Amiga 3000 stuck in reset

[Prime]

I have two amiga 3000's that don't work.
I am trying to get atleast one running, by using whatever parts I need from the other.

Both have the exact same Symptoms:
Black Screen, dim green LED, caps lock fails after about 10 pushes.

Something is causing one of the Amiga's to be stuck in reset.

The other one is not stuck in reset, but same symptoms.

I got much help from this community a couple of years back, so hopefully we can revisit this!

Where to start?

Thanks!

[HammerD]

I have two amiga 3000's that don't work.
I am trying to get atleast one running, by using whatever parts I need from the other.

Both have the exact same Symptoms:
Black Screen, dim green LED, caps lock fails after about 10 pushes.

Something is causing one of the Amiga's to be stuck in reset.

The other one is not stuck in reset, but same symptoms.

I got much help from this community a couple of years back, so hopefully we can revisit this!

Where to start?

Thanks!

Well if the caps lock stops responding it means the 68K cpu is not responding, which is a bad thing since it's soldered.

Is there any battery leakage? That is common for the A3 and A4000's.

[Prime]

A very tiny bit, maybe a small dot by the ground pin.

No damage or leakage to neighboring chips.

[Crom00]

If you have recently dismantled your A3000 make sure that the plastic cover behind the backplane has been plced back inside the machine.

I experienced similar problems when I dismantled and reassembled my A3000 withut this part installed.

[Prime]

I have everything stripped out of it but the daughter card. (So I can probe the chips)
Just the bottom chassis and PSU remain.

[TheGoose]

"Both have the exact same Symptoms:
Black Screen, dim green LED, caps lock fails after about 10 pushes."

Do you have a floppy drive connected? a DF0: ?

[Prime]

Nope, Amiga's will still work without a DF0 or floppy attached.

[TheGoose]

Nope, Amiga's will still work without a DF0 or floppy attached.

Well not an A1000. It would just show a black screen like above without a floppy connected. Never make it to the WOM screen.

Errr, no it was a white screen...

[mingle]

Have you tried booting without a monitor attached?

I had a similar issue when using my A3000 with a non-buffered video cable (on an NEC Multisync monitor)

Cheers,

Mike.

[Prime]

Yup, I tried that too.....

I am more curious as to what would be causing the CPU to be in reset.....
As long as it is in reset, nothing is going to work.

[Brosol]

Have you tried reseating all socketed chips...ram, etc?

[Azryl]

Also check the motherboard crystal, this sets the frequency for lots of internal functions. Pull and re-seat it, make sure you get correct orientation.

Also check if the LEDS at the front of the machine are okay
If you have dismantled the machine a few times you can break the LEDS away from the small circuit board traces. If the traces are broken, repair with a circuit liner silver pen, or a car rear window defroster repair kit. It also has paint on electrically conductive silver paint.

Az

[Prime]

Ok, here is the latest:

I resocketed all the chips. I swapped some of the chips with some other ones I have and the cpu is not stuck in reset anymore however; it still has the same behavior.

Here is what I verified:
Clock lines on all chips are ok.
_fail is ok on GARY and on the RTC.
There is a present TICK signal, but I have also tried using VSYNC.

I put an O-Scope on different data lines on the cpu and see some bits going through the bus.

Now I am totally for a loss. All chips have clock signals and appear to be working correctly... ahhhhhh!

Help.

[Retro_71]

Were the A3000 boards ever working with you or did you get these board from elsewhere and are now putting them together?

What KS Roms are you using? what version of WD SCSI controller? what version of chips have you got like buster, Dmac, etc?
N
ear the CIA have you got all the SCSI termination pins (I can't remember their proper name)?

I would remove that battery if it is the orginal even if it doesn't look like alot of damage.

i know i had a hell of a time with all the jumpers to get my A3000 working.

Are you using zip ram or is fast memory banks empty?

IF you have received these broads from elsewhere I am leaning towards some weird jumper setting.

[stevenlcroucher]

Both of my A3000s had this problem and in my case swapping the Dmac chip for a new one sort of fixed it, but it didn't last long as the machine stopped seeing its fast ram after a while.  I suspected another component feeding the Dmac had a fault.  I never did get to the bottom of it.