Addams Family, The
Bally, 1992I am working on a TAF and neither motor (book case or Thing) works at all. From what I can tell they’re not getting power. All the fuses check OK, but when I put them in test mode and put a meter on I seem to be getting a zero reading. I can’t really tell from the manual – which connector on the power driver board would be the one that’s driving them? Is it J118? Any other ideas for things I should look at?
J122 is where they all are driven from..
the driver switches negative. so you wont see a voltage high from the jumper.. you will see high voltage to ground on the coil/motor driver ..in this case 12v
LED-7 on the power driver board should be lit
and of course check for any broken wires etc.
If all the voltages check out try grounding the tab on the transistors too. just to see if they are firing.
Your last resort check transistor, pre driver and chip.
I had a taf that did something similar, but would randomly work if I hit the flippers. I did replace the transistor , pre driver and chip and stitched some tracers and it was trouble free after that.
Might also be as simple as a broken tracer on the board too.
If you look at the wiring it is a very simple and straight forward circuit. That is why I went with a shotgun approach. Parts are really cheap.
Thanks guys. I looked at the manual again yesterday and saw J122 was the one I wanted (not sure how I missed that before... duh).
I'll take a look at some of those things you mentioned after clearing out tonight's snow. It seems a little odd in that all the other solenoids are working as they should, it's just the two motors giving me problems. I'll dig out my info on testing the transistors and pre drivers and see what I find.
Yep, LED 7 on the power board is indeed lit. I assume I should be getting 12v at pin 1 on J122 when the Thing motor is engaged too, correct? I don't seem to be, but I can't be sure. I seem to be having DMM issues, as I removed the driver board tonight intending to check the transistors, but my DMM is ranging all over the place when I test the TIP102s, even a brand new one. I'll have to look at it again tomorrow.
So I tested all the transistors on the driver board and they checked out OK. LED 7 is lit, and the regulated 12v TP reads 12v as it should. When I engage either motor test and measure the voltage at J122-1 and J122-3 (Thing motor and bookcase motor respectively) I'm showing only .6v, which seems wrong. When the motor is not engaged in the test menu it hovers around .1 mV. So it's seeming like something isn't quite right with what the driver board is outputting.
The only other thing I noticed was that someone had reflowed the solder on J122 and J121 (no other board work was apparant) so I heated it up again and reflowed it myself in case there was dry solder, but the readings were the same before and after. Any suggestions for what to look at next?
Incidentally, I hooked up a 12v battery from a garage door opener and both motors ran fine so at least I know they're not shot.
As spudgunman said, the ground is switched, not the hot. Voltage is potential so think of it like a light switch with a 12 volt bulb first and the switch on the ground side. When the switch is open you will read 12 volts at the bulb and it will be off. When the switch is closed you will read close to zero volts at the bulb and it will be on.
I know it's counter-intuitive.
In your case you should read 12 volts at the motor when it is not engaged. So the supply voltage is not getting to the motor, or something is draining the supply voltage (i.e. - a partial short). For the moment don't worry about the driver board (the switch in my earlier example) and figure out why there's not 12 volts at the motor when in standby.
At this point I would : Socket and replace the chip, replace the pre drivers, and replace the transistors.
but use your dmm to check out the chip and compare those readings to the other chips. Also check the board around the chips.
Quoted from maddog14:At this point I would : Socket and replace the chip, replace the pre drivers, and replace the transistors.
Sorry, but firstly there is no reason to shotgun the problem. Secondly, as I said it appears like a supply voltage problem, not a switching problem.
H
Quoted from terryb:Sorry, but firstly there is no reason to shotgun the problem. Secondly, as I said it appears like a supply voltage problem, not a switching problem.
When is the last time you looked at the wiring for the TAF on that circuit?
Tell you what if I'm right, you give a five dollar donation to pinside, If I'm wrong, I give a five dollar donation to pinside.
I apologize if I'm not being clear, but I don't know how to explain it any better than saying that ground is switched on the special solenoid circuits, not hot.
My diagnosis is based on the following comment by kse001. If I am misunderstanding his point, he is welcome to correct me.
Quoted from kse001:When I engage either motor test and measure the voltage at J122-1 and J122-3 (Thing motor and bookcase motor respectively) I'm showing only .6v, which seems wrong. When the motor is not engaged in the test menu it hovers around .1 mV. So it's seeming like something isn't quite right with what the driver board is outputting.
Just to show what I'm saying empirically I connected my meter from J122-3 to ground on my TAF. When I turned the game on I got 14 volts. When the bookcase started turning during the power-on test the voltage dropped to .6 volts. When the bookcase stopped, the reading returned to 14 volts.
Since ground is being switched this is what I would expect.
So in standby mode he should get 12-14 volts at J122-1 and J122-3. Since he is getting a low reading in standby mode there is either a problem with the supply voltage or the driver transistor is shorted (or being closed by the circuitry). In the latter case though the motor would be running when it shouldn't be (since he explained he tested it), which is not his problem.
First thing I would do is see if there is voltage at the motor. Then I would follow the supply voltage back up through the line and see where it is getting lost. Based on past experience I would suspect the EMI board or connectors to it.
Thanks guys, you've given me more to look at and I will hopefully get to it tonight or tomorrow. I am following what you're saying so I will check it out.
In spudman's earlier post I saw what he was saying about how the motor voltage worked but it was so counter intuitive to me I admit I kind of blew past it. Now that its been expounded on I get it. I'll check it out and post back what I find.
Thanks again to all trying to help me out.
So just wanted to post a followup now that I've finally gotten the motors running. Turned out to be user error on my part - loose connector on the 2 pin molex that's connects the grey/yellow supply voltage wire between the opto board and the EMI boards. Ridiculously simple, but took a lot of time and effort to find.
HUGE thanks to terryb - he spent an unbelievable amount of time examining his own machine, giving me voltage readings to compare to mine, deciphering incorrect wiring schematics in the manual, and many other things I'm no doubt forgetting. By helping me eliminate everything else it came down to having to be a broken wire somewhere under the playfield, and lo and behold that's what it was. Can't thank him enough!
Kyle
For anyone who is interested the diagrams in the TAF manual for the supply voltage to the motor circuits (thing and bookcase) are incorrect.
Note: I'm using the online manual at ipdb.org. The hardcopy manual I've got is even worse (it shows a red-wht wire as the supply voltage for solenoids 25 and 27, which are noted as the motors in the solenoid/flasher table, but shown as something else on the solenoid wiring diagram, which doesn't even list the motors.).
According to the online manual (solenoid wiring page) the two motors get their supply voltage from J122 pins 5 and 8 (gry-yel wire). If you look at the PDB schematic you'll find that J122 pins 5 and 8 are switching circuits rather than supply voltage.
So something is obviously amiss and what gets confusing is the supply voltage for these motors is a gry-yel wire, but not this gry-yel wire.
After much digging we found the supply voltage comes from J116-2 or J118-2 (gry-yel wires). One of our machines used J116 and the other J118, which is not surprising since these two connectors are identical and often get reversed.
This same supply voltage goes to the opto board and then to the two EMI boards that supply voltage to the motors.
I'll post this info on my site with a wiring diagram when I get a chance.
Quoted from maddog14:Tell you what if I'm right, you give a five dollar donation to pinside, If I'm wrong, I give a five dollar donation to pinside.
Just wanted to be the first to thank maddog for his $5 contribution to Pinside.
Quoted from terryb:Just wanted to be the first to thank maddog for his $5 contribution to Pinside.
))))
It's amazing how many things on a pinball machine work because a path to ground is provided...
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Chris Hibler - CARGPB #31
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