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  • dave_m's Avatar
    Today, 12:38 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    I mean 'continuity test', with the Ohmmeter, the repaired signal to make sure its going to all the correct places. If a feed-thru hole was damaged, ...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Today, 11:54 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    I would replace one at a time to see which one is bad and leave the rest alone. If that doesn't fix the problem, then go on with the ROMs one at a...
    104 replies | 2795 view(s)
  • MikeS's Avatar
    Today, 08:35 AM
    Excellent! Congratulations, and good luck with the drive and printer! mike
    18 replies | 286 view(s)
  • MikeS's Avatar
    Yesterday, 06:40 PM
    Almost sounds like someone tried to replace the BASIC interpreter... So, there are only 3 empty sockets, not four?
    18 replies | 286 view(s)
  • dave_m's Avatar
    Yesterday, 06:16 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    There are silver or nickel conductive pens that can be used to repair broken traces on the circuit board if you do not want to use jumper wires.
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 06:09 PM
    Pawel, The NAND gate is added. It seems to be doing something with SEL 9 and SEL B of the address decoder. I would disconnect those wires. The...
    18 replies | 286 view(s)
  • dave_m's Avatar
    Yesterday, 05:42 PM
    Pawel, D6, D7 and D9 are 2332 Commodore 4K by 8 ROMs. The TMS2532 is a pin for pin EPROM replacement. D8 is a 2316 ROM (2K by 8 ). An Intel 2716 or...
    18 replies | 286 view(s)
  • dave_m's Avatar
    Yesterday, 02:33 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Clever Man! The last time I used that 4020 CMOS counter was about 1977! It was part of a watchdog timer that would initiate a System Reset if it was...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 02:20 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    I'm not a good solder man so I always sacrifice the soldered-in chip by cutting off all the pins and just deal with the legs one at a time with...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 02:13 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Don't worry, they can be repaired or jumpered around with small gauge wire. Wire wrap wire is good (30 gauge). At this point, I would cut off the...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 02:04 PM
    Pawel, Here is a little information on the ROM functions: D6 ($Cxxx) 901465-01 : BASIC Routines D7 ($Dxxx) 901465-02 : BASIC Routines D8 ($Exxx)...
    18 replies | 286 view(s)
  • MikeS's Avatar
    Yesterday, 12:56 PM
    You're right, Frank, my finger slipped a line; I think the 901474-01 is for the B version and we're probably dealing with the N version here.
    18 replies | 286 view(s)
  • dave_m's Avatar
    Yesterday, 12:11 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Wow, you are right. You have almost no way to look at the square waves on the Address lines. Using a VOM to measure VAC or average VDC will not tell...
    104 replies | 2795 view(s)
  • MikeS's Avatar
    Yesterday, 10:25 AM
    Umm... four empty sockets??? Only U3, 4 and 5 should be empty; the other four are usually required. I believe the V3 ROMs should be: U6...
    18 replies | 286 view(s)
  • MikeS's Avatar
    Yesterday, 10:06 AM
    MikeS replied to a thread PET 8032? dead. in Commodore
    As Dave says, you're looking at a different version of the NOP generator. The idea is to isolate the system data lines from the CPU and let it read a...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 09:27 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    I can't tell. You decide as you have to do the work. I personally hate replacing big chips due to the possibility of board damage. I would replace...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 09:24 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Twist, Did you solder the piggyback RAMs? You were only supposed to hold them on with your fingers....It is a quick & dirty test.
    104 replies | 2795 view(s)
  • dave_m's Avatar
    Yesterday, 09:20 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Twist, I think you are looking at the wrong adapter. I will try to find the message with Mike's description. The NOP Generator helps check that the...
    104 replies | 2795 view(s)
  • MikeS's Avatar
    Yesterday, 08:42 AM
    MikeS replied to a thread PET 8032? dead. in Commodore
    I wouldn't worry about the video board until we've heard a beep. Maybe time to whip up a NOP generator (only needs one socket) ? Love the...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 08:07 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    One at a time unless you are an octopus. ;)
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 02:38 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Yes, piggyback all eight lower RAM chips per message #23. If no changes, unfortunately it doesn't mean the chips are OK. If chip with RAM bit is...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 02:05 PM
    dave_m replied to a thread PET 8032? dead. in Commodore
    But are there signs of rework? Like bad solder work, messy solder flux, strange jumper wires, etc. Any attempted repair is suspicious because of the...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 11:26 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Jumpers: See Top Assy sheet 7 http://zimmers.net/anonftp/pub/cbm/schematics/computers/pet/univ2/8032090-7.gif If new socket in UD8, try new EPROM....
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 11:00 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    The PET code is still not running. What is test configuration? Are you running with UD6 and UD7 replaced? We should try UD8 next, but there is also...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 10:19 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Oops, yes 1/60 (16.66 mS). Also good insight about Dc averages from checking schematics. OK, then there are still more issues besides flaky...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 10:00 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    Your meter is OK. It means the Sync is pulsing properly, fetching instructions. Your CPU is fine. EDIT: Mine is measuring 1.7 VDC, but it is...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 09:57 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    To maintain test configuration, please log everything you do step by step. You probably know this as you are a good troubleshooter! Keep up the good...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 09:53 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    OK, your Horizontal signal is good. I get 3.66 VDC. On the Vertical (J7-pin 3), I get 4.88 VDC. It is a mostly high signal with a skinny negative...
    104 replies | 2795 view(s)
  • dave_m's Avatar
    June 21st, 2018, 09:37 AM
    dave_m replied to a thread PET 8032? dead. in Commodore
    That may be OK. Let me check my board. It is the same part number main board.
    104 replies | 2795 view(s)
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About MikeS

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About MikeS
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Cromemco,S100,PET,AIM65,PC
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