonna grab some new inductors n caps for the filter tomorrow....
@Bryce .. im i right in thinking that the GBS should be SINKING current through the vga connectors....not SOURCING?
im beginning to think about putting diodes on the RGB+S+GND lines so power cant get back into the CPC with it off...
Diodes will have a forward voltage drop and a forward voltage minimum. The lowest I know of has 0.4 volt drop (and minimum voltage to actually even work).
So you will drop at least 0.4 volts of your max 1V RGB voltage.
More typical diodes will drop 0.7 volts and will make your picture all black, as this is the video standard threshold between all black and all white. (0.3 means black, 1v means white).
So no, diodes in the RGB path will not help anything.
Quote from: WacKEDmaN on 09:19, 05 January 23@Bryce .. im i right in thinking that the GBS should be SINKING current through the vga connectors....not SOURCING?
im beginning to think about putting diodes on the RGB+S+GND lines so power cant get back into the CPC with it off...
No, it's probably providing a reference voltage to detect a video signal, which (if the CPC is turned off) could find a path to GND via the CPC components.
It would only be sinking current if a video signal was present.
Also, could you post a picture or the model number of that buck. It definitely ISN'T running at 52Hz, that's the mains ripple you're measuring.
Bryce.
Quote from: Bryce on 11:48, 05 January 23Also, could you post a picture or the model number of that buck. It definitely ISN'T running at 52Hz, that's the mains ripple you're measuring.
sorry my bad...just looked up the datasheet again...52kHz!.... that 'k' makes a hell of a lot of difference!
https://www.jaycar.com.au/medias/sys_master/images/images/9789550297118/ZV1640-dataSheetMain.pdf
what about the current increase when pulling video from the back when its running....600mA vs 1.1A
this seems to be causing all sorts of issues with the USIfAC, acting like it was before with bad power socket.. runs fine if i get rid of the GBS (and use direct to vga..always see around 1-1.1A)
any possibility that the video connector on the CPC could be causing it... just like the bad power socket allowing the cpc and some expansions to run fine..but not the usifac.. ...oxidised connections?
Quote from: SerErris on 11:18, 05 January 23Diodes will have a forward voltage drop and a forward voltage minimum. The lowest I know of has 0.4 volt drop (and minimum voltage to actually even work).
So you will drop at least 0.4 volts of your max 1V RGB voltage.
More typical diodes will drop 0.7 volts and will make your picture all black, as this is the video standard threshold between all black and all white. (0.3 means black, 1v means white).
So no, diodes in the RGB path will not help anything.
oh yeah...i didnt consider that.... thanks!..i wont waste my time with diodes!
heres some pics showing the 'current' situation! (the bit thats making me bang my head against the wall!)..
its not showing current flow through cpc when off, as im powering the GBS seperately from a wall wart... CPC is powered on the buck with display from the PC PSU.. you can easily see the current drops down alot with this GBS connected to CPC...
that is causing all sorts of issues..like reboots and lockups...
adding usifac makes it worse..but still pulls the same current as if it wasnt even detected.. (eg it still sits around 600mA)..
the current drops even further (0.58A) when i plug in speakers (that are attached to monitor!)
...if yas still think the buck or PC PSU powering cpc is the issue...ill can try powering from 5v wall wart, with multimeter before the cpc to test
i still havent got over to get some inductors yet.. hopefully tomorrow..
I tried to reproduce your issue and found my own (https://www.cpcwiki.eu/forum/Smileys/SoLoSMiLeYS1/picard.gif)
I have 2 bench power supplies. one only puts out 1 amp and I think its a bit too weak for the initial spike. but with my 4amp supply when I try to power both the GBS and CPC it wont boot. I also tried to use the wall wart with the multimeter in ammeter mode and it did the same thing?
It boots no problem with the wall wart and the splitter, but if I try to use a PSU with an ammeter it goes from around 300ma to almost 1amp but no boot. I think maybe I should buy a better, more modern bench PSU?
