*** M E M O R U M ***

Does the power supply need to be recapped? I guess from the weight of it it is a simple transformer / rectifier affair. The reason I ask is I saw some posts in my travels that talked about power block meltdown! and I don't want it to happen to mine. Any preventative measures I can take?

Cheers

JonB

Keep the MTX & PSU in the fridge?

As you have guessed, the "PSU" is just a multi-tapped step down transformer.

From what I have seen, I think you're right - I have heard of a number overheating/failing.
Fingers crossed, mine have been OK, but I did make the mistake of leaving one on overnight once, by the morning, I could have fried an egg on it, though, thankfully, the case had not melted.

I guess that's the obvious thing - make sure the PSU is turned off after use and make sure that it is well ventillated, i.e., has free air circulation around it when it's on.

No other magic tips I'm afraid.

Though it won't affect the PSU itself, others have replaced the caps on the motherboard

http://primrosebank.net/computers/mtx/r ... eplace.htm

which would seem like a wise precaution, although I have not done it myself

regards
Dave

As Dave says, the external PSU is just a transformer - there are no capacitors in it.

As with all transformers, you must allow plenty of airflow around it. Also put it on a hard surface.

With a working MTX with no expansions, the external PSU should be okay. But keep in mind that I suspect it is working only just within it's rating. So if you have some power hunger expansions / add-ons, switch off and allow to cool down every 3 to 4 hours if possible.

Having said that, transformers in general are normally very reliable. And I have not had any problems with mine

The rectifiers, smoothing/filter capacitors and regulation circuitry are all in the MTX itself.
It may be an idea to renew the two main smoothing/filter capacitors, but the ones originally fitted appear to have a good lifespan.
Use one 4700uF 25V 105C radial and one 4700uF 25V axial (if you can get a 105C great, if not use a good quality 85C type).

I have found dry solder joints on these capacitors in the past, but have not renewed many.

Oh and if you remove the MTX board from the case, don't operate it for too long, as the small heat sink that the power transistor and voltage regulators are mounted on gets too hot - in normal use it presses against the MTX metal case to help get rid of the heat.

Mark