SE/30 VIA chip replacement

[croissantking]

This is a satisfying outcome. @MegaImg are you going to buy these chips?

 

[MegaImg]

Already did, Building a new Logicboard, Will try them! Almost all the IC are new, Loking for a damage board to finish it!

 

[codevonlux]

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.

 

[obsolete]

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

 

[plexxer]

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?

 

[croissantking]

Sadly it looks like those WDC chips are out of production.

 

[djc6]

Does anyone know where I can obtain a suitable replacement?

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]

Here’s a nice Mouser project made by someone who likes SE/30s: link

 

[plexxer]

Thanks to both of you for your help. I ordered 2 338S6523 from that outsource.net. I would have ordered a few more but I didn't want to get a surprise tariff bill. The reason I am working on all of my old on-hold projects is to limit my ordering from overseas!