Problem with Amiga 3000T , Please help !

[nscaleworld]

I have an Amiga 3000T that has a couple of problems. First, I can not boot from any disk unless I first hold down both mouse buttons and then turn cpu cach off. Only after turning off the cpu cach will the Amiga 3000T boot from a disk. Second, I can not get the computer to recognize any SCSI hard drive. I can load up HDTools and low level format, partition, and verify a hard drive, but after I reboot, the hard drive does not show up in Workbench 3.1. The harddrive does not even show up in the list on the WB 3.1 Install disk.

Here are the specs of my Amiga 3000T:

030 processor on motherboard
2 megs chip memory
16 megs fast memory
Rev 08 WD SCSI chip
Kickstart 3.1 roms
880K Amiga 3000 disk drive (DF0)
1.76 MB Amiga 3000 disk drive (DF1)
Newer Ramsey and Demac chips

I am really scratching my head on this problem.

PS: Battery was removed and the motherboard is clean, almost new.

[nscaleworld]

Have you changed the caps on the motherboard? I remember I had a similar issue with a 4000D and some caps needed to be replaced along with an IC.

The caps on the Amiga 4000 are smt, the caps on the Amiga 3000T are higher quality thru-hole.  I will be replacing all of the caps with new Nichicon caps from Japan.

[nscaleworld]

So, again, here are the problems:
 
Amiga 3000T will not boot an 880k disk unless I first disable cpu cach.
 
Amiga 3000T will not recognize a hard drive after reboot.
 
Do any of you know what the default jumper settings are for an Amiga 3000T with onboard 68030, I need the default for all of the jumpers on the motherboard.
 
Thank you.
 
Oh, and as far as the battery is concerned, I know that Amiga computers work just fine without a battery, but, I do plan on installing a CR2032 battery holder and diode, because I plan to install Workbench 3.9 and I want the correct date and time displayed.  Do any of you know what diode I should use?  Will a 1N4001 diode work?

[nscaleworld]

http://www.l8r.net/technical/t-3000-jumpers.shtml
 
Spend some time on Google, there's a lot out there...

This information, as far as the jumpers, is basicly useless, because it does not tell you what the working default set by Commodore is.  What I really need is for someone that has an Amiga 3000T, that they have never messed with the jumpers, to pull the cover off and write down what the jumper settings are for all of the jumpers.  Or take a few pictures of the jumpers, showing how they were setup by Commodore.  This would help a lot.
 
Also, why would 880k disks refuse to boot unless you first hold down both mouse buttons and turn off cpu cashe?  I have never seen this problem on any Amiga computer.  It's got me scratching my head trying to figure it out.

[nscaleworld]

...another thought, check your SCSI termination. I believe there are, or should term resistors on the motherboard (but I haven't seen a A3000 in years).

I only have the one 249 mb Seagate hard drive installed.  It is terminated and is set for SCSI ID 0.  The terminator resistor packs on the motherboard were removed and a Commodore terminator is plugged into the 25-pin SCSI port.  I tried 3 different SCSI ribbon cables, does not fix problem with hard drive not showing up in Workbench 3.1.  The ribbon cables are about 6 FEET long.  I wonder if they are too long.

[nscaleworld]

The CPU Cache thing makes you wonder if the CPU itself is 100%. Do you have a 3640 to test with?
Also, what Kick 3.1 are you using? Original or burned? Do you have a set of 2.04 ROM's to use?

Yes, I do have an A3640 board, but, it is a revision 3.0.
 
The Kiskstart 3.1 roms appear to be original, but, I am not sure.  How can you tell if they are burned (copies)?

[nscaleworld]

Ok, I poached this from another A3000T thread going on at Amibay, this looks like the default jumpers but I can't guarantee the source -:
 
 
 
The jumpers back to factory for the CPU, for the onboard 030:
 
J100 1-2
J102 2-3
J103 3-4
J104 1-2
 
J105 ALL OPEN
J106 ALL OPEN
J107 ALL OPEN

Thank you so much, I will try these.
 
I am wondering if it would be wise to install a PPC board in my Amiga 3000T?  I have a GVP video card.

[nscaleworld]

Check the chips inside your Amiga 3000 computer. Most of them did NOT have the military-rated versions as supplied by Commodore only to the government. If this is the case, you are wasting your time. Throw that POS in the dumpster where it belongs, and get yourself an Amiga 2000 computer. Connect it to your stereo, load up a sh!tty Amiga game of your choice, and enjoy. Just don't forget to TURN UP THE VOLUME!

