TRON - Blown L116 and a mess

benkeezer

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I replaced the interconnects on my TRON and I saw SMOKE! I checked the Super CPU board and the L116 10UH Molded and C135 .01 uF Ax. Cer. were melted!!! I've tried Bob Roberts and don't see replacements. Anyone know where I can get them?

1st pic is my backup boardset. Which also seems to have the problem.:mad: The second pic clearly shows something wrong with L116.

Thanks

Ben
 

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OK-

Somebody jump in and correct me if you have a better answer. I think this is due to something shorting out the +12V line on the TOP board. Look for some of the black capacitors across the 12v rail that could be shorted.

I've found some of these before.
 
You can get the molded from Mouser. However, you have another problem going on there. Something else is shorted and causing this. Look over all 3 boards with a Magnifying glass if you have to, there's some other component that probably blew shorted. I have the part number around here somewhere. But the replacement will probably just blow again.
 
OK-

Somebody jump in and correct me if you have a better answer. I think this is due to something shorting out the +12V line on the TOP board. Look for some of the black capacitors across the 12v rail that could be shorted.



Correct, I've had this happen 3 times over the years on different games, each time it was one of the tantalums in the 12v audio circuit. Put your meter across pins 1 & 11 of J2 and see if you have a short, if so it's probably one of the black Tants like kstillin said. I don't have a cap tester so I lifted one end of each cap till I found the bad one. Parts can be had from Mouser,
this is the choke I used, Mouser part #542-77f100-rc for L116. Of course it could be something else too.
Rich H
 
Are you sure you put the cables on correctly? It is VERY easy to have one end of the cable over one pin and shoot 12v where it should not go.
 
OK-

Somebody jump in and correct me if you have a better answer. I think this is due to something shorting out the +12V line on the TOP board. Look for some of the black capacitors across the 12v rail that could be shorted.



Correct, I've had this happen 3 times over the years on different games, each time it was one of the tantalums in the 12v audio circuit. Put your meter across pins 1 & 11 of J2 and see if you have a short, if so it's probably one of the black Tants like kstillin said. I don't have a cap tester so I lifted one end of each cap till I found the bad one. Parts can be had from Mouser,
this is the choke I used, Mouser part #542-77f100-rc for L116. Of course it could be something else too.
Rich H

Thanks. I'll check Mouser.
 
Are you sure you put the cables on correctly? It is VERY easy to have one end of the cable over one pin and shoot 12v where it should not go.

I'm not sure. I know better but was in a hurry. After I fix the board, I'll take my time putting it back together. Thanks
 
On mine it was one of those caps you mentioned, blown shorted. I had to really look for it to find it. But thank goodness it was visible by eyeball. At any rate, mine was an L116 that blew and the 10UH Molded inductor. Certainly wasn't a choke. Mine was on the SSIO board and it certainly didn't look anything like those your looking at replacing.
www.zinfer.com/tron.htm
 
Thanks for posting this up. I have the EXACT same issue on my backup board that I am working on rebuilding and was getting ready to get started on it. I figured the blown inductor was the problem, now I can hunt through the boardset for the culprit before I blow another one.
 
Funny, it's an old thread but I was reading it this morning. Had the same thing happen and thought it was a defective component on the CPU....until the same SSIO fried another CPU board. :) Was a shorted tantalum cap on the SSIO.
 
All of the above. I agree, something is shorted - track everything on the line down and check + to ground. If you get low ohms, you may have found it.

The smoke definately came out - you'll be replacing parts. Watch for damage - in the one picture, it looks like the diode above the inductor got cooked / cracked.

I've found that most of the time, an IC that fries will "crack" and if you run your finger nail down the chip top, sometimes you can pick up the "crack" as a discontinuity. It worked for me.
 
Those little ceramic capacitors....

...do look a lot like diodes.

Thanks for the tip on the IC's.

:)
All of the above. I agree, something is shorted - track everything on the line down and check + to ground. If you get low ohms, you may have found it.

The smoke definately came out - you'll be replacing parts. Watch for damage - in the one picture, it looks like the diode above the inductor got cooked / cracked.

I've found that most of the time, an IC that fries will "crack" and if you run your finger nail down the chip top, sometimes you can pick up the "crack" as a discontinuity. It worked for me.
 
Darn you guys. Keep talking this thread up, now my stack took a dump. Dead after years of being ol' faithful. Split the stack and looking it over. About to take some power board readings.
 
This has happened to me several times, in fact, just happened again! :(

But this time after inspecting the area of smoke, I came upon something unusual, the 0.01uF axial caps were replaced with diodes......

Has anyone seen this before?

Now onto the search for the elusive shorted tant!
 

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This is one of the diodes pulled, there are no markings other that the K band.

Anyone see this MOD before?

Can I assume these are small signal diodes, 1N914? 1N4148?
 

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This is one of the diodes pulled, there are no markings other that the K band.

Anyone see this MOD before?

Can I assume these are small signal diodes, 1N914? 1N4148?


I've seen small ceramic caps that look like that. I wouldn't assume they are diodes.
 
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