(Topic ID: 249035)

TECH: F-14 Solenoid/Flasher Issue


By mikemoorman

12 days ago



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  • 45 posts
  • 7 Pinsiders participating
  • Latest reply 5 days ago by mikemoorman
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Solenoid-Flasher Table.pdf (PDF preview)

#1 12 days ago

I dragged an F-14 out of storage ("it ran when parked") to shop it and rotate it into the herd. There a few things going on.

The good news is the displays are bright - the lamps work - the sound is perfect - all switches work - flippers work.

The bad news is within a few seconds of turning on the 2.5A fuse above the flipper power supply blows (the VIO-YEL circuit) probably as it is doing a ball search and fires a coil. With the fuse removed the games boots and runs in attract mode no problem.

I tested all coils and none were shorted. All were about 5 ohms except the two diverter coils - they were about 15 Ohms.

The power supply seems fine (I think):
+5 VDC = 4.9VDC
+12 VDC UNREG = 11.6 VDC
-12 VDC UNREG = 14.1 VDC
-100 VDC = -103.8
+100 VDC = 103.4

The VIO-YEL voltage out of the flipper power supply the fuse is 75.5 VDC

Some of the flashers work but also lock on the #89 flash lamp located under the left side ball guide in-lane.

When in Coil test there are some anomalies - mostly on the "C" side. A spreadsheet is attached with the results in coil test.

Thanks in advance!
Solenoid-Flasher Table.pdf

#2 12 days ago

How do the Bridge Rectifiers test?

#3 12 days ago

Did you check the diodes for a short?

#4 12 days ago
Quoted from Tomass:

Did you check the diodes for a short?

I will double check the diodes - thanks!

#5 12 days ago
Quoted from Completist:

How do the Bridge Rectifiers test?

Yes I did and the DC voltage out seemed correct.

The voltage output from the flipper power supply seemed a little high (75 vdc) but it is unregulated and not sure it is out of range.

#6 12 days ago

One of the weird things was the flash lamp that locks on when other flashers are pulsing.

#7 12 days ago

Do you mean the diodes at the coils or the diode board - OR both?

I will check ALL the diodes.

#8 12 days ago

I will also confirm the BR are in spec according to this test: http://www.pinwiki.com/wiki/index.php?title=General#Testing_a_Bridge_Rectifier

#9 12 days ago

This one is weird, paging grumpy bump!

#10 12 days ago
Quoted from bobukcat:

This one is weird, paging grumpy bump!

Yep - he is the first person I thought of.....

The #89 that locks on while others are cycling only happens on the "switched" coils/flashers.

#11 12 days ago

Maybe try to isolate solenoids to figure out what's blowing the fuse would be a start? I don't have my F14 Schematics here anymore or I'd be digging through them.

#12 12 days ago

'The voltage output from the flipper power supply seemed a little high (75 vdc) but it is unregulated and not sure it is out of range.'

Should be OK since it is not under load.

Call me dense, but I am not sure I understand your (excellent) spreadsheet notes. "Flashes but also left in-lane #89 on solid" means? Is 02C flasher always on? On only when any of the other 'C' flashers are activated?

If it is 02C, and 02A works, then it is not that driver transistor Q25. It sounds like a short on the driver side of that flasher. Since those flashers have a 'warming' resistor, 330 ohms, it could be a short there. I am pretty sure those stupid warming resistors can be removed. Those boards with the resistors are a source of a lot of flasher problems on these pins.

'2.5A fuse above the flipper power supply blows'. My F14 is all apart being rebuilt, so I cannot easily look through that.

In the manual, there is a 2.5A SB on a Vio-Yel wire on page 59A. [Grin - I think that one also blew on mine when I first got it working 3 years ago.] That does go to the Ball Shooter Lane Feeder plus 6 other solenoids. Unfortunately, I do not remember what that strange symbol means on page 59A that looks like a box with four connections. I vaguely remember having to figure all that out.....

Will scratch head and look further.

#13 11 days ago
Quoted from lhammer610:

Call me dense, but I am not sure I understand your (excellent) spreadsheet notes. "Flashes but also left in-lane #89 on solid" means? Is 02C flasher always on? On only when any of the other 'C' flashers are activated?

Yes- when one of the working flashers is pulsing in coil test the #89 under the ball guide plastic near the left in lane comes on steady (goes out when I switch to the next coil in test) but the flasher in test pulses as it should.

