On my 'new' High Speed, the coil that drives the ramp gates is acting odd. At first, I thought it was busted, it just didn't seem to work. The coil resistance was fine, and it's driving transistor tested ok. But during the diagnostic test, I realized that after leaving the test going for a few seconds, the coil was firing, but really weakly. Then it would get stronger with each pulse, to the point where it seemed to work ok. I then started a game, and the gate worked! But after a ball or two, it stopped I then went back to the test, and it did the same thing again, slowly built up strength with each pulse.

What could cause this? A bad capacitor? A weak connection?

My guess is that the coil has heated up at some point and the sleeve is deformed to the point where it's putting pressure on the plunger. Once the plunger slides through the sleeve a few times, it may warm up the sleeve enough to allow the plunger to move freely.

Pull the coil and check the sleeve. If you can't remove the sleeve, you'll need a new coil (and sleeve).

Thanks, will do when I get home!

My guess is that it is not oiled enough.

Quoted from ALJO

My guess is that it is not oiled enough.

ah ben ! une joke sur l'huile! Claude je pense qu'il y a de l'espoir pour toi !!  

Quoted from cooke

My guess is that the coil has heated up at some point and the sleeve is deformed to the point where it's putting pressure on the plunger. Once the plunger slides through the sleeve a few times, it may warm up the sleeve enough to allow the plunger to move freely.

Pull the coil and check the sleeve. If you can't remove the sleeve, you'll need a new coil (and sleeve).

I couldn't remove the plate holding the coil in. It was just too cramped underneath the playfield to get a screw driver in, since the coil is right on the bottom/back of the playfield. I was able to verify that the plunger moves quite freely in the sleeve though, so I doubt there's any pressure being applied.

Tiny rodent had PM'd me earlier (before I posted this thread) that it may be a loose or dirty connection in one of the connectors, but I haven't found anything.

Any other ideas?

Quoted from jonny_eh

I couldn't remove the plate holding the coil in. It was just too cramped underneath the playfield to get a screw driver in, since the coil is right on the bottom/back of the playfield. I was able to verify that the plunger moves quite freely in the sleeve though, so I doubt there's any pressure being applied.

Tiny rodent had PM'd me earlier (before I posted this thread) that it may be a loose or dirty connection in one of the connectors, but I haven't found anything.

Any other ideas?

The small flipper on my Road Show was'nt very strong too, I checked and there were no screws holding the end with the plunger going through it, put a screw and now it's very strong.... Have you checked if the coil is well screwed in place?

Could be that the spring on that coil is a little too strong, which weakens the coil. This also happened on a ramp divertor coil on another Road Show I use to have.

The coil is screwed in well, it's not loose. The problem isn't that it's weak, it's that it doesn't work at all, unless I leave it on test mode, where it slowly gets stronger and stronger. Then, if it isn't used for a little while, it stops working. I don't see how a bad spring could cause that

Thanks for the tips, keep them coming!

Have you measured the voltage across the suspect coil in test mode (when 'cold' and later when working)?

Still not sure if the problem is actually electrical (transistor, cold solder joint, connector), or mechanical...


Cheers,
- Sylvain.

I'm betting on cold solder joint

Jon did you try the test of jumpering the ground lug of the coil briefly to ground?

Quoted from sylvain

Have you measured the voltage across the suspect coil in test mode (when 'cold' and later when working)?

Still not sure if the problem is actually electrical (transistor, cold solder joint, connector), or mechanical...


Cheers,
- Sylvain.

I didn't know you could test voltage across the coil. I thought it was the same voltage at each lug?

Mrhide,
If it's a cold solder point, would this be at the driving transistor?

Quoted from jonny_eh

I didn't know you could test voltage across the coil. I thought it was the same voltage at each lug?

Mrhide,
If it's a cold solder point, would this be at the driving transistor?

Check this Jonathan. It's an easy test to do.
http://www.pinrepair.com/sys1/index.htm#coils

Quoted from ALJO

Check this Jonathan. It's an easy test to do.
http://www.pinrepair.com/sys1/index.htm#coils

Yup, already tested. The resistance is 3 Ohms.

tinyrodent,
I haven't tested that yet. I just borrowed some alligator clips from a coworker and will try that tonight. If that works, I'll assume it's a cold solder on the board, and will try fixing it there.

Ok, so I finally got a chance to do some more work on this issue.

I tested the coil by shorting one of the lugs to ground, it worked great. So the coil is fine.

I took the board out, and reheated/resoldered the feet of Q15. Now during the coil test, it only takes about 3 pulses to get to full strength instead of the approx 8 or 10. But I'm not sure if it's because of the soldering or if it's from replugging everything in. The connection on the board to the coil seems ok  (1J12-6), no burn marks or anything.

