Post a WTB thread and see what you get. I'm sure with everyone who replaced theirs with LED displays that someone has one they would sell you.

viperrwk

Can you tell what is burned? If you're intending to get rid of it I might be interested, looks like I need a new master display for my Firepower too

If you replace driver transistors you should use a TIP102.

Yes Q12 controls the left kicker. Check the coil and make sure it isn't the culprit. Check resistance across the coil lugs, check the wires and diode at the coil, check for voltage at the coil, ground the non-banded coil lug to make sure it fires. If all that checks out ground the metal tab at Q12. If it doesn't fire then, replace the driver transistor.

viperrwk

Why this isn't in Vid's Sys 3-7 guide I don't know. But he does mention replacing TIP120s with TIP102s in his Bally driver board guide:

http://pinside.com/pinball/forum/topic/vids-guide-quick-bally-driver-board-repair-bulletproofing#post-592747

Anyway, the TIP102 is a more robust replacement for a TIP120. A TIP120/122 can handle 5 amps continuous - a TIP102 can handle 8 amps continuous. Bigger safety margin/no difference in price between a TIP122 and a TIP102. Common best practice when replacing. Buy lots of TIP102s. Don't bother with 120/122.

viperrwk

As viper says, TIP102 is equivalent but better.

The sling switches won't show up in switch test, as they are not part of the switch matrix (only the scoring switch is). The special solenoids are controlled separately by 7408s at IC6 and IC7. Since it works in solenoid test the drivers are fine and either the 7408 controlling it is bad or (more likely imo) a switch wire is not making a good connection (fell off, etc)

And check the resistor/capacitor network on the sling switch as well. They are known to come loose/short from vibration.

viperrwk

What happened to the resistor on the flash lamp board?

viperrwk

If the flash lamps are locked on and Q43 is good, next check the predriver at Q42 and then the 7408 at IC4 on the driver board (assuming of course the resistor board is wired correctly, the resistors are good and there are no wiring problems.)

viperrwk

have you removed the rubber?

Not totally clear. Did you say that even with the wires off the slingshot switches, the coil still fires?

Depends on which switch the wires are off of. They are usually in parallel on those switches. Easy to test by making sure that both switches are out of the circuit. Then start a game and see if the coil comes on.

You did say that the coil pops on as soon as you start a game. Not when you power the game on. Right?

If it comes on as soon as you power the game up, then it is a board problem. If you replaced the driving transistor, it could be something further up the line on the board. This is where I don't have the experience to be much help. Hopefully viperrwk and others will be able to chime in with more help on this.

What happens when you enter diagnostics - specifically after the lamp test? Does it lock on or is it ok? Also, have you checked the resistor/capacitor on the leaf switch for the sling? It could be shorting somewhere causing the lock? What's the coil resistance? Eliminate possibilities at the coil itself first before taking the soldering iron to the board.

viperrwk

Could also be coil diode - clip and check if you don't have a spare or just replace it if you do.

If diode and coil are good, and switches are good, next thing on the driver board after the driver trans, pre-driver and 7402 is the PIA at IC5. You also have to suspect 40 pin. Test ROM and logic probe would be good to have here to keep you from pulling the PIA unless you have to.

viperrwk

Good luck. I hope it works out. I always get nervous when messing with those 40 pin interconnect.

Arcade chips have 68B21 which will do the job.

http://www.arcadechips.com/product_info.php?products_id=145

6821 and 6820 are interchangeable for this application.

Andy

Just a quick socket tip:

Always get the SIP sockets:

http://www.taydaelectronics.com/connectors-sockets/sockets/sip-sockets/30-pin-dip-sip-ic-sockets-adaptor-solder-type.html

You just snap them to any length you want (they come in 40 pin lengths).

This way you ALWAYS have the correct socket on hand for any repair. No need to have 4, 6, 8,14,16, 20 pin sockets in your part drawers.

The ones from Tayda above I've used 1000s of times and never had a bad cell.

You can solder them from the top side of the board too - great when someone's previous "repair" has ruined the through-holes.

If the sling is firing when you get into solenoid test mode, there's a couple possibilities, IC 5 likely wouldn't be it. This one is going active when the solenoid activation signal from IC5 turns on, so the PIA is pretty much working fine. This also rules out Q12, as a stuck transistor wouldn't care which mode the game was in, it would fire as soon as you powered up the machine.

#1 possibility is just a switch adjustment at the sling or something goofy in the wiring. Easy enough to check. On the left side of your driver board, pull the connector closest to the top. This will disconnect the special solenoid switches. If the pop bumper de-powers, it's wiring. If it stays active, it's driver board.

#2 is the driver board. Could be either IC7 or IC9, with an off chance of being R6 or C6 but I rarely see them fail. In audit mode, I'd check the logic states at IC7 pins 8,9,10 and IC9 pins 11,12,13

#3 I's also very unlikely, but ST6 that fires that particular special solenoid actually comes across from the CPU board PIA chip IC18 through pin26 of the interboard connector. Check the logic state at that pin too.

I have too much of a headache right now to dig up all the 74xx logic states to figure it all out, but those are your primary suspects in this situation.

-Hans

Congrats on the repair!

The PIA rarely goes on a solenoid short.

Here is a great tip. You can find bad TTL logic ICs easily and quickly with a DMM. Power off. DMM on diode test. Red lead on ground, black lead on suspect 7408/7402 outputs or inputs for that matter. You should get a reading over .4 or so. Anything below .3 or .2 and that IC is dead. This works 90% of the time on sys 3-7 driver boards.

If i replace a dead solenoid driver transistor I always check the predriver and 7402 / 7408 ICs as well.

Andrew

Since you replaced the 7408, it's either the 4.7K pullup resistor, or more likely the playfield switch, specifically the RC network on it. Common point of failure.

viperrwk