3000T mother board help

[ads1500]

I am looking for any input in getting a 3000T motherboard working.

Bought from thsi post:

https://www.amibay.com/showthread.php?t=30595

All I am getting is a solid black screen, no color cycling or actually any output.

Have tried the following:
- I am using a working 3000T power supply, works fine in my personal 3000T and confirmed correct voltages at 5V and 12V
- 3640 is confirmed working
- Jumpers are set correctly for external card
- also tried jumpers for on board CPU - same black screen
- Tried a different set of kick start chips - same black screen
- reseated all chips
- Tried using a video card (same black screen)
- Tried with and without known working SCSI drive
- Tried with and without keyboard and mouse

Appreciate any other testing advice. thanks

 

[lostrego]

Do you have power & hdd leds attached? If so the power led does lit up?

Any blinking in the power led, also the caps lock led at the keyboard does lit, any blink there?

By black screen do you mean that it gives video signal but black?

 

[ads1500]

Yes black video signal, there is a signal but just black

I don't have a power led but no blinking on Cap key, if I press it, it lights up so behaving normally

 

[lostrego]

Well, I'm not very familiarized with the 3000 line but I remember that those have a memory that store the scsi settings and a change on the scsi chain disposition can lead to a very long delay at the first boot, have you waited ? Say a minute or two.

 

[ads1500]

Yes, left on for 1bout 10 min. Also tried with and without a SCSI drive

thanks for your help

 

[lostrego]

But it seems that is behaving well as the caps lock do response.

Try reseating the zip drams also to see if helps.

---------- Post added at 03:03 ---------- Previous post was at 02:56 ----------

Also try reseating the oscillators (the tiny rectangular metallic cans)

 

[ads1500]

Wil try asap

 

[lostrego]

Also try reseating the oscillators (the tiny rectangular metallic cans)

 

[ads1500]

Oscillators are firmly soldered in place.

---------- Post added at 01:29 ---------- Previous post was at 01:27 ----------

I've spent countless hours already on this... trying to work out a return with the seller

 

[Buzzfuzz]

For a 3000T to start it's keylock needs to be attached too.
And thus the keylock must be open, else the 3000T will never start.

So you need to use your tower and also connect the black connector with small blue wires.

 

[Exilent]

keylock

keylock

no the keylock isn't needed for booting.

Have you tried switching to 31khz, same result?

is there no battery damage?

 

[ads1500]

Same result with both video outputs, no apparent battery damage

 

[lostrego]

But googling around several people claim that with the 3000T the keylock must be attached, if not the result is black screen and no boot, may lead to confussion as this doesn't apply to other keylocked amigas like the 4000D.

At least say that if the caps lock do respose normally that means that the CPU is seen by the mobo and is ok, this issue seems more like a minor thing.

BTW have you checked that the kickstart pair of ics are each one in its correct socket?

 

[Tahoe]

no the keylock isn't needed for booting.

The 3000T most surely does need the keylock both attached and switched to the ON position, otherwise the machine will not boot and the power led will remaining dim. The caps lock led will function normally.

 

[lostrego]

About rom ICs just to rule out common mistakes:

the -1 needs to be on the upper position
the -0 on the lower one

just like here if you zoom in:

http://amiga.resource.cx/photos/gallery/a3000trev61.jpg

Also as Tahoe says the keylock panel must be attached and in ON position

---------- Post added at 16:13 ---------- Previous post was at 16:07 ----------

BTW and being a bit off topic: I never understood why the 3000T needed such a big mess of a mobo just to have only an additional zorro slot

 

[ads1500]

My 3000T (the one I am using the power supply) from boots without the cable from the led/key panel. I used that to connect to this mb I am working on.

Actually in the process of removing the cable, the pins that connect the led and key cable off from the blue cable that goes to the mb and into Cn302. Does anyone have a pic or how the led/key assembly connect or pinout of CN302?

 

[lostrego]

Sorry I haven't such info, however is not possible to remove the whole led/key assembly to test the standalone mobo?

Just guessing as I never had a 3000T, perhaps if someone here have or had one may be more helpful

With the 3000 (either on D or T forms) you must have loads of patience, never underestimate the capabilities that those have to ruin a whole Sunday afternoon and/or give you a headache :roll:.

 

[ads1500]

I did try previously with the led assembly connected and it did not work either


Mine boots even without the assembly

 

[lostrego]

I am running out of ideas, some things that gave me issues on other machines were a loose connection on the mobo's PSU power socket, If the pwr ok (and on the 3000 the tick line) signals do not get properly to the mobo it'll refuse to start, however yours does start and in fact give video signal (black but signal) so I doubt that this can be your problem.

Other issues can be due to a faulty chip somewhere, thing you can test as you have an additional working 3000T, just exchanging them for testing but needs even more time, care and patience.

I'd check the Denise chip first to rule out Video issues.

Before all of that I'll give it another try with the front led/key assembly attached (perhaps some mobo revisions do need it to boot properly and other ones don't) and nothing plugged to the SCSI connector (just to discard additional termination woes) and wait some minutes to see if it does boot or not.

Anyway, good luck with it.

 

[drwho]

I know it's probably tempting to be rid of the board and get a refund, but, since it looks like the board is running in the sellers original thread, it might not be a bad idea to give it one last go.

I know you've probably tried all of this stuff already, but, just humor me.

I had this exact same problem initially on my A3000T when I bought it, black screen, caps lock worked fine (you should be able to hit it ~20 times and then the caps light should freeze, this is a good indicator that the CIA at U350, the ROM and CPU are working for the most part).

1. Get rid of that god-awful A3640 board. Trust me, just because that works in your current A3000T does not mean that it will work on the new board. Everything has to be just right in the universe before that board will work right in a 3000. Unfortunately, I have two, and they are both useless.

2. Set the jumpers back to factory for the CPU, for the onboard 030, you probably already know this but:

J100 1-2
J102 2-3
J103 3-4
J104 1-2

J105 ALL OPEN
J106 ALL OPEN
J107 ALL OPEN

3. There may be a 74F08 chip in the socket at U103, if so, remove it. As you already know, this is only needed with the A3640 and not generally included on the 3000T motherboard.

4. Remove all zorro cards.

5. Remove all SCSI drives.

I know you probably tried all of these things, but, maybe there is something here that has been overlooked, especially in the jumpers part. Sometimes you see pins 1-2 shorted on some or all of J105-J107, which is not factory.

On my 3000T, the blue cable for the keylock MUST be plugged into the board or my system presents a black screen, sometimes it flashes grey/white as well.

Start it up and see if you get the ROM screen, if so, attempt to boot from a floppy.

Hope this helps.