What should my next step be? Can I be certain that it's still a cold solder joint? Can it be a faulty transistor?

Thanks!

Cold solder joints are usually at the connector headers. Reflow the pins of 1J12 and see if that makes any difference.

Also there is another connector to examine, between the board and the coil. It is a large square one that connects the playfield to the head. To find it, follow the wires of 1J12. You should be able to pull the bundle up from the lower cabinet.

You can test the quality of the connection by measuring resistance from the coil to the board.

Ok jonny here is another way to help isolate the ramp gate problem. I just tried it on my machine.

1. Go to coil test mode and verify that #10 (Insert Board Flashers) is working properly. You should see 4 bulbs in the backbox flashing, but if any one of them works it is ok.

2. Power off the machine and remove the 1J11 connector. Now move the 1J12 connector over so that its rightmost two pins are on 1J11-8 and 1J11-9. The key and one of the connector pins will be between 1J11 and 1J12, and the rest on 1J12.

3. Go to coil test mode, and manually advance to #10 again. This should operate the ramp gates.

If you see the same symptoms as before, then it must be in the wiring and/or the connector(s).

If the ramp gates work properly in this test then the problem must be on the board. Most likely a cold solder joint on the 1J12-6 header pin.

Thanks Brett, I'll give that a shot next time I open her up.

Here's the current status:
Since I moved HS into my basement, it seems as though the gates are now working... ish. They seem to fire ok in test mode, and they work when I have a game going if I push the right switch on the ramp with my finger. The problem is that if the ball goes up the ramp during play, it tends to pass the gate before it closes. If the ball goes slow enough, it'll successfully be caught by the gate.
I don't know if the situation was improved by the fact that my basement is warmer than my garage, or if the disconnecting and reconnecting of the playfield wiring did it.

So the ramp gates working reliably now, for whatever reason. They fire in test mode just fine, and during gameplay. The problem is that the ball goes past the gates about 50% of the time, for some odd reason. I can't tell if the gates are too slow, too fast, or not strong enough. I can confirm that they definitely fire though. This is super bizarre. I also fixed the left ramp switch, which wasn't working, but the problem remains.

Sorry for triple posting but I was wondering if it's possible that my switches are getting activated too early. Is it possible that they're set too far to the left? The ramp gates fire for only a moment. Can someone snap a slightly top down pick of their ramp showing where the switches are? This is driving me bonkers. The switches and coils both work fine in test mode, but during gameplay the ball hardly ever ends up in the hideouts!

Here's a crappy pic, hope it helps. In Switch Edges test mode, when you roll a ball through the ramp, does it reliably activate both switches? Does it correctly indicate left and right? If they were reversed it might explain these symptoms.

The game does sometimes intentionally let the ball past the gates, but usually it goes into one of the hideouts. After running the red light, the next two balls up the ramp should go one into each hideout.

Thanks for the pic! Unfortunately, my game looks exactly the same. I've confirmed that in switch test mode, both switches are recognized correctly, and are activated by the ball. The ball never fails to be recognized when it goes up the ramp, just diverted.

I know when the ball passes through, when it should have been diverted. The game will fire the hideout kicker twice, thinking the ball may be in there.

Maybe the original problem is still there, just not as obvious. A "warm up" delay of just a fraction of a second would be enough to miss the ball.

Here's another test you could try. Hook one end of a jumper wire to the tab of the Q15 transistor. Briefly touch the other end to ground. Does the coil fire instantly?

You said "I can't tell if the gates are too slow, too fast, or not strong enough." Start a game with the glass off, and shoot a ball up the ramp with your hand. Watch the gates carefully and try to see exactly what's going on.

Jumpering the transistor to ground makes the gates fire just fine, just like in the coil test.

Throwing the ball up the ramp with my hand, or using the plunger always works fine, but when it's done with the flipper, it almost always misses the gate, or the gate doesn't fully fire, I'm not sure, it happens too fast. Could this be a pre-driver issue?

If it works fine with hand or plunger, then it sounds like the ball must travel a different path or speed via flipper to get a different result. You could try taking a close-up video and watch it in slow motion.

Does your ramp have the transparent cover on it?

Maybe the coil fires a bit weak, and a flipper shot just pushes the gate out of the way? Or the ball flies over the gates?

Not sure what else to suggest.

Ya, the cover's still there.

I noticed the there was a crack right by the right gate exit. I crazy glued it back, maybe that'll make a difference.

