Reply 45640 of 47151, by pentiumspeed
myrsnipe wrote on 2022-07-18, 18:56:
Picked up a 8086 from '87 today. Inside is in mint condition, no blown caps or battery leakage, but it has no picture. Unsure if it's the monitor or graphics driver, although the very high pitch sound that resonates in my skull tells me the monitor may not be working correctly. Going to test with an ISA card later that has VGA port, this one is a DB-9 one that i don't have other monitors for. I recon there's probably some VGA converters available too.
Back in the day around 1990, I was working during summer between high school fixing these junk. Junk.
They had high failure rate, and PSU is one you never can fix properly as Zenith designed PSU so strangely and use house part numbers on the semiconductors in that PSU. One more thing, DO NOT, I REPEAT, DO NOT KEEP TRYING* that computer until you have PSU completely unplugged from the computer and used a junk hard drive for power load and check for voltage output with multimeter!
The one I had was dead and I waited long time with a partially good 20MB MFM hard drive plugged in, then the hard drive's motor blew big cloud of smoke. 🙁
Best way is to empty the PSU shell and install small common PSU in it from another PC baby AT PSU.
Second, you really absolutely MUST keep the steel shield over the pair of drives otherwise computer will not boot from floppy due to monitor's atop the PC magnetic interfering with them. I found this out hard way.
Third, you are extremely lucky to have an ISA riser, really! And PSU is not rated for hard drive as part of power load. It was a optional part. Lot of them didn't have one even the ones I was working didn't.
The Z148 comes standard with pair of floppy drives.
If someone gave me a Zenith, I'm not interested. I had fill of it. I had a Eazy PC brand new (given to me) didn't like it not compatible due to Nec V40 processor, was lucky to have 128K pack with serial port that is not compatible with much of mouses at hand and we tried many till one that worked and had to solder in 40 pin IDE connector, use XT bus IDE miniscribe 20mb, and install correct burned EPROMs in it for hard drive support before I left for the high school year.
Second, I had to repair a friend's Zenith 8088 memory issue, it was not memory, one TTL IC pin was bent and contact in the socket bent so repaired that fixed it.
I rather have generic 286 at this time or a generic 386DX 25 which I saved up and purchased with the summer work money at same job in summer of 91.
Great Northern aka Canada.