Blank/black screen Amiga 2000

[falter]

Well, I finally got my hands on an Amiga 2000. Unfortunately, it doesn't want to start. When I first got it home, I tried hooking it up via an RGB/vga cable it came with. My CRT didn't like it (apparently I was mistaken about it being able to sync correctly). Anyway, changed over to the 'mono' video port, hooked up to a working composite monitor -- black screen. Powered up a few times after pressing chips down -- screen would stay black, or sometimes come up white.

No signs of the unit attempting to boot. It didn't come with a keyboard, so I plugged in an old Commodore PC keyboard I had. The SCRL Lock, CAPS, and NUM Lock all light up and stay solid.

Checked the battery -- voltage is around or under 1 volt... terminals look kinda corroded. Anyway.. thoughts?

 

[NeXT]

I beleive that the earlier version ROMs didn't have the classic "Insert Disk" image so it didn't really doo much but tick the floppy drive every so often in hopes of finding a workbench disk to boot from.
Also, the A2000 keyboard and keyboard port are non-standard to that of a Commodore PC keyboard which is pretty much an AT connection.

 

[falter]

I beleive that the earlier version ROMs didn't have the classic "Insert Disk" image so it didn't really doo much but tick the floppy drive every so often in hopes of finding a workbench disk to boot from.
Also, the A2000 keyboard and keyboard port are non-standard to that of a Commodore PC keyboard which is pretty much an AT connection.

Yeah, I figured.. well, definitely no drive tick. Zero activity really. I did put a workbench disk in there hoping to see something happen.. but yeah, zero. The computer came with an amiga hard disk drive controller (although no drive).. I note when the machine is switched on with the controller card in, the hard disk activity light stays on solid. Removing the card has no effect though.

Looking more closely at the battery though, it is clear there has been significant leakage -- the board in the area immediately around it has been despoiled and one of the mounting screws is rusted. Does anyone know if an A2000 can boot with a dead battery?

 

[Mr.Amiga500]

Well, I finally got my hands on an Amiga 2000. Unfortunately, it doesn't want to start. When I first got it home, I tried hooking it up via an RGB/vga cable it came with. My CRT didn't like it (apparently I was mistaken about it being able to sync correctly). Anyway, changed over to the 'mono' video port, hooked up to a working composite monitor -- black screen. Powered up a few times after pressing chips down -- screen would stay black, or sometimes come up white.

No signs of the unit attempting to boot. It didn't come with a keyboard, so I plugged in an old Commodore PC keyboard I had. The SCRL Lock, CAPS, and NUM Lock all light up and stay solid.

Checked the battery -- voltage is around or under 1 volt... terminals look kinda corroded. Anyway.. thoughts?

Here are my thoughts:

1. The Commodore PC keyboard will not work on an Amiga. It might even cause damage. Get an A2000 (or A3000) keyboard.

2. By hooking the A2000 up through the "mono" composite (actually greyscale), you won't be able to see the boot error code colour. That "white" screen you occasionally get might actually be one of the boot error code colours which will help tell you what is wrong. If you can't find a Commodore RGB monitor to connect it to, you can buy an RGB to S-Video adapter and connect it to a TV. (It won't be as crisp as RGB, but it's not as bad as greyscale composite.)

3. Get that battery out of there and clean the area with isopropyl alcohol. The A2000 will work fine without battery (except real time clock will always be off). Your main concern is avoiding any further damage to the motherboard. That battery acid can cause major damage. It's probably the reason your A2000 isn't booting.

 

[falter]

Here are my thoughts:

1. The Commodore PC keyboard will not work on an Amiga. It might even cause damage. Get an A2000 (or A3000) keyboard.

2. By hooking the A2000 up through the "mono" composite (actually greyscale), you won't be able to see the boot error code colour. That "white" screen you occasionally get might actually be one of the boot error code colours which will help tell you what is wrong. If you can't find a Commodore RGB monitor to connect it to, you can buy an RGB to S-Video adapter and connect it to a TV. (It won't be as crisp as RGB, but it's not as bad as greyscale composite.)

3. Get that battery out of there and clean the area with isopropyl alcohol. The A2000 will work fine without battery (except real time clock will always be off). Your main concern is avoiding any further damage to the motherboard. That battery acid can cause major damage. It's probably the reason your A2000 isn't booting.

Thanks for this!! Yes, damn... I took a second look around the area where the leakage occurred.. it looks like the damage spread to the first four pins of the CPU chip. The sockets for those pins are pretty bad. With the alcohol... what sort of 'tool' do you use on the pin sockets?

 

[falter]

It booted!! (Once)

It booted!! (Once)

After taking the 68000 CPU out, I got some q-tips with alcohol and went at it. I also used a very soft bristle brush tool on my slow speed half dead battery dremel to buff the pins on the 68000, a few of which had really been eaten into.

