Re: Non-working Lisa PSU

From: macmoni <macmoni_at_email.domain.hidden>
Date: Fri, 4 Nov 2005 20:59:48 +0100

Hi Philip

you wrote about your problem with the PSU:
> When it arrived in Japan (100v vs US120v), It worked. Sporadically and
> briefly.
> Now when I use the 1.2 amp PSU and push the power button, there is a
> chirp. Actually 2 chirps, one when you push in, and the other when you
> release the power button. Chirp Chirp!
This is a very common error. The sound comes from the primary regulation, which tries to cut the DC power with several kHz to feed the transformer-coil with energy.

The main errors are:
Too high current consumption of the device(s) which are connected to the PSU
Very likely, if we remember, that you changed the PSU with the 1.8 type and got identical error-results

or

an internal problem of the PSU:
very very often the Dual-Diode, which rectifies the secondary +5V part or
often one of the diodes, which rectifies the secondary +12V or -12V or -5V
or
sometimes a soon dying transistor on the primary-side (one of two of the pull or push circuit)
or
very rare but not least a dry cap at +5V, +12V, -5V or -12V (usually 2200 microfarad 16V)

All errors are listed in the order you should check it. The most likely ones first.
BUT do that only if you are familiar with electronic components. DANGER risk of life !
And don't do that work alone - in order somebody can help you or call a medic, if you tried what will happen if several hundreds of volts bite you :-)
So better go to a radio or TV-expert, he will manage that very easy

greetings TOM from Bavaria, the center of europe, the marvellous castles of Koenig Ludwig e.g. Neuschwanstein and last but not least the original Oktoberfest !

-- 
LisaList is sponsored by <http://lowendmac.com/> and...

Shop buy.com and save. <http://lowendmac.com/ad/buy.com.html>

      Support Low End Mac <http://lowendmac.com/lists/support.html>

LisaList info:          <http://lowendmac.com/lists/lisa.html>
  --> AOL users, remove "mailto:"
Send list messages to:  <mailto:lisalist_at_email.domain.hidden>
To unsubscribe, email:  <mailto:lisalist-off_at_email.domain.hidden>
For digest mode, email: <mailto:lisalist-digest_at_email.domain.hidden>
Subscription questions: <mailto:low_end_mac_at_email.domain.hidden>
Archive: <http://www.mail-archive.com/lisalist%40mail.maclaunch.com/>

iPod Accessories for Less
at 1-800-iPOD.COM
Fast Delivery, Low Price, Good Deal
www.1800ipod.com

Received on 2005-11-04 12:03:24