(Topic ID: 190267)

How to troubleshoot special switches/solenoids?


By harryhoudini

1 year ago



Topic Stats

  • 19 posts
  • 6 Pinsiders participating
  • Latest reply 46 days ago by Sheprd
  • Topic is favorited by 6 Pinsiders

You

Linked Games

Topic Gallery

There have been 4 images uploaded to this topic. (View topic image gallery).

U45.jpg
NOR (resized).JPG
Williams_1986_High_Speed_Instruction_Manual_pdf__page_55_of_63_ (resized).jpg
Williams_1986_High_Speed_Instruction_Manual_pdf__page_57_of_63_ (resized).jpg

#1 1 year ago

High Speed has the left sling that doesn't fire. Since it is a SS it isn't on the switch test. The coil does not fire during the coil test. The board was refurbished by BigDaddy and when I installed a few transistors popped from bad coils. The sling was one of them. I replaced the visibly popped transistors and most everything in the game works. Continuity is good from the switch to the board. The logic probe is on the way but I'm not good yet at reading schematics.

1J182 is the pin on the J18 connector that is the switch. It's labeled SS3T, standing for special switch what? What is STS3D?

I'm guessing the first thing to look at is something a transistor TIP122 at Q71 or Q73 (again, not sure exactly how to read the schematic). Once the logic probe is here I'm sure this would be somewhat easier but I still won't have an idea of what to do. Even where to attach the probe for ground and +5 (is that the test point?).

Can someone tell me which part of the schematic I am actually looking at? Red or yellow?

Williams_1986_High_Speed_Instruction_Manual_pdf__page_57_of_63_ (resized).jpg

#2 1 year ago

Doing some more reading.. so I see that IJ182 is special solenoid 3 switch and IJ193 is special solenoid 3 which appears to have Q79 written next to it. But Q79 is the transistor for the Top Flasher it seems (see image). What am I not reading properly?

Is there some higher resolution resource for schematics? So hard to read some of the items.

Williams_1986_High_Speed_Instruction_Manual_pdf__page_55_of_63_ (resized).jpg

#3 1 year ago

So, to help with reading the schematic: there will be a switch that gets grounded when the solenoid should pull in. This line goes to the input of a NOR gate. The other input to the NOR gate is a blanking signal that disables all the special solenoid drivers until the system is ready... prevents spurious firing during power-up. When both inputs to the NOR gate are low, the output goes HIGH, turning on the pre driver transistor (2n4401) which drives the TIP122 darlington transitor to turn on, effectively providing a path to ground for the special solenoid. The other side of the solenoid is connected to the power source for the solenoid, and is usually daisy chained to multiple solenoids.

To test the circuit, you can "touch" ground the switch input and the solenoid should pull in. A logic probe is not that useful of a tool for this kind of circuit testing. Just using a voltmeter and understanding how the circuit works will allow you to find issues. To check the wiring from the output of TIP122, touch grounding that should fire the solenoid. If you ground the switch input, and do not get a solenoid pull in, then the problem is in the path... NOR gate IC, 2n4401, or TIP122... with the likelihood of failure being in reverse order.

Hope that helps.

Mac

#4 1 year ago
Quoted from harryhoudini:

High Speed has the left sling that doesn't fire.

Page 2 of the manual says the left kicker is special solenoid #1.

Quoted from harryhoudini:The coil does not fire during the coil test.

This should fire in coil test.

Quoted from harryhoudini:1J182 is the pin on the J18 connector that is the switch.

It should be 1J18 pin 5.

Quoted from harryhoudini:

It's labeled SS3T, standing for special switch what?

Special Solenoid 3 Trigger.

Quoted from harryhoudini:I'm guessing the first thing to look at is something a transistor TIP122 at Q71 or Q73 (again, not sure exactly how to read the schematic)

No Q-74 and Q-75

Quoted from harryhoudini:

Even where to attach the probe for ground and +5 (is that the test point?).

5 volt test point is by U-22 and the ground test point is by the battery pack.

