Arcade Collecting > Pinball
VND acting up
LLUncoolJ:
--- Quote from: Q*Bert_24/7 on July 26, 2010, 12:00:01 pm ---I assume you have a digital volt meter...anyways, in DC mode, place the red probe on the +5vdc test point, and the black lead under a ground strap...get close to +5v? Now place the meter on the AC setting...see any significant voltage? If you see more than...say .2vac, you have a capacitor problem...if not, change out the +5v rectifier, I have fixed 3 late model Sega driver boards with failed rectifiers in the past year...this problem seems to be quite common these days...
--- End quote ---
Dumb noob question: I'm assuming I'm testing with the power on, where do I test, on the back side (output) of the capacitor? This seems obvious, but I want to make sure. Thanks for the help QBert.
lilshawn:
worst case if you can find the 5 volt test point, put your black meter probe on the metal of the backbox ground... and the red lead on the case of the silver big round thingie inside of the heatsink on the top left side. that is your 5 volt regulator.
LLUncoolJ:
OK, the board diagramshows 2 test points (24 guage wire loops), one being directly below the BRDG21 rectifier shown in the picture. I'm guessing that would b the logical place for the 5V. The other is on the right side of the board. One is labeled FET TPL1, the other is TIP TPL3. So find the one that is reading 5V and compare DC vs AC...easy enough. :notworthy:
LLUncoolJ:
OK, I just tested the 5V DC, it read pretty close. Then 5VAC, it pegged the needle...so capacitor, no? Well, I shut the door and preesed start out of curiousity and played 2 games without incident. I opened it back up and took readings again, same thing. Then shut it and played another complete game. So what's going on here? :banghead:
lilshawn:
--- Quote from: LLUncoolJ on July 26, 2010, 09:07:22 pm ---OK, I just tested the 5V DC, it read pretty close.
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what's pretty close???? 4.91 volts is known to make a game reset. digital is the way to go here an analog isn't going to be quite accurate enough. i would say borrow or buy one if you can. it will be 10 bucks well spent.
--- Quote from: LLUncoolJ on July 26, 2010, 09:07:22 pm ---Then 5VAC, it pegged the needle...so capacitor, no?
--- End quote ---
i don't know if you know how to properly use a meter, so we will just throw this result out for now... again we are talking a few thousanths of a volt
--- Quote from: LLUncoolJ on July 26, 2010, 09:07:22 pm --- Well, I shut the door and preesed start out of curiousity and played 2 games without incident. I opened it back up and took readings again, same thing. Then shut it and played another complete game. So what's going on here? :banghead:
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dunno, but guaranteed if you mash on both of the flippers i'm sure that you'll see the 5 volt fluctuate. in anyways...
we are going to now systematically eliminate about 75% of all problems... be sure you can dedicate at least 3/4 of an hour for this procedure...
i'm gonna haft to ask you to go ahead and start at one end of the machine's boards and go ahead and unplug a connector, and then plug it back in again, one at a time as not to get lost or forget where it came from. ( i forget which header the 50 volt solenoid connector goes all the time since there are 2 connectors in the same spot.) make sure you get them all. you don't need to leave them unplugged for any amount of time just pull and push. take care not to rip out any wires or bend any pins. don't get all crazy, take your time, we have alloted plenty.
once you're done that i'm going to get you to go ahead and take a screwdriver and slightly loosen, then retighten all the screws holding the boards to the backbox...these points are ground. you want to make sure they are snug.
after that, your going to then close up the machine, turn it on and leave it for about 20 minutes. if it does not spontaneously reset in that time, play a few games. if it still decides to reset, come back here for further diagnostic help.
hopefully you get lucky and that will be it.
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