#14 11 days ago

My spreadsheet is mis-leading on the results for Flasher 2. Flasher 2 is the #89 under the left flipper return frame. When I go to test that flasher in coil test it comes on steady. It will also come on steady when I test other flashers (they pulse as they should).

I am mapping the Flashers now as I wasn't sure where some of them are located.

#15 11 days ago

So 'A' side Q25 is not locking on? It sounds like a wiring problem on the playfield side to me. Something is grounding out that flasher.

#16 11 days ago
Quoted from uncivil_engineer:

So 'A' side Q25 is not locking on? It sounds like a wiring problem on the playfield side to me. Something is grounding out that flasher.

Correct - the "A" side for Q25 works correctly. I will dig into that circuit wiring (02C) and look for shorts or grounds.

#17 11 days ago
Quoted from lhammer610:

'The voltage output from the flipper power supply seemed a little high (75 vdc) but it is unregulated and not sure it is out of range.'
Should be OK since it is not under load.
Call me dense, but I am not sure I understand your (excellent) spreadsheet notes. "Flashes but also left in-lane #89 on solid" means? Is 02C flasher always on? On only when any of the other 'C' flashers are activated?
If it is 02C, and 02A works, then it is not that driver transistor Q25. It sounds like a short on the driver side of that flasher. Since those flashers have a 'warming' resistor, 330 ohms, it could be a short there. I am pretty sure those stupid warming resistors can be removed. Those boards with the resistors are a source of a lot of flasher problems on these pins.
'2.5A fuse above the flipper power supply blows'. My F14 is all apart being rebuilt, so I cannot easily look through that.
In the manual, there is a 2.5A SB on a Vio-Yel wire on page 59A. [Grin - I think that one also blew on mine when I first got it working 3 years ago.] That does go to the Ball Shooter Lane Feeder plus 6 other solenoids. Unfortunately, I do not remember what that strange symbol means on page 59A that looks like a box with four connections. I vaguely remember having to figure all that out.....
Will scratch head and look further.

Yeah, those symbols are for the snubber board relays and I've never understood that or seen that type of symbol used before. I don't believe the warming resistors can be removed unless you switch to LED Flashers and then they have to be removed.

#18 11 days ago
Quoted from bobukcat:

I don't believe the warming resistors can be removed unless you switch to LED Flashers and then they have to be removed.

I do plan to use LEDs in place of the #89 lamps mostly to eliminate the warming resistor boards.

#19 11 days ago
Quoted from mikemoorman:

The #89 that locks on while others are cycling only happens on the "switched" coils/flashers.

Is this the correct flasher?

Quoted from mikemoorman:

Yes- when one of the working flashers is pulsing in coil test the #89 under the ball guide plastic near the left in lane comes on steady (goes out when I switch to the next coil in test) but the flasher in test pulses as it should.

When in test the A/C relay is also being pulsed on and off, that's why it flashes in test.

Quoted from mikemoorman:

Correct - the "A" side for Q25 works correctly.

Find the resistor board with the black/red wire. This wire goes from the resistor board to the diode board. It might be pinched somewhere to ground under the play field. If you unsolder the black/red wire from the resistor board it should turn off.

f-14 (resized).PNG
#20 11 days ago
Quoted from GRUMPY:

Is this the correct flasher?

Yes it is.

When in test the A/C relay is also being pulsed on and off, that's why it flashes in test.

Got it - thanks.

Find the resistor board with the black/red wire. This wire goes from the resistor board to the diode board. It might be pinched somewhere to ground under the play field. If you unsolder the black/red wire from the resistor board it should turn off.[quoted image]

Tracing that black/red wire now.

#21 11 days ago

I removed the BLK/RED from the DRV pad on the resistor board and as expected 02C did not light during the coil test and did not come on steady as it did before. All flashers (except 02C - of course) work correctly.

I traced the BLK/RED to the diode board (terminates on A2). I metered the BLK/RED to ground and it was clean (all the way to 200M ohm - highest on my meter). ALL diodes on the diode board test good. It leaves the diode board on B2 (GRY/RED) and terminates on the CPU at 1P11-3. With 1P11 unplugged from the CPU the GRY/RED was clean of grounds.

Does this point to the CPU as a problem?

PS: I should mention that the 6 RED flashers (01C thru 06C) at the back of the playfield are unplugged (and have been) from the harness.

#22 11 days ago
Quoted from mikemoorman:

Does this point to the CPU as a problem?

