A1200 Stability Issues

[darkwave]

Over the last couple of years my main Amiga 1200 has been far less stable than I would like. A few years ago I fitted an 80MHz Blizzard 1260 (from the fantastic Stachu), a 16Gb CF hard drive, an Indivision Mk1 and squeezed a laptop CD drive into the case. This worked fairly well for a while but after moving house things have besome a little unstable and haven't really taken the time to figure out why, mainly because I don't have any time.

This is kind of annoying because I haven't really been able to sufficiently enjoy this wonderful setup. So over the next few weeks, if I can find the time I'll be putting the system through it's paces in terms of both hardware and software to see if I can pinpoint the random crashes and general instability.

I'll be documenting everything I do here so that some of you knowledgable lot may help me and it'll hopefully be of some use to others.

[darkwave]

First thing was to remove all hardware attached to the motherboard. So, with only the Indivision AGA still attached and booting into Workbench on floppy, the system is still unstable.

I get random crashes, usually consisting of the system completely freezing. This could be minutes or seconds after the system has booted. Right now, the system is refusing to boot at all.

I'll try removing the Indivision to see if that is causing any problems (although I doubt it), but failing that, does anybody have any thoughts?

[demolition]

Could be some bad memory? Or a bad power supply (5V too low).

Edit: Or bad capacitors. Have they been replaced?

[darkwave]

The capacitors have not been replaced. They all look fine, but I gather that doesn't necessarily mean they are working ok.

Power supply should be ok. I'm running off a Goliath 200W PSU, I can check with one of my other PSU's to make sure.

So, what's the best, most definitive way to check for bad capacitors?

[demolition]

Replace them. If it improves, you know the old ones were bad.

But seriously, there's no easy way to test if the capacitors are still good enough, so replacing them would be my first step in troubleshooting a problem like yours.

[Ed Raket]

Originally Posted by darkwave

The capacitors have not been replaced. They all look fine, but I gather that doesn't necessarily mean they are working ok.

Power supply should be ok. I'm running off a Goliath 200W PSU, I can check with one of my other PSU's to make sure.

So, what's the best, most definitive way to check for bad capacitors?

Even if you mesure them "cold" the may seem ok, but under workload they can still collapse... dont guess, just replace them

[tesla]

Ed is right. The caps can be tested, but to buy the equipment would cost more than you'd be willing to put out for one-time use.

I have an o-scope, and several multimeters. They are some of the equipment used to check a power supply. Just because your psu is 200 watts, doesn't mean it is right, or still working correctly. Removing items that are not needed to boot the board is a first step. If you have a friend with a multimeter, you two could measure voltage sag under load, and see if it is within range. With a scope you could measure ac ripple. Too much ripple could mean bad caps, they filter the DC after it is converted from AC. If you can get one, a friends power supply could be used as a quick tester, if that fixes it, scrap the old one, (It's probably not worth repairing).

BTW, when electrolytic caps fail, (the round cylindrical ones being discussed here), often bulge, leak, or "explode" out the top or bottom. When I worked for a power supply company, we used to (as a joke) take the large ones and connect them to 120 volts. the result is they would short, overheat, and expel the liquid inside in a matter of seconds. The result? a mini-mushroom cloud. (that is what it looked like).

BTW, after all of this, you might have a unstable or overheating chip somewhere.

Heat - When we need to remove heat we should to not forget about heat pipes (unknown in Amiga time, nowadays quite common especially for mobile PC computers - old notebooks however they should be quite modern) 642-874 they can be bought for bargain on ebay or junkyard and they are very good source for dense, efficient cooling solutions especially for small Amiga computers.

[Sandro]

Originally Posted by darkwave

Over the last couple of years my main Amiga 1200 has been far less stable than I would like. A few years ago I fitted an 80MHz Blizzard 1260 (from the fantastic Stachu), a 16Gb CF hard drive, an Indivision Mk1 and squeezed a laptop CD drive into the case. This worked fairly well for a while but after moving house things have besome a little unstable and haven't really taken the time to figure out why, mainly because I don't have any time.

This is kind of annoying because I haven't really been able to sufficiently enjoy this wonderful setup. So over the next few weeks, if I can find the time I'll be putting the system through it's paces in terms of both hardware and software to see if I can pinpoint the random crashes and general instability.

I'll be documenting everything I do here so that some of you knowledgable lot may help me and it'll hopefully be of some use to others.

clean the blizzard 1260 connector with alcohol

[bdb]

(This thread was from 2013 and just resurrected with concerns over heat pipes as a solution for instability issues)