CPCWiki forum

General Category => Amstrad CPC hardware => Topic started by: nekitu on 18:32, 10 July 13

Title: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: nekitu on 18:32, 10 July 13
Hi all,
I have an Amstrad CPC 464, trying to start it with a power supply which is 5V 3Amps, power led of the CPC is blinking once and then goes off for 3 seconds, then repeats forever. Signal to monitor is none. A subtle short beep is heard inside the unit each time the led blinks. Could it be from the 3A, do I really need the official 5V 2A for it ? I got the computer with that (unofficial) power supply, so I guess the last owner was powering it ok...
Anyway, thanks for any hint of what can it be going wrong.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: ralferoo on 19:03, 10 July 13
Sounds like your power supply is knackered to me.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: ralferoo on 19:12, 10 July 13
BTW, a 3A supply should be fine. IIRC, the 464 needs about 1.5A when the tape is playing.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: nekitu on 19:19, 10 July 13
Quote from: ralferoo on 19:12, 10 July 13
BTW, a 3A supply should be fine. IIRC, the 464 needs about 1.5A when the tape is playing.


So I guess 1A (which I've tried to no avail) isnt enough?
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: TFM on 19:57, 10 July 13
Try to find out if the Problem is the PSU or the Keyboard first.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: nekitu on 21:12, 10 July 13
I've tried with 5V 1A, doesnt work, tested the PSU it outputs 5V properly, but maybe something else is bad, will try to find another 5V 2A PSU on the flea market and test, thanks for the feedback.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: TFM on 21:20, 10 July 13
Sorry, but it sounds as if the CPC itself would be broken.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: Pentagon on 08:48, 11 July 13
Hello,

i had the same issues with one of my machines some time ago. If the PSU is working fine, you really should check the Power Switch of the CPC. It sounds like a contact chatter between the small steelcontacts inside the Power Switch. Just take a screwdriver and open the power switch carefully. Clean the contacts inside and dont lose the spring inside. Then you close the switch again and the CPC should work again.

Edit: Try to brick  bridge / shorten the switch first and see if the CPC is working then. At CPC464 you can brick bridge the switch with a wide screwdriver. Between the two contacts at the power switch.

Kindly regards
Tom
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: Munchausen on 10:57, 11 July 13
Quote from: Pentagon on 08:48, 11 July 13
Hello,

i had the same issues with one of my machines some time ago. If the PSU is working fine, you really should check the Power Switch of the CPC. It sounds like a contact chatter between the small steelcontacts inside the Power Switch. Just take a screwdriver and open the power switch carefully. Clean the contacts inside and dont lose the spring inside. Then you close the switch again and the CPC should work again.

Edit: Try to brick / shorten the switch first and see if the CPC is working then. At CPC464 you can brick the switch with a wide screwdriver. Between the two contacts at the power switch.

Kindly regards
Tom


Brick sounds a bit dangerous!  :laugh:  But hopefully you really meant bridge ;D
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: Pentagon on 12:14, 11 July 13
Oh yes, i am sorry, please excuse my poor english. My native language is german, so i meant "to shorten" or "to bridge". And not a "brick" LOL  :P

I have edited my post. Thanks for help.

Regards
Tom
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: Bryce on 08:50, 12 July 13
Check what the 5V rail is doing during these cycles. If the voltage is fluctuating with each restart, then you have power problems. If the voltage is staying steady then something is pulling the reset line down.

Bryce.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: nekitu on 14:18, 13 July 13
Hi guys, thanks all for the feedback, but no need to worry anymore, the unit is working great :) I've found another 5V 2A power supply at the flea market, the old one was busted, and now its working great, including cassette drive and such, this is a big relief. Time for some coding and games :) . Cheers!
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: TCMSLP on 00:38, 05 August 13


I didn't have any 5V PSUs at hand.  I opened my 464, cut a power trace and fitted a 5V regulator (screwed to the bottom of the keyboard shield, acting as a heat sink).


I can now use any adapter 7-15V DC and not worry.  Perhaps an idea for others too :)




Steve
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: Bryce on 10:56, 08 August 13
Cool idea (no pun intended). Some pictures and info might be useful for a Wiki article?

Bryce.
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: gerald on 11:06, 08 August 13
Quote from: TCMSLP on 00:38, 05 August 13
I didn't have any 5V PSUs at hand.  I opened my 464, cut a power trace and fitted a 5V regulator (screwed to the bottom of the keyboard shield, acting as a heat sink).
I can now use any adapter 7-15V DC and not worry.  Perhaps an idea for others too :)
I hope you have modded all you CPC like this. Otherwise BOOM  ;)
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: TotO on 11:27, 08 August 13
Quote from: TCMSLP on 00:38, 05 August 13
I didn't have any 5V PSUs at hand.  I opened my 464, cut a power trace and fitted a 5V regulator (screwed to the bottom of the keyboard shield, acting as a heat sink).
I can now use any adapter 7-15V DC and not worry.  Perhaps an idea for others too :)
I hope that nobody will do that... Just destroying hardware... 5V regulated PSU are so easy to find today...
Title: Re: Amstrad CPC 464 not working, Power Led on and off each 3 seconds
Post by: TCMSLP on 16:30, 19 August 13



Not really destroying hardware -  1 minute and a bridged trace later and it's back to normal.


You are correct though - 5V PSUs are easy to find;  I was just impatient for my CPC fix.
Powered by SMFPacks Menu Editor Mod