Is my A1200 dead?

[ifrit05]

Hey all. I had an urge to pull out my A1200 the other day. I bought a TF1230 and started to install 3.2 in WinUAE and installed the ROMS.


Put everything together today and now it wont output anything.



I have an Indivision so I thought maybe it was a wrong config from an old install so I pulled out my PVM and hooked the A1200 up to it using composite (can't find my RGB cable). The PVM gets a sync signal (says PAL on screen) but it still has a blank screen.


Here's some more insights:

• Power seems fine, but floppy does not click or seek like I remember it should
• CF adapter does not show activity (V.H2)
• Chips are getting warm but not too hot
• CAPS Lock still works, as well as Ctrl+A+A
• L+RMB does nothing on boot
• Hi ROM is on bottom, Lo on top. 1 set of pins empty to the left.

I lost the LED board a long time ago so I cannot tell what it's doing. I can't remember the board not working when I put it on the shelf a couple of years ago.


Any ideas?

[aeberbach]

Tried the old ROMs again? Or a DiagROM set?

[ifrit05]

Yeah, same with the old 3.1 roms. I didn't try to boot it before the upgrades so I'm not sure if it was working before hand.

What can I do with DiagROMS?

[aeberbach]

DiagROM is a ROM that contains a series of tests that can narrow down problems. But if you get no boot at all, unlikely to help.

[lilwshu]

Remove all non standard hardware and test again, if it works add them back one at a time until it breaks again.

[Jpor]

Shame you don’t have the LEDs. You may have an issue that could be read from a flashing green power LED.

I take it you’ve got no leaking caps? Has the mainboard been recapped?

[ifrit05]

Originally Posted by aeberbach

DiagROM is a ROM that contains a series of tests that can narrow down problems. But if you get no boot at all, unlikely to help.

Hmm, OK. I watched a few videos and they seem really handy. One person had the same symptoms as me and the DiagROMs ran. I'll look into getting a set.

Originally Posted by lilwshu

Remove all non standard hardware and test again, if it works add them back one at a time until it breaks again.

Yep, right now it's stripped down to the bare board plus KS.

Originally Posted by Jpor

Shame you don’t have the LEDs. You may have an issue that could be read from a flashing green power LED.

I take it you’ve got no leaking caps? Has the mainboard been recapped?

I bough a replacement set a long time ago but never had the chance to install them, and lost them after a move. I think I'll buy another set not sure though if it's a waste if I can't get this working.



Caps seem fine, I would send the board out to someone to recap but I can't find anyone near me (Michigan, USA).

EDIT: Just measured voltage on the power connector and was getting -18 (!) on the -12v pin. That kinda seems outta spec to me... You think this could of damaged any chips/components? I have to work in a bit but I think I'm gonna bust open the PSU and check it later.

[demolition]

Originally Posted by ifrit05

EDIT: Just measured voltage on the power connector and was getting -18 (!) on the -12v pin. That kinda seems outta spec to me... You think this could of damaged any chips/components? I have to work in a bit but I think I'm gonna bust open the PSU and check it later.

If that is unloaded then it might be fine. The two positive rails are the important ones.

[ifrit05]

Ok, under load I'm getting ~+12.03v and 4.98-5.03v. So the rails seem fine. I just tried cleaning out the ROM sockets as well but still getting nothing. Anyone have a good test point for -12?

EDIT: Looking at amigapcb.org I found a better spot for -12v, and am getting ~-12.10, so all voltage rails are actually fine under load. I ordered a set of DiagROMS so hopefully those will help me narrow down the issue. If not, I am thinking about getting a logic probe to check reset lines and what not.

[Tandrews-ny]

I am in NY and run Amiga of Rochester. I can recap it for you as well as ultrasonic it. We are a trusted member of the community as well. DM me

[aeberbach]

I don't believe -12 is going to be a problem - from memory it's only for the opamp and possibly serial comms? Also if unloaded, -18V is not impossible.

