Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: cadillac46 on October 28, 2014, 05:02:04 PM
-
Few days ago I bought an untested accelerator card -the PP&S 68040-3000. It doesn't work, the Amiga was showing black screen and the power diode was dimmed. Yesterday I spent some hours with this card trying to find what's wrong. Now I know there is something wrong with one of the PAL chips. When I pulled one of them out, Amiga started and booted system but was working with motherboard 68030 only. The 68040 was inactive. The accelerator has an ability to switch between 68040 or 68030 from motherboard by software. I think this broken PAL is responsible for switching between these two processors.
Is there any solution to make this PAL get back to work? I'm not an programmer nor electronics guy, but I can check the signals running from accelerator's board to the PAL socket. I mean I can check there are no broken paths or resistors or capacitors etc.
http://www.bigbookofamigahardware.co...ct.aspx?id=241
Please, help me somebody!!!
-
Double check the motherboard settings for this card. Not all accelerators use the same jumper settings.
Few days ago I bought an untested accelerator card -the PP&S 68040-3000. It doesn't work, the Amiga was showing black screen and the power diode was dimmed. Yesterday I spent some hours with this card trying to find what's wrong. Now I know there is something wrong with one of the PAL chips. When I pulled one of them out, Amiga started and booted system but was working with motherboard 68030 only. The 68040 was inactive. The accelerator has an ability to switch between 68040 or 68030 from motherboard by software. I think this broken PAL is responsible for switching between these two processors.
Is there any solution to make this PAL get back to work? I'm not an programmer nor electronics guy, but I can check the signals running from accelerator's board to the PAL socket. I mean I can check there are no broken paths or resistors or capacitors etc.
http://www.bigbookofamigahardware.co...ct.aspx?id=241
Please, help me somebody!!!
-
Double check the motherboard settings for this card. Not all accelerators use the same jumper settings.
Checked. I have the manual for this card.
-
Few days ago I bought an untested accelerator card -the PP&S 68040-3000. It doesn't work, the Amiga was showing black screen and the power diode was dimmed. Yesterday I spent some hours with this card trying to find what's wrong. Now I know there is something wrong with one of the PAL chips. When I pulled one of them out, Amiga started and booted system but was working with motherboard 68030 only. The 68040 was inactive. The accelerator has an ability to switch between 68040 or 68030 from motherboard by software. I think this broken PAL is responsible for switching between these two processors.
Is there any solution to make this PAL get back to work? I'm not an programmer nor electronics guy, but I can check the signals running from accelerator's board to the PAL socket. I mean I can check there are no broken paths or resistors or capacitors etc.
http://www.bigbookofamigahardware.co...ct.aspx?id=241
Please, help me somebody!!!
Unfortunately, the code put on PALS were protected by blowing a fuse inside to prevent it from being read. If that PAL is indeed the trouble your only hope may be to find another user with the same board and try and read the pal(hope its not protected) or get the code from the company who made it(good luck here).
There are ways to reconnect the fuse but they are not easy and don't always work.Of course the PAL you have is likely suffering from bit rot and has lost its info,so at a minimum,you may need access to another accelerator. if you can get the code you will need a PAL programmer(or eprom programmer that handles that particular PAL chip).
-
Just for my own information, how did you determine that the PAL was bad?
-
Just for my own information, how did you determine that the PAL was bad?
I only suppose it's bad. I've changed capacitors, processor from working A3640 card and the accelerator won't work. Then I thought about PAL's in sockets, maybe there's no connection or something. I pulled them out and I cleaned sockets, and put them one by one powering on the Amiga after each PAL was socketed.
That's how I found the bad PAL. I think so. Or maybe it's some other component bad?
-
Well the PAL chips are also gateways to and from other circuits, so removing one and having the whole card ignored just seems a tad shy of diagnostic of a bad chip.
-
Well the PAL chips are also gateways to and from other circuits, so removing one and having the whole card ignored just seems a tad shy of diagnostic of a bad chip.
So what should I do? No one in Poland is interested to look at or repair my card.
-
Did you ask Stan Sedlak (Stachu100) to take a look? He repairs Apollo & Cyberstorm cards and for a price can do a diagnostic evaluation. He in on the forums and pops up on Amibay every so often.
-
Did you ask Stan Sedlak (Stachu100) to take a look? He repairs Apollo & Cyberstorm cards and for a price can do a diagnostic evaluation. He in on the forums and pops up on Amibay every so often.
He's always busy. But I'll try to ask him. BTW I know him from polish forum ppa.pl ;)
-
I may have found your problem:
That Avatar is not a 1946 Cadillac, it appears to be a 1994 Corvette Targa
(http://www.amiga.org/forums/picture.php?albumid=169&pictureid=1227)
This is an avatar of a 1946 Cadillac
(http://www.amiga.org/forums/picture.php?albumid=169&pictureid=1226)
-
I may have found your problem:
That Avatar is not a 1946 Cadillac, it appears to be a 1994 Corvette Targa
(http://www.amiga.org/forums/picture.php?albumid=169&pictureid=1227)
This is an avatar of a 1946 Cadillac
(http://www.amiga.org/forums/picture.php?albumid=169&pictureid=1226)
I own 1994 Corvette and I owned a Cadillac, but not 1946 model. It was Cadillac Eldorado with 4.6 litre engine. But that's not a problem.
-
At least it wasn't a Cadillac with the V8-6-4 engine. What a nightmare that thing was. ;)
-
What model year Eldorado? Front wheel drive or not, some of those required tug boats to park!
-
What model year Eldorado? Front wheel drive or not, some of those required tug boats to park!
It was 1995 ETC version. 4.6 Northstar (Nightmare ;))
-
Today my Amiga's going to another PPA.PL forum friend - jarob. I've to send him the whole computer with the accelerator card, coz he don't have the A3000.
So for the repair time I end this topic.