Quoted from harryhoudini:

Doing some more reading.. so I see that IJ182 is special solenoid 3 switch and IJ193 is special solenoid 3 which appears to have Q79 written next to it. But Q79 is the transistor for the Top Flasher it seems (see image). What am I not reading properly?

This is an error in the manual and not the only one. Q-79 is for SS6 Top flashers.
You are going to need to troubleshoot U-45 which is a 7402 NOR chip. Do some reading on this chip, so you understand how it works and how the pins are labeled and when you get your logic probe I can walk you thru testing it.

#5 1 year ago

Thank you both! Back at it tomorrow (or rather today now)

#6 1 year ago

forget the switch inputs for now. start at the coil and work backwards. I am assuming the driving transistors are Q70/Q71.

0) Game on, put DMM on either lug of coil. should show 35 volts DC.
1) Ground the non-banded coil lug with a jumper wire. coil should fire.
2) ground the transistor lug for this coil (q71) at the cpu board. coil should fire.

if steps 0 to 2 don't give results, you probably have a power issue.

Turn game off...
3) remove connect J19 from the CPU board and using DMM set to diode function (and game off), test the Q71 transistor. black DMM lead on the metal transistor tab. Both outside legs should show .4 to .6. If not, transistor probably bad, replace with a new TIP102. After done testing, replace connector J19.

If still not working....

4) Now turn game on and put the game into coil test, and select this coil. (use the middle diag switch to "stop" the test from moving. this will continually fire that coil, over and over.)

5) use the logic probe. Assuming the coil transistor is Q71, put the logic probe on u45 pin 5. It should "beep" about every second, as the PIA tries to fire the coil. That is, it should be HIGH and momentarily go LOW as the diagnostics pulse the special solenoid in question. If you have nothing here, the PIA chip is probably the issue.

6) if you have a signal at u45 pn 5, look at u45 pin 6. this is the blanking. this should be LOW all the time. Note when the game boots and is not in play or in test, blanking will be HIGH. When a game is started (or diagnostics are started), blanking goes LOW. Pobably not an issue, but worth mentioning. if blanking is high or missing, none of the other coils will fire, so it's probably not the issue (unless there's a broken trace.)

7) What the 7402 chips is doing is looking for two LOW inputs (the blanking, which is always low, and the PIA signal, which is high but goes low for just a moment as the desired coil is pulsed). Now go to the output pin u45 pin 4. the coil test is still running, and this pin should bounce HIGH every second or so (as the diagnostics pulse the coil in question). What is happening is the blanking (pin6) and the input (pin5) both need to be LOW for the output (pin4) to trigger HIGH. if you have no signal on u45 pin 4, the problem is the u45 chip. replace it (and use a socket).

At this point, you can follow the signal to Q70 if you want, and to Q71. But frankly unless the board is damaged (broken trace), the issue is probably Q71 (tip122 but replace with tip102). While you're at it replace q70 too (2n4401). Note the test in step3 is not definitive. Even though the transistor tested as "good" in step3, doesn't mean it is necessarily good. (Opposed to it testing bad, where it means that transistor is definitely bad.)

with this done, the coil should fire in coil test. If the coil fires in test, but not in the game, we can test the switch inputs. But 98% of the time, the switch input is not the problem.

#7 1 year ago

Clay corrected his post to align with the logic below. Thanks Clay for the nice write up.

On a NOR gate, both inputs must be LOW to get the output to go HIGH. The Blanking line would then need to be LOW. If the Blanking signal is HIGH at pin 6, the output pin 4 will always be LOW and not "bounce".

NOR (resized).JPG

#9 1 year ago

And the probe came just in time! Man that thing is awesome. I feel like a freaking surgeon now.

