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avatar_ukmarkh

Why won’t it turn on?

Started by ukmarkh, 20:37, 23 May 18

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ukmarkh

My Amstrad CPC 6128 will not turn on, any ideas?




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robcfg

I'd try to clean the power switch with contact cleaner to begin with, and if that doesn't help, check for broken solder points.

ukmarkh

Quote from: robcfg on 20:54, 23 May 18
I'd try to clean the power switch with contact cleaner to begin with, and if that doesn't help, check for broken solder points.

The power switch does feel a bit stiff as you flick it on and off [emoji848]


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Duke

Quote from: robcfg on 20:54, 23 May 18
I'd try to clean the power switch with contact cleaner to begin with, and if that doesn't help, check for broken solder points.

Yes.

I just received a "not working" 464 today (cost down, yay).
Two problems. Power socket was slightly loose, re-solder it and then the power switch, although it passed the continuity test (beep!), it must have had too much resistance to power the CPC on. Opening and cleaning the switch and the machine is back to life :)

ukmarkh

Quote from: Duke on 21:01, 23 May 18
Yes.

I just received a "not working" 464 today (cost down, yay).
Two problems. Power socket was slightly loose, re-solder it and then the power switch, although it passed the continuity test (beep!), it must have had too much resistance to power the CPC on. Opening and cleaning the switch and the machine is back to life :)

What household stuff can I use to clean it?


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Duke

IPA if no contact cleaner. In lack of anything chemical, just rub the two contact points clean with some toilet paper, whatever :)

ukmarkh

Doesn't look too bad, just wondering how I can strip it with my fat fingers




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Duke

Use a screwdriver to bend the metal legs slightly going around the plastic then you can get the cap off.
You could just try to short the two yellow wires, so you know if it's worth opening it or not.

Quote from: ukmarkh on 21:11, 23 May 18
Doesn't look too bad, just wondering how I can strip it with my fat fingers




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ukmarkh

I shorted the two yellow wires and it turned on [emoji1303]


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ukmarkh

The culprit, horrible vial red stuff...





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Duke

I think that part is supposed to have a bit of grease, what you want to clean is the "platin" knob on the little metal plate and below it in the contact.

ukmarkh




Now all I'm getting is a blue or black screen [emoji22]




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Duke

Quote from: ukmarkh on 22:03, 23 May 18


Now all I'm getting is a blue or black screen

Maybe it's not cleaned good enough and still has too much resistance. Try to short yellow wires again.

ukmarkh

Quote from: Duke on 22:07, 23 May 18
Maybe it's not cleaned good enough and still has too much resistance. Try to short yellow wires again.

Only blue screen with shorting [emoji17] But the lights and everything turn on... Maybe Rom chip has gone


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Chinnery

(oops, replied to an old post without refresh)

ukmarkh

Quote from: Chinnery on 22:13, 23 May 18
First, see if it is the switch.
Unplug it from the board, then VERY CAREFULLY, bob a flat bladed screwdriver between the 2 newly exposed pins. And I do mean very carefully!!!
If it comes on, the switch is dirty/buggered. If not, the issue is elsewhere.

Yeah, I tried that, blue screen...


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Duke

Quote from: ukmarkh on 22:08, 23 May 18
Only blue screen with shorting But the lights and everything turn on... Maybe Rom chip has gone

Does pressing DEL make a sound?
It seems to setup the proper colours with the blue screen (rom chip needs to work for that).

ukmarkh

#17
Quote from: Duke on 22:16, 23 May 18
Does pressing DEL make a sound?
It seems to setup the proper colours with the blue screen (rom chip needs to work for that).

Held Del key down, no noise. I forget, which is the Rom chip, I'm sure I've got spares...

Is it the 40010?




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Duke

Quote from: ukmarkh on 22:18, 23 May 18
Held Del key down, no noise. I forget, which is the Rom chip, I'm sure I've got spares...
Ok :/
Check if any of the RAM chips are hot, would be first thing that comes to mind, but tbh. I am not sure if it would get to setup the blue colours without working RAM, iirc. it will crash somewhere in lowerrom before that and leave you with a grey screen/black border.
40025 is the romchip.

No 40010 is the gate array.

Duke

If none of the RAM chips are hot (small OKI chips), try to replace the Z80 first as it's in a socket, and they can have faults these days.

ukmarkh

Quote from: Duke on 22:34, 23 May 18
If none of the RAM chips are hot (small OKI chips), try to replace the Z80 first as it's in a socket, and they can have faults these days.

Ram chips cool to the touch, changed Z80, no difference, changed 40010, no difference. I'm thinking that bloody ROM chip [emoji22]


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ukmarkh

So, after further investigation and sweating buckets, I found out that the ribbon cables from the keyboard are stopping the CPC from starting up!




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ukmarkh

Can't see anything obvious, but will give it a clean and see how we go [emoji848]




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ukmarkh


This looks like the problem, it's rusted at the keyboard base and has destroyed the membrane, I have a spare hopefully




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