Topic: acorn electron gone faulty  (Read 3513 times)

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Offline traindriver69

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acorn electron gone faulty
« on: February 02, 2015, 12:37:10 PM »
hi all
got my old acorn electron out and it has developed a fault when it has been left switched on for a couple of minutes lines start going across the screen and the computer locks up then when you disconnect the power and turn it back on you get a yellow screen and there is no clicking noise which you normally get when you turn it on but if you disconnect the power there is a clicking noise.
if you leave it powered off for a couple of mins the acorn comes back to life but then it all starts again.
anyone got any ideas please.

Offline Spirantho

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Re: acorn electron gone faulty
« Reply #1 on: February 04, 2015, 08:49:48 PM »
What issue is the motherboard? Some of them have a rather strange ULA in them, and they can need the contacts cleaning. Not hard to do, luckily.
I can probably get it running again for you if you want (would cost £35) - just let me know. It may just need the ULA removing, cleaning, and replacing though (but be careful if you do this and make sure you earth yourself to get rid of static before touching that ULA!)
Ian Gledhill but with a hyphen between "mutant" and "caterpillar"
Mutant Caterpillar Games - vintage computers and games in our shop!

Offline Eratosthenes

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Re: acorn electron gone faulty
« Reply #2 on: April 02, 2019, 06:09:13 PM »
Hi everybody!

As a newbie it's nice to be here...

Even though this topic is older it discribes exactly how my Elk behaves.

The story:
Last weekend I received an "as new" Elk (see photo below if I'm allowed to upload it. The photo has been taken before(!) I cleaned the computer).

Before running it I checked the voltage of the PSU board. +5V and -5V are OK, 19V are not OK as I'm using a DC PSU to run the Elk...
As far as I've read (and as far as I've understood reading the Service Manual) this is OK as 19V are only available on the expansion port which isn't used.

I was happy as the Electron seems to work fine when I switched it on first. - Then came the evil surprise! :(
Half an hour or so the computer works fine but then it flickers and behaves exactly as described in this thread.

Now it's down and only shows a yellow screen when being switched on. As I've read that this is a known issue I've removed the ULA and cleaned the contacts. I also have removed the ROM to ensure that contacts are OK.

This hasn't changed anything. The screen still is yellow and the system doesn't boot up. => No LED, No Beep, no nothing.

Any suggestions? - Do I have grilled the ULA?

THNX for info.

der Eratosthenes
ZX80/ZX81: 1k ought to be enough... (... at least for a computer with shared memory graphics)!