Normally I would have assumed that Q-25 was shorted but you say the 2a solenoid is working correctly.
If you replace the black/red wire and leave 1P11 off, does the flash lamps stay off?

#23 10 days ago
Quoted from GRUMPY:

Normally I would have assumed that Q-25 was shorted but you say the 2a solenoid is working correctly.
If you replace the black/red wire and leave 1P11 off, does the flash lamps stay off?

UPDATE on 02A and02C. I was fooled by 02A thinking it was working correctly. The wire on the coil was disconnected for testing and during coil test I would touch the wire back to the lug. It fired and I removed it. The coil sleeve is so gummed up it doesn't return on its own. What I *should* have done was use a jumper to see that the 02A coil was indeed locked on - same as flasher 02C.

I tested Q25 on the board and it tests good (just like all the others) - not shorted using this method.

"Place the black lead of your DMM on the metal tab of the transistor
Probe each of the flanking legs with the red lead
.4 to .6 volts is a normal reading. Readings outside of this range indicate a failed transistor
Probe the center leg with the red lead
A "short" should be seen. If not, then the transistor has failed."

If Q25 is okay do I look at the pre-driver or beyond?

Sorry to lead you on a goose chase - it is making more sense now and I am learning so much.

#24 10 days ago
Quoted from mikemoorman:

The coil sleeve is so gummed up it doesn't return on its own.

I going to bet it is melted a bit from a transistor that is leaking current with the power on, but tests OK with the power off. I would replace Q-25 and its predriver. This should take care of your first issue.

Now for your second issue, the 50 volt power fuse.

Quoted from mikemoorman:

The bad news is within a few seconds of turning on the 2.5A fuse above the flipper power supply blows (the VIO-YEL circuit) probably as it is doing a ball search and fires a coil.

First is why is it doing a ball search? No balls?

#25 10 days ago
Quoted from GRUMPY:

I going to bet it is melted a bit from a transistor that is leaking current with the power on, but tests OK with the power off. I would replace Q-25 and its predriver. This should take care of your first issue.
Now for your second issue, the 50 volt power fuse.

First is why is it doing a ball search? No balls?

Grumpy - Thanks so much.

I will pull the CPU and replace Q25 (TIP102) and the associated predriver Q21 (2N4401). I also see that U20 is socketed - should I swap it out?

Quoted from GRUMPY:

First is why is it doing a ball search? No balls?

Correct - no balls in the game at this point. I did see one coil with a broken diode when I was testing the coils. I need to get my circuit breaker back from my buddy before I go too far on the 50 volt issue as I only have four 2.5A MDL fuses in my stash.

#26 10 days ago

Put the 4 balls in the game. You don't need a fuse to troubleshoot. Turn on the game. Use a voltmeter and check the metal tabs of the TIPs for the snubber relays. A good tip will have @ 30 volts. If I remember correctly there is 6 snubber relays.

#27 10 days ago
Quoted from GRUMPY:

Put the 4 balls in the game. You don't need a fuse to troubleshoot. Turn on the game. Use a voltmeter and check the metal tabs of the TIPs for the snubber relays. A good tip will have @ 30 volts. If I remember correctly there is 6 snubber relays.

Brilliant! I will do this - thanks again.

#28 10 days ago

Here you go.

f (resized).PNG
#29 10 days ago
Quoted from GRUMPY:

Here you go.[quoted image]

Thank you - this will save me a lot of time!

#30 9 days ago

I removed this post because my screen had not been updated and you had already addressed this issue.

#31 9 days ago
Quoted from lhammer610:

I removed this post because my screen had not been updated and you had already addressed this issue.

Thanks for following - I am getting closer to dialing this in.

I will update later today when I replace Q25 & Q21 and test the SOL drives Q8 - Q9 - Q15 - Q30 - Q31 - Q32.

#32 9 days ago

I replaced Q25 and the pre-driver Q21. I had the exact same results (02A & 02C lock on). I also replaced U20 (7408) since it was socketed and took seconds to do so. No change.

I also tested the solenoid TIPs as mentioned above. 5 of the 6 and had 34.8 volts between GND and the tab. Q30 had no volts. I assume Q30 is bad but it test OK doing a transistor test.

#33 9 days ago

So it looks like both issues are tied together. Time for a logic probe on U -28.

#34 9 days ago

As soon as I turn the power on SOL# 02A locks on.

