SE/30 VIA chip replacement
- Thread starter croissantking
- Start date
codevonlux
Well-known member
I recently worked on a SE/30 Reloaded board. The ADB chip from the donor board is bad so I used a PIC16F87 replacement ADB on this board. (mentioned here: https://68kmla.org/bb/index.php?threads/mac-se-adb-controller.38363 , with a QFN-to-PLCC adapter PCB by max1zzz).
I noticed that if I use W65C22N6TPLG-14 as VIA1 then it is not compatible with this ADB replacement, the mouse movement is sluggish then finally hung, death chime also happens from time to time during boot. Same VIA1 works fine with original ADB chip and Original 65C23 works fine with this ADB replacement.
I guess there might be some timing issue becuase it was mentioned in the ADB thread that the original 3MHz clock is not used in the PIC16F87 and it is running faster than the original ADB chip.
I noticed that if I use W65C22N6TPLG-14 as VIA1 then it is not compatible with this ADB replacement, the mouse movement is sluggish then finally hung, death chime also happens from time to time during boot. Same VIA1 works fine with original ADB chip and Original 65C23 works fine with this ADB replacement.
I guess there might be some timing issue becuase it was mentioned in the ADB thread that the original 3MHz clock is not used in the PIC16F87 and it is running faster than the original ADB chip.
Good info, thanks for posting this. Would be interesting to scope it and see what's going on.
I also had a post from macmike in a thread I started about Reloaded board troubleshooting where he mentioned issues with the WDC VIA and the RTC: https://68kmla.org/bb/index.php?threads/troubleshooting-glue-c32m-and-c16m.46886/post-530164
Figured I should link that here since this thread seems to be the knowledge base on these replacement VIAs
I also had a post from macmike in a thread I started about Reloaded board troubleshooting where he mentioned issues with the WDC VIA and the RTC: https://68kmla.org/bb/index.php?threads/troubleshooting-glue-c32m-and-c16m.46886/post-530164
Figured I should link that here since this thread seems to be the knowledge base on these replacement VIAs
I am working on restoring an SE/30 that functions great aside from the ADB devices - the mouse is barely responsive and the machine seems to not boot when the keyboard is attached. I did a recap (the sound started working!) and it didn't seem like there was any leak damage, but looking more closely I did spot some green-tinged areas on the edges of UK11 65C22 and I believe the IC has become compromised.
The problem I am having is finding a source for the NMOS replacements. Mouser is out of stock of the W65C22N6TPLG as is any other distributor I try. My searches for the R65NC22J4 have also come up empty. Does anyone know where I can obtain a suitable replacement?
The problem I am having is finding a source for the NMOS replacements. Mouser is out of stock of the W65C22N6TPLG as is any other distributor I try. My searches for the R65NC22J4 have also come up empty. Does anyone know where I can obtain a suitable replacement?
croissantking
Well-known member
Sadly it looks like those WDC chips are out of production.
A group buy for SE/30 reloaded boards had a nice BOM attached. Here is the thread: https://tinkerdifferent.com/threads/so-you-wanna-start-an-se-30-reloaded-group-buy.2936/
Here is the BOM: https://docs.google.com/spreadsheet...bEiThW19gc/edit?gid=1837251752#gid=1837251752
It mentions this supplier for a used one: https://www.utsource.net/itm/p/1073631.html
Same part number 338S6523 is mentioned in 2nd post of this thread.
croissantking
Well-known member
Hi!
I bought a couple VL65C22V-02QC from here: https://a.aliexpress.com/_EuQvcl8
It’s the same part number as the original chips in my board. But sadly I can’t tell if they work because my board doesn’t boot neither with these nor with the original ones.
I bought a couple VL65C22V-02QC from here: https://a.aliexpress.com/_EuQvcl8
It’s the same part number as the original chips in my board. But sadly I can’t tell if they work because my board doesn’t boot neither with these nor with the original ones.
croissantking
Well-known member
I just picked up a couple of the same. I’ll test them out.
My problem turned out to be a bad fuse. Not sure why I didn't check it first - I think the fact that there was still -some- mouse movement along with the corrosion led me to believe they were faulty.
croissantking
Well-known member
Mine arrived from the same link you posted, just finished testing them out and they work great. They’re not remarked and they have 338S6523 printed on them, indicating they’re harvested from Macintosh boards.
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