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Dead TMNT credit board


mrjamma

Question

Hey guys

 

A couple of pics below of a friends dead tmnt credit board.

 

Just wondering if anyone could shed some light on why this tmnt credit PCB has some wires underneath? Do you see noticeable trace damage which would require these as link wires for those specific areas?

Or was this for purpose of a repair or to convert it to be used as a credit board for another game?

 

Also when compared to other pics of these boards, looks like an extra diode on top too?

I can see a bad transistor too.

 

I know MK4 is a workaround, just seems like a shame to have to bin an original tmnt sunrise one.

 

BAD:

Bad 1.jpg

 

GOOD - youll see one of the pics has a different design (being 1990 compared to 1989)

Good 1.jpg

 

Edit: The good board with different design, photo of underneath:

20181114_183605.jpg

Edited by mrjamma
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Mine looks like that also, spaghetti of wires on the back and no idea what the hell is wrong with it. I'll be following this thread with interest, as getting the credit board and coin mech working is the last thing I need to do to my machine to make it 100% functional.

 

Mine is even worse though, as the harness has been chopped off and the wires hard soldered to the credit board :( I have a new harness, just need to wait until holidays to start poking it with a stick and seeing what happens.

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Mine looks like that also, spaghetti of wires on the back and no idea what the hell is wrong with it. I'll be following this thread with interest, as getting the credit board and coin mech working is the last thing I need to do to my machine to make it 100% functional.

 

Mine is even worse though, as the harness has been chopped off and the wires hard soldered to the credit board :( I have a new harness, just need to wait until holidays to start poking it with a stick and seeing what happens.

 

any pics for reference? cheers

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Yep that was the original credit boards used with the original coin mechs. I think they started with Sentinal mechs and when you changed from them,( arse of a coin mech), the pulse was either reversed or to short so therefore you had to hack the shit out of them as you are seeing.

 

It was actually easier and cheaper to hack the credit board than convert the machine to use later, more common versions of the coin boards but

in the end most operators did especially after I think it was The Simpsons come out with NRIs in the front door and the later coin boards.

 

You could them buy the complete coin wiring harnesses off LAI to do to your earlier machine what was done on the later non Sentenial machines.

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This is mine. As you can see, hacked to buggery and back. Haven't even looked at getting it fixed yet, I need to get on it. I have a C220 coin mech on loan that I know works, I just need to get the credit board and wiring sorted with a whole shitload of help from people who know more than I do :)

 

46132897_922745314596557_4309635704532500480_n.jpg46098201_909535595915690_4080669846931505152_n.jpg

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Wow. Interesting.

So if wanting to re use as intended with original sentinel whats the play here?

Remove all those patch wires, remove the additional diode and replace the damaged transistor?

Or does it look like some traces were cut up too on the pcb circuit?

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Wow. Interesting.

So if wanting to re use as intended with original sentinel whats the play here?

Remove all those patch wires, remove the additional diode and replace the damaged transistor?

Or does it look like some traces were cut up too on the pcb circuit?

 

They were arses of coin mechs like I said and some of those jumpers were probably put in to overcome the weakening inductor coil that actually samples the metal makeup of the coin. The Sentinals had a habit of cooking this inductor coil to the point of not registering some, most or all coins pasted through them so the signal, through some hacks would buy the mech some more time before hitting the bin.

 

You used to be able to get parts for the Sentinals but after a while it become apparent there was problems with the design and what spares were around quickly dried up.

 

Just to give you some idea replacement Sentinals were $650 and most were "factory repaired units". They also had a habit of breaking the mounts that hold them in place and most of the machines I maintained were held in place with screw in cup hooks and a pinball rubber after the mounts had broken off.

 

Another problem was the wiring connector because in machines like TMNT where you couldn't see the mech to remove them, often the wires were pulled out of the connector and now a simple coin mech clearing job becomes a repinning the connector.

 

You starting to see why I say an arse of a coin mech?. NRI and MCA mechs were just far better plus you didn't need a special programmer to set the coins you wanted the mech to handle.

 

This you would think would be a case of do once and that is it.....No, they do drop there memory from time to time, all coin mechs do but the big issue was the $2. It changing in it's material make up 4 times and each one of these different material makeups had to be included or you ended up with a coin mech not being able to except all $2 coins. I know with the NRIs, the mech in a couple of machines at one site would except lead slugs and someone quickly learnt that.

 

We were pulling hundreds of dollars out of the cashboxes till I decided to kill these mechs from excepting $2 coins.

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@Autosteve , is spot about those awful Sentinal Mechs, they caused a stack of problems and were also susceptible to static interference from the monitor so a shield had to be added to the cabinets.

The sentinal mechs did give a standard low pulse , it was the Mars mechs ( not used in TMNT ) that gave a High pulse which was opposite to everything else.

 

 

Now to the TMNT credit board , it had a special program that stored credits in a credit pool ( keep in mind one coin mech for four players ) they were displayed on the credit display.

