Power light flashing on an A600?

[hjalfi]

I have a new A600, my first Amiga. It was pretty ratty and I've spent a lot of time cleaning it and getting Kickstart 3.1.4 on it.

While it appears to be completely solid in normal use, I'm having trouble with the PCMCIA slot: I have a 2MB SRAM card which, if I boot it with it inserted, causes a crash on startup (Error 0x80000003, with an address somewhere in 0x006XXXXX, which I believe is the fast RAM address space). Setting it up with prepcard does appear to work and it's correctly detected.

The weird thing is that occasionally the system will start up properly with the card inserted. It'll then crash shortly afterwards. I've noticed that when it does this, when it crashes, I'll notice that the power light is changing brightness, from dim to bright and back again.

At least twice I've managed to get the system booting all the way to Workbench with the SRAM card installed, and I've managed to run a memory tester, and the fastram seems fine, and then I get annoyed at the floppy drive click and insert a disk to shut it up, and it instantly crashes... with the power light blinking.

At this point my electronics instincts are strongly suggesting there's a PSU issue. Does any of this seem at all familiar to anyone?

[Jpor]

Originally Posted by hjalfi

I have a new A600, my first Amiga. It was pretty ratty and I've spent a lot of time cleaning it and getting Kickstart 3.1.4 on it.

While it appears to be completely solid in normal use, I'm having trouble with the PCMCIA slot: I have a 2MB SRAM card which, if I boot it with it inserted, causes a crash on startup (Error 0x80000003, with an address somewhere in 0x006XXXXX, which I believe is the fast RAM address space). Setting it up with prepcard does appear to work and it's correctly detected.

The weird thing is that occasionally the system will start up properly with the card inserted. It'll then crash shortly afterwards. I've noticed that when it does this, when it crashes, I'll notice that the power light is changing brightness, from dim to bright and back again.

At least twice I've managed to get the system booting all the way to Workbench with the SRAM card installed, and I've managed to run a memory tester, and the fastram seems fine, and then I get annoyed at the floppy drive click and insert a disk to shut it up, and it instantly crashes... with the power light blinking.

At this point my electronics instincts are strongly suggesting there's a PSU issue. Does any of this seem at all familiar to anyone?

1).. Has the main board been recapped?
2).. All pins in the PCMCIA are straight?
3).. What PSU you are using?

For point 1, you may have bad caps (Or worse leaking)
For point 2, I have in the past managed to bend a couple of pins on my PCMCIA connector which in the outset allowed weird symptoms like you describe.
For Point 3, if using an original PSU then the PSU might be failing.

Basically you need to start doing some troubleshooting

[hjalfi]

(1) No, it's not been recapped --- all original. They look fine with no leaks, but we'll see.
(2) They all look fine. Also, the card does sometimes work, and I'd expect bent pins to cause permanent failure.
(3) I've got the original PSU, and when I measure the voltage under load, I get 12.0V and... 4.3V? Ohhh.

The voltage actually varies from about 4.6V to 4.3V depending how warm things are. I'm going to guess that the card requires a higher voltage than the Amiga itself, and is right on the verge of working; when I stick a disk in the drive and the motor starts, the voltage drops a bit, and 2/3 of the Amiga's memory map stops responding.

I've had a look inside the PSU. All the caps there look fine, non-bulgy, non-leaking, but the PCB itself is warped and crumbling rather at the corners. (It does look like it's made from the finest cardboard.) It probably just wants recapping, which would be easy had I the parts, which I don't. Given that I don't like playing with mains voltage stuff I might just get a new PSU.

[Matt_H]

Power light blinking is the normal indication of a crash. Nothing unusual about that.

Obviously we want to figure out why it’s crashing.
How is the stability of the system without the PCMCIA card?

In addition to the ideas Jpor mentioned (the PSU angle sounds promising), there’s also the possibility that the SRAM card is dead/damaged. You say the memory checks out, but obviously you’re only able to test the memory on the occasions when the system boots. If it’s an intermittent failure, the fault might not show up in your tests.

Side note: once you get the system stable there are numerous software tools to silence the floppy drive click.

[Jpor]

“ (2) They all look fine. Also, the card does sometimes work, and I'd expect bent pins to cause permanent failure.”

I had 2 pins bent back on the right side which caused my Squirrell SCSI card to be seen but not working right. Once I carefully bent them back all went good again ????

You are best trying another PSU to make sure that’s not the cause. Unfortunately it’s Logical troubleshooting you need to do here. So back to basics then work your way from there. The Motherboard doesn’t sound great though ?? Don’t forget these things are 30 years old ??

Oh just to add. Flashing power light as mentioned is an error. In some cases there maybe a pattern sequence which you can look up Otto give you an idea. Google search will give you the answers.

[whaka]

Originally Posted by hjalfi

The voltage actually varies from about 4.6V to 4.3V depending how warm things are.

it's low, very low. where do you pick voltages ?

[hjalfi]

I should clarify that the power light is not _blinking_ on/off. It's changing from bright to dim. I've seen references that the brightness of the LED is actually under software control but the same bit that controls the brightness also controls the audio low-pass filter, so if things are fiddling with that it can cause the LED brightness to change; but I have no idea why it would be doing this.

I think a replacement PSU is my best bet. It's probably mendable, but I'm not comfortable working on it.

I gather that Amiga PSUs provide +12, -12 and +5V. What are the +12 and -12 for? Can the system run without -12 (which is usually only needed for RS232)? I ask because I have a bench power supply which can provide +12 and +5, but not -12.

[ajk]

-12V may also be used by some op-amps in the audio circuit, but not having it shouldn't stop you from booting.

[Lisko]

The power led brightness switching is normal in crashes and reboots. It really reminds me the problem I had with an A600. Crashing during warm reboots or as soon as I inserted floppies in and it was a psu problem. The psu was new bought from ebay and when I tried another one, from eBay too but another seller, all the problems gone away.