Coil fired when I ground the non-banded lug (spark and noise, shocking)

All of the transistors near that J18/19 area are good except Q75 which had the right lug on "OL". So I assume that is bad. The knocker coil doesn't work either (should have mentioned that, forgot about it), maybe related, I didn't trace yet. Wanted to share my results and play some JP

The IC at U45 is definitely the issue. I am not sure which side is up (the schematics are all "upside down" in the manual so I assume we read the board that way and thus the "bottom" of the chip is really the side with pin 1?) but it doesn't matter since when the coil test is firing the left sling none of the pins bounce. And the bottom row, what I expect is pin 3 (I think) has a "fuzzy" signal which, having read https://pinside.com/pinball/forum/topic/terrybs-guide-to-logic-probes/page/2, tells me the chip is definitely bad.

Well, glad I just bought a new Weller, tip tinner and 8 tips. Guess I should watch some IC desoldering and replacing videos now.

Sounds like with both transistors and the chip replaced I should be good to go (as long as traces aren't bad). Guessing all of the locked up coils caused the IC to fry?

#10 1 year ago
Quoted from harryhoudini:

The IC at U45 is definitely the issue. I am not sure which side is up (the schematics are all "upside down" in the manual so I assume we read the board that way and thus the "bottom" of the chip is really the side with pin 1?)

Pin 1 (in blue)

U45.jpg

#11 1 year ago

zaza Woah woah woah... where do I get schematics that look like that?!? I can barely read the stuff in the manuals.

#12 1 year ago

I'm afraid it doesn't exist. This is a piece of an unfinished sys11 layout that I started in 2016. Probably need another year to finish.
This morning I colored this particular area and added some info in U45 to make it more clear.

#13 1 year ago

WOW. Those would be so handy, very cool.

#14 1 year ago

I have updated my post above with some corrections/additional ideas.

#15 1 year ago

Based on Clays correction, I removed the original quote with the error in it in my post above. Thanks Clay.

#16 1 year ago

Thanks again! Amazon is getting that chip here tomorrow (gotta love that!, and I got a socket..well a whole set of them) so hopefully that does it

#17 1 year ago

Sorry it took me a few edits to get everything perfectly correct in my original post. Was trying to do this from memory, and that didn't work so well! had to take apart a high speed to test everything and make notes, so i could update the post for accuracy. I believe it's all correct now.

1 year later
#18 48 days ago
Quoted from Sheprd:

So, to help with reading the schematic: there will be a switch that gets grounded when the solenoid should pull in. This line goes to the input of a NOR gate. The other input to the NOR gate is a blanking signal that disables all the special solenoid drivers until the system is ready... prevents spurious firing during power-up. When both inputs to the NOR gate are low, the output goes HIGH, turning on the pre driver transistor (2n4401) which drives the TIP122 darlington transitor to turn on, effectively providing a path to ground for the special solenoid. The other side of the solenoid is connected to the power source for the solenoid, and is usually daisy chained to multiple solenoids.
To test the circuit, you can "touch" ground the switch input and the solenoid should pull in. A logic probe is not that useful of a tool for this kind of circuit testing. Just using a voltmeter and understanding how the circuit works will allow you to find issues. To check the wiring from the output of TIP122, touch grounding that should fire the solenoid. If you ground the switch input, and do not get a solenoid pull in, then the problem is in the path... NOR gate IC, 2n4401, or TIP122... with the likelihood of failure being in reverse order.
Hope that helps.
Mac

It's been a year but I want to call out what an excellent post this is. Thanks Sheprd

#19 46 days ago
Quoted from Cheddar:

It's been a year but I want to call out what an excellent post this is. Thanks Sheprd

Glad to help!

Mac

Promoted items from the Pinside Marketplace
$ 399.95
$ 14.00
Electronics
Yorktown Parts and Equip
$ 10.00
Cabinet - Sound/Speakers
Gweem's Mods
$ 20.00
Electronics
Yorktown Parts and Equip
Wanted
Machine - Wanted
Hackettstown, NJ
$ 15.75
Cabinet Parts
Tilted Pinball
$ 29.99
Eproms
Matt's Basement Arcade
$ 109.00
Cabinet Parts
Tilted Pinball
$ 164.99
Lighting - Led
PinballBulbs

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside