So I got myself an old 286, victorv286c, that has no video out at the moment. While I was looking around, trying to look for any obvious damage, I found a strange Och on the back of the motherboard. See pictures. What is this thing? It looks professionally made, but would guess not from the factory? Anyone?
A math processor board of some kind?
It also can be an upgrade board, like the one that Adrian Black talked about.
https://www.youtube.com/watch?v=QhqZiMhe5UA&p … W50IDI4Ng%3D%3D
A-Trend ATC-1020 V1.1 ❇ Cyrix 6x86 150+ @ 120MHz ❇ 32MiB EDO RAM (8MiBx4) ❇ A-Trend S3 Trio64V2 2MiB
Aztech Pro16 II-3D PnP ❇ 8.4GiB Quantum Fireball ❇ Win95 OSR2 Plus!
No coprocessor there, and you arent upgrading anything with four 74 series chips 😀 this is some kind of a bugfix discovered in pre production, cheaper than scrapping all already manufactured defective boards.
That looks to me like a good ole fashioned factory bodge wire repair.
Bodge board, I’ve made a few of those, can’t say what this one does though.
There are some processors with flexible pcbs that have stuff similar to this, but this seems to have more attachment points.
Probably fixing something that was messed up, omitted, or to improve compatibility with a cpu.
Actually this is mod board. To fix the original design that was missed when made, saves the cost of redoing whole board again.
See here:
https://youtu.be/jey8NmffhTo?si=MJfoiYpANPD7bZe5
Cheers,
Great Northern aka Canada.
It hooks up to the Bus Cycle Status pair, Hold, Reset, Clock, Memory/#IO on the 286 and the DMA Request and IRQ signals from the ISA riser. I'd assume it fixes something to do with generating Hold for the CPU when a card asserts a DMA request.
Thank you all for the answers! ❤️
