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?
Thanks!
Issue 3 Spectrum vertical red stripes
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- Drutt
- Posts: 19
- Joined: Tue Jun 30, 2020 9:41 am
Re: Issue 3 Spectrum vertical red stripes
Looks like upper ram. I had the same with mine.
Re: Issue 3 Spectrum vertical red stripes
Unfortunately it behaves the same with the upper ram gone.
- Ast A. Moore
- Rick Dangerous
- Posts: 2641
- Joined: Mon Nov 13, 2017 3:16 pm
Re: Issue 3 Spectrum vertical red stripes
1. Check all the data and address lines for shorts/continuity.
2. Replace the ROM.
2. Replace the ROM.
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.
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.
- 1024MAK
- Bugaboo
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- Location: Sunny Somerset in the U.K. in Europe
Re: Issue 3 Spectrum vertical red stripes
It could still be a problem with the lower RAM or a fault on the CPU address lines.
Mark
Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
- 1024MAK
- Bugaboo
- Posts: 3123
- Joined: Wed Nov 15, 2017 2:52 pm
- Location: Sunny Somerset in the U.K. in Europe
Re: Issue 3 Spectrum vertical red stripes
Which diagnostic ROM are you using?
Run the diagnostic ROM on an emulator to see what it normally does, then compare to what your faulty Spectrum does.
I suspect either a short between two different address lines or a problem with one of the multiplexers (IC3 or IC4) but I could be wrong!
Mark
Run the diagnostic ROM on an emulator to see what it normally does, then compare to what your faulty Spectrum does.
I suspect either a short between two different address lines or a problem with one of the multiplexers (IC3 or IC4) but I could be wrong!
Mark
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: Issue 3 Spectrum vertical red stripes
This is the ROM I'm running
http://blog.retroleum.co.uk/electronics ... -spectrum/
As you can see the splash screen is garbled
http://blog.retroleum.co.uk/electronics ... -spectrum/
As you can see the splash screen is garbled
- 1024MAK
- Bugaboo
- Posts: 3123
- Joined: Wed Nov 15, 2017 2:52 pm
- Location: Sunny Somerset in the U.K. in Europe
Re: Issue 3 Spectrum vertical red stripes
Standby alert
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: Issue 3 Spectrum vertical red stripes
A0 on the ULA was shorted to ground...