What could cause IC failure

[eslapion]

My opinion is the same as Mike with one specific exception.

[ken]

I dont heat-sink my chips just because I dont feel the need to
BUT...... if you do heat-sink the chips ,do it properly or you will do more harm than good
I have seen people use glue or use Silicone calk and say its the same a heat-sink grease
if done properly I dont see why not to do it

[Boray]

I have a 9V Vic-20 where the color yellow turns completely gray without a heat sink on the vic chip. With the heat sink on, it's just grayish. I also use two fans with that computer. One inside blowing air out and one under the computer blowing air in through the table. That fan is powered by an iPad power supply. Perfect use of such a thing.

[mrr19121970]

The B VIC powers up to cyan border and white screen. For me this is is described on Ray's page as:

Code: Select all

UE11		901486-01	ROM	BASIC
  Startup screen with borders but no characters. Disk commands do not 
work, but game carts still work.

I don't actually have a cart to test/prove this, but my question is what could cause the failure of the BASIC ROM? I've googled abit an I am not really any clearer here.

Any tips or suggestions?

So now I have a cart to test, same symptoms. White screen. cyan border. Responds to reset & drive also resets. I also tried the BASIC, KERNAL & CHAR RAM in another socket machine and worked fine (until that machine itself developed issues)

Any other pointers on what to try next?

[Boray]

Have you checked that your power supply is good?

[mrr19121970]

It's a Ray Carlson PSU, it's good

[mrr19121970]

No further ideas on what can cause a white screen with cyan border (basic rom is fine) ??

[Mike]

No further ideas on what can cause a white screen with cyan border (basic rom is fine) ??

Could also be defect RAM.

If any RAM cell in the range $1000..$1FFF doesn't work, the RAM test in the KERNAL enters an endless loop with exactly the symptom you're describing (i.e. white screen/cyan border). The RAM test is bypassed, when an autostarting cartridge is present, thus...

[mrr19121970]

Same happens with a cartridge too

[Mike]

What cartridge exactly?

[mrr19121970]

I tried Sargon II chess (I have others, but this one was nearest - and it worked with my other VIC20 with 'issues'). I also have Gorf, Avengers. Any better?

[Mike]

I just checked those three cartridge images: Sargon II and Gorf call the RAM test in the KERNAL ROM by themselves, so would also trip over defective RAM.

However, the init routines of Avenger don't seem to check the RAM, so you should try this one. I'd expect it to boot up, but then crash at some point, or produce corrupt graphics.

In any case, U14 and/or U15 (both are 2Kx8 6116 SRAMs) in your CR VIC-20 then are likely the culprits.

[mrr19121970]

OK, I'll try this. Need to solder in sockets and reseat my chips as all 40 pins are currently all out.

[Mike]

[...] all 40 pins are currently all out.

In case you get this VIC-20 working again, and after the S-Video mod, here's your next project.

[mrr19121970]

In any case, U14 and/or U15 (both are 2Kx8 6116 SRAMs) in your CR VIC-20 then are likely the culprits.

I desoldered my U14 and U15 now. Sockets will be fitted tomorrow with the 40 pin sockets too.

I am right buying this? x2 ? (and maybe some spares for the future too). Alternative here