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TRON transistor help

NateG119

NateG119

Registered
Joined
Aug 22, 2019
Messages
61
Location
Brantham
Hi all,

Currently borrowing Jez’s Tron and I’ve been hit with a dead right flipper. Fuse below the flipper had blown. Tested it by putting the left flipper fuse in that slot briefly and the flipper shot up when the game was powered on (turned off again quickly so as not to blow fuse 2). This suggested a transistor failure based on my online research and it was suggested that replacing the transistor for a new IRL540N one would sort it.

However when replacing the transistor, it fixed the issue until the flipper was flipped once and then the same thing happen again, blew fuse and shorted transistor and it’s dead again. Everything under the playfield seems fine, not sure where to go next! Any ideas?
 
Try replacing both the coil and transistor together at the same time. Also check that the cabinet switch isn't jammed closed.

To explain a bit - a blown coil will destroy the transistor, a blown transistor will destroy the coil.
 
Moonraker said:
Try replacing both the coil and transistor together at the same time. Also check that the cabinet switch isn't jammed closed.

To explain a bit - a blown coil will destroy the transistor, a blown transistor will destroy the coil.
Click to expand...

I popped over to Nate's to try help out (and get a JP2 tutorial ready for the weekend😉), but my limited knowledge of stern SAM games wasn't very helpful.

If it's the coil, would it still fire once before blowing the fuse and transistor?

I did suspect the coil but in an ohm test it didn't show anything that appeared off. The left and right coils are different values so it wasn't an easy comparison.
It would be wonderful if it was just the coil as everything downstream from Q16 is surface mounted 🙈
 
David_Vi said:
If it's the coil, would it still fire once before blowing the fuse and transistor?
Click to expand...

Yep, when or as it activates...! If Nate was really quick in turning off the game then he might have got lucky in not blowing the new transistor but I suspect unlikely. Diode test the transistor is the way to go, if in doubt compare the value with the one next to it but chances are it will be shorted.
 
The new transistor is definitely shorted.
We even tried another one and replaced the associated diode.

Unless 2 faulty (or fake? As I hear this is a thing) transistors it's surely either the coil or something deeper which is beyond me, especially with SMD components!

Before I took a look apparently the flipper would stick up immediately on power on. Since we tried two transistors it would only blow the fuse and transistor when the flipper is first fired in game. Would that point to anything?
 
David_Vi said:
The new transistor is definitely shorted.
We even tried another one and replaced the associated diode.

Unless 2 faulty (or fake? As I hear this is a thing) transistors it's surely either the coil or something deeper which is beyond me, especially with SMD components!

Before I took a look apparently the flipper would stick up immediately on power on. Since we tried two transistors it would only blow the fuse and transistor when the flipper is first fired in game. Would that point to anything?
Click to expand...

Where did you buy the IRL540 ? We stopped using them as we were even getting fakes from 'trusted' suppliers. Unless you bought it from Farnell, RS etc it is 90% guaranteed to be a fake (sadly). I would guess that practically ALL the ones listed on Fleabay 'posted from China' will be fakes!

The only way we stopped this problem was to go directly to a semiconductor factory and have these parts made for us by the semi factory. This has solved the problem for us but min quantities are over the top!

FWIW the part number we use is CS60N10 which is the same package as the 540 but much higher current rating (100V 60A).

I suggest ordering some from a reputable trade supplier such as Mouser, RS comp or Farnell - sorry, 'Element 14' AND check or replace the diode BEFORE switching on with the new part. The coil is very unlikely to have been damaged unless it was left energised for more than a few minutes.
 
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IRL540 is a MOSFET - they are very sensitive to static, so it's easy to blow one whilst fitting it. You need to keep it in an antistatic bag/foam until ready to solder in and earth yourself and the board whist fitting it

If the flipper didnt pop up on starting a game then the new transistor (and its driver circuits) seemed to be ok, but then flipping the flipper the first time causes it to lock on. Hmm I'd replace the transistor again, after checking the coil is in spec ohms wise and any flyback diode across the coil should be replaced.

Fakes are often under spec, i.e. cant handle the current they're supposed to.
 
Thanks everyone for chipping in on this, new mosfets from a good supplier plus a new coil on the way, we’ll try changing both on our next attempt :) game issues are frustrating but you sure do learn a thing or two!
 
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