Pinbot
Williams, 1986Hi all, I recently bought a Pin*Bot that I am trying to get working 100%. While I was playing around with it last night, the left slingshot locked on. It fires as soon as power is applied to the machine. I checked for continuity in the coil and it appears to be good. I don't have the best electronics knowledge and this is my first system 11 game so can anyone point me in the right directon?
Thanks!
First, make sure the slingshot switch isn't closed. Stick a business card between the contacts. If that fixes it then widen the gap on the contacts. Also make sure the rubber hasn't slipped around and is forcing the switch closed.
Quoted from jhend1000:The switches on the slingshot are open so I don't think that's the problem. How do I check the transistor and which one should I check?
Manual to find which transistor - YouTube or Google to learn basic use of a meter and check for a shorted transistor.
LTG : )
Page 27 in the manual will give you the solenoid driver info. Left kicker is Q69.
The following article will explain how to test transistors. Basically though, since you're looking for a short, check each leg of the transistor to every other leg with the DMM in diode/coninuity mode and the game off and see if you've got a short. Beep or zero reading means a short.
http://pinballrehab.com/1-articles/solid-state-repair/tutorials/120-electronics-tutorial-transistors
P.S. - Do not leave the game on while this problem exists or you'll fry something.
Quoted from jhend1000:Thanks, this is very helpful! What type of transistor did they use?
The CPU schematic in the manual shows Q69 as a tip122.
This usually takes out the pre driver too, I would check that as well. If it's still locked on, I believe there is a 7400 series IC behind the pre driver and that can commonly get taken down due to the driver transistor failing.
Quoted from terryb:The CPU schematic in the manual shows Q69 as a tip122.
Which, of course, you can sub a TIP-102 in place of.
Don't let that coil stay engaged long. Doing so may cause additional damage.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
In continuity mode, Q69 appears to compare to the rest of the transistors so we may be good there. Do ou think it could be the diode on the coil itself? The left kicker is one of the special solenoids so could it be the capacitor or the resiztor on the switch as well?
Quoted from jhend1000:In continuity mode, Q69 appears to compare to the rest of the transistors so we may be good there. Do ou think it could be the diode on the coil itself? The left kicker is one of the special solenoids so could it be the capacitor or the resiztor on the switch as well?
Nah...not the diode. The diode merely suppresses the reverse EMI spike when the cils magnetic field collapses.
You need to test the transistor using "diode test" on your meter.
Yes, it could be components upstream of the transistor. The special solenoid a have some extra circuitry. Could be the 7408 that is in the circuit as I see them failed often on System 11 boards I repair for folks.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
Quoted from Atomicboy:This usually takes out the pre driver too, I would check that as well. If it's still locked on, I believe there is a 7400 series IC behind the pre driver and that can commonly get taken down due to the driver transistor failing.
Is this pre-driver also a type of transistor? If it is, what kind? The man I bought it from said that he had to replace some chips on the board before he sold it to me. I'm not sure which ones. It could be the 7408 for the special solenoids so I'll have to ask him tomorrow. Does it matter which brand chip I have to use for this or can I just buy any 7408 out there?
The brand does not matter as long as its a 7408.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
The pre-driver transistor is a 2N4401 (online manual is hard to read, but I think it's Q68).
If we're talking about U45 it's a 7402.
There's also a zener diode in that circuit that can go bad.
Don't suppose you have a logic probe?
Quoted from terryb:If we're talking about U45 it's a 7402.
Whoops. Yup, it's a 7402. Good catch.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info
You can test the driver, pre driver, and 7402 with a DMM for a dead short before replacing anything.
Up to you. I use a logic probe a lot, but as atomicboy said you could possibly find the problem using a DMM in diode/continuity and testing for a short. You could also take voltage readings (although they will read slightly funny) and compare to another circuit.
There are other ways of getting the job done, a logic probe just makes it easier.
They are hard to find, but useful for pinball. Oscilloscopes today can be easier to find, and cheap, but are big and clunky. Either way, test this stuff first. Do you have clay's guides?
Quoted from jhend1000:Ok. I'll probably grab a logic probe if I see one pretty cheap. I'll test with the dmm later today. Which leg is ground?
Here's a good, inexpensive probe...
http://tinyurl.com/c8zx6pa
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Quoted from terryb:Before you start replacing any components I would disconnect the solenoid, go into switch edge test and make sure the game doesn't think that switch is closed.
Definitely. In general, exhaust all "non-invasive" possibilities before heating up the iron. And if you do heat up the iron, be convinced that the part you are attacking is the right part.
You can test the 7402 with a DMM with the procedure outlined at www.pinwiki.com under "General for all games".
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info
I found this Thread when I had the the same issue with a coil locking on and I think it is the same circuit. I followed what was in the thread replacing the transistor, pre-drive transistor and the chip and it fixed the problem all for under $10.
http://pinside.com/pinball/forum/topic/pinbot-help-left-jet-stuck-on
Good luck!
