Hi, sorry, I missed your post - you found the part - and those are the ones I bought myself directly from Mouser.arkadiusz.makarenko wrote: ↑Tue Jan 18, 2022 6:16 pm May I ask what is modern compatible replacement for MOS6522?
I am trying to fixmy 1541, and last thing to test is 6522.
Edit
It is W65C22N... there is even wiki website about it
https://en.m.wikipedia.org/wiki/WDC_65C22
Compatible replacement for MOS6522?
Compatible replacement for MOS6522?
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Re: Compatible replacement for MOS6522?
Thank you.BennehBoy wrote: ↑Thu Jan 27, 2022 8:33 amHi, sorry, I missed your post - you found the part - and those are the ones I bought myself directly from Mouser.arkadiusz.makarenko wrote: ↑Tue Jan 18, 2022 6:16 pm May I ask what is modern compatible replacement for MOS6522?
I am trying to fixmy 1541, and last thing to test is 6522.
Edit
It is W65C22N... there is even wiki website about it
https://en.m.wikipedia.org/wiki/WDC_65C22
I still struggle to get initial boot from my 1541.
What are chances to have both 6522 to be dead at the same time?
Do not trust people. They are capable of greatness.
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~ Stanislaw Lem
Re: Compatible replacement for MOS6522?
Actually worse than you might think, I had a drive with both VIA's deadarkadiusz.makarenko wrote: ↑Thu Jan 27, 2022 11:32 amThank you.
I still struggle to get initial boot from my 1541.
What are chances to have both 6522 to be dead at the same time?
What are the exact symptoms that you are experiencing? I found this guide to be really useful -> https://portcommodore.com/rcarlsen/cbm/1541/fix1541.txt
If you've got a scope, it may be worth doing the obvious checks on the CPU to ensure, clock, reset, irq, data, address are as expected.
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Re: Compatible replacement for MOS6522?
It doesn't boot, so drive is spinning, and red light is on all the time.
I have ordered some spares including 6522s, just to check if simple chip swap would change anything.
I don't have scope, but I have Logic Probe, but it won't show me if lines levels are out of specs.
I think I have another two 7400s ICs to replace which are common cause of this issue (those test fine TL866II programmer software - but I had this issue before ICs test fine, but fail in circuit).
Then I think I will need to get scope to find what is wrong.
I have ordered some spares including 6522s, just to check if simple chip swap would change anything.
I don't have scope, but I have Logic Probe, but it won't show me if lines levels are out of specs.
I think I have another two 7400s ICs to replace which are common cause of this issue (those test fine TL866II programmer software - but I had this issue before ICs test fine, but fail in circuit).
Then I think I will need to get scope to find what is wrong.
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
~ Stanislaw Lem
Re: Compatible replacement for MOS6522?
OK, yeah, worth walking through that guide as there's some MOS logic chips that fail pretty commonly and will prevent a boot.
PS, a cheap logic analyser would probably work quite well too.
PS, a cheap logic analyser would probably work quite well too.
Re: Compatible replacement for MOS6522?
Might be worth a quick swap out of the ROM - those fail really regularly and will also prevent a boot.
I've got some 27cxx to mask ROM adapters if you need one.
I've got some 27cxx to mask ROM adapters if you need one.
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Re: Compatible replacement for MOS6522?
Already tried that. I build adapter and tested it in c64.
I have tried to swapp cpus as well as I have few spare.
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
~ Stanislaw Lem
Re: Compatible replacement for MOS6522?
The guide I linked earlier, although helpful, is not the main one that I used, try this -> https://portcommodore.com/rcarlsen/cbm/ ... 41chip.txt
Really useful for narrowing things down - I assume you've swapped UC2 & UC3 around with one another and it's still failing to boot? More likely that the crappy MOS labelled 74 logic chips have failed than both VIA's imho.
Really useful for narrowing things down - I assume you've swapped UC2 & UC3 around with one another and it's still failing to boot? More likely that the crappy MOS labelled 74 logic chips have failed than both VIA's imho.
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Re: Compatible replacement for MOS6522?
Yes, swapped VIAs and no change.BennehBoy wrote: ↑Thu Jan 27, 2022 8:07 pm The guide I linked earlier, although helpful, is not the main one that I used, try this -> https://portcommodore.com/rcarlsen/cbm/ ... 41chip.txt
Really useful for narrowing things down - I assume you've swapped UC2 & UC3 around with one another and it's still failing to boot? More likely that the crappy MOS labelled 74 logic chips have failed than both VIA's imho.
I am just waiting for delivery of 74 chips on board. (Nuclear option - replace all 74 logic chips just in case )
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
~ Stanislaw Lem
Re: Compatible replacement for MOS6522?
Been there, done thatarkadiusz.makarenko wrote: ↑Thu Jan 27, 2022 9:33 pm [I am just waiting for delivery of 74 chips on board. (Nuclear option - replace all 74 logic chips just in case )
Start with anything labelled MOS.