- Top Stats

Top Posters Top Topic Starters Top Topics
Bryce 710
Audronic 240
CraigsBar 148
TFM 138
llopis 103
Audronic 34
Bignumbas 19
llopis 11
ComSoft612... 9
Querubin 6
X-Mass help please - 20743 Views 00WReX 15:29, 26 February 15
Fixing Floppy-Drives - 10329 Views Shining 00:45, 13 January 15
Interpreting u... - 9446 Views JonB 13:25, 05 April 15
CPC 464 blue s... - 7532 Views Alexandre ... 12:24, 29 July 15
Keyboard or Ma... - 6016 Views talrek 17:57, 21 October 14


Author Topic: One more CPC 6128 with screen of death  (Read 199 times)

0 Members and 1 Guest are viewing this topic.

Offline Kris

  • 6128 Plus
  • ******
  • Posts: 546
  • Country: fr
  • Team Impact
  • Liked: 208
  • Likes Given: 784
One more CPC 6128 with screen of death
« on: 13:26, 12 June 19 »
Hi all,


I have this CPC with strange behaviour: I have a blue screen and black border at boot and the relay is switching ON.
I launch the RAMtest.bin program using my M4 board and got the attached result:


Can RAM issue explain the action of the relay ?

Offline Bryce

  • The Hardware Guy.
  • Supporter
  • 6128 Plus
  • *
  • Posts: 10.806
  • Country: wf
  • It's not broken, it just hasn't been fixed yet.
    • index.php?action=treasury
  • Liked: 3774
  • Likes Given: 390
Re: One more CPC 6128 with screen of death
« Reply #1 on: 14:02, 12 June 19 »
Yes, it could. If the damaged RAM is holding an address or databit high or low (Stuck bit), then this could also alter the data coming from the Firmware ROM and can create false commands going to the CPU or enabling addressed hardware (like the 8255 which is controlling that relay).

However... a damaged CPU or ROM could also give the same results and look like the RAM is damaged too. So try a good CPU first (as it's socketed) and also check whether anything else is getting hot.


Bryce.

Offline Kris

  • 6128 Plus
  • ******
  • Posts: 546
  • Country: fr
  • Team Impact
  • Liked: 208
  • Likes Given: 784
Re: One more CPC 6128 with screen of death
« Reply #2 on: 14:06, 12 June 19 »
I already tried with an other Z80: same results.


I will let it run a while and check if a chip become more hot than other...

Offline Bryce

  • The Hardware Guy.
  • Supporter
  • 6128 Plus
  • *
  • Posts: 10.806
  • Country: wf
  • It's not broken, it just hasn't been fixed yet.
    • index.php?action=treasury
  • Liked: 3774
  • Likes Given: 390
Re: One more CPC 6128 with screen of death
« Reply #3 on: 14:30, 12 June 19 »
I just realised from the photo that Geralds RAM program ran, which would suggest that the data and address lines are most likely ok. In that case, I'd start by replacing the RAM. Do you know what caused the CPC to fail?

Bryce.

Offline Kris

  • 6128 Plus
  • ******
  • Posts: 546
  • Country: fr
  • Team Impact
  • Liked: 208
  • Likes Given: 784
Re: One more CPC 6128 with screen of death
« Reply #4 on: 14:34, 12 June 19 »
NO idea, nothing special happened last time I used it...


I have let it run and nothing become hot, I compare with an other CPC and I got similar temperature.
I will check with a scope if I can see something different on RAM (I only have 6 chip of 4164-10 here and some sockets, I won't be able to change all of them)
« Last Edit: 14:45, 12 June 19 by Kris »

Offline gerald

  • Supporter
  • 6128 Plus
  • *
  • Posts: 1.354
  • Liked: 969
  • Likes Given: 243

Offline gerald

  • Supporter
  • 6128 Plus
  • *
  • Posts: 1.354
  • Liked: 969
  • Likes Given: 243
Re: One more CPC 6128 with screen of death
« Reply #6 on: 18:22, 12 June 19 »
You can also try to boot on the 2nd bank.
http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/need-some-help-fixing-cpc6128-not-booting/msg75204/#msg75204
Forget the idea, I've just noticed that's a pre-asic one. No PAL  ;D

Offline Kris

  • 6128 Plus
  • ******
  • Posts: 546
  • Country: fr
  • Team Impact
  • Liked: 208
  • Likes Given: 784
Re: One more CPC 6128 with screen of death
« Reply #7 on: 22:07, 12 June 19 »
CRTC 4 indeed ;)


Finally, I have no more RAM....I ordered them, have to wait now...

Offline gerald

  • Supporter
  • 6128 Plus
  • *
  • Posts: 1.354
  • Liked: 969
  • Likes Given: 243
Re: One more CPC 6128 with screen of death
« Reply #8 on: 22:18, 12 June 19 »
CRTC 4 indeed ;)


Finally, I have no more RAM....I ordered them, have to wait now...
BTW, you can use the same RAM as the one in a plus (64kx4), it could be cheaper.