Diagnostic cart 586220 and tests ?

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ViperSan
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Diagnostic cart 586220 and tests ?

Post by ViperSan » Thu Sep 28, 2017 8:45 pm

I now have a diagnostic cartridge 586220 which seemed like a tool I'd need for my C64 resurrections.
But am having an issue straight away ...
I popped it in my main C64 ..and let it run ..
Zero page OK
Stack page OK
Screen RAM OK
but the test hung at RAM TEST1 ?
So ..thinking it might be me ..or the cartridge tried it in another C64 ..
There were errors but the test continued ..(I dont have a harness)
RAM test 1 OK
RAM test 2 OK

So ..figured there _must_ actually be a fault on the first C64
luckilly I had fully chip based the RAM chips
U9 > U12 and U21 > U24 (8 x OKI 3764-15RS) ...so swapped them out one at a time ..
Still the test hung ..
Next I figured ...swap out the 2x 74LS257.
These were also swapped out one at a time ..
still the test hung at the same point ?
Is it possible this cartridge doesn't work with all C64 pcb variants
This one is a 250425 1984 ..made in HK
OR ..is there a possibility this fault might lie else where ..and not the RAM ..
I could start randomly swapping out chips ..but I thought it best to seek advice first..
rgds
VS



ViperSan
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Re: Diagnostic cart 586220 and tests ?

Post by ViperSan » Thu Sep 28, 2017 9:12 pm

Ok ..answered my own question ..
Swapped out the PLA ..
Just the same ..
Then it occurred to me ..
perhaps the banks aren't being switched by the cpu..
So .swapped out the 6510 ..
et voila..
problem solved ..
I guess the cpu is only partially operational..
Sadly ..
that was my last 6510..
Anyone know where I can get more (reasonably priced?)
rgds
VS

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eslapion
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Re: Diagnostic cart 586220 and tests ?

Post by eslapion » Fri Sep 29, 2017 3:55 am

ViperSan wrote:
Thu Sep 28, 2017 9:12 pm
Sadly ..
that was my last 6510..
Anyone know where I can get more (reasonably priced?)
I have a few of them left. PM or e-mail me.
Wealth, like happiness, is never attained directly. It comes as a by-product of providing a useful service. -Harland D. Sanders

ViperSan
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Re: Diagnostic cart 586220 and tests ?

Post by ViperSan » Fri Sep 29, 2017 9:25 am

eslapion wrote:
Fri Sep 29, 2017 3:55 am
ViperSan wrote:
Thu Sep 28, 2017 9:12 pm
Sadly ..
that was my last 6510..
Anyone know where I can get more (reasonably priced?)
I have a few of them left. PM or e-mail me.
Cheers I appreciate the offer ..but searching on fleabay last night found someone in the far East selling 2 for £14 including postage..
so took a chance and ordered 2 ..
a risk I know ..but it seemed a relatively inexpensive risk.
I will keep your kind offer in reserve if I may ..just in case.
rgds
VS

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