Williams Solved Jokerz! (Williams, 1988) System 11 flipper not working

[zero_koop]

I posted this question at another forum, but since that forum didn't specialize in pinball I was hoping to get overall better advice here. No offense to them.

I'm really stumped on this one. I'm not a pinball repair expert but I am an electrical engineer so I'm fairly familiar with what I'm looking at under the hood. That said, I cannot figure out what is wrong with my left flipper.

How it broke: The left flipper always had a problem with sticking in the up position. Not because a solenoid was engaging, it just stuck because of dirt, etc. So I took the solenoid off to clean it. This usually fixes the problem until it becomes dirty again. But this time when I was reconnecting the wires to the solenoid I put them on wrong. I powered up the system and the flipper didn't work. When I realized my mistake I put the wires on right, but the flipper never worked again.

What I have done so far: In trying to determine if the problem was the solenoid itself or something else I switched the left and right flipper solenoids. Still, only the left flipper didn't work. In other words, the solenoid that was originally not working in the left flipper position did work in the right flipper position so I know the problem is not with the solenoid but with the circuit.

My buddy thinks I may have broke a transistor. He pointed me to a guide that would tell me how to test transistors and the solenoid itself.
http://hansbalk.home.xs4all.nl/rep/sys11/index2.htm#flip0
I don't know if the person who wrote it guide is wrong or I am, but I can't get anything he says to try to work. First, he says I should read 50-80V on the flipper. I can't get any voltage reading on any solenoid. All of my solenoids (except the left flipper) work during gameplay. For some reason I can't get a voltage reading off any of them. I checked my DMM and it works. It can accurately read 1.5V off of a AA battery for example.

Then the guide says I can attach an alligator clip to the metal side rail and touch the ground prong of a solenoid to fire it.
http://hansbalk.home.xs4all.nl/rep/sys11/index2.htm#trans
I can't get this to work either. I am trying this on both the working solenoids and the broken left flipper solenoid. Neither work!

I have no idea what I am doing wrong, does anyone have a clue? Thanks.

 

[faralos]

did ya' check its fuse? the two flippers usually have their own fuses
and if the solenoid is working that may be the problem
you also say that it sticks in its up position but does it make any buzzing sound when it sticks? or does it just stay up?
if it's buzzing then yes the transistor may be on its way out
if it just sticks look as to why it does
it may be a bent shaft or the shaft end may have 'mushroomed' due to heavy play
here is a site with some answers:
http://groups.google.com/group/rec....62aae56b2db83/bb5b8c2253cfb475?lnk=raot&pli=1
sorry for such a long addy!

 

[zero_koop]

did ya' check its fuse? the two flippers usually have their own fuses
and if the solenoid is working that may be the problem
you also say that it sticks in its up position but does it make any buzzing sound when it sticks? or does it just stay up?
if it's buzzing then yes the transistor may be on its way out
if it just sticks look as to why it does
it may be a bent shaft or the shaft end may have 'mushroomed' due to heavy play
here is a site with some answers:
http://groups.google.com/group/rec....62aae56b2db83/bb5b8c2253cfb475?lnk=raot&pli=1
sorry for such a long addy!

Thanks faralos.

Yes, all of my fuses checked out okay. The solenoid does work so I'm thinking it could be a transistor, but I don't know how to test for that.

It sticks in the up position and as far as I remember it does NOT make a buzzing sound. I'm pretty sure it is something like a mushrooming or something like that. I was planning on sanding those surfaces once I get it working again, but to be honest I don't think it looks that "mushroomed". When it's stuck it will get unstuck whenever I activate the other flipper. Sometimes it takes several knocks of the other flipper to get the stuck flipper all the way back down to its resting position. I think even knocking on the side of the cabinet helps get it unstuck.

 

[zero_koop]

Trouble posting. I'm not sure what happened to my last response. I seem to have trouble posting here. So this is a test post.

 

[zero_koop]

did ya' check its fuse? the two flippers usually have their own fuses
and if the solenoid is working that may be the problem
you also say that it sticks in its up position but does it make any buzzing sound when it sticks? or does it just stay up?
if it's buzzing then yes the transistor may be on its way out
if it just sticks look as to why it does
it may be a bent shaft or the shaft end may have 'mushroomed' due to heavy play
here is a site with some answers:
http://groups.google.com/group/rec....62aae56b2db83/bb5b8c2253cfb475?lnk=raot&pli=1
sorry for such a long addy!

Ok, since my response never made it on the board I'm going to try to retype it:

Yes I've checked the fuses and they are all working.