There is something going on that I don't understand right off hand.
https://drive.google.com/file/d/1fduS-IFp6oYwDoxuoHwDuMTKOqjIJ1r-/view?usp=sharing
Quote from: jb2590 on 18:57, 07 January 23I tried to reproduce your issue and found my own (https://www.cpcwiki.eu/forum/Smileys/SoLoSMiLeYS1/picard.gif)
I have 2 bench power supplies. one only puts out 1 amp and I think its a bit too weak for the initial spike. but with my 4amp supply when I try to power both the GBS and CPC it wont boot. I also tried to use the wall wart with the multimeter in ammeter mode and it did the same thing?
It boots no problem with the wall wart and the splitter, but if I try to use a PSU with an ammeter it goes from around 300ma to almost 1amp but no boot. I think maybe I should buy a better, more modern bench PSU?
There is something going on that I don't understand right off hand.
https://drive.google.com/file/d/1fduS-IFp6oYwDoxuoHwDuMTKOqjIJ1r-/view?usp=sharing
How are you measuring the current? It sounds like you connected the meter in parallel instead of series.
Bryce.
heres my attempt at a linear supply with filtering...
dunno.. shoulda got bigger caps... 100uF are 25v.. 10uF are 16v... ok for 12v supply (which is usually max for me)... but as it can take 37v input i guess i should have grabbed 50v caps... but ...this should do...(maybe just remove the 10uF from input side)
ive still gotta solder it up...and drop the resistors in... ive got a few IN4007 diodes for protection but not sure if they are really needed...
i could only get a 5A 100uH choke too...
what do you think
@Bryce?
I connected the multimeter the same way as the last test with the DMM positive and negative leads in series.
But the strange thing is that even without the multimeter just trying to power both the gbs and cpc on a single bench psu caused the same issue. I will try to get back to this soon to see if I can figure it out, it doesn't make sense to me that they both power up just fine with the wall wart and a barrel jack splitter, but not when using the same splitter but feeding power into the GBS power input pins from a bench supply, unless maybe there is a protection diode somewhere that wont let me backfeed the power like that from the gbs. I will let you all know what I learn next time I check it out. Thanks
ive had 3 attempts at making this filter and voltage regulator...(yeah yeah i suck!..easy on a breadboard..PITA on perfboard!)
first time i was getting the same voltage out as i was putting in...pulled half it down...then realised i forgot to connect the ground :doh:
next attempt worked... i used 150ohm and 470ohm resistors on the LM317, but it was putting out 5.3v... (the resistors should have set it to 5.166v..but i guess the tolerance is too high on them)....
so i pulled it down again....
tried again with the 33K and 100K resistors and was getting around 9v with a 10v input..dunno what i screwed up..maybe the heatsink (and therefore the output pin) touching the incoming rail... :/
so... im gonna inject 240v into the LM317!...and just use a 7805 5v regulator and do away with the resistors!
(and ill stick a plastic sheet under the heatsink so it doesnt make contact with the pre tinned through-holes)
i give up...i really dont think its gonna fix the issues....im just gonna use seperate supplys n be done with it....
5 attempts at making this bloody thing.... all bodgy with the LM317T.... last attempt was to try a 7805CT... got it all done...powered it up... effing pinout on the 7805CT is different than the pinout i looked up... toast! (and dont have any spare)
then tried straightening my soldering iron tip...well i snapped the bastard in two and took a chunk outta my hand and leg at the same time SMH....so no more soldering for me for at least a month....
Quote from: WacKEDmaN on 06:12, 19 January 23i give up...i really dont think its gonna fix the issues....im just gonna use seperate supplys n be done with it....
5 attempts at making this bloody thing.... all bodgy with the LM317T.... last attempt was to try a 7805CT... got it all done...powered it up... effing pinout on the 7805CT is different than the pinout i looked up... toast! (and dont have any spare)
then tried straightening my soldering iron tip...well i snapped the bastard in two and took a chunk outta my hand and leg at the same time SMH....so no more soldering for me for at least a month....
