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General Category => Amstrad CPC hardware => Topic started by: fgbrain on 20:33, 20 May 19

Title: USB power supply for CPC/PLUS
Post by: fgbrain on 20:33, 20 May 19
Hi, I am wondering if its possible to use power from a USB charger/power bank with proper cables as a  neat PSU for cpc or plus...
I know that these use 5V like cpc does...


Please give recommendations about specs and specific  models.
Title: Re: USB power supply for CPC/PLUS
Post by: rpalmer on 21:24, 20 May 19
In short no, the USB power chargers do not supply enough current. The CPC needs at about 1.5A and all USB chargers only supply at most 1A.Also you could not drive the 3 inch drive as it needs 12V @ 1A.
rpalmer
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 22:45, 20 May 19
Well, for my Smok Rha I have an 2 A PSU, but never tried it with CPC since I use the PSU of LED lights (up to 5 V, 5 A) for it (with HxC, M-X4 etc.)

Title: Re: USB power supply for CPC/PLUS
Post by: tjohnson on 00:39, 21 May 19
I have a modmypi USB adapter that came with my pi3 that says it is 2.5a but I've not tried it.
Title: Re: USB power supply for CPC/PLUS
Post by: pelrun on 06:35, 21 May 19
Quote from: rpalmer on 21:24, 20 May 19
all USB chargers only supply at most 1A.


Even though they're routinely sold with 2.4A ratings?  ;D
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 18:51, 21 May 19
I am almost certain that I have seen a cable for this... But can't remember where!!


I know you need 12V for a 3" drive... But who uses a drive anyway!


We got Wifi - Gotek nowadays.. 8)
So 2 5v plugs are required.
Title: Re: USB power supply for CPC/PLUS
Post by: Cholo on 18:06, 22 May 19
I noticed on ebay (uk) there is a 6128 psu kit being sold that includes both a psu for the keyboard + a psu for the drive (and a scart cable). Of cause this dosnt solve your USB charging question, but if you are looking for a psu kits its available. Donno how long its been for sale, as usually i only see the one psu 464 style kits, so i thought it worth mentioning  ;)
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 21:41, 22 May 19
Thanks I am aware of this psu.
I use pc power supply for my CPCs but I search for more neat solutions..
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:36, 23 May 19
Quote from: fgbrain on 21:41, 22 May 19
Thanks I am aware of this psu.
I use pc power supply for my CPCs but I search for more neat solutions..

Using a PC powersupply on a CPC isn't a good idea. These supplies can usually supply >20A on the 5V rail. Any short circuit would burn the traces completely off the PCB and make the CPC unrepairable.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 15:32, 23 May 19
What is your suggestions then??


Are there any safe PSU apart from the monitor??
Title: Re: USB power supply for CPC/PLUS
Post by: logiker on 18:27, 23 May 19
Some years ago I used a PSU that I ordered from the greek ebay user ikonsgr74. I think it had 3A and it worked very well. I also got a TV cable (Scart) from him.
The only thing I am not sure about is, if and/or how I connected a drive. I think I just used a HxC drive.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 18:31, 23 May 19
Burning rails off the PCB can happen also when touching the joystick port and the screen (newly switched on) at the same time. 5 A nevertheless is enough for the whole system :)

Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 21:09, 23 May 19
Quote from: GUNHED on 18:31, 23 May 19
Burning rails off the PCB can happen also when touching the joystick port and the screen (newly switched on) at the same time. 5 A nevertheless is enough for the whole system :)

Yes, anything more than 5A is above what the PCB traces could handle, so try to get a supply that can only deliver between 3A and 5A.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 02:46, 24 May 19
Quote from: Bryce on 21:09, 23 May 19
Yes, anything more than 5A is above what the PCB traces could handle, so try to get a supply that can only deliver between 3A and 5A.

Bryce.


