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General Category => Amstrad CPC hardware => Topic started by: retro_4_ever on 17:58, 27 August 20

Title: cpc 464 power supply ??
Post by: retro_4_ever on 17:58, 27 August 20
any recommendation for cheap power supply for theses  puppies ? they only require  5 volt 2 amp but the cheap ones all show noise interference on the video .. no interference when i connect a pc ATX supply.. this seems a little overkill though ...
 
Title: Re: cpc 464 power supply ??
Post by: protek on 19:54, 27 August 20
I bought a Mean Well unit that provides 5V at 4 Amps. A good choice if you're planning to install expansions.
https://www.meanwell-web.com/en-gb/ac-dc-industrial-desktop-adaptor-output-5vdc-at-4a-gst25a05--p1j (https://www.meanwell-web.com/en-gb/ac-dc-industrial-desktop-adaptor-output-5vdc-at-4a-gst25a05--p1j)
Title: Re: cpc 464 power supply ??
Post by: John_Vella on 11:21, 28 August 20
I know that the link I'm about to post also has a scart lead, but I needed one of those as well, so I got this:


https://www.ebay.co.uk/itm/AMSTRAD-CPC-464-TV-CONNECTION-KIT-PSU-ADAPTER-ACTIVE-RGB-SCART-CABLE/390401137879?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.co.uk/itm/AMSTRAD-CPC-464-TV-CONNECTION-KIT-PSU-ADAPTER-ACTIVE-RGB-SCART-CABLE/390401137879?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
Title: Re: cpc 464 power supply ??
Post by: Skunkfish on 11:25, 28 August 20
My site is now selling power supplies for the CPC 464:
https://www.cpcstore.co.uk/product/power-supply-for-amstrad-cpc-464-664-6128-5v-2-5a-uk-plug-/14?cp=true&sa=false&sbp=false&q=false&category_id=5
Title: Re: cpc 464 power supply ??
Post by: retro_4_ever on 11:59, 28 August 20
thanks guys,,, great links i will have a good look later ... yeh i make my own RGB leads as i have found issues with the standard method of creating a blanking signal from the composite sync ie some models seem to experience random jumps if you dont have a 100uf cap in the scart but if you have the cap the jumping stops but then they are prone to ghosting .. so i remove the  luminnance  signal  from the din and use the pin and stick voltage from the power rail via a resistor to pull the voltage down .. (i think the model i experienced this on was the very early one)

Title: Re: cpc 464 power supply ??
Post by: Bryce on 13:22, 28 August 20
By the way, using a PC PSU on a CPC is a really bad idea. These can supply >16A on the 5V rail, so any simple failure (RAM) or short circuit would evaporate the traces off the PCB and the computer would be unrepairable.

Bryce.
Title: Re: cpc 464 power supply ??
Post by: John_Vella on 13:29, 28 August 20
Quote from: Skunkfish on 11:25, 28 August 20
My site is now selling power supplies for the CPC 464:
https://www.cpcstore.co.uk/product/power-supply-for-amstrad-cpc-464-664-6128-5v-2-5a-uk-plug-/14?cp=true&sa=false&sbp=false&q=false&category_id=5 (https://www.cpcstore.co.uk/product/power-supply-for-amstrad-cpc-464-664-6128-5v-2-5a-uk-plug-/14?cp=true&sa=false&sbp=false&q=false&category_id=5)


Sorry, I didn't even know that this shop existed until I saw your post.


Forget my eBay link, get it from this guy!

Title: Re: cpc 464 power supply ??
Post by: retro_4_ever on 16:17, 28 August 20
Quote from: Bryce on 13:22, 28 August 20
By the way, using a PC PSU on a CPC is a really bad idea. These can supply >16A on the 5V rail, so any simple failure (RAM) or short circuit would evaporate the traces off the PCB and the computer would be unrepairable.

Bryce.


this is true if a major fault was to happen ... although i do have fuses installed inline .. not sure if the fuse would go before the mother board to be honest.. i have been researching how create a circuit that will cut out above a preset current like a bench supply.. but i have yet to understand how i can accomplish this ...
Title: Re: cpc 464 power supply ??
Post by: retro_4_ever on 16:04, 03 September 20
Quote from: Skunkfish on 11:25, 28 August 20
My site is now selling power supplies for the CPC 464:
https://www.cpcstore.co.uk/product/power-supply-for-amstrad-cpc-464-664-6128-5v-2-5a-uk-plug-/14?cp=true&sa=false&sbp=false&q=false&category_id=5 (https://www.cpcstore.co.uk/product/power-supply-for-amstrad-cpc-464-664-6128-5v-2-5a-uk-plug-/14?cp=true&sa=false&sbp=false&q=false&category_id=5)


just ordered a couple of these..  :)
Title: Re: cpc 464 power supply ??
Post by: retro_4_ever on 16:10, 03 September 20
these didn't make the grade !!!!
Title: Re: cpc 464 power supply ??
Post by: Bryce on 18:13, 03 September 20
Quote from: retro_4_ever on 16:17, 28 August 20

this is true if a major fault was to happen ... although i do have fuses installed inline .. not sure if the fuse would go before the mother board to be honest.. i have been researching how create a circuit that will cut out above a preset current like a bench supply.. but i have yet to understand how i can accomplish this ...
An LM317 and a few passives are all you need to limit the current. Google "LM317 current limiter" and you'll get example circuits and the algorithms needed to set it up.

Bryce.
Title: Re: cpc 464 power supply ??
Post by: Skunkfish on 19:22, 03 September 20
Quote from: retro_4_ever on 16:04, 03 September 20

just ordered a couple of these..  :)
They've just been shipped, should be with you on Monday hopefully!
If they're not what you are after then you can always return them for a full refund!  :D
Title: Re: cpc 464 power supply ??
Post by: retro_4_ever on 21:37, 03 September 20
good stuff .... i had a look around the net and they are well priced .. and good spec
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