To get at the sockets themselves, I took florist wire and after dabbing a bit of alcohol in there, scrubbed into the sockets. Didn't remove a lot, but a bit. Also did this to the keyboard port.

Anyway, hooked it up to the bench. Got a bunch of flickering. Damn. But, because I'm that type of guy, I shut down and restarted again. This time I got something different -- (again, this is on a composite monitor in mono mode). Bright white screen, darker grey screen, bright white.. back and forth like that a few times. Got the sense something was happening. Shut down a couple more times, started up. Each time the 'pattern' became more deliberate. Finally, on about the fourth try, the machine booted up. Booted right into Workbench and was fine there for 5 minutes while I played around.

Wanting to see if I could repeat this trick, I shut the system down again and tried. Back to alternating 'colours'. Tried a couple more times -- solid white screen. Did not change.

Anyone know what might cause this kind of behaviour? Why it got better with each successive attempt, finally starting, and then back to nothing again? Hoping I can figure out which part to focus on.

One other question -- as a soldering novice -- do I need to worry about the battery exploding when I'm trying to desolder it?

 

[falter]

Took the dremel to the CPU pins again, scraped more rust away... boom. System starts every time now.

For those that might freak about the 'dremel' -- this is the weak, handheld battery powered variety -- not the 10k+ RPM monster. I'm using just a very gentle wire brush.. barely strong enough to remove the caked on crap from the battery. I've used it successfully the clean the contacts on Intellivision cartridges.. doesn't seem to harm the PCB on those at all.

The florist wire seems to help too.. the paper wrapping around it allows you to get some alcohol deep into the socket. Not very strong, but apparently good enough! Now I just need to find out how to safely remove that battery, and she's good!

 

[Mr.Amiga500]

Took the dremel to the CPU pins again, scraped more rust away... boom. System starts every time now.

For those that might freak about the 'dremel' --

I freaked when I saw the word 'dremel'.

One other question -- as a soldering novice -- do I need to worry about the battery exploding when I'm trying to desolder it?

I don't think it'll explode (...unless it's been rigged to explode with C4 plastique by some anti-Amiga terrorist...). I've desoldered a few and they just pop out. On one A501, I didn't even bother carefully removing it, just clipped the pins and ripped that ****er out of there.

 

[deathshadow]

Next time, try and old tooth brush and some tarn-x. The classic silver cleaner does wonders on soiled pin connectors. It's how I keep one of my compaq's in working order.

Just be sure to rinse it and dry it throrough when done... and don't overdo the tarn-x since it will eat away ALL the metal given a chance.

 

[geoffm3]

I beleive that the earlier version ROMs didn't have the classic "Insert Disk" image so it didn't really doo much but tick the floppy drive every so often in hopes of finding a workbench disk to boot from.
Also, the A2000 keyboard and keyboard port are non-standard to that of a Commodore PC keyboard which is pretty much an AT connection.

This is not correct. All versions of Kickstart will prompt you to insert a floppy disk if one isn't present. KS 2.0+ added an insert disk animation (on a purple screen with a rainbow checkmark), but previous to that there was a static image of a hand holding a floppy disk on a white background.

 

[falter]

Just to update, I was noticing that after moving the 2000 around, the system would stop booting up and I'd have to go in, press firmly on the 68000 cpu and then it'd work again. Took out the CPU, cleaned it with toothbrush and alcohol... no dice. I don't know if the socket is worn/weak, but only by pressing the chip down with maximum force did it work.

So I hit on another idea.. I stripped some of that florist wire, cut small pieces off, put a piece in each of the suspect pin holes, and then pushed the CPU back in. Made a nice snug fit.. and, well, it works every time now. Must not be getting a good contact. I guess if it works I won't mess with it?

 

[Mr.Amiga500]

You could unsolder the socket, check it and solder it back in (or possibly replace it) - but that's a pain in the ass. If it works, I'd just leave it as it is.

You still might get random crashes when it heats up if the contact isn't good. But you're not going to be doing "mission critical" work (like landing on Mars with it), so an occasional crash won't be a big deal anyway.

 

[geoffm3]

Yep... Sounds like a bad socket. If you are good at desoldering I'd say go ahead and replace it. It is easy to tear up the plated through holes if you don't know what you're doing... So you could potentially make it worse if you botch it.

 

[Maverick1978]

Exactly what one of my A2000's stored at my parents' house is doing. Just did a quick search to confirm if my hazy memory was right and white=cpu failure... glad to see I've not completely lost it, and can put these tips to use (I've got some crud in one of the card slots, all around the battery, a completely corroded resister that I'll most likely need to replace, and obviously a CPU that I'll need to pull and clean)

Always fun, these vintage computers. As I've a few A2000's, I'm considering doing my first dishwasher run with this one if I run into trouble cleaning the sockets and slots... we'll see!