eisapc wrote on Today, 08:03:

Picked up a Zenith Data Systems ZF-148 8088 PC from the basement. Had to search for a matching XT keyboard and RGB/RCA monitor […]
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Picked up a Zenith Data Systems ZF-148 8088 PC from the basement.
Had to search for a matching XT keyboard and RGB/RCA monitor for a while.
The system was not powering on, but after replacement of the shorted tantals the system powered up and booted from FDD at least.
Unfortunately the HDD seems dead and after a few minutes the RIFA inside the PS released its magic smoke.
Replaced the RIFAs as well. Will have a closer look at the HDD which is actually 3,5" MFM drive mounted on hardcard with full lenght controller board.

Is the hard card Zenith branded by any chance? In 1989 3.2 BIOS there is a separate section for old style XT MFM controller they call "Tempest". They detect its presence by checking for ZD signature in HDD Bios stored at C81Bh https://github.com/raszpl/Zenith_ZBIOS/blob/m … 03.2C.lst#L5027

1seg000:1840 MFM_Tempest_detect_presence proc near
2  mov     cs:MFM_Tempest_controller, 0
3  push    ds
4  push    ax
5  mov     ax, 0C800h      ; C800h address of MFM ROM
6  mov     ds, ax
7  assume ds:nothing
8  cmp     word ptr ds:1Bh, 'DZ' ; Check for Zenith Data Systems "ZD" signature
9  jnz     short end
10  mov     cs:MFM_Tempest_controller, 0FFh
11end:
12  pop     ax
13  pop     ds
14  assume ds:nothing
15  retn
16MFM_Tempest_detect_presence endp

No, the hardcard is not original. I remember adding it myself some years ago, when it was still working like a charm.

Stripped my K7S8X of it's VRM FETs and all major caps - replacement coming in on monday probably.