Jumpy screen with GBS-8200

Bryce · 11:48, 05 January 23

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.

WacKEDmaN · 12:23, 05 January 23

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?

WacKEDmaN · 12:25, 05 January 23

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!

WacKEDmaN · 10:07, 06 January 23

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..

CaptainRon · 18:57, 07 January 23

I tried to reproduce your issue and found my own :picard:

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

Bryce · 12:27, 08 January 23

Quote from: jb2590 on 18:57, 07 January 23I tried to reproduce your issue and found my own

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.

WacKEDmaN · 02:38, 09 January 23

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?

CaptainRon · 21:55, 09 January 23

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

WacKEDmaN · 07:24, 17 January 23

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

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)

WacKEDmaN · 06:12, 19 January 23

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....

Bryce · 09:24, 19 January 23

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.

WacKEDmaN · 10:27, 19 January 23

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!

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...

pelrun · 10:35, 19 January 23

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.

WacKEDmaN · 11:00, 19 January 23

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

pelrun · 11:17, 19 January 23

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.)

WacKEDmaN · 11:33, 19 January 23

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...

WacKEDmaN · 06:43, 20 January 23

back at it... with many thanks to The Clueless Engineer on youtube...
..just need to re-arrange my whole setup first

also.. new GBS8200 v4.0 dated 20220916 arrived today..
(HD9600 V5.0 dated 2015.01.15 and original GBS8200 dated 2019.10.18)

WacKEDmaN · 07:03, 21 January 23

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!

WacKEDmaN · 05:25, 23 January 23

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

WacKEDmaN · 04:13, 24 January 23

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!....

CaptainRon · 04:56, 25 January 23

I'm glad the new GBS8200 solved the jumpy screen. It is odd how the current drops when the rgb is connected though

WacKEDmaN · 05:55, 09 February 23

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)

WacKEDmaN · 13:58, 10 February 23

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..

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Jumpy screen with GBS-8200