Re: My sick 2/10 from Quanda Computing on 2004-11-26 (lisalist1)

From: Quanda Computing <quanda_computing_at_email.domain.hidden>
Date: Fri, 26 Nov 2004 00:30:38 -0500

I removed the drive cage. Thwump got a little louder. I removed the RAM cards. Thwump got a little louder again. Removed the CPU card. Thwump got even louder. Removed the entire card cage. Nothing happened when I pressed the power button. I would assume this is normal because the power button connects to the card cage :P

I made a recording of the sound. http://users.tc3net.com/gperkins/Thwump.wav You can hear the thwump followed by the click of the switch.

I also noticed that right after the thwump from the speaker I could hear what sounded like the high voltage PSU in a monitor when you turn it off, that kind of quick high pitched sqweak. So perhaps there is a short somewhere else? I had taken Lisa mostly apart a while ago, and didn't see anything that looked out of place. I also turned her upside down and shook her really hard and no bits of metal fell out, so I'm gunna say no paperclips are lodged down in there.

I will try checking voltages next. I would like to check at the line supplying the Widget, and if possible, right at the power supply. Which lead(s) are the power leads in the Widget connector? Is there any way I can 'trick' the power supply into turning on when I have it out of the system, so that I can measure voltages right at the edge connector? Looking at the schematic David provided, it looks like one of the connectors is +300v! Perhaps checking the PSU out of the system isn't that good of an idea...

Thanks again!

-Jason

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From left to right 8 connectors with 7 cables are:
X-Mozilla-Status: 0001
X-Mozilla-Status2: 00000000
X-Mozilla-Keys:                                                                                 
(+5V) (+12V) () (Ground) (+12V) () (empty) (-12V)



> and if possible, right at the power supply.


Plese do this first, and mail again. The rest of the proceedure is very
complex compared to the measuring work you have to do now



> Is there any way I can 'trick' the power supply into turning on ...


Yes there is a "trick". But first make some measures.



> ... it looks like one of the connectors is +300v!


Yes, there is high voltage. I mailed you in my last mail, didn't I do so?
If you really want to go on (after you made your measures), then you will
have to confirm, that you are familiar with electrical safety rules and
perhaps there is someone (an radio- or tv-mechanic), who will do that for
you. There's risk: danger of life


... but first do some measures :-))

greetings TOM from bavaria


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Received on 2004-11-25 21:32:08