Issue 3 Spectrum vertical red stripes

For experts to discuss very technical stuff and newbies to ask why the Spectrum they bought off ebay doesn't work.
Post Reply
BlackFX
Berk
Posts: 3
Joined: Sun Jul 26, 2020 6:40 am

Issue 3 Spectrum vertical red stripes

Post by BlackFX »

Hi all

I am banging my head against the wall with this, I have an issue 3 that's showing a consistent white border with red stripes as in this pic - I've swapped all the lower ram and buzzed it all out with my meter checking for any broken traces. Any thoughts on where to go next?

Image

Thanks!
0 x

PootisSpencer
Berk
Posts: 19
Joined: Tue Jun 30, 2020 9:41 am

Re: Issue 3 Spectrum vertical red stripes

Post by PootisSpencer »

Looks like upper ram. I had the same with mine.
0 x

BlackFX
Berk
Posts: 3
Joined: Sun Jul 26, 2020 6:40 am

Re: Issue 3 Spectrum vertical red stripes

Post by BlackFX »

Unfortunately it behaves the same with the upper ram gone.
0 x

User avatar
Ast A. Moore
Dynamite Dan
Posts: 1685
Joined: Mon Nov 13, 2017 3:16 pm

Re: Issue 3 Spectrum vertical red stripes

Post by Ast A. Moore »

1. Check all the data and address lines for shorts/continuity.
2. Replace the ROM.
0 x
Every man should plant a tree, build a house, and write a ZX Spectrum game.

Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.

User avatar
1024MAK
Manic Miner
Posts: 904
Joined: Wed Nov 15, 2017 2:52 pm
Location: Sunny Somerset in the U.K. in Europe

Re: Issue 3 Spectrum vertical red stripes

Post by 1024MAK »

It could still be a problem with the lower RAM or a fault on the CPU address lines.

Mark
0 x

BlackFX
Berk
Posts: 3
Joined: Sun Jul 26, 2020 6:40 am

Re: Issue 3 Spectrum vertical red stripes

Post by BlackFX »

So I put diagRom on an eeprom and now this happens

Posted in the order it occurrs. So CPU is alive but something tells me it's almost dead

Image

Image

Image

Image

Image

Image

Image
0 x

Post Reply