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Nmitchn47

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About Nmitchn47

  • Rank
    Space Invader

Profile Information

  • Gender
    Male
  • Location
    Harrisonburg, VA
  • Interests
    Vintage game collecting, Atari 2600 / Intellivision / Colecovision / NES / PS1
  1. 7805 regulator was bad, open output leg at 153v. Checked it before and thought I read 5.2v, but after seeing high voltage at the F8 Chip, I went back. System purrs now.
  2. Power supply is good, capacitors and regulators are working. Definitely a chip issue at this point. Hopefully someone can chime in on what the chips are, primarily FCM 9102 & FCM 9101/N. Thanks!
  3. Hey guys, just received my first Fairchild Channel F System 2 as a bday gift and was told it wasn't working. System turns on, led light is on and screen shows vertical lines in green, black & white. No sounds when anything is pressed. Unhooked the ribbon cable from the cartridge reader and no change as well. I swapped out the SL31291 chip with my Fairchild System 1 and it worked just fine, so it tells me the CPU is fine. No burnt spots or heavy oxidation on either side of the board. I looked into the VES manual and the technical guide is suggesting it's a possible PSU problem. Since this system is more compact, I can not make out what chip does what to isolate my problem. Anyone knowledgeable with this or the grandstand clone? - SL31291 (CPU) - SL31253 ?? - SL31254 ?? - FCM 9102 ?? - FCM 9101/N ?? - SCM90004C (x4) (RAM) I'm going to check voltages tonight to be certain I don't have a feed problem. Thanks.
  4. Purchased a Fairchild Channel F model 1 and the power supply brick was busted open. Wires were ripped out of the transformer and is beyond repair unfortunately. If anyone has an extra power supply laying around or one from a parts console, please message me. I would like to purchase a used power supply.
  5. Spent a few hours on Christmas Eve comparing boards and I might be going crazy but both boards are doing the exact same thing. I relocated all the known good/new chips over to the newly acquired 7800 system, including the reset IC's Osgeld sent me, and so far no prevail. I'd much rather work on this new board due to it being a slightly older board with better traces and just cleaner looking. I'll keep the other board for parts. Moving forward, I've ordered DIP sockets to install on the board so I can swap out all the IC's. Need to check the Ram and OS chip first. Can the TIA and RIOT chips be interchanged from a known working 2600 to the 7800? Best Electronics is listing them too work.
  6. Thanks guys for all the help so far. I think I will have to invest into a logic probe to see if the chips are functioning correctly for further diagnostics. But some good news after I'm almost giving up on this pile of plastic. Local gamestore is closing shop and I was grateful to have known the owner, so they let me look at their repair shop in the back and had a non-functioning 7800 for parts. I grabbed it alongside a few other 2600's to tinker with. It looks to be an earlier model with the expansion port but the board is the same layout. Now I can spend a day comparing both boards. I did snag a holy grail item that was sitting in a box over the side of the room. Early model Fairchild Channel F. Can't wait to look at this beast.
  7. Update, the chips Osgeld sent me came in and the following was replaced with no change: - 4013 (U10) - 74LS174N (U11) - 74LS32N (U12) - 2N3906 (U8) Back to following the repair flowchart that I printed out for the system and it is saying to "check pin3 of 4013 goes low on depression of on/off switch". What does "low on depression" mean and how can I check that?
  8. Yep, continuity is good on all three traces. Checked on both end origins while criss-crossing to see if they tapped into each other. Osgeld is sending me all three 3 chips for the reset circuit. Will update soon.
  9. Crossbow, Dark Chambers, Pole Position 2, Ms Pac Man and Centipede
  10. Surprised I didn't see this before but everything checked good with a continuity test on both ends of the traces for all three. Also no shorting between traces. Double checked continuity at the slot pins and motherboard while I was it. The cartridge guide had a sharp edge on the bottom plastic where it was pressing down on the motherboard and digging into the traces. Poor molding of the piece back in the day. Someone before me may have bashed the game in the slot figuring it would help fix it.
  11. After looking back on the picture again, you might be on to something. I'll check them out later today.
  12. Osgeld, I would be hugely interested in whatever leftovers you might have. PM me and I'll forward payment via Paypal.
  13. Tested it after the regulator didn't work, working good.
  14. I'm following the 7800 repair flowchart and it says to check a low depression on some of the pins. How would one go about doing so?
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