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 listReceived on 2010-12-10 07:00:09
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