mecha
Well-known member
this is a monitor I capped last July and was never able to get a dead-on B+ adjustment with it. the monitor would still go into shutdown (reason I capped in the first place) every so often. it's also worth noting that when I was readjusting the colors, brightness, focus and contrast, the monitor would also shut off when you got the focus where it needed to be.
so where we're at is just yesterday, the monitor didn't turn on at all, and once I was able to power the cab up with none of the other games on at work, I heard tick-tick-tick. the HOT was shorted, so I put another good one in and replaced the flyback for added measure (the focus thing I found suspect).
monitor works again, and because the monitor still periodically went into shutdown after I capped it last year anyway, I decided to fine tune the B+ once more. this is where it gets interesting: Randy Fromm's flowchart says the B+ should be 130VDC, modessitt says 117VDC, and quite certain Chad Entriger says 118VDC. I just would like to know once and for all where these are supposed to be set at.
the B+ walks between a volt, which I'm sure is normal depending on if the screen is bright/dark, but I don't remember which one you want to set it against. I set it for 117VDC one time, the voltage dropped to like 116.4 and that's when the monitor went into shutdown again.
Fromm's flowchart told me to test some diodes too in instance of shorted HOT, and they all checked out fine. the caps he lists though I wasn't able to find at all, they're nothing from the cap kit, they must be the other kind of caps.
so specifically I need to know:
1) why the HOT shorted in the first place.
2) what the B+ should be set at.
3) why it still randomly shuts down. (I would lean towards bad shutdown pot, but the shorted HOT thing is alarming and shows that maybe a resistor somewhere's out of whack).
I don't do schematics, unfortunately, so if there's any particular parts I should be targeting, please let me know.
thanks.
so where we're at is just yesterday, the monitor didn't turn on at all, and once I was able to power the cab up with none of the other games on at work, I heard tick-tick-tick. the HOT was shorted, so I put another good one in and replaced the flyback for added measure (the focus thing I found suspect).
monitor works again, and because the monitor still periodically went into shutdown after I capped it last year anyway, I decided to fine tune the B+ once more. this is where it gets interesting: Randy Fromm's flowchart says the B+ should be 130VDC, modessitt says 117VDC, and quite certain Chad Entriger says 118VDC. I just would like to know once and for all where these are supposed to be set at.
the B+ walks between a volt, which I'm sure is normal depending on if the screen is bright/dark, but I don't remember which one you want to set it against. I set it for 117VDC one time, the voltage dropped to like 116.4 and that's when the monitor went into shutdown again.
Fromm's flowchart told me to test some diodes too in instance of shorted HOT, and they all checked out fine. the caps he lists though I wasn't able to find at all, they're nothing from the cap kit, they must be the other kind of caps.
so specifically I need to know:
1) why the HOT shorted in the first place.
2) what the B+ should be set at.
3) why it still randomly shuts down. (I would lean towards bad shutdown pot, but the shorted HOT thing is alarming and shows that maybe a resistor somewhere's out of whack).
I don't do schematics, unfortunately, so if there's any particular parts I should be targeting, please let me know.
thanks.