Yes, probably 3 A is just fine. Also it's probably the best to connect computer, HxC, Imperium solo, Mother-X4 and anything else (somehow connected to the CPC) with the same PSU.  :)
Title: Re: USB power supply for CPC/PLUS
Post by: pelrun on 04:19, 24 May 19
Quote from: GUNHED on 18:31, 23 May 19
Burning rails off the PCB can happen also when touching the joystick port and the screen (newly switched on) at the same time.


Oof, don't remind me.  :picard2:


Although that's extremely high voltage and negligible current, and is more likely to blow up the AY than any traces.
Title: Re: USB power supply for CPC/PLUS
Post by: shifters74 on 11:33, 01 June 19
As i have a gotek fitted in my 6128 i dont't need 12V and use a meanwell GS18B05-P1Jwhich costs £20 delivered.  Its the best PSU for delivering what its supposed too that i have tried i.e. 5V!!!  Others i have tried don't come close.  Works fine with a 6128, powered scart and gotek, MX4 with M4 and xmem installed.

found at RS here: https://uk.rs-online.com/web/p/desktop-power-supply/7212168/?relevancy-data=636F3D3126696E3D4931384E53656172636847656E65726963266C753D656E266D6D3D6D61746368616C6C7061727469616C26706D3D5E2E2A2426706F3D31333326736E3D592673723D4175746F636F727265637465642673613D6D65616E77656C6C20677331386230352673743D43415443485F414C4C5F44454641554C542673633D592677633D4E4F4E45267573743D6D65616E77656C6C2047533135423035267374613D6D65616E77656C6C204753313542303526&searchHistory=%7B%22enabled%22%3Atrue%7D
I have 4 of these now on different machines (Atari 800XL, C64 as well as 6128 and 464) and all seem rock solid and barely get warm.
cheers
shifters
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 12:02, 01 June 19
Quote from: GUNHED on 02:46, 24 May 19

Yes, probably 3 A is just fine. Also it's probably the best to connect computer, HxC, Imperium solo, Mother-X4 and anything else (somehow connected to the CPC) with the same PSU.  :)

That doesn't burn rails it "only" fries the AY. All voltage and no current.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 15:26, 01 June 19
Quote from: Bryce on 12:02, 01 June 19
That doesn't burn rails it "only" fries the AY. All voltage and no current.

Bryce.


Well, it happened to me once. But at least I still had warranty.
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 10:38, 02 June 19
Absolute no to using a USB power supply. It's amazing people still want to take short cuts despite all the info given out on this forum over the years. The CPC has no internal regulator, no smoothing circuitry, no protection, nothing. Get it wrong and you'll fry the AY and burn out circuitry. This is quite unlike, say, a 48k Spectrum which has a 5v regulator on the input (it's why the first thing to check on a dead Spectrum is the regulator).


Get the best standard 5v PSU you can afford. We've been through this many times. The RS supply we've recommended in the past is not discontinued but on the page there is a link to a replacement. Full data sheets on the RS website. Such good smoothing that when I was using my CPC and we had a sudden brown out (the power kept dipping) the CPC kept going while everything else was losing it's shit! (Ovs I saved and switched off).
Title: Re: USB power supply for CPC/PLUS
Post by: tjohnson on 10:57, 02 June 19
Quote from: chinnyhill10 on 10:38, 02 June 19
Absolute no to using a USB power supply. It's amazing people still want to take short cuts despite all the info given out on this forum over the years. The CPC has no internal regulator, no smoothing circuitry, no protection, nothing. Get it wrong and you'll fry the AY and burn out circuitry. This is quite unlike, say, a 48k Spectrum which has a 5v regulator on the input (it's why the first thing to check on a dead Spectrum is the regulator).


