Anyone have an idea how long can A500 last (or vintage comps in general)

[trogdor]

Just curious from a technical standpoint... Do silicon chips and other components on the MB have some sort of decay time. In other words if I stocked up on a couple of working A500s and kept them unused how likely would they be to power up ok years from or how good their custom chips etc would be to use for spare parts.

[meega]

Capacitors are prime failure points, other than that the thing should last for decades. LEDs will eventually burn out, as will voltage regulating/dumping resistors, springs in the keyboard will weaken, sooner or later the floppy drive will fail, but they are generally very robust. Please correct me if I'm wrong on this point - the custom chips in an A500 are NOT eprom or such, they are "genuine" silicon and can be expected to survive until punished by truly excessive quantities of radiation (nuclear strike nearby) or a random cosmic ray from a stellar event just happens to punch a hole clean through the substrate...

It also makes no real difference whether you use it or not, however powering up/down is the major cause of stresses to the system (thermal shock), so there is little to be gained from trying it out now and again "just to check it's still ok" as that is when there is the greatest likelihood of damage/failure.

I don't know the MTBF of an entire A500 though...

[Homer]

Capacitors seem to be the main problem, as they dry out over time. You would only find they had dried out when the mobo did odd things, which may be too late for sensitive components. Normally they will bulge when they dry out, but on a stored mobo may not. The only other problem could be E(E?)proms (Do we use them as ROMs ?) that may have to be reprogrammed every X years.

[save2600]

As far as I can tell, chips and other silicon based components (ie: transistors) seem to last indefinitely - assuming other components such as the power supply maintain proper voltage to 'em. Capacitors and batteries are the beasties you've got to keep an eye on. When caps blow, they usually take out other sensitive components near the area. And if they or a battery leaks, the acid will eat up circuit board traces.

[Homer]

Hi meega,

I think the MTBF for an A500 has long passed, especially if it was calculated with 217f (I don't want to say "Mil. Standard Handbook" as everyone will start making Doomy references again).

[trogdor]

Thanks for all the responses.
So from what you guys are saying it sounds like you could maintain the system for quite a while (I assume the appropariate capacitors and transistors which seem to be the main points of failure can always be purchased at radioshack and such, right)

[Damion]

Thanks for all the responses.
So from what you guys are saying it sounds like you could maintain the system for quite a while (I assume the appropariate capacitors and transistors which seem to be the main points of failure can always be purchased at radioshack and such, right)

Caps are probably best purchased from an electronics store like DigiKey, Radio Shack parts are usually not the best quality available. SMT radial caps in A600/A1200/A4000 were junk, thru-hole caps used in the earlier models weren't all that bad (Elna, SHOEI, Nichicon), but will still need replacing eventually.

[orb85750]

As far as I can tell, chips and other silicon based components (ie: transistors) seem to last indefinitely - assuming other components such as the power supply maintain proper voltage to 'em. Capacitors and batteries are the beasties you've got to keep an eye on. When caps blow, they usually take out other sensitive components near the area. And if they or a battery leaks, the acid will eat up circuit board traces.

Are there any warning signs with respect to the capacitors not operating correctly before they go out completely?  I suppose they're used in many areas, so maybe there's no simple answer.  Which type of caps are most likely to fail -- anyone know?

[Damion]

IMHO, if you're going through the trouble of removing the motherboard to replace the caps, might as well do them all. Symptoms usually begin with general instability... lockups, reboots, etc. (Worst are A600/A1200/A4000.) Often the problems don't show up until an accelerator or other expansions are connected.