If this doesn't work, I think I'll need to set up a 'high speed' camera to see the problem.

While playing around with the switches, I noticed an odd behaviour. If I activated the left ramp switch with my finger right before activating the right ramp switch, the gate wouldn't come out the whole way, it wouldn't fully activate! What gives? Can something that the first switch activates interfere with the gate's firing? I am soooooooooo confused. I don't think I'm even making sense anymore.

So, I opened up the High Speed Manual/schematics from ipdb.org and in that version someone write next to Q14 on sheet 2 of the CPU schemtics 'Ramp Gates'. This is weird because according to the solenoid table Q14 is the knocker and Ramp Gates is Q15. So who's right?

Also, My CPU board has been heavily worked on. There's a component called 'SR4' that has been replaced, and it has 2 resistors tacked on to it. What gives with that? Could it have an effect? One of the legs of SR4 that is attached to a resistor is attached to Q11 which predrives Q15.

The only pattern I can discern is that the ramp gates have problems during gameplay but not tests. During gameplay, the flashers usually fire just before the gates activate. When the flashers are not firing (i.e. when plunging the 2 balls right after escape), the gates seem to work. The flashers happen to be on the same connector as the ramp gates, and connected to SR4 too. It makes me wonder if SR4 is the problem. What does SR4 do? Should I replace it?

Sounds like a switch sensitivity issue to me.  You know you can adjust the sensitivity by bending the wires?  You can make them more or less sensitive. i.e. make it so the wire needs to be pushed in a LOT before triggering or triggering almost as soon as the wire is touched by the ball..

From the sound of it I'd say the switch triggers too late - when the wire is pushed almost completely in.  This means that if the ball is travelling fast (from a flipper shot), it may not trigger long enough for the gate to work properly.

Mike

Nope it's not that Mike. I've adjusted the switches to be really sensitive, or less sensitive. I'm convinced now that the problem is related to the board. The gates just don't fire fully, or not at all, during gameplay. The exception is when it's quiet after doing an escape. Then the switches/gates work fine.

You said that grounding the tab of Q15 activates the gates, so you know the answer to that question.

SR4 is a 560 ohm bussed resistor network, equivalent to individual 560 ohm resistors connected from pin 1 to each other pin. If the resistance measures close to that with a DMM then the hack should be ok. Great Plains sells the resistor network if you really want to replace it.

Bingo, the resistance for the pin connected to the pre-driver is only 340 Ohm, all the other pins are close to 560 Ohm like you said.

I could just replace the hack resistor with the right one, correct? Could this be the explanation for funny ramp gate behaviour?

Not sure if it would explain the ramp gate behaviour. Wish I could offer you a replacement resistor network, got a few different ones but the 560 ohm was not available at the time.

I haven't done this before, but to hack an individual resistor, the corresponding leg of the network must be removed. The hack resistor would then go from the hole in the board to pin 1.

Ya, that appears to be the case (leg cut from the bussed resistor), but I think whoever did this used the wrong resistor, it's too low. I'll just run out and buy a replacement resistor or stack, whatever is available. Let's see what happens.

Although you have located a resistor of the incorrect value,
and it should be replaced for reliability of the circuit,
I doubt very much that it will help with your timing issue...

Nothing to lose to try...


Good luck !
- Sylvain.

Quoted from sylvain

Nothing to lose to try...


Good luck !
- Sylvain.

Crap, I was hoping to read a Sylvain post explaining stuff about transistors, ohm's law, base/collector currents and how its obvious that a 330ohm resistor would cause this..  

Good luck Jonny, eh!

Quoted from Tuborg

Crap, I was hoping to read a Sylvain post explaining stuff about transistors, ohm's law, base/collector currents and how its obvious that a 330ohm resistor would cause this..  

Good luck Jonny, eh!

Ya, I was too!

BTW, the colours on the resistor are 560 Ohm, but the reading is not. Must be a bad resistor.

340 ohm is suspiciously similar to the value one might find on a flasher board. When measuring be sure to remove the 1J12 connector.

Oh ya, the board isn't even in the cabinet.

Ok, I think I 'may' have solved it! I thought I'd look up what the other hack resistor was connected to and saw that it was Flasher #4. This made me take an even closer look (been staring at the board all day!) and realized that the two resistors may in fact be touching! (At the non-ground side, bad!) This would explain the flashers interrupting the gates! Right?!

So I pried the two resistors far apart. The one connected to the ramp gates still reads too low, I should probably replace it.

I put it all back together and it seems to work better now. The ball still misses the gate maybe half the time but it could be a switch/timing issue. It could also maybe be due to the bad resistance, but I have no idea and it's getting late.

