Hi all - I just acquired a Zenith Z-157 model 2/3 system, part number ZDH-1111-B0. While externally it looks identical to the other Z-150 series machines, internally it has a standard motherboard with the memory and CPU etc on it, unlike the others that have a backplane with the CPU and memory residing on an ISA card similar to a SBC. I've looked at the Z-150 series manuals, but nothing in them applies to the Z-157. The only information I found is a jumper and board diagram on stason.org and what appears to be the identical info on another site. But even this information is incomplete - the Z-157's keyboard port and 25-pin serial port reside on a proprietary daughterboard that slots onto the motherboard, and on that daughterboard are about 20 jumpers, and no etching to tell what they do. The M-151 ROM software is likewise fairly useless.

I believe that there were updated Technical Bulletins that ZDS put out to cover new models and changes and faults; I haven't been able to find OCR's of these. I'm only aware of them from defunct ebay listings Google pulls up.

If anyone out there has the bulletins or other info about the Z-157, I'd appreciate it. Or if you have suggestions where to look. I've already spent hours searching so I'll take what I can get.

Thanks!

The stason page: https://stason.org/TULARC/pc/motherboards/Z/Z … -2-MODEL-3.html