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RandomRetro

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So a blast city I just picked up was working after pickup and initial tests. Then, bloop just clicking on power up but no picture or neck glow. AC power is getting to the board but a lot more testing to go.

What’s the clicking btw? I assume something to do with the auto detection of signal.
 
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If it's not turning on the Clickingg is likely ocp (over current protection) of the SMPS (switch mode power supply). Means something is drawing too many amps probably from a shorted component. Power supply tries to turn on, says nope not right, then shuts down, then tries to turn on says nope and shuts down, this continue until you remove Ac power. First suspect for shorted component is usually hot (horizontal output transistor).
 
Try turning your screen voltage knob to the right on the back of your transformer.

 
No change when adjusting the fly back.

The clicking is basically a three fast clicks right after turning on power. Then when you turn the machine off it takes like 20seconds and then you here the clicking again. Seems like OCP being triggered.

I fear it is the flyback but going to have to pull the monitor so I can truly test.
 
Good luck. I had six of these at one point with those symptoms. Recapped, replaced the HOTs and the vertical ICs, flyback swapped with a known good one. Nothing.

2931 are awful.
 
Yeah was just reviewing your thread from last year. Sucks cause it worked right when I got it and then dark. I cleaned the exterior and was just hoping I forgot something but there are just the three wires under the marquee. So I guess time to learn, try, and cross fingers.

Did you end up swapping in new monitors? @rewrite
 
I just got both my 2930 and 2931 recapped and tested and they are dull as ever.

I am going to try a "heater resistor" symptom and if that doesn't work I'm going Mak. I don't wanna go Mak either..
 
I thought the Maks were supposed to be pretty good. I guess sans the cost.

This in is my second cab to have issues basically the second day of owning them. First was just a power supply at least. Then flyback, but was a K7000 so pretty simple fix.

I will keep posting to let you know how this goes.
 
@RandomRetro they weren't mine. I was working on them for someone else. Got offered a couple if I could fix others, and someone else had failed before me, so it was a long shot to begin with, ha.
 
Ah ok. Well that sounds more enjoyable than owning 6 non working. All the threads seem like people working on them to no avail which is discouraging. I am going to try and keep a positive outlook until I have to drop kick the damn thing :)
 
The protection circuit in these is so finicky. There's all kinds of Diodes and optocouplers and a couple of weird transistors and some transformers before you to get to HV. Any of those could be your problem, you'd basically have to shotgun replace every single last chip or component on the chassis to get right if you don't have a HV capable probe and a place to power it in at an odd angle so you can probe everywhere. Also, the board/traces are particularly sensitive to heat, so it's really easy to burn out a trace or two.
 
@rewrite did you by chance ever try this to bypass the protection circuit?

"Some monitors may have an issue with the protection circuit; this can lock you out of some of the resolutions and may make you think that the monitor is dead. Jumping H sync and Vsync together should change the resolution and revive the monitor."

Quote is from the AO page link here
 
@RandomRetro I never caught that post in my searches. Fingers crossed it works on your end!!
 
@rewrite did you by chance ever try this to bypass the protection circuit?

"Some monitors may have an issue with the protection circuit; this can lock you out of some of the resolutions and may make you think that the monitor is dead. Jumping H sync and Vsync together should change the resolution and revive the monitor."

Quote is from the AO page link here
I did actually try this and unfortunately it didn't work for me, but a full recap did. I hope its something this easy for you!
 
Me too, fingers crossed. Will be digging in more this weekend and will keep you posted...
 
So wanted to close out this thread with bad news, and good news...

Bad News: This chassis and the issues were far beyond my capabilities.

Good News: I sent the chassis to http://sharpimagerepair.com/ and they were able to make the needed repairs in short order and I didn't have to swap the flyback. I learned some things and was able to test a good bit while trying to diagnose the issue(s).

So in the end I learned, got my chassis cleaned, recapped, and repaired. I am going to call this a big success for me and my 2931! Now back to playing games...
 
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