Well, I unhooked the wire form the coil and played a quick test game. A lot of features that
Were previoiusly working are now not. I now have two dead jet bumpers and one ofthe flashers in the visor stays on all the time. It was also scoring the 5,000 vortex without me touching it as if the switch were stuck but I turned if of and on again and startrd a game but it didn't do it again. It seems fine otherwise. I'm thinking that the 7402 is bad for sure. What do you guys think?
Quoted from jhend1000:Well, I unhooked the wire form the coil and played a quick test game. A lot of features that
Were previoiusly working are now not. I now have two dead jet bumpers and one ofthe flashers in the visor stays on all the time. It was also scoring the 5,000 vortex without me touching it as if the switch were stuck but I turned if of and on again and startrd a game but it didn't do it again. It seems fine otherwise. I'm thinking that the 7402 is bad for sure. What do you guys think?
I think that is not even close to what I suggested.
Quoted from terryb:Before you start replacing any components I would disconnect the solenoid, go into switch edge test and make sure the game doesn't think that switch is closed.
You are moving too fast. Did you desolder two wires from one coil lug, and they are now not connected? If so, you just broke the connection for the rest of the daisy chained coils, which is why they don't work.
I thought this was already narrowed down to a coil issue. If it is not, go into the switch test and make sure the switch works, and test every other switch in the row and column.
If that checks out, and AFTER soldering back on the wires to the CORRECT lugs, fire all coils, and make sure all coils in the same daisy chain set work (just fire all coils in the game, if you only missing the shooter, you know the rest are fine).
THEN, it's time to check the resistance of the coil. THEN check the driver to see if it's shorted, if it is, check the pre driver and the 7402. It could also have gone back to the PIA behind the 7402, but you can't check that with a DMM.
There is a line of assault that you need to follow, which backtracks the issues.
Quoted from terryb:I think that is not even close to what I suggested.
Well, I think someone screwed up the auto up-manual down switch because there are three buttons and not a switch so I wasn't able to test it that way.
Quoted from Atomicboy:You are moving too fast. Did you desolder two wires from one coil lug, and they are now not connected? If so, you just broke the connection for the rest of the daisy chained coils, which is why they don't work.
I thought this was already narrowed down to a coil issue. If it is not, go into the switch test and make sure the switch works, and test every other switch in the row and column.If that checks out, and AFTER soldering back on the wires to the CORRECT lugs, fire all coils, and make sure all coils in the same daisy chain set work (just fire all coils in the game, if you only missing the shooter, you know the rest are fine).
THEN, it's time to check the resistance of the coil. THEN check the driver to see if it's shorted, if it is, check the pre driver and the 7402. It could also have gone back to the PIA behind the 7402, but you can't check that with a DMM.
There is a line of assault that you need to follow, which backtracks the issues.
I only desoldered one wire. The top jet bumper still works. I couldn't get past the sound test in the diagnostics menu and was unable to locate the auto-up manual-down switch to do so like I said before. Unless it's located somewhere else than where it is in a system 6 game, I think someone who owned it before me hacked it.
Sorry, I was combining two different threads in my head last night. Forgot the switch stuff, I was thinking of someone else's issue. Do start by testing with a DMM all the drivers, then pre drivers, then the 7402.
A TIP122 will take higher voltages than a TIP120. Just because the numbers are close together doesn't mean anything. As Chris said previously you could replace a TIP122 with a TIP102.
Quoted from jhend1000:Well, I think someone screwed up the auto up-manual down switch because there are three buttons and not a switch so I wasn't able to test it that way.
Those buttons are switches.
Suggest you read this thread. I had the exact same problem. Lots of valuable info here:
http://pinside.com/pinball/forum/topic/pinbot-help-left-jet-stuck-on
Quoted from terryb:A TIP122 will take higher voltages than a TIP120. Just because the numbers are close together doesn't mean anything. As Chris said previously you could replace a TIP122 with a TIP102.
Those buttons are switches.
As of now, I've learned a lot more about how these machines work and you are right, the TIP102 will work better. Also, the auto up-manual down switch has been replaced with an actual button sometime in it's life. Not sure why really...
I'll let everyone know how that goes later, thanks!
Quoted from charliex:Suggest you read this thread. I had the exact same problem. Lots of valuable info here:
http://pinside.com/pinball/forum/topic/pinbot-help-left-jet-stuck-on
Read the thread, I'll be sure to look at the 7402 as well, thanks!
Hi all, I think I've got everything repaired finally but I'd like to clarify one thing; is this ic chip a compatible replacement for the 7402? http://www.marcospecialties.com/pinball-parts/74LS02
Quoted from jhend1000:Hi all, I think I've got everything repaired finally but I'd like to clarify one thing; is this ic chip a compatible replacement for the 7402? http://www.marcospecialties.com/pinball-parts/74LS02
Yep. Logic IC Quad NOR Gate.
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