Posted By
Netsurge
on 2020-07-22
01:11:37
|  Red and Green lines
Hey all. Long time Commodore user, first time +4 issues.
I have 2 +4s that are exhibiting the same issue. Every time I turn them on I get red and green lines across the screen and nothing else.
I have swapped the cpu and ted with known working ones and even tried the cpu and ted in my c16 without issue.
Anyone have any idea where I should start looking?
Thanks.
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Posted By
SVS
on 2020-07-22
03:49:00
 | Re: Red and Green lines
If you use the TV signal as output, you could try the direct output signal (composite) in order to exclude that the problem is inside the RF generator.
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Posted By
Chronos
on 2020-07-22
08:22:51
 | Re: Red and Green lines
swap the "PLA" chip too!
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Posted By
Netsurge
on 2020-07-22
14:26:20
| Re: Red and Green lines
@SVS - I have tried both composite and RF.
@Chronos - I tried a known working PLA from my C16 and it's a no go. I have tried the CPU, TED and PLA from the Plus 4 in my C16 and it works. I do see the red/green lines on the C16 for a split second (both with it's own ICs and with the Plus 4's ICs) when I first power it on but then it boots up fine.
I'm wondering if it's a timing issue.
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Posted By
siz
on 2020-07-22
16:02:42
| Re: Red and Green lines
Try the ancient debug method: switch on the computer and after several minutes put your finger on the ICs. The one that is unusually hot or cold is the dead one. My guess (after TED/CPU/PLA - but you already checked those) would be one of the RAMs.
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