R3LL1K
Well-known member
Anyone know a good place to start?
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Read the section non-working coils of the pinrepair.com sys9/11 guide.
That coil is part of the special solenoid section - not cpu controlled.
Check the ohms of the coil to see if it has a broken winding.
Check power at the coil by putting your DMM to dc volts. Put the black lead on the ground strip of the cabinet and put the red lead on each coil lug. Should be the same volts on each side.
If power is good, find the appropriate TIP122/102 on the cpu board. Connect an alligator clip to the ground strap in the backbox, and briefly touch the other lead to the tab of the TIP. If the coil fires, the problem is on the CPU. If not, you have a wiring issue (of course, the previous test would have already found this).
Read the section non-working coils of the pinrepair.com sys9/11 guide.
That coil is part of the special solenoid section - not cpu controlled.
Check the ohms of the coil to see if it has a broken winding.
Check power at the coil by putting your DMM to dc volts. Put the black lead on the ground strip of the cabinet and put the red lead on each coil lug. Should be the same volts on each side.
If power is good, find the appropriate TIP122/102 on the cpu board. Connect an alligator clip to the ground strap in the backbox, and briefly touch the other lead to the tab of the TIP. If the coil fires, the problem is on the CPU. If not, you have a wiring issue (of course, the previous test would have already found this).
Thanks, I was thinking the same thing but don't have any experience working on pins so I wasn't too sure of where to start. I think I'll probably replace the diodes on all of the coils to start.Check the coil diodes. Sounds like you have a short in the wiring.
I had a question about this as well. I've been testing the coils by placing my test leads on the lug eyelets. Testing this way, none of them had read as shorted or with resistance lower than 4 ohms. Is this about right?Have you checked the coils for shorts?
As soon as the cabinet is powered up the special solenoids are engaged and the fuse blows. All of the special solenoids are engaged with the exception of the non-working slingshot. Any clues?
No, I would expect a shorted coil not to work. I was thinking something would have been shorted period for the coils to energize. I was just replying to Shardian's question on whether or not I tested the coils.A shorted coil wouldn't cause the coils to energize when you power on the game. I assume that's what you're saying here?
I checked the switches on the solenoids that are being energized and they do not test as shorted/closed. I also didn't think this was the problem since the slingshot and pop bumpers are so far from each other on the playfield it didn't make sense.A 7402 IC could be shorted internally if the transistors are being energized when you turn the game on. Either that or a bunch of the special solenoid switches are stuck closed. Or all the driver or pre-driver transistors are shorted.
No, I would expect a shorted coil not to work. I was thinking something would have been shorted period for the coils to energize. I was just replying to Shardian's question on whether or not I tested the coils.
As soon as the cabinet is powered up the special solenoids are engaged and the fuse blows.
IIRC, the special solenoids have a daisy chained power supply.
You're right. All of the solenoids in the game should be "daisy chained" together.
Yes, and if somewhere in the line you have a shot diode and the power tied to ground, it will effectively short out all of the transistors because power will be flowing on the gang ground trace on the board.
The only path to ground should be through the driver transistor. I'm not sure what you mean by "power tied to ground". Even with a shorted coil diode there should be no path to ground anywhere until a driver transistor is biased (or shorted). The diodes on the coils are there to absorb the reverse voltage spike on coil colapse. Unless I'm missing something?