Hi Mike, I read the thread on VCF. Here are the voltages I'm getting off the CPU: Ready pin 2: 5.06 VDC Sync Pin 7: 0.98 VDC Reset Pin 40: 4.71 VDC clock (phase 2) pin 39: 1.8 VDC I tried moving the ROM's around as you suggested but that didn't change anything, I'll try putting the ROM in a socket with pin 18 lifted and try reading them again. Phil On May 14, 2011, at 4:21 AM, MikeS wrote: > If you have a spare 24pin IC socket, bend out pin 18 to isolate it and put > it between the 2316 and your programmer socket, and you might be able to > read the H5 - H7 ROMs that way; if not, try connecting that 2K resistor > between the bent-out pin 18 and pin 24. > > Pleasant dreams ;-) > > m > > ----- Original Message ----- From: "MikeS" <dm561@torfree.net> > To: <cbm-hackers@musoftware.de> > Sent: Friday, May 13, 2011 3:06 PM > Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc. > > >> The ROM numbers and locations look good, but I would expect H1 to H4 to >> all >> read OK. Why not try putting your respective 2716 equivalents into H1 and >> H3, leaving the originals in H2, 4, 5, 6 and 7. >> >> BTW, can you program 2532s and do you have any? >> >> m >> >> ******************* >> >> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com> >> To: <cbm-hackers@musoftware.de> >> Sent: Friday, May 13, 2011 2:39 PM >> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc. >> >> >> Don't worry, I'm not insulted at all. >> >> I believe I have the following ROM set (I'll double check in the morning): >> >> Location Part Number >> ------------------------------ >> H1 901447-09 >> H2 901447-03 >> H3 901447-05 >> H4 901447-06 >> H5 901447-02 >> H6 901447-04 >> H7 901447-07 >> >> And I have followed the above convention for placement. 09, 03, 05, 06, >> 02, >> 04 and 07 in that order. >> >> When I read the original ROMs in my burner I got the following: >> >> H1 - full of 00's >> H2 - good >> H3 - full of FF's >> H4 - good >> H5 - full of FF's >> H6 - full of FF's >> H7 - full of FF's >> >> so is it possible that H5, H6, ad H7 were not read correctly by my >> programmer. H3 also shows full FF's, but H1 read as full 00's...Could it >> be >> that H1 is the only one that is indeed dead? >> >> I'll remove the two 6520 PIAs, and I'll take a look on VCF for the >> voltages >> thread. >> >> Thanks again for your time. >> >> Phil >> >> On May 14, 2011, at 3:17 AM, MikeS wrote: >> >>> Sorry, emails crossed and you answered my question before I asked it ;-) >>> >>> A crude way would be to measure the voltage on the various 6502 pins, >>> especially the Reset, Sync and Ready pins. >>> >>> There's a thread on VCF right now that might be relevant. >>> >>> m >>> >>> ----- Original Message ----- From: "Philip Lord" <random6000@mac.com> >>> To: <cbm-hackers@musoftware.de> >>> Sent: Friday, May 13, 2011 1:55 PM >>> Subject: Re: PET 2001 fix Part 3 - RAM/ROM board etc. >>> >>> >>> Thanks André, >>> I only have limited tools. Logic probe, eprom burner and multimeter. >>> >>> I'll have to snag the keyboard out of my working pet to try the 'LOAD' >>> test. >>> What other ways can I test if the CPU is working? >>> >>> Phil >>> >>> >>> On May 14, 2011, at 2:39 AM, André Fachat wrote: >>> >>>> >>>> >>>> Looking at the further discussion, you are concentrating on the video >>>> part, but is the CPU actually running ok? I didn't see that, may be I >>>> overlooked it. But you mentioned burning new ROMs as the original ones >>>> were dead. >>>> >>>> If the cpu is not running ok, this could explain the random characters >>>> on >>>> one side and also the "snow", as some random code would not wait for the >>>> vertical retrace when writing to the screen memory. >>>> >>>> Did you try checking for example with a tape and typing LOAD and >>>> pressing >>>> the Play button that the tape starts turning? >>>> >>>> I'd concentrate finding why the CPU isn't working and looking at the >>>> video later. >>>> >>>> André >>>> >>>> >>>> -------- Original-Nachricht -------- >>>>> Datum: Fri, 13 May 2011 19:27:34 +0200 >>>>> Von: "André Fachat" <afachat@gmx.de> >>>>> An: cbm-hackers@musoftware.de >>>>> Betreff: Re: PET 2001 fix Part 3 - RAM/ROM board etc. >>>> >>>>> >>>>> -------- Original-Nachricht -------- >>>>> >>>>>> So now I have a screen of random and slightly deformed characters >>>>>> (seems >>>>>> like the same or similar character layout on each start up though), >>>>>> with >>>>> a >>>>>> pixel flicker through them. I've put pics and a short video up on the >>>>> same >>>>>> page here: >>>>> >>>>> Sorry to chime in so late only. The pixel flicker might be from the >>>>> fact >>>>> that the CPU accesses the video RAM. The oldest PETs had video RAM with >>>>> max >>>>> 1MHz operation only, so when the CPU accesses the video RAM the video >>>>> display presented "snow". The CPU controlled access to the video RAM by >>>>> sampling >>>>> the vertical retrace on a VIA pin (VIA Port B ($e840, 59456), bit 5). >>>>> This >>>>> could relate to the fact that characters seem stable when the machine >>>>> resets (switching off?) >>>>> >>>>> Maybe the VIA has a problem here? >>>>> >>>>> On a side note: the fact that switching this vertical retrace off >>>>> resulted >>>>> snow, but also faster screen output - no wait anymore - a certain POKE >>>>> was >>>>> found to make that VIA input pin an output - accidentally destroying >>>>> some >>>>> newer models, the "killer poke". >>>>> >>>>> André >>>>> >>>>> -- >>>>> NEU: FreePhone - kostenlos mobil telefonieren und surfen! >>>>> Jetzt informieren: http://www.gmx.net/de/go/freephone >>>>> >>>>> Message was sent through the cbm-hackers mailing list >>>> >>>> -- >>>> Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir >>>> belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de >>>> >>>> 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 2011-05-14 05:00:08
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