Possible the meter is in AC mode?

-----Original Message-----
From: owner-cbm-hackers@ling.gu.se [mailto:owner-cbm-hackers@ling.gu.se] On Behalf Of Philip Lord
Sent: Tuesday, August 11, 2009 8:31 AM
To: cbm-hackers@ling.gu.se
Subject: Re: Dead PET 2001

Update:
With the red leads detached from the capacitor I tested the voltages
again this evening.
Where as before I was getting over 8VDC, now I'm only getting 0.5VDC
on the cathode side of the diodes...very strange. I wish I knew what
was going on.
Maybe it's time to start by removing the diodes and testing them.

Phil


On Aug 10, 2009, at 3:14 PM, Philip Lord wrote:

> Thanks William,
> I did as you described.
> I removed the red wires from the capacitor and re-measured the
> voltages on either side of the two diodes.
> As before I get just over 8VAC on the anode side, but now I get
> just over 8VDC on the cathode side.
>
> I also tested the large capacitor using the ohm meter on my digital
> multimeter. It starts at Zero ohms and slowly rises.
>
> I apologies for my lack of electronic knowledge, and once again ask
> what I should try next? Hopefully we are narrowing down the problem.
>
> Cheers again
> Phil
>
>
>
> On Aug 10, 2009, at 1:07 PM, William Levak wrote:
>
>> On Sun, 9 Aug 2009, Philip Lord wrote:
>>
>>> oops...Please excuse my bad typing...what I mean to say was:
>>>
>>> Yes, I admit I was checking the voltage on the inside of the
>>> diodes with my multimeter (digital) set to AC. I just rechecked
>>> with it set to DC and the reading is still in the millivolt range.
>>> If the diodes are indeed the culprit, I find it strange that both
>>> diodes would be open?
>>> As for the J8 connecter, it basically looks new, no dirt, or
>>> burning at all.
>>
>> You said the fuse blew several times.  That would be enough to blow
>> the diodes.  Disconnect the red wires from the capacitor, and check
>> the voltages again.  Also check the capacitor for shorts.  If you
>> don't have a capacitor tester, you can use an ohm meter.  The
>> resistance should start at zero and build up.
>>
>>     Message was sent through the cbm-hackers mailing list
>
>
>      Message was sent through the cbm-hackers mailing list


       Message was sent through the cbm-hackers mailing list

--
This message has been scanned for viruses and dangerous content by IDSi's  MailScanner.



       Message was sent through the cbm-hackers mailing list