Teenage Mutant Ninja Turtles
Data East, 1991On TMNT, I recently gave it a thorough cleaning and installed a playfield protector. I fired up a game and it played a ball, then the flipper got stuck up and blew a fuse. I've run into this before with Hook, but it was a bad diode. Why would the flipper get stuck and blow transistor and fuse? This is a Rottendog by the way. I didn't remove anything from the flipper but the bat itself.
The transistor went bad first and shorted to ground which caused the flipper to energize and blow the fuse. Transistors just go bad sometimes. Probably nothing you did.
Quoted from schudel5:The transistor went bad first and shorted to ground which caused the flipper to energize and blow the fuse. Transistors just go bad sometimes. Probably nothing you did.
No, transistors rarely just go bad....usually there is a reason for this (stuck switch, broken coil diode, etc..)
"Check the flipper coil diode. If the flipper coil diode is broken or shorted on, the flipper coil will stay energized after using it. Replace this diode with a new 1N4004 or 1N4007 diode. The counter EMF (Electro-Motive Force) produced by the magnetic field in the coil collapsing is a reverse polarity voltage. This reverse polarity voltage can cause damage to the flipper board. In most cases, it will gate the SCR (Silicon Controlled Rectifier) in the holding voltage circuit, causing the flipper to remain energized as if the player was holding the cabinet flipper button in. This was mentioned in service bulletin number 58"
Quoted from wayout440:No, transistors rarely just go bad....usually there is a reason for this (stuck switch, broken coil diode, etc..)
"Check the flipper coil diode. If the flipper coil diode is broken or shorted on, the flipper coil will stay energized after using it. Replace this diode with a new 1N4004 or 1N4007 diode. The counter EMF (Electro-Motive Force) produced by the magnetic field in the coil collapsing is a reverse polarity voltage. This reverse polarity voltage can cause damage to the flipper board. In most cases, it will gate the SCR (Silicon Controlled Rectifier) in the holding voltage circuit, causing the flipper to remain energized as if the player was holding the cabinet flipper button in. This was mentioned in service bulletin number 58"
It definitely was not the diode.
I would disagree that transistors never "just go bad." Especially on 30-year old games anything can just go bad. I've had many transistors just go tits up on a whim.
I replace the transistor and any associated coil just in case.
Is this an Eos normal open or closed game when flippers aren't engaged? Either way I suppose, if the flipper was binding (against the protector) after you reinstalled the bat and the hold coil wasn't engaging because the Eos just happened to get a little out of adjustment, transistor would blow and then fuse would follow.
You probably already checked for binding though.. but usually I see flip transistors blow due to Eos issues or as mentioned a shorted diode.
With Data East, they do not use a traditional EOS switch. What they do is after 40ms the High Voltage kicks off. Here is what is says on a technical site.
DataEast was the first company to use solidstate flippers. The solidstate design again used a single winding coil (instead of the traditional two windings, one for high voltage, and one for low voltage hold). A solidstate version of the Deger design, the single winding coil had different voltages for the initial power and the flipper hold (only one diode, a 1N4004 voltage snubbing diode, is used). When the flipper button was pressed, 50 volts DC is directed to the single winding flipper coil. After a short duration (40 milli-seconds, which is not variable), the high power is turned off and 9 volts is left to hold the flipper coil. The lower 9 volts allows the flipper button to be held, without burning the flipper coil. Note this is different than the solidstate flipper system used by Williams; which used two separate flipper coil windings (a high and low voltage winding) to achieve this.
There were some complaints that the new solidstate DataEast flippers didn't have the same feel as a traditional EOS (End Of Stroke) system flippers. This was because DataEast/Sega's design had a fixed timing (40 milliseconds) for the high voltage. On an EOS switch dependant flipper, the flippers react to the EOS switch, and turn off the high voltage accordingly.
Quoted from CrazyLevi:I would disagree that transistors never "just go bad." Especially on 30-year old games anything can just go bad. I've had many transistors just go tits up on a whim.
I replace the transistor and any associated coil just in case.
This was a 6 month old Rottendog
I just remembered something.
I got the game and the left flipper had been rebuilt and was playing fine. The right flipper was not but was working fine. I was going to put it in a new coil sleeve, coil stop, bushing etc. The allen wrench screws were secured with Locktite. I got it to come off, but at one point, the wrench slipped and I punched the left flipper. I checked everything this morning, but the coil physically looks fine and the coil tested okay.
Transistors definitely do go bad. I work doing repairs at an arcade and I replace a transistor about once a month. Not saying there might be some exterior conditions causing failures on some of these, but most just went bad. Granted some of what I have to change are on games the guy just bought that typically have one or two shorted. Simply changing them and we're golden.
I'd replace the coil diode with a 1N4007 (if you haven't already) and change the transistor and replace the fuse. There really isn't anything else in the flipper circuit. Not sure what transistor Rotten Dog uses, but the 20N10L transistors Sega/DE used always seem to go bad. I've replaced 5 in the past 6 months on games I service.
