[mc68k]

I have 3 broken Impact boards:

1. Solid Impact - it produces a picture, but freezes after 2-3 seconds when I start any 3D app (e.g. Atlantis demo)

2. High Impact - produces black picture. Sync signals are present.

3. Maximum Impact - produces red image, the text is readable, but as it seems only one bitplane is working. This card has been degraded slowly by time: first produced only few bad lines. After using it for 10-20 minutes the image has been stabilized. But now it is totally unusable.

I need your opinion: what to check, what to fix if someone has succeeded a such repair?

Thank You in advance.

[robespierre]

boot stand/ide

[0xDEADBEEF]

I am betting it is something with VRAM, either chips themselves or the data lines.
I have a Max Impact board that seems working except of black dot patterns, which seems like bad RAM or RAM data line.
I have some Solid Impacts so I will investigate when I will have some time.
Anyone has any idea what RAM did SGI use for these impact boards?

[weblacky]

I'll eventually be getting to this type of stuff but it's a few years off. I thought that when I looked at the TRAM stuff specifically, that all that was proprietary chips and not regular video ram like a lot of VGA cars used in the 90s. That doesn't necessarily mean there's not normal "RAM Chips" all over the device for other purposes but I remember that the texturing ram specifically is proprietary.

We haven't done much work in this area because there's not much of a price point on these indig2 parts that make repair worth commercial rates at the current time. That doesn't mean they're not repairable. I would say personally I would start looking for cracked solder joints on all the ic legs and I probably use a diode test on all the transistors or small SOT-23 sized diode packages you can find look for potential disconnect or damage.