Help to repair a MFM 8-Bit ISA Card

[Bob-O-Rama]

Given that it's a Far East origin (Taiwan?) board with lots of missing components and 2 electrolytics where tantalums might be a better choice, I strongly suspect MLC just from the point of saving quatloos by the vendor.

Just an aside on some of the missing components: the WD10C came in various incarnations. The WD10C23 reduced the number of needed support parts down to 3, from 11 to 15 required by the prior versions. Several of these versions were being simultaneously produced by WD, but the WD10C23 could replace all of them as it supported MFM and RLL, hard and soft sectoring, and a faster data rate.

 

[Chuck(G)]

Yes Bob, but you should be able to identify most of the missing components.

 

[modem7]

So, you put your multimeter into resistance mode, and measured 0 ohms, or 1 ohm, or 2 ohms, something like that?

No. Using the Continuity Mode (Beep).

Be aware that the beep of continuity mode is not a short-circuit indicator. More on that is at [here].

 

[ayandon]

Be aware that the beep of continuity mode is not a short-circuit indicator. More on that is at [here].

Oh! Thanks a lot for the tip.

 

[twolazy]

That is a pretty late 80s XT compatible, notice just 1 bios chip, no hi/low. Maybe even early 90s like 91/92. Would explain bios support, as well as it having an embedded floppy controller. And that motherboard is not happy, lower left corner, left of the ISA slots ... very corroded. ISA bus transceiver maybe?

 

[ayandon]

That is a pretty late 80s XT compatible, notice just 1 bios chip, no hi/low. Maybe even early 90s like 91/92. And that motherboard is not happy, lower left corner, left of the ISA slots ... very corroded.

yes, battery damage.
Under treatment....

 

[twolazy]

Guessing a 74LS245