What the heck are you talking about dude?  :confused:

[nscaleworld]

To get something a little more constructive in this thread:
 
The 'does not boot unless cache turned off' problem may be due to mismatched ZIP RAMs. When the first bank consists entirely of static column (SC) chips Ramsey's burst mode is turned on - but it will only be used for filling the cache.
 
A problem arises when the rest of the RAMs are not 100% SC (xx4402) but fast page (FP xx4400) - the burst will not work and the machine will crash.
 
Check if ALL chips are SC and if they're mixed move one of the FP chips to the left frontmost socket.
 
 
As to SCSI cable length: we're talking SCSI-1 here, so the cable may be up to 6m (nearly 20'). I'd stay below 3m (for Fast SCSI) to make sure.
 
Double and triple check termination, some A3ks have misprinted socket labels, so terminator (resistor) packs installed 'correctly' may not work. The 220 Ohm side must go to termpower (5V), the 330 Ohm side to GND. Check whether termpower reads 5V (or close to), the fuse may be blown. If you have the chance try cable terminators, preferably active ones. Most have a LED to show whether termpower is on.

Will the zips actually have SC or FP printed on the chips?  What kind of zip memory should I have installed, SC or FP?  Where do I check for the 5v termpower?  The termination resistor packs on the motherboard were removed so that I have the option of using the 25-pin SCSI port.  Right now there is a Commodore terminator plugged in.

[nscaleworld]

I'm fairly sure the chart tells you, by revision what the jumper settings should be, but hey why bother helping?

So, which set of jumpers do I use, the ones under 313181 -01,-03,-05 or the ones under 313181 -02,-04,-06 ? What the heck does that even mean?

[nscaleworld]

Well, I checked my stash of zip memory chips and they are indeed mixed.  So, they are most likely mixed in my Amiga 3000T too.  I did not know that there are 2 different types of zip memory and that you are not suppose to mix them.  So, I just spent the last hour sorting thru my pile of zips.  I put all of the SC in one anti-static bag, and all of the FP zips in another.  So, this mixup will never happen again.  Tomorrow, I will remove the Amiga 3000T motherboard from the case.  Then I will remove all of the zip memory and start over.  So, SC zips are best for the 030 processor?
 
I want to thank all of you guys for helping me.  But, I will continue to need your help until I get the old girl back up and running perfectly.  I think correcting the zip memory will fix the disk drive and cpu cashe problem.  I am also going to install the coin battery and hopefully that will fix the problem of Workbench 3.1 not "seeing" the hard drive.
 
Thanks a lot, guys, you are a big help.  :razz:

[nscaleworld]

Dude, why waste your time trying to fix that POS computer? Everyone knows that the best computer is the Amiga 2000. (The great Doom Master even thinks so!) It's a work horse and never has issues like this!
 
My A3000T is also not working. I think it has a flakey CPU slot on it. It's just a big hunk of metal right now. Dead as a doornail. I have to open it up every so often and reset the CPU card on it to get it to work. Never have this problem with my Amiga 2000's...

This is the reason why I am using the onboard 68030 chip.  I will be sorting out the zip memory problem and I will install a CR2032 coin battery.  I will let you guys know how this turns out.  Even though the Amiga 2000 is more stable, I think that the Amiga 3000T is an absolutly beautiful computer, and I always wanted one.  I plan to install a PPC board and Amiga OS 4.0  I already have a GVP graphics board and a network board.

[nscaleworld]

Make sure that the threaded standoffs that are used to secure the processor board in the Amiga 3000T computers cpu slot are the correct size. If the standoffs are the wrong size you will have problems with the cpu slot.  You can not just plug in the processor board.  It must also be screwed to the aluminum standoffs, and the standoffs are screwed to the motherboard.

[nscaleworld]

IT'S ALIVE, IT'S ALIVE! I finally repaired my Amiga 3000T. There were 3 FP ZIP memory mixed in with the SC ZIP memory. I also installed a CR2032 battery holder, diode, and a new CR2032 coin battery.  I posted a picture of my work in the Amiga 3000T section of the Gallery. The computer works perfectly, and keeps the correct time and date. My Amiga 3000T is in like brand new condition, and I am so happy that she is working again. :pint: