Re: Dead PET 2001

From: Philip Lord <>
Date: Mon, 17 Aug 2009 23:05:44 +0900
Message-id: <>
I have replaced nearly all the power circuit components:

4 x  7805 voltage regulators
3 x 1.0uf tant Caps (C11 thu C13)
4x 16v 47uf Caps (Actually replaced with 25v 47uf)
1 x CR3 Diode (replaced with 3004)

...and nothing has changed. I still reading about .31 MVAC on the  
cathode of CR3, and the machine is still dead as a dead thing!!!

The only things i didn't replace was CR1 and CR2 and C51 and C50

So frustrating! Not sure what to do now :-(


On Aug 17, 2009, at 1:12 AM, Nate Lawson wrote:

> I agree. I went there a few times in 2005-2006 and it wasn't the same.
> Raw components were hard to find, and the sleek consumer electronics
> stuff had moved to mega stores like Bic Camera in other areas of  
> Tokyo. Sad.
> -Nate
> Philip Lord wrote:
>> Yes..I'm quite privileged to have such an electronic mecca just  
>> 30mins
>> away.
>> Unfortunately Akihabara as I once knew it is dead (or at least it's  
>> in
>> it's death throws). Gone are most of the small 'nook and cranny'  
>> stores
>> where you could rummage for hours and find all sorts of interesting
>> junk. It's now populated by Otaku anime and Cos-play shops and multi
>> floor mega stores.
>> :-(
>> On Aug 13, 2009, at 10:54 AM, Bil Herd wrote:
>>> All us old Commodore types used to hit Akihabara whenever we were in
>>> Tokyo.  Rumor has it that CBM-J would occasionally run down there to
>>> buy a few scoops of 7407's to keep production flowin.
>>> Bil
>>> -----Original Message-----
>>> From:
>>> [] On Behalf Of Philip Lord
>>> Sent: Wednesday, August 12, 2009 9:37 PM
>>> To:
>>> Subject: Re: Dead PET 2001
>>> Great!
>>> I'm going to race into Akihabara this lunch time and get all the  
>>> CR3,
>>> C11, C12, C13, VR3, VR4, VR5, and VR6 parts.
>>> Hopefully I'll have time this weekend to attack the board starting
>>> with the CR3 diode.
>>> Thanks again for your help, and I'll let you know how I go.
>>> Cheers
>>> Phil
>>> On Aug 12, 2009, at 2:40 PM, William Levak wrote:
>>>> On Wed, 12 Aug 2009, Philip Lord wrote:
>>>>> I was just about to say that Pin2 is connected to one of the red
>>>>> leads that goes to the capacitor, therefore with the red leads
>>>>> disconnected there would be 0V at pin2, but instead I decided to
>>>>> test it anyway...I got 0.5VDC!!!! Then I realized what is  
>>>>> happening:
>>>>> When I disconnect the two red leads from the capacitor, but still
>>>>> have the two leads connected together the voltage reads 0.5VDC at
>>>>> pin4 and pin2. When the red leads are disconnected from the
>>>>> capacitor, and also disconnected from each other I get just over
>>>>> 8VDC at pin4, and 0VDC at pin2 (as expected).
>>>>> for a glow from the monitor filliment, I had to turn off all
>>>>> the lights to see it, but yes indeed, there is a glow.
>>>> This is good!  This means that the transformer, the big filter
>>>> capacitor, and CR1 and CR2 are all good.
>>>> The problem is localized to CR3, C11, C12, C13, VR3, VR4, VR5, or
>>>> VR6. One or more of those is bad.  The prime suspect is CR3.  If it
>>>> was working, you should see 8V on pin 2.  These diodes get hot when
>>>> operating. If it is cold, it is probably open.
>>>> Now would be a good time to remove the circuit board.  Small  
>>>> things,
>>>> like paper clips, sometimes get trapped under there, and short
>>>> things out.
>>>> The screw on the left rear of the board is a ground to the chasis.
>>>> The others should not contact any circuits.
>>>> SDF Public Access UNIX System -
>>>>    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
>>      Message was sent through the cbm-hackers mailing list
> -- 
> Nate
>       Message was sent through the cbm-hackers mailing list

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Received on 2009-08-17 08:00:08

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