Ok. IM new. But one of my best buds in RL is Xanathar. And I have been doing the electrical work helping him to get his Star Trek: The Next Generation working properly. Our current issue is that I cant get the backboard lights to work. The J120 port simply does not work. Xanathar had the power board tested and it was given a clean bill of health. I have followed up with a testing of the circuits that govern the J120 port. All were clear. We also switched the J121 connector out and put the J120 connector in. The backboard lit just fine so no problems there.

We are completely at a loss as to what to do now. I could replace all the components but there is no guarantee that would work. Any advice?

If I recall, J120 and J121 are on the same exact circuit. Pin for pin.

Sounds like your headers on J120 might need to be replaced.

Stop!

Solder Time.

Check continuity on the board. Isolate where J120 is losing the circuit.

Yes. They are parallel. And I checked that. Getting full continuity to the tip of the pin with a 0.2 ohm resist between pin tip and other end of the trace.

LordBreetai said:

Yes. They are parallel. And I checked that. Getting full continuity to the tip of the pin with a 0.2 ohm resist between pin tip and other end of the trace.

Looks like we were 2 secs apart on the posts. So if you are getting continuity from the male pins to the back, check continuity at the fuse. Not just the same side, but check the continuity from the from to back as well.

Kinda like keep making the "line" you are checking longer each time. hth

Ill have to look into it. The fuses themselves are fine. We even swapped them around with no change. But I will admit I dont think that could be it. But its always worth double checking.

Hey all its Xanathar

Yes. If anyone can offer some good advice on this it would be greatly appreciated. Just to re-itterate we took the connector for the Backbox and pluuged it into J121 and the backbox lights up, and if we take the GI for the playfield that originally goes into J121 and plug it into J120, only about 1/2 of the GI playfield lights work.

Put everything back the way it should be, Playfield GI works fine, but backbox no longer works at all.

We are at a complete loss. Its driving us nuts. If anyone in the Cleveland area can donate some time to help us it would be most appreciated.

My friend LordBreetai will also be monitoring this post for help as well

Thanks a lot

Xan

Since you guys are saying that the fuse is good,connecter is good,continuity is good and the driver board was given a clean bill of health.The only other thing that comes to mind is the ribbon cables,You need to go over and reseat all the ribbon cables.The ones going from the driver board to the CPU etc.You might be a few or a whole row of pins might be off,It's very easy to make this mistake and it does happen.Do this with the power off.

If this doesnt get it then there is a problem with some components on your driver board most likely a BR,caps,or broken trace that might need to be jumper wired.Look at the schematics starting with that connector and follow it all the way through and what components its leading to,Then test those components.

You can also swap out the driver board that's in your T2 and try it in your STTNG,This will easily tell you if the problem is in the playfield or on the driver board.

Well there was one cable. reseated both sides but no effect. And a good idea on the board swap....... if whoever had the T2 before hadnt soldered wires to the pins instead of using connectors

Well I just had the J120 connector replaced on the Power Driver Board. Lets hope this fixes it. Otherwise I'm gonna scream!

Odds are that it will.

I hope you are replacing both sides of the connector.

i.e. the pcb side pin header and the wire side female molex w/ recrimped wires. Also, make sure you didn't have to install a stitch through the pcb via.

It would suck, if you did all that work, and you found that you still didn't make a good connection.