I went to start a game knowing I would have to substitute my finger for some coils and as soon as I pressed the credit button the SOL# 02C (left flipper return lane flasher) comes on and the A/C relay starts toggling.

The game plays and scores so other than the SOL# 02A & 02C issue and the 50 volt circuit (which might be Q30) it is close.

I am going to update the coil test spreadsheet later today as some of the results have changed as I understand things better.

#35 9 days ago
Quoted from GRUMPY:

So it looks like both issues are tied together. Time for a logic probe on U -28.

Yes - I agree. I just ordered one and it will be here in a couple of days. I might borrow my friend's - I am anxious to get to the finish line!

#36 6 days ago

I have received the Logic Probe. I did some reading on TTL and think I understand truth tables and some basic gates (AND - NAND - OR - NOR - XOR - MUX).

Where is the best place to pick up GND and +5VDC to test U28? I assume the ground braid for black lead, is the +5VDC on the 8345 power supply ok for the red lead or does it need to be taken from the CPU itself?

I have a copy of the 74LS374 datasheet and understand the pin-outs.

#37 6 days ago
Quoted from mikemoorman:

I have received the Logic Probe. I did some reading on TTL and think I understand truth tables and some basic gates (AND - NAND - OR - NOR - XOR - MUX).
Where is the best place to pick up GND and +5VDC to test U28? I assume the ground braid for black lead, is the +5VDC on the 8345 power supply ok for the red lead or does it need to be taken from the CPU itself?
I have a copy of the 74LS374 datasheet and understand the pin-outs.

Most of them aren't too picky about input voltage, mine is rated for 5-13V, so it shouldn't matter as long as it's a solid source.

#38 6 days ago
Quoted from bobukcat:

Most of them aren't too picky about input voltage, mine is rated for 5-13V, so it shouldn't matter as long as it's a solid source.

Thanks. Mine is rated 4 - 18V so I will find a regulated output and start there.

#39 6 days ago
Quoted from mikemoorman:

Where is the best place to pick up GND and +5VDC

Both test points are on the cpu board.

#40 6 days ago
Quoted from GRUMPY:

Both test points are on the cpu board.

Thanks Grumpy. I will dig into this in the morning.

#41 5 days ago

My weird issues are nearly solved!

I was using my Logic Probe on U28 and documenting the results when I noticed on some pins as I push to make contact one of the coils would fire (either right flipper or right sling). That made me think a pin or pins weren't making contact in the socket. I pulled the chip - examined it - re-installed it everything started working with no locked on coils/flashers. I would have never thought to re-seat the chip (but do it all the time on ribbon cables for displays).

I reconnected all the VIO-YEL coils and test for 35VDC to the transistors and ALL were good. I replaced the 2.5A fuse and it did not blow. It actually started a game.

I went back into coil test to verify all coils/flashers were working (they are) but noticed a phantom firing of the Rescue Kickback when some coils fire in test.

Video here(the clicking you hear is Line of Death coil - SOL# 12 - firing in coil test):

It is a weak firing as it is easily stopped with a finger. I lifted the diode on the Recuse coil and it tested good.

Here are the coils that will make the Rescue coil fire:

SOL# 03A
SOL# 05A
SOL# 07A
SOL# 10
SOL# 12
SOL# 21
SOL# 22

The game is very close and I would not have gotten this far without help and would have never started probing U28 without grumpy pointing me directly to it. I had multiple issues (locked on coils - shorted 50V) that are behind me. I have learned so much, which is nice since I love SYS11 games and have several in the collection (Cyclone - Bad Cats - PinBot - F14).

Thanks again to all that assisted me - cheers!

#42 5 days ago
Quoted from mikemoorman:

It is a weak firing as it is easily stopped

Has the power supply been recapped? Check the 24 volt power with a voltmeter for both DC and AC.

#43 5 days ago
Quoted from GRUMPY:

Has the power supply been recapped? Check the 24 volt power with a voltmeter for both DC and AC.

No - the power supply has not. I was in the middle of ordering a cap kit when this post came in. I will report back after I re-cap the 8345.

Thanks a million!

#44 5 days ago

You are getting a pulse on the 24 volt line causing the relay to pulse, since only the one relay is pulsing there may also be a issue with that snubber relay.

#45 5 days ago
Quoted from GRUMPY:

You are getting a pulse on the 24 volt line causing the relay to pulse, since only the one relay is pulsing there may also be a issue with that snubber relay.

I will take a close look at that associated snubber - thanks!

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