TMNT has 4 cabinet buttons above the panel that were credit deduct buttons not start buttons as they look to be , they needed this because the game board had 4 coin inputs so you needed to press one of the deduct buttons to send the stored credits to the correct coin input on the board. Basically this is the same feature on the Sunrise MK4 credit board called " Stored Credit Mode" .

 

Pretty much every game that come out after TMNT had a single coin input so the stored mode on the TMNT credit board couldn't be used because if you pressed player 2, 3 or 4 deduct buttons the credits went nowhere.

The Burnt transistor is the lamp driver , it blows when the lamps / lamp wiring is shorted.

The Mod on the back of the board in effect is using the lamps drivers active signal to send a low signal to the deduct input when a coin input is sensed and lights the credit lamps, this is a clever mod in that when the lamps light the Emitter of the transistor changes state and pulses the credit deduct input to issue the credit instantly sending them to the player 1 coin input on the game board. , this is making the credit board simulate the MK4 credit boards "Direct Credit Conversion" mode

In this mode if you were to drop a $1 coin in , the lamps would quickly flicker and the game would be credited straight away , the lamps would never flash like they used to when configured for TMNT.

The diode is put in place so the feedback from the Emitter won't ever go above 0.6volts because the lamps run on 12volts and IC inputs can only handle 5volts .

 

 

 

For reference the Start buttons inputs on TMNT were joined to each players Sw1 Jump or Sw2 Attack inputs, there was no actual start button on TMNT.

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Great info guys!

Man those Sentinels sounded like an operators nightmare for commercial use. Sounded painful

Fortunately this would be used in a home restoration, literally just to function on occasion with a C220 or Sentinel. Like namastepat said, an Mk4 can be used, but for originality's sake would be a shame to just bin the tmnt one.

 

@Jomac thanks once again for such a detailed insight into the circuits workings. How would the best way be to save this poor credit board to function as TMNT again for restoration use?

 

Would this be right?

- Cut out that extra diode i pointed out on top

- Cut off all those green link wires

- Replace that lamp transistor which is blown. Looks like 2n4401, not sure if that can be substituted

 

Only thing im unsure on is whether any traces were cut with all that wiring modification. Kind of looks like it was, but dont have another unmodified 1989 one to compare to.

 

Does anyone have a pic of the rear of one of the 1989 ones for comparison?

 

e.g. these are my concerns:

 

traces.jpg

Edited by mrjamma
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Yeah i should be able to provide pics of anything needed, it's the one part of my machine that i'm so glad has worked flawlessly all these years.

 

That being said, I feel even just looking at this thread is going to jinx that - so if something happens - fk you guys :P haha

 

If you have the 1989 version of the credit board (the 1990 pcb is slightly different) and could take a clear pic of front and rear thatd be much appreciated for a reference.

Thanks heaps

Ive also msged another member who may be able to help as well :) thanks all

Edited by mrjamma
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Not a good machine to fix when you had coin problems but it was in your interest to keep TMNT going because it did make damm good money when it was current.

 

We rotated games through the cabinets when TMNT died money wise with games like Capt. America, Street Fighter etc and over time converted them all to front door coin mechs.

 

If I had a complaint about these cabs other than the stupid above coin mech location and type it would be the bloody weight of these cabinets. Just picture how you would get these things either in the back of a Mitsubishi L300 van or a jap ute by yourself?.

 

You topple them on there back gentle till the back rails come in contact and jump around the front and push real hard. They side pretty good on those back rails.

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The biggest problem with these boards especially when things have gone wrong is that the main IC that looks like a normal EPROM is dead , It's actually a very old obsolete MPU with built in RAM & EPROM which is protected, If they were available only Nigel from Sunrise could program them because it's his work. ( They cannot be read or copied ) .

If the IC is good then there isn't anything that can't be repaired on them., a quick test is if the display stays blank its normally dead.

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Thanks guys

 

Been trying to repair one of these boards. All functions work except coin counter and the digital display. Another known working tmnt cred board allows these functions to work okay.

 

Just a question, is this specific transistor shown below labelled with 2N4401 on it? Pretty sure it is and thats why i replaced due to the original one being all cracked up and damaged but it didnt resolve the issues mentioned. Just making sure I put one with the right values.

 

Edit: or is it supposed to be 'mpsa13' transistor?

 

Thanks @madal @Roger Xplosion

 

20181118_203817.jpg

Edited by mrjamma
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Damnit lol. I read the sunrise diagram and makes sense thats the one . Also would explain why its not feeding the coin counter signal.

Cant work out why the data/clock signals wont work on this credit board and signal the credit display though.

Based on the circuit diagram, the pins from the rom chip feed directly to pin 14/15 on the edge connector. Continuity is fine between them so not sure. Maybe the rom is stuffed.

Ill try the transistor and go from there.

Worst case my own credit board works perfect, was just trying to fix this 2nd board as a spare.

Thanks

Edited by mrjamma
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