you all are great professionals here.. managed to move on. Is ZMC2 worth checking?
- Thread starter r67055
- Start date
channelmaniac
Professional
Yes. It's what muxes the graphics. On the 2 slot you can see that each of the two NEO-257s takes the graphics data from the appropriate slot and sends it to the ZMC2. The ZMC2 muxes and sends it on to the chipset for processing/display.
ohhh
This is not a 2 slot board. MV1FS stereo board.
there are no NEO-257s in this
channelmaniac
Professional
Same principle applies. Two data sources being muxed down... you just don't have the NEO-257s there to choose which slot to get the data from.
Hello,again.
unfortunately I made a mistake. I thought I would clean the pcb from the black glue stains (circled in the picture). After that, unfortunately, the pcb did not start, only unibios 4.0 starts (all functions work flawlessly in unibios 4.0). the original bios only gets to the green screen. the repair eprom shows no errors. I checked the cleaned parts but I didn't see any signs of wear. can you help me where to look for the error?
Thanks
unfortunately I made a mistake. I thought I would clean the pcb from the black glue stains (circled in the picture). After that, unfortunately, the pcb did not start, only unibios 4.0 starts (all functions work flawlessly in unibios 4.0). the original bios only gets to the green screen. the repair eprom shows no errors. I checked the cleaned parts but I didn't see any signs of wear. can you help me where to look for the error?
Thanks
Attachments
hmmm
I removed the spacer screw and it started. it works again.
Attachments
channelmaniac
Professional
Green screen of death = problem with the clock / calendar circuit. Look for power on pin 14 of the D4990 clock chip over on the opposite side of the board from the battery. Then check the tiny round clock crystal and 2 little green capacitors next to it.
On my repair notes, I have Calendar crash (stuck on green screen) causes as :
-RTC chip faulty
-RTC / Save RAM battery power line.
With diagbios you can test if RTC pulses are in sync. IIRC Unibios just bypass Save and RTC tests
I had a 1F board where RTC test was wonky, but with the logic probe I saw the 1s ticks on the RTC test point. Turns out a corroded via on the battery power line, and somehow the logic probe was able to kickstart the RTC ! That trace went coast to coast, and on the MV2F it does as well I think, battery is top left, RTC is bottom right. So check that trace.
-RTC chip faulty
-RTC / Save RAM battery power line.
With diagbios you can test if RTC pulses are in sync. IIRC Unibios just bypass Save and RTC tests
I had a 1F board where RTC test was wonky, but with the logic probe I saw the 1s ticks on the RTC test point. Turns out a corroded via on the battery power line, and somehow the logic probe was able to kickstart the RTC ! That trace went coast to coast, and on the MV2F it does as well I think, battery is top left, RTC is bottom right. So check that trace.
yes, this line between the D4990 clock chip is very long. I checked this line and it was fine. the error was still there. After I removed the screw, all errors disappeared.
thank you for writing your experience.
channelmaniac
Professional
That is very odd. Either it was cutting into a trace or it's flexing the board a bit and causing a bad trace to go open.
yes, that's weird. maybe it's the water too. I also washed the glue spots with water. I dried it properly. I do not know.....
hi again!
I turned it on again 4slot MV4FT an unexpected error occurred. I put it on the shelf without error. VRAM error. I replaced the VRAMs. There was no change. I installed the repair eprom.
can i ask for help?
i check line :
RAM7
1 LSPC2 (96)
2 LSPC2 (95)
3 LSPC2 (93)
4 LSPC2 (92)
5 LSPC2 (91)
6 LSPC2 (90)
7 LSPC2 (89)
8 LSPC2 (8
9 LSPC2 (67)
10 LSPC2 (6
11 LSPC2 (69)
12 GND
13 LSPC2 (70)
14 LSPC2 (71)
15 LSPC2 (73)
16 LSPC2 (74)
17 LSPC2 (75)
18 GND
19 LSPC2 (99)
20 GND
21 LSPC2 (86)
22 LSPC2 (9
23 LSPC2 (97)
24 VCC
RAM8
1 LSPC2 (96)
2 LSPC2 (95)
3 LSPC2 (93)
4 LSPC2 (92)
5 LSPC2 (91)
6 LSPC2 (90)
7 LSPC2 (89)
8 LSPC2 (8
9 LSPC2 (76)
10 LSPC2 (7
11 LSPC2 (79)
12 GND
13 LSPC2 (80)
14 LSPC2 (81)
15 LSPC2 (82)
16 LSPC2 (84)
17 LSPC2 (85)
18 GND
19 LSPC2 (99)
20 GND
21 LSPC2 (86)
22 LSPC2 (9
23 LSPC2 (97)
24 VCC
all ok
I turned it on again 4slot MV4FT an unexpected error occurred. I put it on the shelf without error. VRAM error. I replaced the VRAMs. There was no change. I installed the repair eprom.
can i ask for help?
i check line :
RAM7
1 LSPC2 (96)
2 LSPC2 (95)
3 LSPC2 (93)
4 LSPC2 (92)
5 LSPC2 (91)
6 LSPC2 (90)
7 LSPC2 (89)
8 LSPC2 (8
9 LSPC2 (67)
10 LSPC2 (6
11 LSPC2 (69)
12 GND
13 LSPC2 (70)
14 LSPC2 (71)
15 LSPC2 (73)
16 LSPC2 (74)
17 LSPC2 (75)
18 GND
19 LSPC2 (99)
20 GND
21 LSPC2 (86)
22 LSPC2 (9
23 LSPC2 (97)
24 VCC
RAM8
1 LSPC2 (96)
2 LSPC2 (95)
3 LSPC2 (93)
4 LSPC2 (92)
5 LSPC2 (91)
6 LSPC2 (90)
7 LSPC2 (89)
8 LSPC2 (8
9 LSPC2 (76)
10 LSPC2 (7
11 LSPC2 (79)
12 GND
13 LSPC2 (80)
14 LSPC2 (81)
15 LSPC2 (82)
16 LSPC2 (84)
17 LSPC2 (85)
18 GND
19 LSPC2 (99)
20 GND
21 LSPC2 (86)
22 LSPC2 (9
23 LSPC2 (97)
24 VCC
all ok
Attachments
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There are 4 vram chips on the board, 2x slow vram and 2x fast vram. The error address points to the slow vram chips, but you replaced the fast vram chips. The slow vram chips are the ones between the LSPC and the fast vram chips.
channelmaniac
Professional
Error at $8000 is the DIP RAM... Error at $0000 is the surface mount RAM connected to the LSPC.
channelmaniac
Professional
Then use Windows Calculator... 0400 hexadecimal is 0000 0100 0000 0000 in binary. The upper 8 bits has a stuck bit. You either have a short or an open on that pin... or multiple bad RAMs. You could also have a popped pin on the LSPC chip for that bit.
I checked the lines between RAM and LSPC, each line is connected to a pin.
I don't know exactly which leg should go to which.
thank you for the instruction. I will check another board.
I will check which leg should be connected where. Is it possible that the LSPC is faulty?
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