Treasure Wheel SB 150B plus troubles

[Kershawa]

I have acquired a Sigma SB 150B Plus Treasure Wheel machine. Unfortunately it had some rough past few years, but it looks to be in good shape externally. Problem that I am having is that I cannot get it to display anything on the Winner Paid and Credits LCDs. The blue LCD display shows only one underscore or dash in the upper left.

What I have done so far: I have repeated all of the electrical connectors to the LCDs, on both ends of the cables. I have inspected the internals of the power supply for anything obvious, corrosion broken wires etc. Nothing. I found the ribbon cable to the Winner Paid LCD had 2 broken wires in it. I was able to splice a new wire in place of both of those. I have cleaned off as much of the dirty board as possible with 99% iso alcohol and allowed it to dry a day before reconnecting. I have replaced the 3v battery with a new one. I did find both of the CMOS chip power terminals had came undone from the board. I had to run a jumper on one of them by following the trace on the board. I have pulled the 7 chips that had sockets on the board. I cleaned the sockets and the chip pins gently and reinstalled them. I did find several connections to the chips that were loose not making good connection to the chip pins. I checked them with the back of a 0.3mm drill bit to feel if they had drag on them.

Not sure where to go at this point. It would be nice to be able to start at the power supply to make sure it has correct power and ground before going after the board itself.

[Chris-socal]

Does it have one power supply providing all 3 rails or does it have 3 separate power supplies mounted on the ceiling? You absolutely should voltage check the power supplies under load, It is the #1 issue with Sigma machines.

Chris

[Kershawa]

Its one single power supply mounted to the back wall of the machine.

When I said I went through and looked at the power supply, I was looking inside the metal encasement behind the coin hopper. I plan to do a visual check over of the actual power supply tomorrow.

If there are pointers I should look or test for, I would appreciate that. Also I understand doing a voltage test when loaded, but how do you go about putting a load on the circuits? (May be just getting ahead of myself, curiosity and always learning)

[Kershawa]

I investigated the power supply and found several cold solder joints to the board on the connector and the transformer were no so good. They got reworked with good flux and new solder. I am unsure of how a loaded voltage test is performed, but I get static numbers. Each of the grounds were good and both 5v wires had 5.10v on them. Confirmed with all ground wire connections. The 12v wires were at 12.42v. The 24v wire was at 25.3v. I seen test points on the board, so I got readings from each of those to ground as well. TP1: 0.05v. TP2: 5.05v. TP3: 12.33V. TP4: 25.3V Yes I had the reels out to test at the connector of the power supply if it matters. Each of the board test point readings were using a ground at the power supply connector too.

[Chris-socal]

Thats great work, exactly what needs to be done. Many times the switching circuit blows out and they are very temperamental to repair…I have a pile of them that I tried to fix but they still won’t wake up.
Personally I put them under load by connecting light bulbs, then connect a voltmeter and watch it for awhile, they have a tendency to drift, not critical on 12v or 24v but very critical on the 5v rail, which is the rail you adjust that screw for, it should be set at 5.1v or so and it should never drift below 4.95. The computer board will start resetting if the voltage drops below 4.9v under load.
If you did a search on the subject you probably found the video I made on the subject. You can also just stick your voltmeter leads into the 5v connector while it is installed in the machine and
 turn it on. Or clip onto a component on the circuit board and monitor it for 30 minutes or so. Again, the 5v rail is extremely critical and should not drift down much, if it drifts down a little it will probably keep drifting down as it gets hotter. That is exactly what a switcher power supply should not do!

https://youtu.be/Xu2-fTX1xt0


Chris

[Kershawa]

That will be my next tests is to see how they perform under load. I should have some spare 12v lights around here somewhere that I can rig up for testing the 5v and 12v rails. I will check to see if I still have my incandescent light rig just like yours still from troubleshooting a magnet charger to find leaking diodes. (thats a separate story). I will update when I get them tested.

[Chris-socal]

If you already have yours put back together just clip onto a 5v and ground lead on one of the components on the computer board. That is the best real-world test.

[Kershawa]

I finally got some time to load test the power supply. I did testing at the board while it was all reconnected, those were the test point readings in my last post. I did let it run long while under load before recording my measurements. 5v rail with a 194 light bulb attached, also had the main board still connected was at 5.09v solid. The 12v rail with the same light bulb connected to it went down to 11.23v from 12.33v. The 24v rail was 25.3v while connected to the main board, i did not have a light bulb setup to test it like in your video. Again, all os these measurements were with the main connectors still attached to the power supply.

I am feeling like 12v supply should be better than that when a load connected to it. What are your feelings?

[Chris-socal]

Not concerned about the 12v reading at all. Even if it went to an onboard regulator to drive the 5v system there is plenty of overhead. I think that only drives bulbs. Your PS looks great.
So, what exactly happens when you power the board up? Do you get any sounds or error messages on the LED readouts?

Chris

[Kershawa]

Only sound is a low level drone. I get a louder buzz noise when powered up and door is open. Nothing on any of the LCDs.

[Chris-socal]

Yeah, the CPU is being held in shutdown for some reason. Those boards have a lot of Logic IC’s, and a ton more traces! It could be a failed Logic IC, bad trace, CPU pooped out, they are really difficult to trace out, believe me, I have been working on one for a few weeks off and on. I was all excited because I found 3 traces that were open, one of them going to the CPU. After fixing them it still won’t boot, just that humming sound and occasionally a tilt error that isn’t really just a tilt error!

Can you attach a picture of the computer board from above?

Chris

[Kershawa]

Trying like hell to put the picture in here.

I have a picture in my profile albums. Maybe you can access it there???

[Chris-socal]

The image needs to be set with less than 1000 on one dimension, or email them to yourself and let the email program optimize the image. I can’t look at your profile but I don’t see any images there.

[Kershawa]

Picture of mainboard resized to upload

It worked! But not good resolution if you zoom in too far.

[Chris-socal]

The image is fine for what I needed to know. That is known as the newer version of the board, it has SMD components and the square CPUs. Much more difficult to pull a component but higher tech and less likely to have component failure. But it is still very Logic driven which requires a ton of traces that need to be toned out.
Im really curious why it has a backup capacitor and a backup battery, that doesn’t seem right. Plus, those boards have a charge circuit so it seems like the battery should be rechargeable type. I could be wrong on that second one that is right on the edge of the board, maybe they do use standard lithium, but I don’t know why it needs two.
The other unfortunate news is that I heard the test station at K-Lar is no longer there, they can only test the older style of board.

My recommendation would be to be to find a working board and move your game chips over. Unless you are up to testing every trace on the board, which is a daunting task. Im 4 weeks in on mine and still finding issues. I would reach out to KLar and see if they have a board that they know works. Unfortunately I don’t have a magic pill and I don’t know many techs that spend time on these, they are far too time consuming.

Chris