Nanao MS8-29FSG Monitor Shutdown After a Few Mins...

[JAMMArob]

Hey fellas

I've owned this Astro City for about 10 years. In the last year or so, the monitor has developed an issue where it will power off while the cab is on. The issue went from being very occasional, to every use.

Now, the monitor won't stay on for more than 10 minutes, and that's only after it has been off for a while. It's more like 10 seconds between short power cycles.

Here is what I have done so far:

Changed all caps except the 3 large filter caps
Reflowed the connector on the neckboard
Swapped power supplies with another known good PSU

Beyond caps I am stumped. The monitor looks beautiful while it's powered on! Any ideas on what I can check?

[JAMMArob]

A few people have suggested adjusting the B+ voltage. I'm not too familiar with this process, or if it's even a good idea!

[grantspain]

sounds like caps or bad solder but thats already all been done

b+ should be 94v,test at fuse 902 and a cap ground

[JAMMArob]

Thanks grantspain. I measured DC voltage at a capacitor near the fuse (measured continuity to be certain the trace is in circuit). It's reading a fairly stable 93V before and after shutdown

[JAMMArob]

Thoughts on changing out one (or all three) of the caps in the B+ section? Specifically C906, C905, C909

[PrincessPrinPrin]

Am I measuring this accurately?

Considering the B+ is a DC voltage I would say you're not.

[JAMMArob]

Derp. I thought it was AC for some reason. I'm just trying not to die while working on it.

[JAMMArob]

I think i'll send this guy off to the pros!