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(Topic ID: 235315)

Jokerz draw poker tech question


By MT45

1 year ago



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  • 17 posts
  • 6 Pinsiders participating
  • Latest reply 1 year ago by MT45
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#1 1 year ago

Hey guys - just picked up a project/players Jokerz and in the middle of a shop/restore

My Draw Poker flashers in the backbox are staying on all the time - I read the linked thread and checked my schematics and it looks like transistor Q16 is the culprit ... before I sent this post I ran out to take a picture of it - sure enough, it's toast (see pic).

I have a TP102 on hand but I don't see anywhere in the schematics (probably me) where it lists the other components that might need replacing?

I saw in the old thread below some comments on replacing the "pre-driver"?

I'm pulling the board to replace Q16, I might as well knock it all out while I'm in there.
What exact other components do I need to replace?
How did that Q16 get blown up like that? (guessing a short to high voltage?)

Thanks

Old thread I referenced:
https://pinside.com/pinball/forum/topic/jokerz-need-help#post-3750313

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#3 1 year ago

Bump for the "after dinner" crowd (east coast)

#4 1 year ago

Looking at the schematic, Q16 is driven by Q12, a 2n4401.
I agree, if you’re taking the board out, and you have the parts, might as well replace them both.

Good luck
Jeff

#5 1 year ago

make sure you don't have a shorted socket.....replacing the tip102will probably fix it....you can measure the pre driver to see f it is shorted....look out for burnt traces!

#6 1 year ago
Quoted from Grangeomatic:

Looking at the schematic, Q16 is driven by Q12, a 2n4401.
I agree, if you’re taking the board out, and you have the parts, might as well replace them both.
Good luck
Jeff

Thanks for that and now that I know, I'll read the schematic again to see the link that I missed. I've got both a TP102 and a 2N4401 so parts are on hand

Quoted from Startek2:

make sure you don't have a shorted socket.....replacing the tip102will probably fix it....you can measure the pre driver to see f it is shorted....look out for burnt traces!

I pulled the 1J12 connector and they went off ... so assuming I do NOT have short (hope my assumption is right there)
I'll have to read up on how to measure the pre-driver for short - probably not that hard. That way I'll know that replacing it was a help

Thanks both of you guys for the detailed reply!

#7 1 year ago
Quoted from Startek2:

make sure you don't have a shorted socket.....replacing the tip102will probably fix it....you can measure the pre driver to see if it is shorted....look out for burnt traces!

So I pulled the board, while I had it out I used my Hakko to remove the on board battery box and soldered in a remote one
I also replaced TIP102 at Q16 and the predriver at Q12 but now the draw poker flasher lights simply don't work at all (before they were locked on)

You were right about burned traces. Looking at the board installed, I believe that the TIP102 Base is left, Collector center and emitter is right. (Check me on that)
The install on the Q12 (2N4401) was a breeze, Hakko out, iron in, flush cut the leads - done.
The install on the TIP102 was not simple. Here's the issue and another question.
The center leg trace was definitely lifted, but still appeared intact, so I fed the leg thru the lifted trace
The right leg (again, viewed as board installed in game) thru hole was so blown out that as I added solder to the heated pin, it appeared it wouldn't stick.
I was wrong because what it was doing was dropping into the wide thru hole and collecting below and building up across all 3 legs - ugh
I unsoldered it, cleaned it for another try - this time, I took a close look at that pin and it looked like this leg was grounded so I flipped the board and scratched the coating nearby the thru hole to expose some of the ground below. I then tried again.

The left leg soldered normally
The center leg seems OK, but trace was lifted
The right leg I was able to get some solder onto the leg and from the leg to my scratched off/exposed ground on the board.

I reinstalled but now the flashers don't lock on, they just don't come on at all
I have zero confidence that the TIP102 is soldered with a good connection ....so

How can I test continuity with this (can I?)
Am I right in assuming the right leg is the emitter and its grounded on the board?
Cant I just add jumpers to this?
If so, what gets jumped to what?

Sorry for the 20 Qs but I know that I'm close to sorting this but it looks like that blown transistor did some damage when it went out and I'll need to be creative to fix it
Thx

Pics below of new remote battery holder install and the blown out transistor

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#10 1 year ago

Have you checked the fuses? (Always check them with a meter, eyeballing fuses isn't foolproof)

You can check continuity from each leg of the transistor to wherever they lead to. Even though the work may not look pretty, it might be ok. You'll definitely want to make sure each leg is reaching their respective circuits.

#11 1 year ago

frunch thanks for the fuse idea. I missed the obvious and will chase that down first.

Meantime ... can anyone tell me where each of the 3 legs of Q12 go to and same for Q16?

Thx

#12 1 year ago

For Q16 the emitter is common so verify continuity to emitters of Q17, Q9 and Q8, collector to 1J12-4, base to SR5 pin 5 or Q12 emitter.

For Q12 you can verify continuity for the collector at R42 and the Base at SR4 pin 4 or U18 pin 8

Use the known good circuits above and below Q16 (Q8, Q9, and Q17) to verify you are testing continuity correctly and also to verify your soldering is not shorted anywhere. Again use the other circuits to validate the readings you get - the 4 circuits should all read the same.

Post pictures of your solder work at Q12 and Q16, both sides of the board, just in case its something obvious

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#13 1 year ago
Quoted from boscokid:

For Q16 the emitter is common so verify continuity to emitters of Q17, Q9 and Q8, collector to 1J12-4, base to SR5 pin 5 or Q12 emitter.
For Q12 you can verify continuity for the collector at R42 and the Base at SR4 pin 4 or U18 pin 8
Use the known good circuits above and below Q16 (Q8, Q9, and Q17) to verify you are testing continuity correctly and also to verify your soldering is not shorted anywhere. Again use the other circuits to validate the readings you get - the 4 circuits should all read the same.
Post pictures of your solder work at Q12 and Q16, both sides of the board, just in case its something obvious
[quoted image]

Thanks for this. Hugely helpful ... I’ll report back

#14 1 year ago
Quoted from MT45:

My Draw Poker flashers in the backbox are staying on all the time

They’re not LED flasher bulbs are they?

rd

#15 1 year ago
Quoted from rotordave:

They’re not LED flasher bulbs are they?
rd

No, they are standard 89s. Is there something about LED flashers and system 11s I might need to know?
I ask because I'm going to switch them all to LEDs in hope of avoiding the issue again when/if transistor pops and they might lock on.

Seems like 89 would get hotter than led style although I've seen LEDs get toasty too!

Also ... to add to the resolution, I buzzed the ground leg of the TIP102 and I'm not getting continuity on it to ground like other similar circuit transistors so this might be my culprit. I'll try to pull the board soon and resolder that leg

#16 1 year ago
Quoted from MT45:

No, they are standard 89s. Is there something about LED flashers and system 11s I might need to know

Yes. Most Sys11s don’t like Led flashers as they have little warming resistors in the circuit before them. These hold a little voltage to “warm” the bulb so they flash immediately - but for LEDs the small holding voltage runs the bulb. So they never turn off. You can remove the resistor from the circuit and they work.

rd

#17 1 year ago
Quoted from rotordave:

Yes. Most Sys11s don’t like Led flashers as they have little warming resistors in the circuit before them. These hold a little voltage to “warm” the bulb so they flash immediately - but for LEDs the small holding voltage runs the bulb. So they never turn off. You can remove the resistor from the circuit and they work.
rd

Thx Dave. Appreciate the detail

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