Re: Pet64 DOA

Well, it seems like the power might be ok after all, so I broke out my  
logic probe...it's a cheap one but has helped me fix many simple  
issues over the years.

The first think I noticed after probing around is that I'm not getting  
any pulsing (or at least that what the probe indicates), lines are  
either high, or low, or nothing, but there doesn't seem to be any  
pulsing at all!

So I guess I should look at the timing circuit or Xtal? Anywhere else?  
Not sure how to test is a Xtal is working as I don't think my probe  
can do that.

Cheers

Phil



On Dec 9, 2010, at 2:10 PM, Philip Lord wrote:

> Great...so then maybe my power voltages are all good? Should I find  
> some test point on the C64 motherboard and get some voltages there?  
> Any idea what I should check next?
>
> Re-PET board. Ethan has been working very hard, and he believes he  
> has fixed both boards now (but can not test loading as his C2N data  
> cassette deck is in need of a new drive belt). Last I heard  
> everything is almost packed up and ready to ship. It would be great  
> to get the boards back before years end, as I have been building a  
> number of add-ons in anticipation for their arrival and I'm excited  
> to try everything out.
> I have built one of Nicolas Welte's Ram/Rom boards which will  
> hopefully take my ram to 32k and allow me to use various basics (V1  
> through V4) and not have to worry about failing RAM in the future. I  
> have also built a number of adaptor boards to replace the video ram  
> and character ROM. Finally I got myself a C2N232 as I don't know how  
> reliable the original cassette drive is. I'm hoping to 'fail proof'  
> this machine for at least another 30 years ;-)
>
>
>
>
> On Dec 9, 2010, at 1:44 PM, MikeS wrote:
>
>> 5V DC and 9V AC - sounds OK.
>>
>> Did you finally get your PET boards back and working?
>>
>> m
>>
>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com>
>> To: <cbm-hackers@musoftware.de>
>> Sent: Wednesday, December 08, 2010 10:41 PM
>> Subject: Re: Pet64 DOA
>>
>>
>>> 8.91 vac
>>> On Dec 9, 2010, at 12:31 PM, MikeS wrote:
>>>> Hi Philip!
>>>>
>>>> What AC voltage do you get between the two white wires?
>>>>
>>>> mike
>>>>
>>>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com 
>>>> >
>>>> To: <cbm-hackers@musoftware.de>
>>>> Sent: Wednesday, December 08, 2010 10:07 PM
>>>> Subject: Re: Pet64 DOA
>>>>
>>>>
>>>>> Sorry maybe I should have tested the some lines using AC not DC.
>>>>> So here again is what I believe I have (suing the black line as  
>>>>> GND):
>>>>> White: - 5.8 vac
>>>>> (KEY)
>>>>> White - 0.5 vac
>>>>> Black (I'm guessing this is ground)
>>>>> Red - 4.98 vdc
>>>>> Of course I could just be confused as I've never owned a C64  
>>>>> before.
>>>>> Looking at schematics seems maybe the two white lines could/ 
>>>>> should  be  9vac, and maybe the red line should be 5 vdc???
>>>>> Phil
>>>>> On Dec 9, 2010, at 11:16 AM, Philip Lord wrote:
>>>>>> I just got myself a PET64 from Yahoo Auction Japan. Quite a  
>>>>>> rare   machine I hear, so I'm not sure how one ended up in  
>>>>>> Japan. I got  if  for a decent price as I don't think the  
>>>>>> Japanese knew exactly  what  it was.
>>>>>>
>>>>>> Anyway, It arrived the other day, after a quick internal   
>>>>>> inspection,  I powered it on. I can hear the transformer   
>>>>>> buzzing(!), but no  action at all on the screen at all, and it   
>>>>>> doesn't seem like the  chips are getting warm at all Maybe need  
>>>>>> to  leave it on a little  longer to make sure, but I didn't  
>>>>>> want to do  that incase bad  voltages kill anything more).
>>>>>>
>>>>>> There are 4 wires leading from the small PCB which is attached  
>>>>>> to   the transformer to the C64 motherboard, and I have  
>>>>>> measured the   voltage from the black wire (GND?) to the 3  
>>>>>> others. Here are the   reading i get:
>>>>>>
>>>>>> White: - 100mv
>>>>>> (KEY)
>>>>>> White - 100mv
>>>>>> Black (I'm guessing this is ground)
>>>>>> Red - 4.98v
>>>>>>
>>>>>> That's as far as I have gotten. Next I will remove the   
>>>>>> motherboard  and see where exactly these 4 wires go.
>>>>>> Anyway, I was just wondering if anyone had any insights or  
>>>>>> thoughts.
>>>>>>
>>>>>> Cheers
>>>>>> Phil
>>>>>    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
>>
>>     Message was sent through the cbm-hackers mailing list
>
>
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