Get the best standard 5v PSU you can afford. We've been through this many times. The RS supply we've recommended in the past is not discontinued but on the page there is a link to a replacement. Full data sheets on the RS website. Such good smoothing that when I was using my CPC and we had a sudden brown out (the power kept dipping) the CPC kept going while everything else was losing it's shit! (Ovs I saved and switched off).
I thought all USB supplies were 5v and regulated, maybe not.
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 14:15, 02 June 19
https://www.sellmyretro.com/offer/details/usb-power-cable-%28amstrad-cpc-464-or-ti-99~~4a-32kb-sidecar-memory-card%29-32181 (https://www.sellmyretro.com/offer/details/usb-power-cable-%28amstrad-cpc-464-or-ti-99~~4a-32kb-sidecar-memory-card%29-32181)
I found the link I was talking about but seems currently unavailable!
Perhaps  because it's not safe to use???
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 15:53, 02 June 19
Quote from: fgbrain on 14:15, 02 June 19
https://www.sellmyretro.com/offer/details/usb-power-cable-%28amstrad-cpc-464-or-ti-99~~4a-32kb-sidecar-memory-card%29-32181 (https://www.sellmyretro.com/offer/details/usb-power-cable-%28amstrad-cpc-464-or-ti-99~~4a-32kb-sidecar-memory-card%29-32181)
I found the link I was talking about but seems currently unavailable!
Perhaps  because it's not safe to use???


Just because someone sells something doesn't mean you should use it.
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:51, 03 June 19
Quote from: GUNHED on 15:26, 01 June 19

Well, it happened to me once. But at least I still had warranty.

Really? To burn tracks you need current. Where was the current coming from?

@tjohnson (http://www.cpcwiki.eu/forum/index.php?action=profile;u=2129): Yes, USB charger PSU's are all regulated, but they are usually rather weak too. There are not many of them that could power a CPC.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: ComSoft6128 on 07:54, 03 June 19
I need one of these (RS) for a Plus, is there an adaptor for the output connector?
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 12:48, 03 June 19
Quote from: Bryce on 07:51, 03 June 19
Really? To burn tracks you need current. Where was the current coming from?


Well, I touched the CRT and the joystick port by accident, the CPC went dead and I took it to the shop where we got it. They told me that the tracks were bent up. But I don't remember if I actually did see it with my own eyes. Because that was in 1987 - basically 2745 bottles of Jack Daniels ago.  :laugh:
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 13:38, 03 June 19
I doubt the tracks were fried. The charge from a screen is static electricity. It has a very high voltage, but almost zero current, so there is not enough energy present to burn the track. You can try it for yourself: Charge yourself up on a carpet and then short yourself to a radiator using the thinest wire you can find. A spark will jump across the gap (indicating a very high voltage), but the wire won't burn or even get hot (indicating very low current).

Semi-conductor materials on the other hand are voltage sensitive, which is why static destroys chips.


Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 13:56, 03 June 19
Well, I won't try it by myself (again).  ;) :)
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 18:56, 03 June 19
Quote from: tjohnson on 10:57, 02 June 19
I thought all USB supplies were 5v and regulated, maybe not.


You only need to watch Big Clive's Youtube channel to see how badly some perform. At best they are designed for charging, not powering a 35 year old micro. Sure they'll work but if you insist on using one at least use one rated to work with a Pi.
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 18:57, 03 June 19
Quote from: ComSoft6128 on 07:54, 03 June 19
I need one of these (RS) for a Plus, is there an adaptor for the output connector?


Yep. Got mine on Ebay. About a quid. Just get the best deal at any given moment, will be loads.


Or if you use the PSU search on RS they may have one at the right size for a Plus. But personally I just use the same supply + the adaptor.
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:54, 04 June 19
Quote from: chinnyhill10 on 18:56, 03 June 19

You only need to watch Big Clive's Youtube channel to see how badly some perform. At best they are designed for charging, not powering a 35 year old micro. Sure they'll work but if you insist on using one at least use one rated to work with a Pi.

Yes, but Big Clive tears down the cheapest Chinese rubbish he can find. Inside an original Samsung / HTC / Sony USB PSU looks a lot different.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 10:25, 04 June 19
Quote from: Bryce on 07:54, 04 June 19
Yes, but Big Clive tears down the cheapest Chinese rubbish he can find. Inside an original Samsung / HTC / Sony USB PSU looks a lot different.

Bryce.


