Re: Lisa 1.8A Power Supply Problem

Hi Rudolf,

it's definitely the Cap behind the primary rectifier. It's very likely that it has been drying, so if it gets powered up a part of the electrical energy can't be stored by the cap and will be transformed in thermal energy with the conclusion, that the cap will heat up a little.
Pay attention: This status is short before the cap will "explode". You should not use the power-supply further more until you replaced that cap!
As you know, I am a guy, who repairs Lisas with original parts so you get this advice: It's also possible to get this cap to work again; you only have to carefully open it by removing the rubber at the bottom, then fill in some caps-oil (I don't know the english expression for that fluid) and then the cap should work properly again. Be careful, sometimes the cap-making factories used Biphenyle, which can cause skin cancer.

P.S. If it is not the circuitbreaker but the live-saving unit, which shuts off, then it should be the small cap (mostly 0,047 up to 0,22 mikrofarad) short after the power-plug.

There are some other - but not very likely - part, which could cause such a fault, but first try this ones as written above.

Tom, from Bavaria - the country of the Alps (as Austria, too), the marverllous castles of Koenig Ludwig and the original Octoberfest in Munich

Am 02.07.2014 um 22:30 schrieb Rudolf Brandstötter:

> Hi guys,
>
> I have 2 1.8A PS with the same symphtom: when the PS warms up after
> 5-6min it shuts down. It looks like when it gets warm it does not
> work anymore. The circuit breaker in my house shuts down the power
> in the room. When the PS cools down after 1h it works again a few
> minutes. Do you know some typical suspects where I could look? I
> have a working PS as reference but I'm not really experienced in
> repairing PS. Thanks for any hint where to look!
>
> Rudi
>
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