(Topic ID: 265108)

Transistor Blowing Fuse, Replaced Went Bad Again???

By PinballGurus

1 year ago


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  • 17 posts
  • 4 Pinsiders participating
  • Latest reply 1 year ago by Inkochnito
  • Topic is favorited by 1 Pinsider

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#1 1 year ago

Having issue with Bally Special Force blowing the 1amp fuse under the playfield. I pulled out the main board and Q14 was measuring low so I replaced it with a new 2N6045 and the game didn’t blow the playfield fuse, and the game seemed to work for a cycle and I was even able to play a bit. So, I turned it on and back off and it started having the same issue and the Q14 started registering bad again. What could cause this? Maybe a bad IC chip?

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#2 1 year ago

Bad transistor, lost continuity of the legs through the board and across the board. A cracked trace or something can drive you nuts.

LTG : )

#3 1 year ago

Inspect your left slingshot coil.
If you have a spare, replace it just to be sure.
Check the diode on the coil.
A bad CA3081 can happen, but then you would see the left slingshot activated constantly.
Transisors mainly go bad because of external factors, bad coil, diode, short.....

Did you reflow the print headers?

Why didn't you use a TIP102 as a replacement for the 2N6045?

#4 1 year ago

Not sure what print headers are?

Quoted from Inkochnito:

Inspect your left slingshot coil.
If you have a spare, replace it just to be sure.
Check the diode on the coil.
A bad CA3081 can happen, but then you would see the left slingshot activated constantly.
Transisors mainly go bad because of external factors, bad coil, diode, short.....
Did you reflow the print headers?
Why didn't you use a TIP102 as a replacement for the 2N6045?

#5 1 year ago

Is a TIP102 the preferred replacement? I was told this NTE261 was the same at the 2N6045.

#6 1 year ago

1amp seems light for a solenoid fuse.
Are you sure that is the proper value, and is it slo-blo?

#8 1 year ago

Yes. It’s correct. Says on the playfield.

Quoted from DNO:

1amp seems light for a solenoid fuse.
Are you sure that is the proper value, and is it slo-blo?

#9 1 year ago

I pulled the board back out and the transistor is back to reading good. Ugh. Confusing.

#10 1 year ago

1.5A slo-blo is the right fuse for under the playfield according to the manual.
My Tech Chart might be helpfull: http://www.pinballrebel.com/pinball/cards/Tech_Charts/Bally_Special_Force_Tech_Chart.pdf

Print headers are the pins on the boards that the connectors slide on.
The TIP102 is a more robust transistor and is used in a lot of games.

#11 1 year ago

So I unsoldered the left sling coil and tested the diode on the coil and it reads good. I also changed out the diode on the switch. I replaced the board and tested it with the coil wires unsoldered and the fuse doesn’t blow... but the only way I can get the left sling to fire is by pressing the flipper buttons.

It will not fire thru the left sling switch when reconnected.

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#12 1 year ago

I’ll reflow the print headers and report back soon.

Quoted from Inkochnito:

Inspect your left slingshot coil.
If you have a spare, replace it just to be sure.
Check the diode on the coil.
A bad CA3081 can happen, but then you would see the left slingshot activated constantly.
Transisors mainly go bad because of external factors, bad coil, diode, short.....
Did you reflow the print headers?
Why didn't you use a TIP102 as a replacement for the 2N6045?

49611609-44A6-4598-8092-CAD8F944B2D7 (resized).jpeg
#13 1 year ago

Does the left slingshot also fire with the flipper if the switch wires are detached?

If the slingshot fires with all wires connected, check the switches for the right gap.
Flipper vibrations can cause the switch to act when the contacts are closed.
If the contacts are closed you can't activate the switch by hand because of the closed contact.
The vibrations cause the contacts to open for a very brief moment thus activating the switch again upon closure.

Did you use the switch test of the game to check this?

#14 1 year ago

Yes the left sling fires with the switches detached, but not the coil.

Quoted from Inkochnito:

Does the left slingshot also fire with the flipper if the switch wires are detached?
If the slingshot fires with all wires connected, check the switches for the right gap.
Flipper vibrations can cause the switch to act when the contacts are closed.
If the contacts are closed you can't activate the switch by hand because of the closed contact.
The vibrations cause the contacts to open for a very brief moment thus activating the switch again upon closure.
Did you use the switch test of the game to check this?

#15 1 year ago

Did you check for pinched wires between the cabinet and the backbox?

It look more and more like a short at the wire to the backbox.
Can you remove the Yellow-White wire from J6-4?
Just leave it loose, but safe.
Maybe use electric tape to isolate.
Test it again.
If the slingshot gets activated with the wire disconnected, you may have an intermittend ground short.

#16 1 year ago

The slingshot only activates with the coil attached, even if the switch is detached. What’s the best method to find an internment ground short?

Quoted from Inkochnito:

Did you check for pinched wires between the cabinet and the backbox?
It look more and more like a short at the wire to the backbox.
Can you remove the Yellow-White wire from J6-4?
Just leave it loose, but safe.
Maybe use electric tape to isolate.
Test it again.
If the slingshot gets activated with the wire disconnected, you may have an intermittend ground short.

#17 1 year ago

I repeat...
Did you check for pinched wires between the cabinet and the backbox?

It look more and more like a short at the wire to the backbox.
Can you remove the Yellow-White wire from connector J6 pin 4?
No at the coil, but at the connector.
Just leave it loose, but safe.
Maybe use electric tape to isolate.
Test it again.
If the slingshot gets activated with the wire disconnected, you may have an intermittend ground short.

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