STTNG problems

[good_buddy83]

OK, I have a STTNG that won't boot anymore. Pretty sure it's my fault, but here is what happened:

-3 of the 5 GI strings were not working on the playfield.
-Opened up the head and the connector J115 was crispy. It litterally fell apart in my hands.
-I replaced the connector, but notice one of the board pins was loose (felt like a loose tooth)
-I powered up and the GI's all worked if I wiggled the wires. Figured needs to be repinned on the board.
-Tried playing a game and kept getting resets. I figured this was related to the GI issues. Time to repin the board.
- When I was repinning the board, I lost two delaminated solder pads, due to the heat of the previous cooking. So I ran jumper traces behind the board to be sure I had good continuity.
-So I just finished re-pinning the crispy and loose pins, power it back up and nothing, garbled display and no activity. I figure this sounds like a ribbon cable. in fact I am sure it is a ribbon cable. I reseated that ribbon cable at least 10 times now and nothing. Sometimes I got two two dots, sometimes I got garble.

Am I missing a wire?
-My next step is to swap the board with another WPC and try to isolated that it is a power board problem, but if anyone has more ideas, please let me know. I am extremely frustrated and need to walk away and think for a bit.

 

[Chris Bardon]

Not sure if I can offer anything specific, but I'd try disconnecting as much as you can. What if you disconnect all the GI? Can you get down to just CPU/DMD-never tried that? Are any of the ICs socketed? Where were the places where you ran the jumpers-could that be the issue? If you have another game with the same boards, maybe try the cables before you pull the board and test that?

 

[Menace]

Based on the picture you posted, your MPU is not seeing ANY 5VDC from the driver PCB. As I can see from your pic of inside the head your driver PCB is missing the regulated 5VDC as LED4 is not lit, and D21 on the MPU is out as is the 5V led on the Aux8 PCB.

You need to check F113 to see if it's blown. If it's good then you have a broken trace / cold solder joint / bad connector/header, an open bridge rectifier or even a failed 5V regulator. Using your DMM and the schematics you should be able to track this issue down pretty quickly.

If that's over your head and you're in the GTA drop me a line and we can setup a service call.

D

 

[good_buddy83]

Awesome, Thanks for the help. I'll have another crack at it. I'll try a board swap first and if that works, I'll try to figure out why I have no 5V to the logic board.

 

[Menace]

The issue will be on the driver PCB for sure.

D

 

[good_buddy83]

Menace,

You are absolutely correct. It is definitely an issue on the PCB. I tried the F113 fuse, metered OK, but replaced it just incase. Still no go. I am not that familiar with this circuit on the Power driver, but I love a challenge. I know is has the associated big bridge and cap which I had replaced a while back due to reset issues. The board is out of the machine now and I'll try to chase it down over the weekend. Let me know if you think of any other know culprits on the logic power circuit to check first.

 

[good_buddy83]

I was also going to try the board in my TAF just to be sure. I want to make sure it is getting the correct power input to the board from the transformer.

 

[Menace]

If you replaced the bridge and cap, grab the schematics and ring out every trace from the input AC connector on the right side of the PCB through to the MPU power connector on the left side of the driver.

You can test it in your TAF no problem, but the AC input usually isn't the issue. My money is on a broken trace or a failed bridge.

D

 

[good_buddy83]

Thanks Menace. I am with you on this one. I am wondering if the new bridge failed, but I'll check continuity everywhere first and I am sure I can chase it out. Thanks.

 

[good_buddy83]

Issue is not on the board. This is power drive board for STTNG running perfect in my TAF (minus the flippers since there is no switch relay on this board).

All that is left is the connector itself at J101, or the transformer. I seem to recall in the past that this machine had reset issues once and while and wiggling J101 often seemed to fix the issue. I am betting it is a case of bad connector. Connector is cheaper and easier than a transformer, so let's go with that first. I replace it with the newer style and get rid of the V grooves since I trust a crimp more. Please let me know if anyone else has any better ideas, but I think we are running out of options. Thanks.

 

[Menace]

If the connector in your STTNG is in fact bad, you should also replace the header for it on the driver PCB as the plating on it is likely tarnished and will cause issues with the new connector (higher resistance creating more heat and runing the new connector)

D

 

[good_buddy83]

New pins now installed on the PCB. Runs like a champ now. LED on 5V is bright, reconnected everything and we were good to go. BTW the GI (which was the problem I was originally trying to fix) is working 100% now too. Thanks for all the help. Feeling much better now. Cheers.