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Astro City MS-8 only turns on after power cycle, any thoughts?

Aurich

Aurich

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I have an Astro City, MS-8, that suddenly stopped turning the monitor on. No flyback whine, no static on the screen, totally off. Okay, that happens. Here's what's funny. If you turn it on for a bit, turn it off, and—this seems to be the key— wait a bit, then turn it on again it suddenly powers on just fine and works the rest of the night.

Quick power cycle doesn't seem to work, you really do seem to have to have it on for a minute, off for a minute, then back on to get it to work. It's consistent, works every time.

Because any time you have any monitor problem the first thing people are going to suggest is a recap and check for cold solder joints. Done and done. Full recap on the chassis, reflowed anything suspicious. Picture looking great now when it's working, but same problem.

Any thoughts given the symptoms on next place to check? I'm guessing it's on the HV side since there's no flyback, but little stumped with the odd 'warm up' behavior.
 
I guess everyone else is stumped on this one too huh? Will keep poking!

In the meantime the stupid on/off trick seems pretty reliable, so at least I can get the cab running for arcade nights.
 
That’s really odd behavior.

Given that the picture works after a warmup I would say cold joints but you already looked into that. Also, cold joints would make more sense if it was a missing color or picture sizing solved by powering on/off trick.

My next thought would be an issue with AC lines but given that the warmup workaround is so consistent I would think it’s something else.

When you first turn the cab on and the monitor isn’t working, does the sound work? Like, is everything except the monitoring running?
 
The cab is part of a linked pair, and is the master cab with the board in it, so I don't even need to guess blind. Everything else works, marquee light comes on, 3S starts running on the second cab, just the monitor issue on the first one.
 
Can you bypass cab power? Power unit from wall (or step down depending where you from) see if you experience same issue. If you do have same issue then can you isolate and load SMPS output on the chassis to confirm it work consistently on its own?
 
Was the big filter cap that is on the B+ changed as part of the re-cap? Generally those large filter caps are not included in cap-kits and need to be purchased separately. I am wondering if the B+ is coming up too quickly and throwing the chassis into HV shutdown. Only after being on for a bit does that cap re-form and provide the stable B+ needed to keep it out of HV shutdown.
 
dewmansnk said:
Was the big filter cap that is on the B+ changed as part of the re-cap? Generally those large filter caps are not included in cap-kits and need to be purchased separately.
Click to expand...
Yeah, pretty sure it was replaced, my friend hand picked out all the caps, we didn't use a kit. Don't think that's it, but it's an interesting theory.

Arcade game said:
It’s definitely a cold solder joint
Have seen this many times
Click to expand...
I will never discount the possibility of a cold solder joint, but where? We reflowed anything on the chassis that looked suspect. Any clue where we might have missed something?

It doesn't really feel like a cold solder joint would reliably respond the way this is. Why I figured a cap issue at first. Something like what dewmansnk said.
 
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