Looking for EIII CPU Board

[Gul Dukat]

Thanks Niko ! And welcome to the great Emulator Forum 

[dr.c]

Hi Nico,

Can you please put all this shit back in place ?   
If you take the boards out, this machine will NEVER start, at least because alle the management memory ids in the microcontroler board (the top one).

If I unedersatnd well, the PSU is ok, when you power up, the disk starts to run anc licks like normal, but the display stays blank, having squares when the contrast is at maximum.

Didi you check the second SCSI cable, the one going to the external SCSI plug ? Is it burned, maybe (that's a great "classical" shit) ?

Verify all teh flat cables (going to te right place and well positionned) try with another disk, cahnge the damn HCT240 (if I remember well, unless its a HCT244)

[Nikolaus Riehm]

If I unedersatnd well, the PSU is ok, when you power up, the disk starts to run anc licks like normal, but the display stays blank, having squares when the contrast is at maximum.

No, it's completly dead - no disc access and all LEDs are off. The HCT240 is only a driver for FDC command lines and the MIDI thru and it'll therfor only cure floppy related errors.

But I revealed one major fault: the boot EPROMs were dead and completely filled/erased with FFs. I burned new ones from binaries Matt sent me along with the EIII (a download from this forum site: http://eiiiforum.com/eiii.zip). I dont't know which version of boot loader they are. I replaced one of the address muxes (S158) and one CS demux (LS138) because of obviously high load on the CPU bus due to the LS and S types and the signals look quite good now with HCT equivalents. But the EIII is still doing nothing. Only CS signals for the boot proms and the LCD are generated, all others remain high without any activity (even the scanner MPU gets nothing on its NMI line).

The clock generator and the FPU of the NS32016 triumvirate get realy hot but I think this is normal for those kind of circuits. The NS32016 itself seems to be good, all signals are in a shape of making sense (beside some glitches on the high byte of the multiplexed address/data bus but I think this is attributet to the demultiplexing).

[dr.c]

I didn't talk about disk access, I just asked if the disk starts spinning and doing its job withits own controler board, wich means takin the heads off the parking place.

[Nikolaus Riehm]

I didn't talk about disk access, I just asked if the disk starts spinning and doing its job with its own controler board, wich means takin the heads off the parking place.

That's what I meant with disc access    Thus: no spinning, no motor activity, nothing. The HDD is inoperable, too. My thought on this was that it's waiting for a SCSI start command that never comes because the CPU never starts up to this point.

[dr.c]

Can you please put another disk, a SCSI disk, any kind of, preferably an old Quantum, and try to start the Emu, please ?

[recoil]

Hi!
similar issue here.
in my case i just have a blank screen. no contrast function responding.
buttons don`t work only two of them are lighted (edit and digital processing).
changed the scsi HD and spins fine
no lights in the floppy drive
psu is ok

what should i replace or test now?.

there is just one cable disconnected: digital connector to the external scsi.