[ifrit05]

OK, some progress. Installed the DiagROMS and it boots!!! Well, at least a little. It gets to "Doing ROM Checksumtest" and halts after the first green line.

At lease I know Lisa/Alice are still kicking and the CPU is at least doing something. Any ideas where to look next? I ordered a logic probe so hopefully I can look at high/low signals in a couple of days.

MAJOR EDIT:

Woah! On a whim I took my older ACA1221 and installed it to see what would happen, AND IT BOOTED TO THE DIAGROM MENU!!!

I'm kinda stumped though, why would the internal 020 and my new TF1230 not boot, but my old ACA1221 does??? Hmmmmm... I'm really confused.

Anyways, pretty much everything checks as good (chipmem, IRQs, CIAs, audio, DF0, IDE, Graphics, etc).

[utri007]

Accelerator has it's own capasitor, wich helps Amiga 1200 also. I would say that this is 99% problem is capasitors.

[Jpor]

Originally Posted by ifrit05

OK, some progress. Installed the DiagROMS and it boots!!! Well, at least a little. It gets to "Doing ROM Checksumtest" and halts after the first green line.

At lease I know Lisa/Alice are still kicking and the CPU is at least doing something. Any ideas where to look next? I ordered a logic probe so hopefully I can look at high/low signals in a couple of days.

MAJOR EDIT:

Woah! On a whim I took my older ACA1221 and installed it to see what would happen, AND IT BOOTED TO THE DIAGROM MENU!!!

I'm kinda stumped though, why would the internal 020 and my new TF1230 not boot, but my old ACA1221 does??? Hmmmmm... I'm really confused.

Anyways, pretty much everything checks as good (chipmem, IRQs, CIAs, audio, DF0, IDE, Graphics, etc).

Which revision is your A1200 motherboard? Only asking as it could also be a timing issue. 123c and 125c caps still in place?

[ifrit05]

Originally Posted by Jpor

Which revision is your A1200 motherboard? Only asking as it could also be a timing issue. 123c and 125c caps still in place?

1D.4, and yes, 123/5C are present. I'll try to find a tip that's small enough in my drawer of solder stuff and report back. Weird though as the stock CPU doesn't play nice either with diagROM (ACA1221 is a 020, but diagROM reports it as a ec020 in the menu though).

EDIT: No change.

[aeberbach]

Does it boot with 1230 installed but 030 jumper disabled?

If not recapped that would be the next step for me. If you sniff the board does it smell at all fishy? Even if they look fine they can have a much lower capacitance than they should after decades.

[Jpor]

Originally Posted by ifrit05

1D.4, and yes, 123/5C are present. I'll try to find a tip that's small enough in my drawer of solder stuff and report back. Weird though as the stock CPU doesn't play nice either with diagROM (ACA1221 is a 020, but diagROM reports it as a ec020 in the menu though).

EDIT: No change.

The aca1221 I believe is an EC 020. I take it there is a separate FPU?

[ifrit05]

Originally Posted by aeberbach

Does it boot with 1230 installed but 030 jumper disabled?

If not recapped that would be the next step for me. If you sniff the board does it smell at all fishy? Even if they look fine they can have a much lower capacitance than they should after decades.

Nope, only with the ACA1221. Tried that while doing the process of elimination. xD


Board does not smell "fishy", I would notice right away as I absolutely DESPISE the smell and taste of fish. Just smells of old musty 80s/90s electronics.

Originally Posted by Jpor

The aca1221 I believe is an EC 020. I take it there is a separate FPU?

Nope, MC68020-16. http://wiki.icomp.de/wiki/ACA1221


_____


Poking around with my new logic probe (wow, why have I never gotten one of these before now?), RESET goes High>Low>High on boot, as it should. HALT stays high even when diagROM gets stuck.


I think I will try to send this out to get recapped before trying anything else... Never sent anything trough the mail before so this will be an experience.