He's also torn down high quality supplies, indeed the Ikea 3 port units I use I purchased on his recommendation. Still wouldn't use one to power a CPC though.
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 11:10, 04 June 19
Maybe I've only watched his "thrashy" videos :)

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: ComSoft6128 on 12:43, 04 June 19
Thanks to everyone that contributed to this thread, the info was helpful - RS PSU ordered this morning.

Cheers,

Peter
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 08:38, 09 June 19
Okay... everyone said NO in short
But I like experimenting!!


https://youtu.be/XNh52-vJc6M (https://youtu.be/XNh52-vJc6M)

I have now a mobile 6128!!! :P
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 09:38, 09 June 19
Eh, no. I never said it wouldn't work.

If the USB device can supply enough amps, then any 5V supply will power a CPC. How many amps can that powerbank supply?

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 11:07, 09 June 19
It has two outputs of 5V:.  One with 1A and the second with 2.4A.
I use the second one..
When I get a second cable I will try adding an external drive or my Gotek.
Title: Re: USB power supply for CPC/PLUS
Post by: chinnyhill10 on 19:09, 09 June 19
Quote from: fgbrain on 08:38, 09 June 19


I have now a mobile 6128!!! :P



Clearly it will work. But what is the protection for the CPC inside the power bank? Rather misses the point we have been trying to make. The CPC has no internal protection, your PSU must be good quality to PROTECT the CPC.
Title: Re: USB power supply for CPC/PLUS
Post by: remax on 21:31, 09 June 19
In a few weeks, a new topic "i fried my CPC, can someone help me ?"  ;D
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 11:35, 10 June 19
2.4A is ok and any decent powerbank will have better protection and regulation than the GT65 or CTM's ever had.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: pelrun on 07:23, 11 June 19
Seconding what Bryce says here. Modern switchmode power supplies are *extremely* well regulated. Unlike the old transformer power bricks which often had an open-circuit voltage significantly higher than the rating.


I actually recently found USB and other 5v power supplies are actually *too low* for reliable operation of my 6128. I've not had much luck with my M4 wifi card or other peripherals, even when externally powered. There's a good .5v or better voltage drop across the system. Replacing the supply with a 5.1v PSU I recently obtained for my Raspberry Pi's seems to have fixed it. My M4 now works perfectly even without the recommended second supply!
Title: Re: USB power supply for CPC/PLUS
Post by: dragon on 15:33, 11 June 19
 Have here a dual usb that tell it  output 4,2a


https://www.amazon.it/Ewent-Caricatore-Portatile-Doppia-Bianco/dp/B00O2RD59A
Title: Re: USB power supply for CPC/PLUS
Post by: fgbrain on 18:57, 11 June 19
Quote from: pelrun on 07:23, 11 June 19
...
Actually recently found USB and other 5v power supplies are actually *too low* for reliable operation of my 6128. I've not had much luck with my M4 wifi card or other peripherals, even when externally powered. There's a good .5v or better voltage drop across the system.....


I think I agree. If i use the splitter cable and power both CPC and Gotek Emu from the power bank, the picture gets black n white but everything else looks good...
So to my poor knowledge this means USB power is weaker.
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:44, 12 June 19
Quote from: dragon on 15:33, 11 June 19
Have here a dual usb that tell it  output 4,2a


https://www.amazon.it/Ewent-Caricatore-Portatile-Doppia-Bianco/dp/B00O2RD59A (https://www.amazon.it/Ewent-Caricatore-Portatile-Doppia-Bianco/dp/B00O2RD59A)

That'll be 4.2A total, so 2.1A per socket. Most USB cables would get very warm trying to pass 4.2A, which is why all these new fast charging systems such as Qualcomms quick charge use up to 12V instead of 5.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: protek on 18:40, 12 June 19
This is not USB but it supplies both 5 and 12 volts.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F222415223126 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F222415223126)
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:11, 13 June 19
Quote from: protek on 18:40, 12 June 19
This is not USB but it supplies both 5 and 12 volts.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F222415223126 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F222415223126)

I wouldn't reccommend any bare 220V PSU to anyone who doesn't know exactly what they are doing. If members want to leave the forum that's fine, but I'd prefer they don't do so in a box.

Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 10:11, 13 June 19
So, does this mean that the PSU pesented by Protek is bad? Let's assume it's in a save box, would be be a good pick?

Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 10:25, 13 June 19
Quote from: GUNHED on 10:11, 13 June 19
So, does this mean that the PSU pesented by Protek is bad? Let's assume it's in a save box, would be be a good pick?

It looks relatively well designed and built. Of course the actual performance can only be confirmed by having one and measuring the output. It's impossible to say how good a PSU is just by looking at it. The only reason I would choose something else to recommend, is the fact that it is extremely dangerous in the delivered state if you don't know what you are doing.

What I can say about the design just by looking: The capacitor on the left of the transformer (EC1) would charge up to almost 400VDC and I can see no bleed resistor to discharge it on either side of the PCB. So even after disconnecting this from the mains it would have the potential to kill you. Something most beginners will not know. It also looks like the design has been "cost optimised" several times, so the performance will not be as good as the designer intended.


Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 10:51, 13 June 19
Since you asked and I have a minute. Here's some visual analysis of the PCB (regarding cost optimising) which would all speak against buying this:

A, B + C: These should be the mains filter capacitors. Leaving these out won't effect the output of the device, but will cause it to create noise on the mainsline - Effect: Expect noticable interference on monitors and audio equipment that are in the same room.

D + E: They've removed one rectifying diode from each power rail, so the device is only rectifying one half of the sinewave wave now - Effect:
More ripple on the 5V and 12V output rails.

F + G : They've removed the two output inductors - Effect: Ripple and/or noise on the 5V and 12V rail. Probably too much for a CPC at this stage.


H: They've removed the output capacitor (most likely on the 12V rail) - Effect: Because D + F are already gone, the 12V rail is more or less unfiltered now, it will look a mess. I wouldn't connect it to a CPC.

I: The hot-side capacitor has been downsized. In itself, this shouldn't effect the output of the device, but it would shorten the expected lifetime of the device.

Hope that gave you some insight.


Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 11:19, 13 June 19
That is shocking!  :-\


EDIT: Slowly I begin to think that we (as CPC community) should do something like a data collection of "save things" regarding hardware (and maybe also other topics). Something like a positive list.

Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 11:31, 13 June 19
Possible, but it's difficult for things like this. A PSU that is available today may not be available in 6 months. And even if it is, if it's a closed device, you don't know what they changed over time.

The example above is a classic case of cost-optimising - Remove anything that doesn't stop it from working. This is done on everything these days. Design it well, sell a load of them and then optimise it down to increase profits. This is why you'll often hear: "The early edition was better" on everything from Laptops to Washing machines. It happens less on things like phones, because their lifecycle is so short.


Bryce.
Title: Re: USB power supply for CPC/PLUS
Post by: GUNHED on 11:52, 13 June 19
Well spoken... so it's good advice to check a product careful every time (even if a buddy got a good one...).

Title: Re: USB power supply for CPC/PLUS
Post by: protek on 16:41, 13 June 19
Thanks for your insight, Bryce! I've got one of those as I was planning to make a psu for my 1541-II, but now I'm having second thoughts.


Would it help if the missing components were added?
Title: Re: USB power supply for CPC/PLUS
Post by: protek on 16:54, 13 June 19
Probably should stick to Mean Well units.


https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F252875775568 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F252875775568)
Title: Re: USB power supply for CPC/PLUS
Post by: Bryce on 07:27, 14 June 19
Quote from: protek on 16:41, 13 June 19
Thanks for your insight, Bryce! I've got one of those as I was planning to make a psu for my 1541-II, but now I'm having second thoughts.


Would it help if the missing components were added?

Yes, you could easily add the components again and improve the situation. The only slight difficulty would be the inductors, as the value of these is quite critical, so you'd have to do a lot of measurements and maths to choose the right part. All the other parts don't have critical values (caps) or the part number is known (Diodes).

Bryce.
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