It does NOT make a buzzing sound when it sticks. I'm fairly certain it is a mechanical problem. I think it may either be the playfield brushing or a mushroomed stopper. Either way, I will solve that problem after I get the circuit working again. I'll check out the link, thanks.

 

[spalmer]

Before you will get voltage at the flipper, you need to make sure a game is started. There is a relay that cuts the power in attract mode.

Humor me, swap fuses F5 and F6 on the auxilary driver board and see what happens. There is no transistor that would cause this problem.

Sean

 

[zero_koop]

Before you will get voltage at the flipper, you need to make sure a game is started. There is a relay that cuts the power in attract mode.

Humor me, swap fuses F5 and F6 on the auxilary driver board and see what happens. There is no transistor that would cause this problem.

Sean

Well I was able to get 63.8V off the right (working) flipper when I held the flipper down. No voltage on the left flipper. But I did notice that when I push in the right flipper I get a small spark at the flipper button and a reading of about 2V at that switch. I do not get the voltage on the left flipper switch nor does it spark when pushed. I think the left flipper but may not be getting power. How do I fix that?

I switched fuses F5 and F6 (both tested positive) but nothing changed.

 

[zero_koop]

OK explain this one to me :
I read 2V across either side of the right flipper button. But when I follow those wires back to the circuit board they go to J10-1 and J10-7 on the Backbox Interconnect Board. At that point I get a reading of 74.6V which is the same reading I get at fuse F6 on the Aux Power Driver board which I think supplies power to the flipper solenoid. How can two ends of the same wire read a different voltage?!

 

[zero_koop]

I wanted to add one thing to make sure we are clear. My problem is NOT that the flipper gets stuck in the up position. That was original problem until I tried to fix it and hooked up the wires wrong. Now my problem is that the flipper does not work at all.

Thanks.

 

[zero_koop]

I think I may have narrowed down the problem. So if anyone wants to follow along and help, grab a copy of the schmatics here:
http://mirror2.ipdb.org/files/1308/Williams_1988_Jokerz_Schematics.pdf
On page 84 of the manual (page 88 of the PDF) you see the Power Wiring Diagram. In the lower left corner you see the Left Flipper Circuit. Starting at the top of that diagram there is 5p12 pin 2 (this is on the Aux Power Driver Board which I think is "board 5") which I read on my DMM as 75V. Then I follow the Gry-Yel wire to jumper 2j5 pin 3 which also has 75V (this is on the Backbox Interconnect Board which I think is "board 2"). Going down on the diagram you get to jumper 2j8 pin 8 which reads 0V. So the problem is somewhere around there because if I read the voltage at the same spot for the Right Flipper Circuit I still get the 75V. So, going back to the left circuit, you can see there is a resistor coming off of the main flipper circuit going to the Lane Change Switch. I also get 0V reading at that resistor. I checked the resistor and it is still providing the proper resistance. Moving past the resistor on the diagram you get to a microchip 2u2. I found this on the circuit board and it is a "4N25 ISOCOM I844". My only theory right now is that this chip has gone bad and is causing a short which is drawing all of the power from my flipper solenoid.

Any other theories? Does anyone know how I can test the chip? Does that require removing the chip from the circuit board? If any of that didn't make sense just ask me and I can explain. Thanks.

 

[Hoppel]

Where did you find those schematics. I need them for 2 of my machines... Thanks

 

[zero_koop]

Where did you find those schematics. I need them for 2 of my machines... Thanks

Just go to IPDB.org and search for you table.

 

[zero_koop]

I have solved the broken flipper problem!!!! The trace behind the node that I was talking about had become burnt out. So I just soldered a new wire in its place and bingo, back in business! Using some continuity tests I figured out the problem had to be somewhere along the traces, so I removed the board and it took about 2 seconds to identify the problem. It was completely burnt out in one spot. Thanks for your help!

 

[Hoppel]

Thanks, I do have the original manual and part of the troubleshooting sheets that came with it but are missing some... Looked on the ipdb and couldnt find them.

Can you help.

Thanks, Mark

 

[zero_koop]

I do not know what table you are looking for. Jokerz is at http://www.ipdb.org/search.pl?any=jokerz&search=Search+Database&searchtype=quick

 

[Hoppel]

I am looking for Black Knight.
It goes into attract mode but won't play and the sound does not work.
Display 3 and 4 and the credit display show 5's and 7's and I can't get it to go into free play.
I have the manual and part of the troubleshooting sheets but I need help reading the schematics and where to do the tests.
I did buy a multimeter and tested the fuses for continuity.

Can you help?

Mark