Tech: G07 blows F901

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Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Hey group,

I've got two G07 chassis here that are both blowing F901. They both
had this problem before any work was started. Both of them got
capped, new HOT's and Flybacks. They both still blow F901.

With a new fuse, powering up the monitor, it does come to life for
about a second, then the fuse pop's and kills it.

I've been over both chassis a couple of times, all transistors, diodes
etc... seem to check out, no bridged solder joints.. etc..

Anything common with these and this fuse (besides the flybacks/HOT's)
???


Thanks,
Dave
 
G

Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Check the HOT again you may have a bad high voltage cap that is making
the HOT go bad. Also check the voltage reg if your voltage is high that
will blow the HOT. Ted
 
G

Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Check the HOT again you may have a bad high voltage cap that is making
the HOT go bad. Also check the voltage reg if your voltage is high that
will blow the HOT. Ted
 
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Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Check all your transistors on the chassis to ensure that the legs
aren't shorting against each other. Also, check to see if any of the
transistors are shorting against the chassis frame.

John
 
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Archived from groups: rec.games.video.arcade.collecting (More info?)

Yes, be sure none of the chassis mounted transistors are shorted to the
metal frame. Both the B+ regulator transistor and the horizontal output
transistor must have a mica insulator between the transistor and the
metal frame. They also must have the mounting screws pass through the
white plastic insulating bushings.
 
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Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Thanks guys,

Both chassis mounted transistors are properly mounted, the insulators
are intact and no shorts to the chassis on either one.

I guess I'm to the point now where I need to open up parts of the
circuit and see if I can narrow it down. Maybe power up the chassis
with the HOT unsoldered and see if it still pop's the fuse, then work
my way back?


Dave
 
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Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

are you testing these both on the same tube? i had a tube that made my
G07 chassis' do the same thing. i tested 3 "good" rebuilt chassis on
the same tube and they all blew that fuses as well. i was in the same
boat you are, i just rebuilt 3 chassis and tried them all out on the
same tube and the fuses blew.
when i replaced each fuse and tried them on another tube, they were all
ok and did not blow anymore.
 
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Guest

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Archived from groups: rec.games.video.arcade.collecting (More info?)

Well, these still blow the fuse with the HOT unsoldered from the
chassis, so that rules that out.

I have seperate tubes for each chassis. I suppose I could have two bad
tubes.

I haven't had any time this week to mess with them further, other
things in the shop have had priority. Just for the sake of getting
this documented in case somebody else runs into this, I'll post back
with what finally fixes them when I get the chance to work on them
again.

Thanks