Quoted from schudel5:Transistors definitely do go bad. I work doing repairs at an arcade and I replace a transistor about once a month. Not saying there might be some exterior conditions causing failures on some of these, but most just went bad. Granted some of what I have to change are on games the guy just bought that typically have one or two shorted. Simply changing them and we're golden.
I'd replace the coil diode with a 1N4007 (if you haven't already) and change the transistor and replace the fuse. There really isn't anything else in the flipper circuit. Not sure what transistor Rotten Dog uses, but the 20N10L transistors Sega/DE used always seem to go bad. I've replaced 5 in the past 6 months on games I service.
I found the schematic online last night and am going to get the transistors today. I do change transistors a lot in arcades, especially HOT and color transistors. So lets hope I just have a weak one that finally went.
Quoted from CrazyLevi:I would disagree that transistors never "just go bad."
I didn't say never.
I can tell you that many, many times I've seen or heard about folks here replacing transistors and having the replacements fail later, because some other fault was the original cause. Nobody sees any possible correlation to the OP messing with the flipper bats and cleaning the game...and so we'll just chalk that up to coincidence and say that transistor just up and failed? Sure that's possible...but it leaves a little doubt in there, doesn't it? We'll just have to see if it holds up after replacing it.
Quoted from wayout440:I didn't say never.
I can tell you that many, many times I've seen or heard about folks here replacing transistors and having the replacements fail later, because some other fault was the original cause. Nobody sees any possible correlation to the OP messing with the flipper bats and cleaning the game...and so we'll just chalk that up to coincidence and say that transistor just up and failed? Sure that's possible...but it leaves a little doubt in there, doesn't it? We'll just have to see if it holds up after replacing it.
Coincidences like this happen all the time to me. I'll replace something and another thing goes. Usually has nothing to do with each other. I don't really see how installing a playfield protector would have anything to do with a blown flipper transistor.
Blown transistors, either a short, bad coil, or bad luck. As long as he checks wiring very closely and replaces the coil, and checks EOS (for games that have one) that'll usually take care of it. I would ALWAYS replace a coil in event of a blown transistor regardless of how it tests. Just not worth the risk.
Guess you're just an unlucky fellow there, Levi. As far as the playfield protector goes, op had to remove the bats, which in most games are integrated to the shaft that goes to the coil mech, in turn meaning you have to mess with the mech. The OP even said his wrench slipped and "punched" the left flipper. Am I saying that is definitely the cause?? No, but it is something to make note of.
I think I have a spare coil for that mech. I'm also going to rebuild the power supply, it has been suspect for other issues and I am picking up caps with my transistors today.
Quoted from wayout440:Guess you're just an unlucky fellow there, Levi. As far as the playfield protector goes, op had to remove the bats, which in most games are integrated to the shaft that goes to the coil mech, in turn meaning you have to mess with the mech. The OP even said his wrench slipped and "punched" the left flipper. Am I saying that is definitely the cause?? No, but it is something to make note of.
I think we are both saying the same thing? Check it out, refer to your "notes" and past work, but don't get hung up on it. The only place we disagree is that you think it's highly unlikely a transistor can blow "on it's own" and I don't. Certainly if he stabbed a flipper coil with a metal tool that would make that coil suspect - I already recommended he replace any coil related to a blown transistor to be safe, so if I were working on the game it would be irrelevant anyway. A blown transistor makes that coil suspect just as stabbing it does.
Now it's DOUBLE suspect!!!!
Quoted from CrazyLevi:Certainly if he stabbed a flipper coil with a metal tool that would make that coil suspect
It wasn't the wrench, it was my bloody fist. I have the busted knuckle to prove it 
I contacted Rottendog and their tech called me back to provide some input. Really good customer service. I wasn't technically the customer, the guy I bought the game from was. But they truly wanted to stand behind their product.
He told me about the more basic things to check that I already knew about but he gave me some other stuff that never occurred to me. He gave me tips on how to work on the board. Just an all around good experience. I'll update you after I work on some stuff tonight.
Quoted from futurepinhead:I contacted Rottendog and their tech called me back to provide some input.
What phone number did you call and when, there is another thread on here at present looking for contact info for them:
https://pinside.com/pinball/forum/topic/rottendog-phone-number
I just called the number on their Contact Us page
http://rottendog.us/contact%20us.html
His voicemail was full but I got a returning phone call within 2 mins and it was the owner Jerod. He had his tech call me within the hour.
We fixed it. We narrowed it down to the HV coming from the PS caused it. When I pulled the PS out to rebuild it, it was black on the back side. I had enough parts to rebuild most of it, but I was missing all the cement resistors. I had the game on less than 5 mins and it was so hot, we couldn't remove it without getting burned. We were trying to get it ready for the Louisville show, but it's too much of a liability to take in its current state.
Thanks for your help
Picked up a sm over the weekend and one flasher didn't work. Had an led flasher in it, but was not lighting in test mode. Put a regular bulb in it and the light was immediately locked on. Obvious blown transistor. Replaced the transistor and it works fine now.
Why doesn't the fuse blow as well? What could cause the transistor to blow?
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Berea, OH
Newmarket, ON
