JonathanHunt
Member
- Joined
- Feb 7, 2020
- Messages
- 19
I have an IBM 5170 type 339 I'm trying to get running. This has the type 3 motherboard at 8mhz with 512k, and has the 11/15/85 BIOS.
Power supply and hard drive spin up, but no video init and no sound from speaker.
Remove dead CMOS battery and inspect, no visible corrosion anywhere, all looks good. No battery installed but based on schematic it should still boot
Checked power supply voltages, everything AOK.
Installed POST Card, consistently get 03, (Verify shutdown byte in 146818 RTC chip, after 80286 register test and ROM checksum OK)
Pulled all cards and 80287, same result.
Burned and installed Landmark Diag ROMS from minus zero for AT.
Never initializes video, but throws many audio codes:
8254 Timer channel 0, 1, 2
DMA Controller 1,2
8042 Parity Detected
and then several cannot initialize monitor codes
Pulled the RAM off the motherboard, tested it all with a DRAM tester, passed with no problems.
With no ram on board, Landmark throws the same codes plus 16k critical memory region (understandable with no RAM)
If I let the landmark run, after a 2 runs the computer loses the ability to generate tones and just generates clicks from the speaker instead, one for on and one for off.
Once its in this state, even if I power cycle, it will still do this. If I let it rest for 10 mins or so it will go back to normal tone generation.
Anyone seen symptoms like this in the past? Any tips on how I can pin down the issue? Could it actually be the RTC chip?
Thanks!
JH
Power supply and hard drive spin up, but no video init and no sound from speaker.
Remove dead CMOS battery and inspect, no visible corrosion anywhere, all looks good. No battery installed but based on schematic it should still boot
Checked power supply voltages, everything AOK.
Installed POST Card, consistently get 03, (Verify shutdown byte in 146818 RTC chip, after 80286 register test and ROM checksum OK)
Pulled all cards and 80287, same result.
Burned and installed Landmark Diag ROMS from minus zero for AT.
Never initializes video, but throws many audio codes:
8254 Timer channel 0, 1, 2
DMA Controller 1,2
8042 Parity Detected
and then several cannot initialize monitor codes
Pulled the RAM off the motherboard, tested it all with a DRAM tester, passed with no problems.
With no ram on board, Landmark throws the same codes plus 16k critical memory region (understandable with no RAM)
If I let the landmark run, after a 2 runs the computer loses the ability to generate tones and just generates clicks from the speaker instead, one for on and one for off.
Once its in this state, even if I power cycle, it will still do this. If I let it rest for 10 mins or so it will go back to normal tone generation.
Anyone seen symptoms like this in the past? Any tips on how I can pin down the issue? Could it actually be the RTC chip?
Thanks!
JH