I rebuilt the flippers on my Stern Trident this past weekend. I played a bunch of games right after and then a few later that evening. I went to play last night and after the first ball drained all of the feature lights went out. It did this to me once before and if I remember right I went to turn it on a few days later and they were working again. I checked all of the fuses and reset all board connectors but couldn't get them to come back on.

Can anyone tell me where and what I should look at first?

I checked it out at lunch. I took my DMM and put one lead on the braid and one on the socket lead where the wire is soldered and got no power whatsoever. I checked multiple lights with the same result.

I just checked the braid on the feature lights and I have 3.6vdc. While I was at it I also checked my GI and I have 3.6vdc there as well. I guess it's not a power issue. What should I check next?

Ok, didn't know GI was ac. I guess 3.6 is too low for the control lights to even try to light because I have nothing at all, not even dim lights.

I wanted to check TP1 on the rectifier board. I put the black lead on the ground braid and red on TP1 with the DMM set to DC and no reading. I then switched the black to a ground over by the service outlet on the wood panel and got negative 3.6 at TP1. Why am I getting a negative reading and no ground on the ground braid?

I checked all of the rectifiers on the board and all tested good. One of the connectors was a little burnt so I went ahead and changed it out and my control lights came on. All of the lights worked except for one below the left spinner. I saw it was a red wire with a green stripe. I found a red with green wire on the lamp board, checked it, and wasn't getting continuity so I replaced the wire but the light wasn't coming on when it was supposed to; it is supposed to come on when you hit the top stand-up target but it was on without hitting anything. I got to looking at some of the other control lights and saw another one that wasn't working- the left most light for the stand-up targets that you knock down for the bonus multiplier and it turns out that light has the exact same red with green wire so I swapped my new wire to where the other red with green wire is and the light below the spinner that I put the new wire on lights properly now when I hit the upper stand-up target.

I started checking the other red with green wire and I was getting continuity from the connector to the wire on the lamp socket. I checked and I also am getting voltage but the light is not lighting up. I thought maybe something was wrong with the socket but I used a jumper wire from the lamp socket wire next to it and the light will light up nice and bright. There were a couple times that the problematic light would light up but it was dim and if I wiggled the bulb it would go out and not come back on until I re-booted the game and it didn't come back every time I re-booted the game. I pulled the light board and re-flowed that pin but it didn't change anything. I then did the test where you hook up to TP6 on the MPU and touch the wire for the light in question and the test led lit up which I believe verifies the scr, trace, and connection is good. I also stuffed a wire in the back of the connector, verified I had continuity and voltage on the added wire but the light still wouldn't light.

One thing that is also weird is once I was able to get my control lights back on after replacing the connector and crimp contacts was I was only getting something around 3volts at TP1 on the power driver board and on the control lights buss wire. After I replaced the wire for the first red with green wire I noticed my lights were brighter so I checked voltage at TP1 on the power driver board and the control lights buss wire and was getting a little over 5 volts.

Any ideas on what is going on or what I need to check next? Are the two red with green wires related even though they do different functions or is it coincidence and the factory just happened to use the same wire on two different control lights and that I had problems with both?

So instead of keep chasing my tail I swapped the lamp driver board over from my Meteor, even though it's a Bally board, don't think that makes any difference and the light I was having problems with worked but a few others that were working weren't with the board out of my Meteor so either there are some problems on my Meteor board or it's not directly compatible since it's a Bally.

Is there anything I would want to look at on my original Trident board besides the SCR for the lamp that doesn't work?

I re-flowed the pin for the lamp I'm having trouble with and when I had the board out I verified I have continuity from the pin on the front side to the back side of the board and verified continuity from the backside of the board over to the SCR.

I'll try the test you mention, but let me make sure I have it right. I take a jumper wire and jump from the top leg of the SCR to TP3 on the lamp board and if the lamp on the playfield doesn't light the SCR is bad, is that right?

Cool, thanks for letting me know about the test and verifying! I think you are correct about TP1 being ground on the Stern board; I figured that out when I was trying to test board voltages and I was told to check TP1 for 5vdc and I didn't come up with anything. I'll give the test a try and post up my results.

Ok, I thought so but wasn't 100% sure. I guess the ground TP is different between Bally and Stern though?

I did some testing. Ground to the top Center leg of the scr didn't do anything. When I went from test point three, 5vdc, to the bottom right leg on the scr the light lit. Does that mean the scr is bad?

I did read through the entire thread, some parts more than once. He says: "The top (middle) leg of the small SCRs is the "Gate" leg - you can see next to Q4 it is marked "G". Connecting TP3 on the lamp board to the gate leg manually switches on the SCR. If the respective lamp doesn't light, the SCR is suspect." This not what I did, I went from TP3 to bottom right, guess I should have went to the top leg? I went from top leg to ground which didn't do anything. I'm wondering what I did, TP3 to bottom right does, I'm guessing bypasses the SCR and powers on the light?

TP1 is ground since I'm working on a Stern board but last night I tested ground to the top leg per what we were talking about earlier. I will have to try TP3 to the top leg and see what happens.

Is the gate leg the bottom right leg when it's mounted on the board? The bottom right to TP3 is what made the light come on.

My game has a Stern lamp board in it, LDA100. I am trying to fix J3 pin 3 for the drop target # 1 lamp. I did see and made reference that the pin number one is at the bottom and go up from there. I've been testing Q60 which I believe is the correct SCR for J3 pin 3

I would like to double check which one it is but I'm almost positive it's Rev A because it's a bluish color. If it's Rev A, which I think it is, what test do I need to do to see if the SCR is bad? I went from TP3 to bottom right and the light lit.

Ok, I'll try and grab a picture of it at lunch.

Pictures of the board, Q60, and a label on the board.

IMG_20190507_141355 (resized).jpg

IMG_20190507_141406 (resized).jpg

IMG_20190507_141418 (resized).jpg

Yeah, I know this is something I should look into and it bothers me seeing the battery on the board like that.

I ran a jumper wire from TP3 to the top leg of Q60 and as we suspected the light did not light and the SCR is bad.

Yes, it lit running a jumper from ground to the bottom right leg.

Just wanted to let you guys know I bought a soldering / de-soldering station, replaced my first board component, which was this SCR and now the light that didn't work is fixed! My friend came over and gave me a good tutorial on soldering / de-soldering on board work and he also brought his Pinitech control lamp tester that was referenced earlier in this thread; that thing is awesome!! We checked my EBD and Meteor, found a few SCRs that need replaced so more solder work for my new tool!

Thanks to everyone for the replies, info, and helping me get that one pesky light going that was driving me crazy!

No problem! I try to follow-up on all of my threads that get resolved in case someone stumbles upon it in the future or I might even be the one to need it a few years later and forgot what I did to diagnose and fix the problem. Big thanks again to the contributors that provided info.

I know, I feel I could be dangerous with it also! I'm glad I bought it, especially since I have quite a few older games, I feel at this point it's a mandatory tool for the size and current games in my collection.