Ceronix 1492 Electrical Arcing

[leewoo]

I've been trying to resurrect a 1492 and did a cap kit.  After the cap kit, a picture would slightly form then collapse vertically and repeat.  So I ended up replacing the LA7830.  It didn't help because after replacing it,  the picture was more of a line straight down and then collapsing and repeating again.  I tried turning it back on and filming it but ended up just getting a bad arcing noise as heard about 1:55 into the video.  Is this the flyback and this chassis is hosed or is there another possibility here?

https://youtu.be/qZ7NkN3RR9c

[Chris-socal]

The first thought is Flyback. When 1492 flybacks age they commonly arc to the heatsink near it (if you are lucky) or to the frame which is right where your fingers go to adjust the pots. If you turn the light off and look at the flyback you will probably see it.
If it's not Flyback the only other thing I have experienced an arching noise was when the yoke coil burned through and was arching to the other coils around it. Rare, but it did happen, could be that someone hit it with something and broke the wire, who knows. I still have the monitor hoping one day I will get a donor yoke.
In your case I highly suspect Flyback, in which case keep your hands away from the flyback, these have a history of biting because they are known to arch to the front to the frame which is where the knobs are.

Take a look at the flyback and you will probably see cracks, and one of them will have a melted spot right in the middle.

Updated post with pictures, forgive my messy arrows. The area circled is a common fail point, it arcs to the heat sink. My arrows are trying to point to the front section of the housing around the face plate. These spots will almost always have cracks but the give away for arcing is when the spark blows through and leaves a small (sometimes large) melted hole on the crack line. The one pictured is good, I'm just using it to point.

Chris

[leewoo]

Thanks!  I'll get the monitor back on the workbench tonight, turn the lights off, and try booting it as safe as possible.  I'll post the results.

[Chris-socal]

You are powering it using an isolation transformer right?

[leewoo]

Honestly, I don't know.  I bought the poker machine with the monitor not working.  I didn't check that it had an ISO in it or not.  I'll verify tonight. 

I created the extension harness in the video so that I could power it from the poker machine itself, but on my bench.  I don't have a setup on my bench that is compatible with the Ceronix.

[Chris-socal]

You are good if you are powering it from the machine.

[leewoo]

Well, definitely not the results I had expected.  No arcing.  Picture on the screen. 

https://www.youtube.com/watch?v=z0vGZgtQf-o

[Chris-socal]

That doesn’t prove anything, a failing flyback can arc intermittently, but a few things are clear.
You need to put a cap kit in it, at least the critical caps. There aren’t that many.
There is clearly something wrong in the video circuit but we won’t know until it gets the critical caps replaced. These boards are notorious for bad caps.

It could also be the PRA-H board or any one of the PRA-B color boards. If one color fails the entire board wigs out.

Also, look closely at the ribbon cable that goes to the neck board, some eras had really thin solder and if the sync wires don’t have a good connection it can mess with your image.

The retrace lines are screaming something is wrong. Are you sure you have the H and V sync wires correct?

I would pull the board so you can get a good close up view of all the components.

Once you remove the front two screws the board will slide out. I would discharge the 2nd anode just to be safe. Most factory 1492 flybacks usually discharge well buy don’t trust “usually”.

If you are interested in having someone look at the board send me a PM. If you aren’t sure about how to pull it I have a video I can send.

Chris

[leewoo]

I already did a full cap kit on the chassis before this.  I'll check my wiring as well as direct connect the monitor and test instead of running through my harness.  I'm pretty sure my harness is solid, but I'll check anyway.  I'll inspect the board fully including the ribbon cable and auxiliary boards.

[Chris-socal]

Sorry I forgot that. The 1492 conversations all run together for me, plus I almost always have one or two that Im working on personally.

You know, there is one other thing that can cause arcing. The neck board socket.
You would need to remove the cover where the wire is soldered on. I have only seen one Ceronix board where that solder joint failed but it could be happening.

It could still be flyback.

Chris

[leewoo]

Pretty sure I just bought a working 1492 chassis off of you.  I'll troubleshoot this one as I can or maybe just send it your way to fix up.  I'll let you know.

[Chris-socal]

Ah yes.  You have a Bally machine, right?  You will need to change jumpers and add a Posistor at 244 for the Degauss coil. I might have a board that already has a posistor on it but I haven't tested it yet.
Let me know how you want to proceed, we can cancel or modify that purchase. The most important part is that I adjust the SN if they will let me.
If you don't want to use the degauss coil you don't need the posistor but you will certainly need to jump it for Bally, it's about 8 solder jumps and you will need to un-do the IGT (Q,S,X&Y). Most of the boards you find are IGT and they don't typically use the degauss coil. 


Chris

[Chris-socal]

Lee
Your inbox is full and I cannot reply to your message. If you delete some old messages it should clear space.
The second chassis is in the mail, it will be there Saturday.
Could be dealing with a problem in video section of MPU, it can happen. The chassis I sent had issues but not vertical collapse.
You have the green dag ground wire connected to the neck board?
Check the yoke connector, its possible one of the wires has broken off the pin, I see that occasionally.

Chris