A3000T woes

[nine3o]

Hi all,

Looking for any type of help regarding my A3000T.  This problem seems to have started when I first got this beast a few months ago, here is what happens:

When I power on the tower, after it has been powered off for a few days, it takes for ever to power on.  What I mean is the power LED is on dim with a black screen, the LED on the hard drive itself (not the HDD activity light on the front console) stay on solid.

The keyboard does work because the caps lock LED can be toggled from on to off, and if I hit the 3 key combo reset, it resets the amiga (because the cap lock LED flickers ON to OFF).

I have stripped this down to bare bones config with just 2 meg chip and 12 meg fast and unplug the hard drive from the picture as well but it still does this.

Now, after a few resets and holding both mouse buttons down, the machine comes back to life.  If I power it off and plug in the hard drive it boots up, but keeps reseting multiple times for about 20 minutes with the intervals of resets less frequen and the system becomes more and more stable as it stays powered on.

Any ideas on what this could be :-?

Could it be a bad could this be a bad DMAC or something else :-?  :-?  :-?

Or did i end up buying a lemon?

Any help or input would be much appreciated guys.

[countzero]

sounds like bad/dying caps.

[nine3o]

Well, after playing around with the A3000T for couple hours trying to figure out what the issue is (reseating chips and power connector) it seems to have gone solid now.

When I power on the Amiga all I get is a black screen with the power LED being dim as if the reset button is being held down  :cry:

Any one interested in a dead A3000T?  If so PM me offers as I don't have time to play with my Amiga's any more...  Just frustrated with all the problems I have been running into lately.

If no offers up on e-Bay it goes.

By the way it has 2 meg chip 12 fast, 1 gig SCSI, 2.04 roms, and I live in Toronto, Canada.

[T3000]

Check your power supply voltages.
Try swapping the 3640 with a known working one.
My A3000T power led is half bright and the system goes to a green screen. I had replaced the the PS when mine tested bad. Then burnt up the floppy drive while hooking up a good PS. Have yet to go further with diagnostics.
 

[nine3o]

@T3000

Thanks for the input, I will check the power supply voltages tonight (I was also told to take the mother board out and make sure nothing is shorting out the back of the mother board).

As for the A3640, it's not installed (I know its good because I tested it on my A4oooT, it's a 3.1 version) just running on the mother board '030 for diagnostics right now, and it reacts the same with the '040 in or out.

If I don't make any progress by the end of the week, and I am still frustrated when I get back from Vacation, this thing definitely going for sale.

[Matt_H]

If you've simply pulled the 3640 out, then you will run into trouble - a bunch of jumpers need to be adjusted when adding/removing an accelerator.

The CPU connector is extremely sensitive. Without the appropriate physical mountings, it sometimes takes 4 or 5 reseating attempts for me to get one of my machines booted.

[nine3o]

Hi Matt_H,

Thanks for the info, and the tip about the 200 pin connector being sensitive.  I am aware of the jumper settings for the A3640, I have tested CSMKII in there as well, but to no avail.

I understand that a black screen tends to mean dead cpu, but I just don't undertand the contstant reseting before this turned solid, just my luck as I payed a premium for this system to be added to my collection. :-(

[nine3o]

OK, well I checked the voltages on the mother board, and here is the break down:

 12 volts = 11.75
  5 volts =  4.95
-12 volts = -11.89
 -5 volts =  -5.02

I also pulled the mother board to see if there is anything shorting out behind the motherboard, did not see anything, BUT, I did find a small brass pin sitting on top of the ISA slot pins (the pins that meet the motherboard, if I knew how to add pictures to this thread I would show you what I mean)

Well, I removed the pin and powered it back on, still the same black screen on power up and dim power LED.

Is it safe to assume that this motherboard is now dead because of that pin shorting out on the ISA slot?

I just to verify that I have the correct jumpers set up:

A3640 CPU
J100 3-4
J102 2-3
J103 1-2
J104 2-3

MKII & Onboard 030
J100 1-2
J102 2-3
J103 3-4
J104 1-2

@Nine3o

Thanks for e-mailing me the picture.

The brass pin you mentioned (and showed me) undoutedly came from the disintegrating safety keyhole. It seems to have shorted the last pins on the topmost Zorro III connector.

I would tend to think it has destroyed your super buster. Software Hut seems to have them but they don't update their web site anymore.

Is there anyone with a reliable source for these chips?

Does anyone know if there could other chips involved?

[countzero]

vesalia has them and they're quite reliable.

[Zac67]

Yes, Vesalia is highly recommended.
I've got a spare Super Buster -11, 20€ shipped to Canada. I could send it on Saturday if you're interested.

[nine3o]

@eslapion

First I would like to thank you for offering your A3000 as a test bed to figure out which of my socketed chips are fried, you are true friend and a stand up guy!!!

@all

thanks for your input thus far, I think I am making progress.

@Zac67

I think I will take you up on that offer for the buster 11 chip (as long as it is working of course :-D  )
I sent you pmail with my information.

[nine3o]

Well, I have swapped out all the socketed chips with an A3000D (thank you eslapion for using one of your A3000D) and after looking at the wiring diagrams, the brass pin shorted across ground, +5, -5, and +12.  My guess is that +12 on +5 and -5 lines fried components that I can't swap out with out a soldering iron (and my soldering iron skills suck) so offers are now open to any one interested in this unit.  

All the socketed chips have been tested and work.

2 meg chip
12 meg fast
Extra mounting hardware
A3000T manual

PM me your offers, or PM me your e-mail address if you would like pictures.

[TjLaZer]

How much you looking to get for the case?  I have a MB and might be looking for a complete case for it.

[nine3o]

Do you want just the case with no mobo?  Do you want the keyboard and 3 button pregnant mouse?

It all depends on what you want, everything or just specific pieces.