Check the capacitors on the upgrade board to see if any are shorted.

The chips on your expansion board seem to be of the correct type (256K x 8 FPM VRAM), but I wonder if the slower speed may be causing issues (they're 80ns as opposed to 60ns on the card). Maybe it's a module for an older card?

Not sure if the VRAM-based cards allow you to mix and match memory types, but I can tell you that my Stealth 64 DRAM T VLB (Trio64) can happily take EDO chips in the expansion sockets despite the memory soldered to the card being FPM. So it's definitely not out of the realm of possibility.

For getting replacement chips, if you can't find any on eBay, your best bet would be something like utsource. I've found them to be pretty reliable, other than them lying about the actual availability of the chips they claim to be "in stock". Just google for 60ns 256Kx8 FPM VRAM in SOJ-40 package to find product numbers for manufacturers other than Samsung, then you can search for those in utsource.

I didn't notice the RAM speeds were different.

Anyway, I have an upgrade board P/N 23030064-009 for "ST 64 video VRAM memmod C3 Diamonf Multimedia Systems" that uses only 4 x KM4216c256G-60 chips.

@Unknown_K

Good call on the caps! I'll break out my continuity tester and see what's what and report back.

Does your upgrade board connect to a card with 4 x chips or 8 x chips? I am curious to see whether there is cross-compatibility, and suspect there probably is, as @TheMobRules mentioned.

---
@TheMobRules

Thinking about what you said makes sense--a module for an older card is certainly possible. One interesting and odd thing is that the module has a date of 1996 on the back, presumably signifying when it was sold. The chips have date codes in the ~1993 range! Weird stuff.

Thanks for the suggestions and thoughts about mixing FPM/EDO. Great call there, and what you're saying makes sense, as I've done that with a Trio64 and it works. I may get the EDO VRAM module and see.

Also, thanks for the Utsource recommendation. I plan on ordering some chips, as they have the originals in stock. I've never used them before, but it's nice to know they are an option.

---
Thank you both for your thoughts! I really appreciate it and will keep this thread current as I explore further options.

---
Edited original post for clarification.
VRAM module failure is reported on the card itself without the expansion board connected. Those are the chips I intend to swap.

I think EDO can be used (without all added functionality) in place of FPM, but VRAM and EDO/FPM are not.

Just 4 chips.

@Unknown_K

Thanks for the information!

Hm, I see. I am a bit hesitant to order another module with just 4 x chips.
I think I may wait and find an OEM 8 x chip module.

Well, update: I ordered some replacement VRAM chips from utsource.

In anticipation, I removed the originals and, while cleaning the pads, I accidentally lifted a pad.

I feel really awful about this. Guess my soldering skills weren't up to par.

Anyone have any suggestions? I'd really appreciate the help.

I've attached a picture.

Don't feel too bad about it, happened to me a couple of times despite being really careful. The pad doesn't seem to connect to anything on that side of the board, so you need to follow the via on the other side and see where it goes.

One option could be to insert a really small wire through the via and use that as your new "pad"... but first make sure where it connects to, it may be easier to just use a bodge wire.

When cleaning the pads, use flux and try to wick parallel to the pad as there's less chance of lifting it. Also, don't go back and forward with the braid, do one pass, wait a few seconds and do it again. And more importantly, you should not apply any force at all, let the braid "glide" over the pad.

@TheMobRules

Thanks for the reassurance and for the advice.
For a little bit there, I really felt the immense frustration one feels when doing something real silly like this.

I took a quick look at the via and traced it. I'll have to grab my multimeter and test for continuity, but it seems to run pretty far to the buffer chips near the VLB connector. I'll bear in mind the ideas regarding the pad and bodge wire options. It sounds like the latter might be an easier option in this case.

That's exactly what my problem was--I think I was traversing the pad in a perpendicular motion. I will definitely keep this in mind for next time. I have to admit that I am very amateurish when it comes to soldering; I can do through-hole soldering and I've built some kits here/there, and I have repaired some QFP legs, but I can't say that this is in my wheelhouse.

I really wish I had better eyesight. Unfortunately, I am extremely nearsighted and have always struggled with surface-mount soldering. I was really hoping to try it one more time and get it right; it's kinda been that specter haunting me. It's nice to know the card isn't a write off but I really am doubting my skills. Part of me wants to give it another go and not give up, but another part of me is interested in seeing if someone can step in and help me with this, as I'd rather not muck it up beyond repair once the replacement chips come in.

microscope (with barlow lense for better distance) or one of those inspection/soldering cameras with HDMI output or dedicated LCD is great for bad sight
I was going to recommend mini preheater https://www.youtube.com/watch?v=JKlTd1B6Au8 would minimize chance of ripped pads, but not using it correctly can lead to popcorning (as seen in that review). hotair is another great option for bad eyesight, you dont need to be 100% precise, everything happens with surface tension straightening parts into place.