Hi all, long time lurker, first time help-asker.
I'm working on four(!) NeXTCubes, and having the same no boot issue on three of them. Wondering if there are additional troubleshooting steps I should take before getting the boards re-capped or the SIMMs tested?
**More details**
1x 68030
3x 68040, non-turbo, (ROMs v2.0, v2.1, and v2.5; all have 16MB RAM)
All are connected via a NuIO soundboard and Rob's Y-splitter cable.
The 030 boots, but the three 040s won't boot under the same setup.
Power button clicks the relay on, the fan spins/load board light turns on, a monitor sync signal is sent (monitor shows 1152x864), but after that is just a black screen.
There's no response to command-power after boot (won't turn off like the 030) and leaving them alone doesn't do any good. I can see the red indicator LED on the boards turn on very briefly and then stay off, which happens much faster than it does on the 030.
My understanding is that this behavior indicates an early failure in the POST process. Unclear if that means CPU issue, bad RAM, or something else?
I've done the usual things- disconnected drives, tried different PSUs, made sure the backplanes aren't failed, verified board batteries are good, etc.
I have not yet tried swapping the RAM around or trying to isolate possible bad SIMMs.
I'm a bit confused to see the same issue on three different boards, so I am unsure if I am missing something very simple required to boot the 040 vs the 030, or if this is just a common failure on the 040s that needs addressing.
Hoping I can get some expert guidance on where I should start additional troubleshooting, or if getting the caps done first is the preferred next step.
Thanks in advance!
-Warren
the older PSUs (two versions exist AFAIR) need a real NeXT MegaPixel Display or a resistor consuming enough current to power up the cube. see also:
http://www.nextcomputers.org/forums/index.php?topic=4182.msg24432#msg24432
Quote from: mikeboss on January 06, 2022, 03:15:21 PMthe older PSUs (two versions exist AFAIR) need a real NeXT MegaPixel Display or a resistor consuming enough current to power up the cube. see also:
http://www.nextcomputers.org/forums/index.php?topic=4182.msg24432#msg24432
Hi @mikeboss!
Thanks for replying. I forgot to mention the PSUs I am using:
I have an older 152 PSU and have the load board from barcher174/Rob@Black Hole connected with the 12v 5W halogen lamp. On power button press the lamp turns on for all three 040 and will power and boot the 030.
I also have a newer 983 model PSU that boots the 030 without trouble (and no load board) and seems to power up the 040s- or at least provides identical behavior to the 152 above.
I get fan spin and the relay "click" on the 040s after hitting the power button regardless of which PSU I use.
Do you see a flashing LED on the motherboard? If so can you count the blinks? (short and long).
Quote from: barcher174 on January 06, 2022, 11:19:24 PMDo you see a flashing LED on the motherboard? If so can you count the blinks? (short and long).
I see the status LED light up and then go out, no blink codes.
So to summarize:
Regardless of power supply, all 68040 boards boot to a black screen, but your monitor has sync? The LED flashes red and then turns off?
Make sure you disconnect everything from the boards - All disks and all RAM. Put back a single bank of RAM from the known working board.
It's really strange they all show the same behavior, but at this point if the above doesn't work it has to be a board level fault. First thing to check is to replace all capacitors. From there, there's no easy answers.
Even without any memory it should boot to the ROM Monitor. One flash from the LED is normal behavior during the early boot process and does not indicate a problem. Shorter flash on 68040 compared to 68030 is also normal.
Quote from: barcher174 on January 07, 2022, 11:44:36 PMSo to summarize:
Regardless of power supply, all 68040 boards boot to a black screen, but your monitor has sync? The LED flashes red and then turns off?
Make sure you disconnect everything from the boards - All disks and all RAM. Put back a single bank of RAM from the known working board.
It's really strange they all show the same behavior, but at this point if the above doesn't work it has to be a board level fault. First thing to check is to replace all capacitors. From there, there's no easy answers.
Will do. Thanks for the input. I agree, this is super bizarre to get the same on all three boards.
Quote from: andreas_g on January 08, 2022, 01:54:03 AMEven without any memory it should boot to the ROM Monitor. One flash from the LED is normal behavior during the early boot process and does not indicate a problem. Shorter flash on 68040 compared to 68030 is also normal.
Thanks, I'll try without RAM too and see what happens. Also appreciate the note on the LED.
Hello Omni: My first guess is ram , make sure they re matching sets of 4 , you can also remove all of the ram and disconnect the drives and see if the boot process changes.... that may narrw it down to a board level issue ..... if needed I would be able to loan you a known good 68040 motherboard as a last resort ......
Hi all- no progress so far. The 040 boards have the same behavior with RAM in or out, drives connected or disconnected, no matter what I do. Very, very strange. The boards definitely power on but the ROM Monitor never comes up. Hoping it's not something fried in the ROMs or the RTC?
Going to get them re-capped and see if that fixes anything, and then report back.
Any other input would be appreciated. Thanks!
Quote from: Rob Blessin Black Hole on January 12, 2022, 05:17:46 PMHello Omni: My first guess is ram , make sure they re matching sets of 4 , you can also remove all of the ram and disconnect the drives and see if the boot process changes.... that may narrw it down to a board level issue ..... if needed I would be able to loan you a known good 68040 motherboard as a last resort ......
Thanks Rob. I dropped you an email earlier today. Would like to use your guy to do the re-cap & etc.