can i see some pix. is it a pet or c64??? ----- Original Message ----- From: "Philip Lord" <random6000@mac.com> To: <cbm-hackers@musoftware.de> Sent: Friday, December 10, 2010 7:08 PM Subject: Re: Pet64 DOA > Thanks Richard, > It's the PLL version as far as I know, as It's the original 326298-01 REV > A board. > > Well, I'm not sure I have any equipment that can test the clock circuit, > and I haven't the first idea how to approach it actually. > > I think trying to acquire a second c64 motherboard would be a good idea, > but certainly not a cheap one as I'd probably have to buy a c64 from ebay > and have it shipped from the US to Japan!!! > > There is a C64 on Japan Yahoo auction at the moment, but it's like US > $100+ !!!! > > :-( > > > On Dec 10, 2010, at 1:29 PM, Richard Atkinson wrote: > >> Is it a MOS 8701 based clock circuit or a discrete PLL version? Probably >> the latter if it's an early C64 board. That's quite a complex circuit >> with lots to go wrong. You should be looking for a 14.31818MHz crystal >> and a working circuit for that for the colour clock, a divide by 14 >> circuit producing a 1.02MHz clock and an 8MHz voltage controlled >> oscillator producing the dot clock, which gets divided down by 8 by the >> VIC-II chip to produce another 1.02MHz clock. These two 1.02MHz clocks >> should be kept phase locked by the circuit controlling the 8MHz VCO. >> >> Have you also tried the standard C64 chips trick of finding another C64 >> board of the same era that's known to work, and swapping out all the >> socketed chips in the Pet 64 board for the ones in the other board? >> >> Richard >> >> >> On Dec 10 2010, Philip Lord wrote: >> >>> Thanks Richard, >>> Maybe I should have checked there first... >>> The reset pin 40 on the 6510 seems to get the correct reset signal, It >>> starts low then goes high. Can I assume that the reset is working? >>> >>> Maybe next I should look at the clock circuit as it doesn't look like >>> I'm getting any pulsing. Does anyone know what I should check next? >>> >>> Cheers..again >>> Phil >>> >>> On Dec 10, 2010, at 11:42 AM, Richard Atkinson wrote: >>> >>>> Start from the 6510 RESET# line and work backwards. What is that >>>> connected to? >>>> >>>> >>>> On Dec 10 2010, Philip Lord wrote: >>>> >>>>> Ok this morning I printed out the schematic and theory of operation >>>>> for the C64. >>>>> >>>>> The theory of operation states that the reset signal is originally >>>>> produced at pin 9 of the 556 time (MC3456p in my case). The output >>>>> is active high. I have tested this pin with my probe, and it does >>>>> indeed switch from low to high on power- up. The theory of operation >>>>> then says that this signal is sent to pin 13 of a 7406 hex inverter >>>>> (U8) and the output from the 7406 is active low from pin 12...this >>>>> is the reset signal. >>>>> >>>>> However, on my machine pin 9 of the 556 is tied to pin 13 (on the >>>>> same 556) with some wire, and I have tested the continuity from pin >>>>> 9 of the 556 to pin 13 of the 7604, and I can't see any physical >>>>> connection between these pins which in contrary to the schematic >>>>> and the theory manual. Maybe I'll pull the board out and have a >>>>> look at the bottom side for any damage or cut traces. >>>>> >>>>> I probed pins 12 and 13 of the 7406 and pin 12 is always low and pin >>>>> 13 is always high. >>>>> >>>>> So I'm a little confused...this doesn't seem right. Maybe I can I >>>>> briefly apply 5v to pin 12 of the 7604 to see what happens? >>>>> >>>>> Maybe I have the wrong schematic, but I don't think so. I'll look >>>>> for others anyway. >>>>> >>>>> >>>>> >>>>> >>>>> On Dec 10, 2010, at 12:43 AM, MikeS wrote: >>>>> >>>>>> The supply voltages to the ICs are all correct? >>>>>> >>>>>> Reset line is being released? >>>>>> >>>>>> >>>>>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com >>>>>> > >>>>>> To: <cbm-hackers@musoftware.de> >>>>>> Sent: Thursday, December 09, 2010 3:23 AM >>>>>> Subject: 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 >>>>>>>> >>>>>>>> >>>>>>>> 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 >>>>> >>>> >>>> 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 > > __________ Information from ESET NOD32 Antivirus, version of virus > signature database 5690 (20101209) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > > Message was sent through the cbm-hackers mailing listReceived on 2010-12-10 10:00:09
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