Jump to content


  • Content Count

  • Joined

  • Last visited

Community Reputation

481 Excellent

1 Follower

About ChildOfCv

  • Rank

Recent Profile Visitors

3,893 profile views
  1. There is a NTSC rev D and a PAL rev D, and the revs have nothing to do with each other. But if you've disconnected -5V and -12V from the video memory and added +5V where needed, then you should be good.
  2. All versions of CV use the same video memory technology, so any solution you find for NTSC should work for PAL too. Console5 has a chip replacement kit specifically for CV. It uses a different type of 16K memory chips, rather than 64K chips.
  3. Did you reconnect the modulator? If you have an old VCR, it might be useful to try to inject its video output into the RF modulator video input to see if you can get a picture. You could do that by patching to the blue wire that goes from the top of the board to the modulator and connecting VCR ground to ground.
  4. I suppose one possibility is that the CSYNC output of the 1881 doesn't just separate the sync signals, but gives a solid sync during vertical retrace, or something like that. @Falonn Well, one idea for a V3 design might be to include jumpers for the SYNC input to the final amps, to come from either the 1881 or the Y signal.
  5. Yeah, looks like cables meant for the Genesis 2 already have 75-ohm resistors (and also capacitors) built in on the R, G, and B connections. They do not expect a resistor at all on the CSYNC. So at the very least all 4 of those resistors should be removed and bridged on the TMS-RGB for that. It's weird that you need the composite video though. The TMS-RGB seems to output the correct csync voltages on the CSYNC 75 pin that he's using.
  6. Looks like a sync issue to me. Is the SCART connected directly to the TV? Does the cable have internal resistors that the 8-pin test did not?
  7. He's getting a solid 5V. Also, the TIA chip does seem to be outputting color and reacting properly to the potentiometer. The chip supply is dwindling, so replacing it on a whim is increasingly a bad idea. Best is also becoming increasingly concerned that people decide they REALLY need a new TIA before buying one. The best bet is likely to let someone with better test equipment examine the system. A scope that "might" be useful for this task would run at least $80. Most likely choice would be a USB scope for your computer.
  8. Ooooooh, okay. I was thinking the Mean Well one was that monstrosity that was adapted from a full computer PSU as seen in another thread. So this is a plastic box with a DIN output, and the CV cord plugs into it. According to the datasheet, it's the awesomest replacement. Obviously there are some asterisks involved though. It's probably that it needs 0.2A minimum on the 12V supply. I doubt that CV draws anywhere close to that. That's a 60 ohm minimum load equivalent. You probably a 2.5W 60 ohm resistor between 12V and GND to get the kind of stability that it advertises.
  9. Is the little baby gonna cry? 😜 Yeah, TI seemed to enjoy confusing us. They show pins in the opposite order that you'd expect and also number bits that way. Makes it hard to keep things straight when interfacing with other non-TI chips, or when constructing values in software. TI seems to have sobered up eventually though.
  10. Does the Mean Well happen to have a ferrite choke on the CV plug wire? Most of the time, the +12V is intended to run motors such as the hard drives, so I guess smooth output on those rails isn't as important. The +5 and +3.3 both tend to have extra smoothing chokes built in. On the old PC with a floppy drive, it used +12V to run the head magnets, but the disk drives have about 4 capacitors on the +12V line alone, to eliminate crap. (and about 11 on the +5V line) On the CV, the +12V powers the video circuitry, so smooth power is absolutely necessary. TMS-RGB bypasses the +12V part, so it's not surprising that it's unaffected. It would be instructive to look at the +12V with an oscilloscope.
  11. Those are both parallel connections to ground, so 0V is correct for the top sides. This shows that they are all connected together. The bottoms of R214-R217 should also measure 0.19. Again, this is with the game running? That composite mod is interesting. Might need someone to identify it. It doesn't use the simple amplifier that we typically see, but instead it uses a specialized 3-channel TV amplifier chip (but only one channel of it). The simple amp mods will also inject some DC voltage into the system, so you'd see a voltage greater than 1V. The chip used here does not, so maybe that's an expected voltage. One thing: Try to find a game that fills the screen with white or at least a very bright color, and see if the 0.19 voltage increases. Other than replacing the mod board, I'm not sure there's much else that can be done without better test equipment (oscilloscopes and such). One thing to make sure of though: Make sure the +5V and the GND are connected to the main board. You can unplug the system and then check those connections in continuity mode.
  12. C211 "bottom" definitely ought to be joining the b/w signal at that point, so that voltage is too low. It ought to be connected to R222 and C215 (and R214-217). So either the capacitor is dead, or as you say, the solder joint may be suspect. What is the reading for the rest of the solder points between C211 and R222? (And keep in mind, this is with a game running)
  13. So the TIA seems to be outputting color signals. The output goes through C210, C211, and R210. Those are all near the RF module. Could you give voltage measurements on those components?
  14. I see. Did the power supply look brand new, or salvaged? I'm pretty sure they're all repurposed, and if they have a power switch instead of a soft start like ATX computers from the mid 90's and on expect, that almost screams "new old stock". What you're describing sounds like a dirty +12V output, which may mean bad caps or something.
  15. Okay, those voltages make more sense. What is the voltage at pin 10 of TIA show? It probably needs to be more than 4V, and R213 adjusts its output. Does the voltage at pin 9 change when it's running a game? Does adjusting R213 affect it?
  • Create New...