nanao 29" monitor issue

i tagged the question on bill's thread about re-capping, but since it might not be a capping issue (which would suck..) here we go..

was playing when the monitor flickered (lost horizontal hold) twice in a couple seconds, then it just died out.

board runs fine on my second cab, so its def the monitor or something to do with the connection to the monitor i guess, but as its been working kudos for months i doubt its anything with the connection.

ideas? cap issue? other? good tests?

thanks,
-bay

dave k indicates that a total loss of picture (black only) wouldn't be a cap issue, rather perhaps a power issue?

anyone have a pdf or hardcopy of the nanao monitor manual? 29".. i dunno how many versions of this monitor there are, i'll be pulling it when i get some time.

are there fuses on the neck board? if so how many, and whats the best way to determine if the fuses are blown?

what other power related tests can i do on the monitor?

since my monitor is in an astro city, is there a seperate fuse for the monitor as well as board/jamma harness, coin mech, etc?

-------- more stuff ------

so i was looking around and decided to try and get more of a picture of whats going on with the astro city.

1) power to the pcb via jamma is fine
2) power to the marquee light is fine
3) power to the monitor may be fine, when i turn on the cabinet the common hissing of a tv/monitor is present, however the tube stays black.
4) no pcb connected, same thing
4a) no pcb connected on my other cab, results in the tube displaying a gray diagonal pattern that moves.
5) on my astro city power supply all i see is a 4A fuse, doesn't seem to differentiate between any of the devices in the cabinet.

so is there a fuse on the monitor? im sure it's worth checking out, however if i hear the hissing of the monitor coming up does that mean power is getting to the monitor? would there be a seperate fuse to the guns/neck board? versus the main board of the monitor?

does this sound like a flyback problem? =(

---------------- more info ------------------

1) all the connectors are secured
2) doing a comparison between the 2 astro cities, the working one i can see an amber glow from the base of the tube neck, the non-working one i do _not_ see an amber glow from the base of the tube neck.
3) the working monitor has static on the screen when on, while the non working monitor does not. the whine/hiss from the monitors do exist on both.





thanks,
-bay

EDIT: more n00b questions
EDIT: more info

Sounds like you may have a dry joint around the horizontal oscillator stage, or maybe a flakey hold pot. If the horizontal freq goes way off it can lead to failure of the horizontal output transistor. Your description of events seems to indicate this.
I agree a cap kit will not get this going.

ttooddddyy said:

Sounds like you may have a dry joint around the horizontal oscillator stage, or maybe a flakey hold pot. If the horizontal freq goes way off it can lead to failure of the horizontal output transistor. Your description of events seems to indicate this.
I agree a cap kit will not get this going.

Click to expand...

how do i go about testing for this "dry" joint? since the monitor was actually tated, the vertical hold may have been off instead. seeing that it flickered on the horiz (as a vertical monitor)...

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what i've posted @ shmups:

the fuses are ok on the board, so would it be natural to guess that the issue is with the flyback transformer? or the B+ rail? i gotta find the B+ rail first.. but someone suggested testing it, then testing HOT.

is there any way for me to do tests on the flyback myself? anyone have experience with the B+ and HOT on these mainboards?

secondly, whats the suggested way to clean pcbs (specifically the mainboard and neckboard), they are mad dirty.

thanks!

anyone have a monitor tech anywhere in the continental USA that i can send these boards + flyback to for testing?


EDIT: board information