But for now, I'm considering the mystery of the flash vs ramp gate issue solved! Until next time that is  

Thanks to everyone, especially tiny rodent, for helping me out.

Resistors can often read low when tested in circuit.

Mike

Quoted from MrMikeman

Resistors can often read low when tested in circuit.

True.

This occurs when other component(s) end(s)-up being in parallel with the resistor
being measured, somewhere else on the board, or via connectors/coils/etc.

This is why for instance that a diode cannot be properly tested when connected to
its coil (they are in parallel, and the resistance of a typical pinball coil is very low).
Sometimes, one leg of a component under test needs to be unsoldered to be properly measured.

The equivalent parallel resistor can be calculated with this formulae  
R = (R1 x R2)/(R1 + R2)

in jonny_eh's case, R is the measured (too low) value, R1 is the expected 560 ohms
value of the resistor, and R2 would potentially be the parallel device (transistor?).
(otherwise, the resistor itself is bad, too low. However, this is rare that resistors
drop in value, unless overheating. In antique radios, resistors usually drift to a higher
value

Cheers,
- Sylvain.

Quoted from Tuborg

Crap, I was hoping to read a Sylvain post explaining stuff about transistors, ohm's law, base/collector currents and how its obvious that a 330ohm resistor would cause this..  

Good luck Jonny, eh!

There you go!!  Sylvain pulls through again!!

Quoted from sylvain

The equivalent parallel resistor can be calculated with this formulae  
R = (R1 x R2)/(R1 + R2)

in jonny_eh's case, R is the measured (too low) value, R1 is the expected 560 ohms
value of the resistor, and R2 would potentially be the parallel device (transistor?).
(otherwise, the resistor itself is bad, too low. However, this is rare that resistors
drop in value, unless overheating. In antique radios, resistors usually drift to a higher
value

Cheers,
- Sylvain.

Ya, it's weird that the resistor reads low and is definitely a clue. Even though my game is working a bit better now it still is working quite right yet. I wonder what it could be parallel to, all the other pin on SR4 read normal.

Not that ths will help at all but my HS was doing similar things but was simply an adjustment of both the switch and the position of the diverter.  Mostly the diverter had to be adjusted to the point where the ball wouldn't be interfered with when passing by, but close enough so it would come out fully.  Now, very rarely the diverter pops out when the ball is moving too slow and wacks it back down the ramp.  Not that its your issue, but it worth adjusting.

Mike

I took my High Speed driver board over to jonny's place and the gates work fine with it installed. So, the problem is definitely on his board. I brought it home to repair, will post here with results.

The pre-driver transistor tested out of spec in-circuit so I removed it. But out of circuit it tested ok. So something else is out of whack. I also removed the resistor network hack, and the driver transistor; cleaned up all the mess; and replaced the parts with new ones. However it did not solve the problem.

Next component in the circuit path is the 7408 chip. Fortunately I have a bunch of those, just got some to replace a faulty one on my High Speed. Probably give that a try tomorrow.

Quoted from tinyrodent

The pre-driver transistor tested out of spec in-circuit so I removed it. But out of circuit it tested ok. So something else is out of whack. I also removed the resistor network hack, and the driver transistor; cleaned up all the mess; and replaced the parts with new ones. However it did not solve the problem.

Next component in the circuit path is the 7408 chip. Fortunately I have a bunch of those, just got some to replace a faulty one on my High Speed. Probably give that a try tomorrow.

Problem solved. Replacing the 7408 chip did the trick. This seems to be a common point of failure - two required replacement on my board, and two on jonny's. The police light is not working with jonny's board, I'll debug that tomorrow. However the knocker and GI controls are working properly. jon I think you'll find that the GI relay on your power supply board is either bypassed or locked on.

Good work !

Cheers,
- Sylvain.

Quoted from tinyrodent

The police light is not working with jonny's board

A very easy fix - turn on the police light in the game settings.

There is still one pair of flashers not working with either board, must be a problem with the playfield wiring.

Thanks tiny! Quite a treat to login from the UK and see this great news.  It's a shame you discovered more problems than you solved

The flasher problem: If you're refrring to th top flashers (below the ramp), I noticed that they didn't work at first, then one day they started to work, weird.  I also don't know if they're worth fixing since yu can't even see them or notice them.

In fact it was the top flashers, but after carefully examining the wiring, they started working with both boards. My bet is a dodgy connector though I did not identify which one.

I believe your board is now 100% working and ready for league play.

Awesome - haven't played high speed since school days.   I think Tiny is the official "get games working for tourney play" professional.   Thanks Tiny & Jon!