Search found 8 matches

by Jayhay
Sun Feb 24, 2019 2:54 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hi everyone, Sorry for the long time before coming back - it's been a hell if a month. Anyway - I tried disabling the upper ram by connecting pin 5 to the positive rail and powering up. And it didn't start up at all. It just became completely unresponsive. Powering up didn't work, resetting, nothing...
by Jayhay
Sun Jan 20, 2019 6:52 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hey guys, thanks for the advice and feedback. I will try disabling first, then Desoldering. I just haven't had a chance to look at anything all week, it's been a busy one!
by Jayhay
Mon Jan 14, 2019 6:36 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hey there, thanks for the reply. So, here is what happens when do the "new" command: https://drive.google.com/file/d/12Jdy4CrQRN6iYxSW4pEC4nOAmfFSMvTn/view?usp=drivesdk Then I get screens like this after every reset: https://i.postimg.cc/D8mhns3P/20190114-182402.jpg But if i disconnect the power, I ...
by Jayhay
Sun Jan 13, 2019 12:40 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hi guys, again - thanks for all the help. So I replaced IC11 and it's done something! https://i.postimg.cc/0bZrF770/20190113-115919.jpg The vertical red lines against black are gone and instead we have this pink striping thing! You can see the copyright message, though and it responds to key presses...
by Jayhay
Sat Jan 12, 2019 1:45 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hi Mark I've checked everything over again. The board is a 1983 issue 4s. Unfortunately I don't have any test gear but I can probably knock together an oscilloscope or something. When powering up, it's identical every time. Border is white, and the screen is black with alternating solid and dashed t...
by Jayhay
Sun Jan 06, 2019 11:37 am
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Hi again - thanks for the input. I've checked the voltage lines. All -5v pins are reading -4.86v which seems within range. All +5v pins are reading +4.94v All +12v pins are reading +11.82v The voltages are all stable, with none of the chips running hotter than any others. In fact, no single componen...
by Jayhay
Sun Jan 06, 2019 10:53 am
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

Re: ZX+ lower ram diagnostic help

Thanks Mark. I'll check the voltage today and see what might be going on!
by Jayhay
Sat Jan 05, 2019 12:47 pm
Forum: Hardware
Topic: ZX+ lower ram diagnostic help
Replies: 25
Views: 1768

ZX+ lower ram diagnostic help

Hello everyone. I was given a ZX+ for Christmas which worked for a little while, managed to get a few round of Jet Set Willy and Dizzy in before it just crapped out on me. See the image for the issue I'm having. I've looked around online and discovered that it could be a lower ram issue. Im a compet...