Re: HELP Lisa dead 150W Power Supply

From: Scharpf Thomas <thomas_at_email.domain.hidden>
Date: Fri, 28 Dec 2001 16:59:27 +0200

Hi Alex, James and Jim (alphabethical order)

all of you three a happy new year and your Lisa's, too. They 've been altered one more year in 2002, some of them will soon become adult! Thanks for Jim's hint to look at applefritter. I tried the link, which was suggested, but the server of applefritter was broken down, I'll try later again. Hope this schematic is the one of the 1,8 A power supply; seems to me that there are schematics which are really different from the real power-supply all over the web, and nobody cares; or nobody seems to repair the 1,8 A supply!
James: In far away future, a few years, when I'm out of work, I will draw a schematic of my three identical 1,8 A supplies. Then it will be more neccessary as today, cause you will get supplies very hardly than today. And we here in europe use only the 1,8 A supplies, cause of our 230 V powerline. Alex has the right idea, perhaps is it the total disjusted pot, have to try several adjustments, not very happy to do that on a opened, flying board with high voltage in it!
James' idea with the switch on the back panel isn't the way to do, cause the problems starts later in the heart of the supply long after the switch's point to interfere, but the suggestion with the perhaps corrupted overvoltage protection is really good. I'll try and keep you on track with any news - and of course my pidgin english-slang!


>Betreff: Re: HELP Lisa dead 150W Power Supply
>Datum: Fre, 28. Dez 2001 5:44 Uhr

> Hi Tom,
>>unfortunately I have to notice, that the pot R11 2k Ohm is not the cause for
>>that little problem I got with the power supply. As I described, I changed
>>the whole part platine 99P0108-000 (where this pot is mounted on) and I'm
>>still not able to start the unit.
> I think Alex was suggesting that the pot be adjusted. Some Lisas won't
> start up because the power supply has drifted over 5.1 volts, so the
> crow-bar (over-voltage protection) engages, and the Lisa won't start up. In
> that case, you hear the tell-tale "click, click, click" but I guess you
> don't hear that. Alex had this problem with his Lisa and the 1.2 Amp power
> supply, which is a bit different as you found.
>>I have the 150 V at the two 470 microfarad after the rectifier, so the unit
>>could work if it wouldn't be permanently inhibited.
> Perhaps you should check the safety interlock switch on the back panel?
> We have needed a schematic for this (1.8 Amp) power supply for a long
> time... perhaps you would be willing to draw it?
> Happy New Year!
> James

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Received on 2001-12-28 08:05:48

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