Title: NeXTstation Turbo Color - Corrupt Video Display, HELP!
Post by: sdinet on December 30, 2015, 04:34:24 PM
Post by: sdinet on December 30, 2015, 04:34:24 PM
Hey everyone, here is a new one for you all =)
I am seeing vertical red stripes (most noticeable on black) on the display from my NeXTstation Turbo color. I have swapped RAM, cables, monitors, etc, and am certain it's an issue with the motherboard. Any suggestions on which component could be the culprit?
I am seeing vertical red stripes (most noticeable on black) on the display from my NeXTstation Turbo color. I have swapped RAM, cables, monitors, etc, and am certain it's an issue with the motherboard. Any suggestions on which component could be the culprit?
Title: NeXTstation Turbo Color - Corrupt Video Display, HELP!
Post by: pentium on December 30, 2015, 06:12:24 PM
Post by: pentium on December 30, 2015, 06:12:24 PM
Bad VRAM can cause graphical glitchyness and while the memory on the color slab is not surface mount it is ZIP which is typically not a fun thing to source.
It's those 12 black vertical standing strip things.
It's those 12 black vertical standing strip things.
Title: NeXTstation Turbo Color - Corrupt Video Display, HELP!
Post by: barcher174 on December 30, 2015, 06:32:14 PM
Post by: barcher174 on December 30, 2015, 06:32:14 PM
And to add to this, if you haven't replaced the capacitors, that's a good place to start. Make sure to pay extra attention to the area around the BT463 when cleaning.
Title: NeXTstation Turbo Color - Corrupt Video Display, HELP!
Post by: cubist on December 31, 2015, 01:44:00 AM
Post by: cubist on December 31, 2015, 01:44:00 AM
Ah, you're going to have fun with this. Looks like a stuck bitline.
Do a screen grab that shows the red and move the captured image to a working machine. If the lines show up there, you have a stuck bitline somewhere between cpu and vram (possibly vram itself).
No red line you likely have a stuck bitline from vram to bt463 and possibly internal to the 463. You're scaling the image on your monitor so it's hard to see the periodicity but it looks like every fourth pixel which would match the 463's multiplexing model in some modes. It's not full-gun red so not the MSB but not LSB either. Could also be in the 4-bit-per-pixel mode data but seems unlikely with this pattern.
Do a screen grab that shows the red and move the captured image to a working machine. If the lines show up there, you have a stuck bitline somewhere between cpu and vram (possibly vram itself).
No red line you likely have a stuck bitline from vram to bt463 and possibly internal to the 463. You're scaling the image on your monitor so it's hard to see the periodicity but it looks like every fourth pixel which would match the 463's multiplexing model in some modes. It's not full-gun red so not the MSB but not LSB either. Could also be in the 4-bit-per-pixel mode data but seems unlikely with this pattern.