That soldering iron looks like it was ready for retirement anyway.
Bryce.
Quote from: Bryce on 09:24, 19 January 23That soldering iron looks like it was ready for retirement anyway.
well shes retired now!...
mate is gonna gimme his spare temp controlled soldering iron tomorrow... so i can get back to stressing over the linear reg! :P
i cant believe how bad i am at building this up!... i know it should be like a 15min job.. but do ya think i can get it right? SMH
might do a run over to the electronics shop tomorrow and grab a few more 7805s...and/or some low tolerance resistors to use with the LM317
..maybe i should grab some bigger perfboard too... so im not so cramped on the soldering side...
Not that I want to laugh at others misfortune, but trying to straighten one of those irons with brute force only ever has that one outcome...
It's an opportunity though - get a pinecil v2 to replace it (and a proper usb-c charger like the pinepower if you don't already have one), they're incredibly capable and far too cheap to ever consider buying one of these dodgy old mains irons ever again.
Quote from: pelrun on 10:35, 19 January 23Not that I want to laugh at others misfortune, but trying to straighten one of those irons with brute force only ever has that one outcome...
It's an opportunity though - get a pinecil v2 to replace it (and a proper usb-c charger like the pinepower if you don't already have one), they're incredibly capable and far too cheap to ever consider buying one of these dodgy old mains irons ever again.
laugh all you want! i would! it was pretty dumb!... id got away with it a few times before!
lucky i didnt electrocute myself tbh!.. one of the wires to the heating element was flapping about when it hit my hand and leg!
yeah nah on the pinecil... not into them little toys!... but thanks for the tip anyways
should have something like this on the way tomorrow
https://www.jaycar.com.au/duratech-48w-temperature-controlled-soldering-station/p/TS1620
not the greatest... but better than that stick iron
You misunderstand. The pinecil (and the TS100 before it) is not a toy. It is *literally* more powerful than the conventional weller/hakko soldering stations in the $500 range, and really is only second to the absolute high-end JBC or Metcal stations that are $1000+. I'm not exaggerating, I've used them all extensively and this is my professional opinion.
And yet it's only US$25. (US$50 if you need the USB-C charger as well.)
Quote from: pelrun on 11:17, 19 January 23You misunderstand. The pinecil (and the TS100 before it) is not a toy. It is *literally* more powerful than the conventional weller/hakko soldering stations in the $500 range, and really is only second to the absolute high-end JBC or Metcal stations that are $1000+. I'm not exaggerating, I've used them all extensively and this is my professional opinion.
And yet it's only US$25. (US$50 if you need the USB-C charger as well.)
ive seen plenty of reviews on the pencil type irons... i havent liked any of them... i dont see how this would be any different
as i said.. ive got a temp controlled one on the way from mate tomorrow... so i dont need anything else atm... but will keep your recommendation in mind should i need a new one in the future...
i really had no issues using the mains iron...apart from forgetting to switch it off and leaving it on for days...and the tip bending (probably coz it was on for days!) ..soldered up the whole CPC board with it perfectly fine...
back at it... with many thanks to The Clueless Engineer on youtube...
..just need to re-arrange my whole setup first :D
also.. new GBS8200 v4.0 dated 20220916 arrived today..
(HD9600 V5.0 dated 2015.01.15 and original GBS8200 dated 2019.10.18)
so setup the new power supply.. ran 5v out to CPC (its display is slightly off..multimeter reads 5v when its set to 4.8v)
powered new GBS with 12v wall wart power.. now pulls a solid 1amp (with usifac and usb..even up to 1.2 with tapedrive)..
plugging the GBS into the CPC doesnt cause any current draw... (the buck is out of the mix)
i havent noticed any jumpy text...but every now and then i see the whole image flicker...
