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VintageC
January 5th, 2014, 07:06 AM
Dear VCF members.

Today I was trying to fix a Amiga 1000 but when I turn it on I got nothing on the screen.
The red ligt burns and the fan is running but nothing else happends.
I took the Amiga apart to see if I could run it with minimal components but I did not know where to start.

I have no idea which is the CPU etc. I only saw it had some extra memory expansion but thats all I know from the Amiga.

Could someone give me some ideas where to start looking?

Thanks.

VintageC
January 8th, 2014, 09:49 AM
Nobody has any suggestions? :confused:

KevinO
January 8th, 2014, 11:27 AM
Nobody has any suggestions? :confused:

I have personally never worked on a 1000, but check the power supply voltages (should be +5v and +12v) and then look at the ongoing thread about the A500 that giobbi has been working on. That may also give you some ideas.

geoffm3
January 8th, 2014, 12:26 PM
On the A1000, the Power LED should flash bright/dim alternately fairly quick for a second or two when you first turn the machine on before you are presented with a prompt to insert the kickstart disk. First thing I would do is disconnect the trap door RAM under the front panel, and then probably try reseating the write-once memory board that's piggybacked to the motherboard and see if that helps.

Richard Lagendijk
January 9th, 2014, 03:04 AM
Maybe this can help

http://www.bombjack.org/commodore/amiga/amiga-commodore/

VintageC
January 9th, 2014, 11:19 AM
On the A1000, the Power LED should flash bright/dim alternately fairly quick for a second or two when you first turn the machine on before you are presented with a prompt to insert the kickstart disk. First thing I would do is disconnect the trap door RAM under the front panel, and then probably try reseating the write-once memory board that's piggybacked to the motherboard and see if that helps.

Update:
I turned the A1000 on in its original state but nothing happend. The power light didnt flash but its a bright red steady light.

I took off the front memory and it was the same story so I took off the piggybacked memory to and still nothing happends.

But when I took off the piggybacked memory I noticed some hand made modifications (see pic):
16755

Do I need to disconnect the hand soldered cabels?

geoffm3
January 9th, 2014, 12:01 PM
Update:
I turned the A1000 on in its original state but nothing happend. The power light didnt flash but its a bright red steady light.

I took off the front memory and it was the same story so I took off the piggybacked memory to and still nothing happends.

But when I took off the piggybacked memory I noticed some hand made modifications (see pic):
16755

Do I need to disconnect the hand soldered cabels?

You'll need to make sure that the piggyback board is installed in order to boot. It won't work without it installed. Some of the ICs on the daughterboard were intended to install directly onto the motherboard, but they had to move them to the daughterboard in order to get access to the signals necessary for the write-once memory (this was originally done as a stopgap measure since Kickstart wasn't ready to burn to ROM in time for production, and then they just stuck with it for the whole A1000 model). Reseat it and try again.

Not sure what that mod is all about. There were some issues with improperly grounded PAL chips on A1000s on some revisions of boards, but this isn't a PAL chip. There was also another wire mod that was popular to disable the low pass filter (on all other amigas this is switchable with the power LED state, on the A1000 it is always enabled).

VintageC
January 9th, 2014, 12:39 PM
You'll need to make sure that the piggyback board is installed in order to boot. It won't work without it installed. Some of the ICs on the daughterboard were intended to install directly onto the motherboard, but they had to move them to the daughterboard in order to get access to the signals necessary for the write-once memory (this was originally done as a stopgap measure since Kickstart wasn't ready to burn to ROM in time for production, and then they just stuck with it for the whole A1000 model). Reseat it and try again.

Not sure what that mod is all about. There were some issues with improperly grounded PAL chips on A1000s on some revisions of boards, but this isn't a PAL chip. There was also another wire mod that was popular to disable the low pass filter (on all other amigas this is switchable with the power LED state, on the A1000 it is always enabled).

I`ve reseated everything twice but still nothing happends. The power light does not flash and there is no screen output.
I did remove the disk drive but does that mather? Also the front memory is not needed for booting is it?

I did try all kinds of configurations but no change at all.

geoffm3
January 9th, 2014, 01:40 PM
I`ve reseated everything twice but still nothing happends. The power light does not flash and there is no screen output.
I did remove the disk drive but does that mather? Also the front memory is not needed for booting is it?

I did try all kinds of configurations but no change at all.

