(Topic ID: 231287)

Gottlieb System 3 Blowing mosfet

By gcanali

5 years ago


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  • Latest reply 5 years ago by gcanali
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#1 5 years ago

I Have a Gottlieb Wipe Out (System 3). The bottom left kicking rubber mosfet (Q4) keep blowing off. I have already replaced the Coil diode, the 2.2k resistor, I have measured the coil resistance (16 ohms). Everytime I replace the mosfet, it works for a little bit, and after a while it blows Q4 and after that it blows the 1.5A fuse. Any ideas?

#2 5 years ago
Quoted from gcanali:

I Have a Gottlieb Wipe Out (System 3). The bottom left kicking rubber mosfet (Q4) keep blowing off. I have already replaced the Coil diode, the 2.2k resistor, I have measured the coil resistance (16 ohms). Everytime I replace the mosfet, it works for a little bit, and after a while it blows Q4 and after that it blows the 1.5A fuse. Any ideas?

Check your coils again. I show A-17876 coils with 24 ohms as the resistance for my Cue Ball Wizard System 3. Check the left sling coil vs. the right sling coil.

<otherwise if the same>
Compare all your measurements to the right kicker ( I assume that works with no problems) If you don't spot anything with some comparisons, try taking an overall resistance measurement from the driver board transistor to the coil, again comparing the right to the left kicker

#3 5 years ago

Probably due to bad ground connection.
Shunt all white wires near the tranformator as it is preconised on pinrepair.com.

#4 5 years ago
Quoted from Benhurr:

Probably due to bad ground connection.
Shunt all white wires near the tranformator as it is preconised on pinrepair.com.

Not likely, since the other transistors on the board are using the same ground path, and they are fine.

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#6 5 years ago

I think that I found the problem. The kicker's switches were so close to the rubber band and this caused the unnecessary activation of the kicker, blowing the mosfet. I adjusted the switches, and so far so good. I have also replaced the 1.5A fuse for a 1A fuse and it is working perfectly. Thanks for your ideas folks.

#7 5 years ago
Quoted from Benhurr:

Probably due to bad ground connection.
Shunt all white wires near the tranformator as it is preconised on pinrepair.com.

I did that two weeks ago, I connected all the ground wires together and I still blew the mosfet.

#8 5 years ago
Quoted from wayout440:

Check your coils again. I show A-17876 coils with 24 ohms as the resistance for my Cue Ball Wizard System 3. Check the left sling coil vs. the right sling coil.
&lt;otherwise if the same&gt;
Compare all your measurements to the right kicker ( I assume that works with no problems) If you don't spot anything with some comparisons, try taking an overall resistance measurement from the driver board transistor to the coil, again comparing the right to the left kicker

I did compare the left side and right side measurements, and they were exactly the same.

-1
#9 5 years ago
Quoted from gcanali:

I think that I found the problem. The kicker's switches were so close to the rubber band and this caused the unnecessary activation of the kicker, blowing the mosfet. I adjusted the switches, and so far so good. I have also replaced the 1.5A fuse for a 1A fuse and it is working perfectly. Thanks for your ideas folks.

Your welcome. I didn't think that would be the problem, because on System 3's if the kickers machine gun repeatedly the games CPU shuts them off and they stop working until you turn the game back on. This is designed to save the transistors...and you didn't mention that they were repeatedly kicking. Glad it was simple in the end.

#10 5 years ago
Quoted from wayout440:

Your welcome. I didn't think that would be the problem, because on System 3's if the kickers machine gun repeatedly the games CPU shuts them off and they stop working until you turn the game back on. This is designed to save the transistors...and you didn't mention that they were repeatedly kicking. Glad it was simple in the end.

You are right. But the kicker was not "machining gun". I don't understand why the mosfet did not blow again.

#11 5 years ago
Quoted from gcanali:

You are right. But the kicker was not "machining gun". I don't understand why the mosfet did not blow again.

Yes that is strange Could there have been a difference in the part numbers between what was originally installed and your replacements?

"Transistors: keep a few of each of these around: 12N10L or IRL530 or 20N10L or 22NE10L or IRL540 (driver board and auxiliary driver board). The 20N10L or 22NE10L or IRL540 are the best replacements, as they have higher drain current capabilities. These are used for coils transistors. The "L" means it's a logic-level MosFet. These parts should *not* have a "F" anywhere in the part number"

#12 5 years ago
Quoted from wayout440:

Yes that is strange Could there have been a difference in the part numbers between what was originally installed and your replacements?
"Transistors: keep a few of each of these around: 12N10L or IRL530 or 20N10L or 22NE10L or IRL540 (driver board and auxiliary driver board). The 20N10L or 22NE10L or IRL540 are the best replacements, as they have higher drain current capabilities. These are used for coils transistors. The "L" means it's a logic-level MosFet. These parts should *not* have a "F" anywhere in the part number"

I replaced the Q4 four times with the same part. I bought Qty 10 12N10L. When I bought these mosfets I was sure that the letter "F" did not appear anywhere. It is very strange. I don't understand why the mosfet is working properly now.

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