Re: Dead PET 2001

Re: Dead PET 2001

From: William Levak <wlevak_at_sdf.lonestar.org>
Date: Sun, 9 Aug 2009 00:45:21 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.0908090037330.23009@sdf.lonestar.org>
Sorry.  Wrong wire.  The two red wires are the output of the diodes and 
should be about 20V.  The other terminal is ground as you have described.

It would appear that cr1, cr2, and cr3 are open or you would have some 
voltage.  This is however DC, although with a large ripple.  If you are 
using a digital meter you may not see anything on the AC range.  Try DC.

Also check the obvious,  are the pins for the plug clean and making good 
contact?


On Sat, 8 Aug 2009, Philip Lord wrote:

> Firstly, I'm not sure my wiring is correct, so I just want to quickly 
> confirm.
>
> I have three black wires connected to one terminal of the capacitor:
> - one grounded to the chassis
> - one from terminal 5 of the transformer
> - one to pin 3 of the J8 connector
>
> I also have two red wires connected to the other terminal of the capacitor:
> - one to pin 2 of J8 connector
> - one to pin 4 of J8 connector
>
> Is this correct???
>
> Thanks
> Phil
>
>
> On Aug 8, 2009, at 1:40 PM, William Levak wrote:
>
>> On Fri, 7 Aug 2009, Philip Lord wrote:
>> 
>>> Hi again,
>>> Sorry it took me so long to get around to measuring the voltages off my 
>>> machine...I hope you are all still here.
>>> So here we go (All voltages are approximates):
>>> 
>>> Between the two transformer tabs that go to the monitor - 16VAC
>>> Pin1 - 8VAC
>>> Pin2 - 0V
>>> Pin4 - 0V
>>> Pin5 - 8VAC
>>> 
>>> I also took measurements on the 7805's and as they are tied to pin2, there 
>>> is no voltage read. 0V.
>>> Pin2 and Pin4 both come from the same place off the huge blue capacitor, 
>>> so maybe I can assume this is dead?
>>> Is there anyway to test this capacitor?
>>> 
>>> Any further advice would be greatly appreciated.
>> 
>> The capacitor has two terminals; two wires from J8 on one terminal, and one 
>> wire from the transformer on the other.
>> 
>> Disconnect the wire from the transformer.  Measure from that wire to 
>> ground.  If it is zero, the transformer is open.  If not, the capacitor is 
>> open.
>>
>>     Message was sent through the cbm-hackers mailing list
>
>
>     Message was sent through the cbm-hackers mailing list

wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

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Received on 2009-08-09 03:01:08

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