No, the disk drive shouldn't need to be installed to at least get the kickstart prompt. If everything is working like I said, you should get the flashing power LED, a little chime, and then a couple seconds later the kickstart prompt (hand holding a disk) should appear. There are several socketed chips in the machine, you might try reseating everything carefully as well.

VintageC
January 11th, 2014, 12:18 PM
I reseatd every single chip that was on the board and still nothing happend :confused:. I found a little burn under one chip which was allrdy reconnected with some wire.
16799
It looks like that should not give a problem. Anyway whats the minimum of chips you need to see some screen output?

Also there are 2 sockets not filled.
16800
Are these chips needed?

tingo
January 11th, 2014, 01:40 PM
Your pictures are very small, it is hard to see anything from them.

dabone
January 11th, 2014, 03:41 PM
One, it looks like you are missing 2 8250 CIA chips.

Here is a 1000 board fully populated.


http://amiga.resource.cx/photos/photo2.pl?id=a1000&pg=2&res=hi&lang=en

Warning, VERY HIGH RES!

(4120 3646, 3957 kB)

Later,
dabone

VintageC
January 11th, 2014, 09:50 PM
One, it looks like you are missing 2 8250 CIA chips.

Here is a 1000 board fully populated.


[URL="http://amiga.resource.cx/photos/photo2.pl?id=a1000&pg=2&res=hi&lang=en"]http://amiga.resource.cx/photos/photo2.pl?id=a1000&pg=2&res=hi&lang=

Were are those chips used for?

I cant upload bigger pics because then the file is to large.

geoffm3
January 13th, 2014, 10:27 AM
Were are those chips used for?

I cant upload bigger pics because then the file is to large.

Those chips are used for the joystick, mouse, serial and parallel ports, and also contain timers that the system uses for general purpose timing. It definitely won't boot without them. They are the same as the A500 so if you have a spare, you can use them, and they are still available new old stock from a couple suppliers in the EU reasonably cheap, so you should be able to source some replacements.

VintageC
January 13th, 2014, 12:45 PM
Those chips are used for the joystick, mouse, serial and parallel ports, and also contain timers that the system uses for general purpose timing. It definitely won't boot without them. They are the same as the A500 so if you have a spare, you can use them, and they are still available new old stock from a couple suppliers in the EU reasonably cheap, so you should be able to source some replacements.

I have a A500 lying around so im kind of lucky and I can try it out. If I'm able to fix it with those chips I can buy new ones.

Thanks for the info. Will tell if its working.

geoffm3
January 13th, 2014, 12:52 PM
I have a A500 lying around so im kind of lucky and I can try it out. If I'm able to fix it with those chips I can buy new ones.

Thanks for the info. Will tell if its working.

This is one of the places I was talking about:

http://www.vesalia.de/


They've got them for €7.90 a piece.

VintageC
January 14th, 2014, 10:16 AM
This is one of the places I was talking about:

http://www.vesalia.de/


They've got them for €7.90 a piece.

Tryd the chips of the A500 and it was working. It asked for the kickstart, which I dont have :(.

But thanks a lot I will buy some new ones so my a1000 is a working peace of my collection :)

geoffm3
January 14th, 2014, 10:23 AM
Tryd the chips of the A500 and it was working. It asked for the kickstart, which I dont have :(.

But thanks a lot I will buy some new ones so my a1000 is a working peace of my collection :)

That's a nice easy fix! Kickstart disks can be copied with the right software. Hopefully there's someone in Europe nearby that can make you some copies.

VintageC
January 16th, 2014, 11:36 PM
That's a nice easy fix! Kickstart disks can be copied with the right software. Hopefully there's someone in Europe nearby that can make you some copies.

I thought I had one lying around also but it seemed to be something else writen over it :(

KevinO
January 18th, 2014, 01:47 PM
Glad you got it fixed, or at least partially. Now to find a Kickstart disk....

RobertB
January 18th, 2014, 10:56 PM
I thought I had one lying around also but it seemed to be something else writen over it :(
If you are in Maarssen on February 15, you can go to the bi-monthly Netherlands Commodore Show and probably get a Kickstart disk from one of the Amigans attending the show. The show will have plenty of Commodores and Amigas to see, and there is also a sales table with plenty of software and hardware. For more information, see

http://commodore.hcc.nl/events

Going to the show on June 21,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug