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channelmaniac

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Everything posted by channelmaniac

  1. Audio caps. Don't mess with the HA13003. They rarely ever fail, but the audio caps are well known for being shite and causing low or no audio out or audio missing from a channel and even for the audio to repeatedly thump badly and kill power supplies. (TK brand caps suck) The thump is an audio oscillation and is bad enough that it can cause large current draws on the +12v line to the point the 5v line will sag and reboot the game. That high current pull will kill a power supply if left on.. So... there are 2 bits of audio on the NG... audio generated by the FM synth function and then audio samples. First, clean the slots. Next, check the ports on the YM2610 for activity - you're looking for lines with missing signals. The schematics are hard to read and fuzzy... but at least that's what's available. Trace the missing signals back to a custom (NEO-257, IIRC)... then back to the slots.
  2. What do you get when you have a dead, corroded CPS2 A board? You get a source of... RC filters for inputs, Z80 8MHz, 2 crystal oscillators, some DIP RAM, misc SMT chips, and... (Drumroll please...) a CPS-A-01 and a CPS-B-21 custom chip!!! Those of you unfamiliar with Capcom boards... the CBS-B-21 custom chip can be used to repair a C board on a Capcom CPS-1 boardset or to convert a crappy game into a better one. The CPS-A-01 chip is the custom that consistently fails on the CPS-1 boardset's A board and is the bane of its existence. In other words: You can use the dead CPS-2 board to: Fix a CPS-1 game with graphic corruption Convert a CPS-1 game to a better one Repair a Z80-ERROR on a Neo Geo game Repair a game that has bad CPU RAM - 8K x 8 .300" wide RAM. Fix a game that has fried RC input filters and more! Enjoy! RJ
  3. Can't make out all the connections. :( Looks like A11 isn't connected to anything.
  4. I have that in one of my repair logs... :) I wonder if you came across one of my forum posts about those Tantalums. :D
  5. All together would be best on shipping. I can pay you for the 054544 modules now if you wish.
  6. I'll take 3x for X-Men and 2x the other type... shipping to USA 75077. Let me know a total and your PayPal please.
  7. Or the solder joints have popped because of someone flexing the PCB. I've run into that on those all-in-one PCBs before.
  8. Flip the board over and check power. There's one contact out of the four on the edge connector on the +5 that goes to power the parts that control the inputs.
  9. I can't help you with that. I've never done the mod before... I just am pretty good at finding parts. :)
  10. Google found this one: https://www.electronicaembajadores.c...nators-csb384p I searched for '384k ceramic resonator"
  11. Even metal film or carbon film will have some minor inductance, they are still used for amplifier circuits and have better tolerances than solid carbon.
  12. Resistors! These are so dang simple but people get them so confused. Resistors do what they say, resist the flow of current in a circuit. They come in many different forms - adjustable (pots / potentiometers / rheostats) or fixed. They are made by using packed carbon in a package, thin carbon film over a carrier, thin metal film over a carrier, or wirewound. Resistors do not fail shorted. They fail by going UP in value or by going open, not shorted. Potentiometers fail by going intermittent, getting dirty (static), or just breaking physically makes them go open. Take monitors for example. There are plenty of resistors limiting current to other parts of the circuit which lets you ignore those parts for blowing fuses. You can calculate the current based on the voltage and resistance if you wish. Say F501 (fuse) is blowing. It takes some good current to do that, but if you look at the path the current takes, you'll see there's a limited path for that much current to flow without burning resistors up. The path has lots of parts on it. Caps can short or blow up/open, semiconductors can short, resistors do NOT short. They go up in value when they get damaged. They also show obvious signs on heating. So, if you have a blowing fuse you can do the current calculations and determine that it can't be because of R507, R502, R311, R313, and R363 and since those resistors aren't burned up, you usually can ingore that segment circuitry beyond them. Capacitors CAN short, but the electrolytics usually vent or explode when that happens because of the heat and pressures generated inside of them. So that's C404, C507, C501 (all low risk), and C363 (high risk) which are suspects. It's rare for the ceramic caps to go old and die, but common for semiconductors. Semiconductors can go leaky when they fail, but usually simply short circuit. When D501, D502, D503, D504, or IC401 shorts the fuse will blow. Sure, current flows through other paths, but if you have a bad path you'll usually have a burned resistor. Take the +175v source, for example. That comes off the flyback, through R702, through a high frequency Schottky diode (D702), and over to a cap. When the diode fails, the resistor will burn up because of the extra current flowing through it, but the fuse will rarely fail. Now, can you replace a resistor with another resistor, even an old one? Yes, usually. BUT... You really don't want to put a carbon or a carbon film resistor back where a metal film resistor was - they are fire hazards. The metal film resistor (a.k.a. Flameproof Resistor, a.k.a. Safety Resistor) will open up before it catches fire but the older carbon and the carbon film reistors can catch fire, possibly destroying the PCB material under it. Some monitors use special non-inductive high wattage resistors. You cannot replace those with standard wirewound high wattage resistors as those will have inductance which could cause the ciruit to not work, or worse to perform incorrectly.
  13. This is where it sucks to be on the other side of the world... shipping is horrifically expensive from Canada's underwear to Down Under.
  14. I can afford 8... so please put me down for 4 each.
  15. How much each? If they aren't too many arms and legs, I'd like to get up to 10... (let some of the locals go first... I need 3 but do repairs for folks)
  16. Disassemble the carts and use a Pink Pearl to clean the edge contacts. Clean all the eraser dust off before reassembling them.
  17. The SPI boards I've worked on with graphic glitches needed the custom SMTs reflowed.
  18. I use a pre-made JAMMA adapter on my test bench. Works quite well.
  19. The solder pads on the bottom side need to be the absolute minimum in size to help keep from bridging under. If yours is designed that way, I'll take 10 boards, shipped to Texas.
  20. In the USA the marquee lights are EL panels that switch to light up the game currently in play. Those EL panels go out over time. You can find replacements from time to time on eBay, but you have to trim them to size and figure out how to connect wires to them. When they stop lighting up, you'll probably hear a loud squealing sound from the cabinet. That's the power supply for the panels. Some folks just rip out the EL panel system and install a standard fluorescent tube fixture. For the card reader, they tend to fill up with dust drawn in by the fan. Other than that they tend to have bent pins on the card reader port. If that happens you just have to find a parts PCB to pull one from as they are unobtanium - well at least they are here in YankLand.
  21. What does the bottom look like? The HUGE problem with one of the others on the market is the large size of the pads on the bottom of the PCB which leads to solder shorts under the PCB and around the pins being used. You have to solder the pins VERY lightly to keep that from happening. It's a real pain in the ass.
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