...next ill try putting the buck back in the mix, power both the GBS directly from the PSU with 12v out, and 12v into the buck dropping it to 5v for the CPC... ..see if theres current draw on the buck...and see what happens on the main power rail too...
..if that doesnt work..ill removing the buck and finish building and replacing it with the Linear...
..ive used the soldering iron for a small job so far and i love it!.. gets up to temp in seconds, and has way better thermal capacity.. and a much finer tip is a joy!...also coz it has the display, its easy to remember its switched on so i wont screw the tip by leaving it on for days on end!
finally got the filter + linear working!..nice stable 5v (used 7805CT)...havent tested with CPC yet ...
CPC been pritty stable on new bench PSU...im still having some issues with USIfAC.. ..not sure if expansion connector ..or bad power (1.18A current draw with USIFAC connected)...or something else :'(
will go back to PC PSU soon, running both GBS and CPC from same 12v rail .. (cpc through the filter+reg)
im also currently running GBS through my TV so we will see if there is any difference there
did some testing today....
GBS8200 .. not bouncy with same power supply! ..only the HD9600 is doing it...
ok so i have jug cord coming in, powering PC PSU and LCD monitor
...12v from PSU powering buck with current display, at 8v...connected to the filter and linear (damn it gets hot..burnt fingers!)...
5v from PSU powering GBS... (no bounce!)
but.. theres STILL the current issue remains...even WITH wall wart...
its causing issues with power(usifac/random crashes and glitches)
..power up CPC without GBS connected... 1.02A (with USIfAC) being pulled....
..plug in RGB connector... current drops to 550mA...(even with wall wart)
so i pull the power on the GBS.... NO change in current!! (we on to something!)
so next i pulled the VGA connector (with RGB plugged into running CPC, GBS still NOT powered!)..current to CPC increased back to normal 1A (from 550mA)
so next i tried my VGA connection on my TV....
current drops to 800mA...nowhere near as bad but still an issue...
next i powered the LCD from a seperate power adapter.. (right next to the 12v wall wart for GBS)...
current dropped to 890mA!....
I'm glad the new GBS8200 solved the jumpy screen. It is odd how the current drops when the rgb is connected though
got around to some more testing...
new GBS8200 has been modded with full GBS-Control mod..(esp8266+clock board) working much much better than previous (ghost n goblins is now playable!)
still noticing current draw through the RGB connection, but its stable, no bounce... it seems only the HD9600 is "bouncing"..(even before doing GBS-C mod the GBS8200 was stable)
im also noticing a large voltage drop... bench power supply says 5.00v...multimeter on barrel jack reads 4.9v... on the board side at the barral socket, 4.8v, and 4.3v at the +/- of the usifac serial connector...
i think this is causing issues with the usifac, it wont reboot properly after enabing usb (locks up before rom line)..
ive increased the bench power supply till im seeing 5v on the board.. but its not helping
rest seems rock solid...just not having any luck with USIFAC...(can connect to PC, but it wont load anything..i can load dsks from usb, but i cant run "direct" files, they all require the reboot to work)
GBS8200 with GBS-C mod completed!..i managed not to kill the gbs processor this time!
for some strange reason my ESP8266 only wants to work right with 5v instead of the usual 3.3v for esps (this has no reg..just breakout board and ESP12 chiplet)..
atm im running CPC from bench power supply 5.1v@1.01A with USIFAC and USB enabled..
ive pissed off the PC PSU and replaced it with a 4 way power board!.. that has the monitor and 12v wall wart to power gbs
running sweet (apart from some usifac issues)...
im not seeing any current draw on the bench psu with the CPC off like i was with the buck cc/cv and display.. maybe its bodgy!
...i dont see a use for the filter + linear atm... (the linear doesnt like 12v! overheats and drops output voltage after like 1min!)
i also found a 5v 2A wall wart ..im thinking about using it to power the CPC eventually..