F-14 Tomcat
Williams, 1987i been working on f14 tomcat upper diverter wasnt working when i got it so after looking at the board Q76 Q77 were blew i changed them and nothing so i went ahead and changednQ68,69,70,71,72,73,74,75,76,77,78,79 and nothing swapped u50 now it fires and locks on soon as the game is turned on and doesnt turn off any info or where to look next would be greatly appreciated also changed diode on the coil itself rest of the game works
also zr7 and zr8 diode were changed and checked all solder spots nothing looks to be touching anywhere on the board and any recommendations on a logic probe or are the all the same ?
update i rechecked the transistor at Q77 was bad replaced it and turned it on and was fine for about 5 to 10 seconds then it popped on and locked so its killing 102 transistor at Q77
Quoted from kingsparts123:and turned it on
Remove 1J19 connector before doing any testing to stop burning up parts. There is a limited number of times you can replace a TIP before you cause board damage. You need to wait for the logic probe.
im going pick one up later today and im aware of that i just wasnt aware that it was blowing it, while i have board out i tested few resistors in that line and found r102 was bad so replaced it as well
Quoted from kingsparts123:found r102 was bad so replaced it as well
Was it out of spec or was it open? If it were open and Q-76 had some leakage it would turn on Q-77.
Q76 was out of spec it got HOT instantly on fire up last about 5 sec then coil re energized and stayed energized after it failed replaced the Q76 then tested and Q76 and Q77 they test fine now havent tried any further testing till i pick up logic probe but thats when i found the bad resistor at 102 also im assuming it just got burnt along the line i dont think it would be the problem but im new at this i suspect the problem is up the line at u49 7407n or even pia 6821p at u54
would it be possible for the problem be coming from a bad diode on a diff coil or bad diode under playfield or is this in the board ?
keep in mind upper diverter wasnt working at all till q76 q77 and u50 were changed they were all bad probably burnt from being locked
Something failed ( Q-77 most likely) which locked on the coil and melted it, but before the fused burnt Q-76 was over stressed and burnt out and stressed U-50 causing it to be damaged. Now if R-102 was damaged ( not normally) and burnt open this will leave the base of Q-77 floating and any leakage from Q-76 would turn on Q-77 and damage Q-77,Q-76 and the coil and diode again. So I always leave 1J19 off until I 'm sure everything is working correctly and I have installed a fuse with a 1.5 sb fuse for each diverter coil.
im not sure looks like someone fixed this issue once or attempted to anyways waiting on my logic probe to arrive i still think its a pia problem even with all the parts replaced soon as power is turned on it burns out Q77 in seconds and since theres no switch has to be something sending power back or stuck on like pia and the diverter doesnt come on till well after Q77 is red hot and bad
Quoted from kingsparts123:any suggestions?
Disconnect 1J19 from the CPU board, this removes the grounds from the special solenoid coils so you will not burn them up while testing. Connect your logic probe to the 5 volt and ground test points on the CPU board. Set it to TTL.
Power up game in attract mode and locate pins 1,2 and 3 of U-50. In attract mode pins 2 and 3 should be high and pin 1 should be low. Note any deviations. Then start a game and pin 3 should go low, but pin 2 should stay high and pin 1 should stay low. Note any deviations. During this time the base of Q-76 (middle lead) should stay low and the base of Q-77 ( look at pic) should stay low. Let me know what you find.
i think the power thats returning from the coil in pin8 1j19 is roughly 77volts same as pin 9 but when i attach the wire to pin 8 if i remeber correctly it kills the pin 1 base part of transistor Q77 causing it to lock on after it fails but i really have no idea i have changed the coil and diode out as well
Quoted from kingsparts123:i think the power thats returning from the coil in pin8 1j19 is roughly 77volts
This is a low power coil, it should only show @ 32 volts. If you put 77 volts on a TIP 122 or 102 it will burn out. The high power is made by the flipper power supply and goes to the flippers and also goes to the purple/yellow wire for the high power solenoids. Is there some way that the high power could be contacting the low power wire?
purple and yellow wire leaves this other board flipper power board at 77 v this purple and yellow wire travels to other coils including both diverters at 77v and near the diverter this white wire with black stripe is connected to the purple wire not sure if its suppose be there or not im assuming so all the other special coils are not run by purple/yellow but a red/white
i believe that white wire is replacesment wire it runs back into a butt connector to purple/yellow and goes to the connector on flipper board in other pic with it unhooked i still have 78v going to all the other coils on that purple/yellow which is both diverters all locked ball coils and kicksave
The high voltage(p/y wire) should only go to coils that have snubber relays controlling them because the TIPs on the CPU can not handle this amount of power. This is why all special solenoids are low voltage (32 volt) coils.
ok that makes sense still unsure of the power in the wire while being unplugged from top of flipper board does it get 78v from another wire
does kick save have a snubber board it seems be ran off the purple/yellow wire as well cant locate snubber board for it
Quoted from kingsparts123:ok that makes sense still unsure of the power in the wire while being unplugged from top of flipper board does it get 78v from another wire
This is a problem for sure. The purple wire is only powered from the flipper board at the top, then to the fuse and then to the 7 coils that are controlled be snubber relays.
I would start by cutting the white/black wire off and then check voltages.
Quoted from kingsparts123:does kick save have a snubber board
The snubbers are listed on page 59a.
i think i solved that i believe they were just holding power in capicators after few min the voltage dropped off then i reconnected the connector then disconnected it same thing after few min power dropped off but the bigger question what wires are suppose run to the diverters if the purple yellow chain is to high voltage?and why does the lower diverter hold up to high voltage and not the upper
The TIP122 will handle 100 volts max and 5 amps max. But only 65 watts, at 77 volts it only takes 0.85 amps to blow this transistor. At the correct voltage 30-32 volts the coil can draw 2 amps before blowing. Any amount of friction can cause the coil to draw a little more current and blowing the TIP. You are lucky the lower diverter isn't blowing the TIP. This will need to be rewired correctly to stop your problems. This is why I run a 1.5 amp fuse for each diverter coil.
thanks alot i did a quick patch i jumper the red/white 36v same as other special coil wire over to the coils and took purple out of it works fine now i cant believe someone did such a stupid hack job i was about to buy a new board u saved me bunches thanks for all your time
one more question on the kick save it hits ball fine but seems like it stays out for few seconds sometimes longer than others is that normal or should it retract instanly
Quoted from kingsparts123:seems like it stays out for few seconds is that normal or should it retract instanly
This is a snubber relay controlled coil and they react slower because of the relay. But it is normally less then a second.
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Indianapolis, IN
