Hantarex MTC9000- no neck glow

[ifkz]

This was non working monitor and I installed a new HOT, Flyback, & complete cap kit from Bob Roberts and I got it working well.  Unfortunately I put it in my Centipede and its ARII gave it too much voltage (too much -12 that should have been -5) and blew something out.  I also put a WG4900 on the Centipede and it blew out the green power regulator on the neck board.  The WG4900 and the ARII have been repaired, but this one is giving me fits!  Any thoughts?
The B+ was tested on the long white ceramic resistor and that's okay but it is getting very hot.
As per flowchart we pulled R216 on the neckboard and it was okay.  A neck glow is not present.
UPDATE:  No voltage to on pins 9 & 10 on neck board (power to filament).  Check all transistors on neck board, all okay.  Checked all diodes in HV section, they checked out.

[grantspain]

how good are you with electronics,i mean are you safe working with monitors?
if so i can point you to some very handy advice

[cw]

he has local help with it greatspain.... what do you want to try?

[grantspain]

check the schems here http://www.freeinfosociety.com/electronics/schemview.php?id=2245
i worked on a lot of these chassis back in the 80's/90's and they had lots of faults
first check your voltages at test points 10(130v) and 14(190v),check tp12(+12v)
there is another transistor(tr20 i think) under the big load resistor(r105),that caused problems also check the resistance of the big load resistor
check tp1(+24v)
when the resistor r105 gets really,really hot thats usually a sign the hdt(hot)is shot,perhaps yours has blown again-pull it out the chassis and check it,better still change it as its a bu508a
when you said your board sent the chassis -12 do you mean through the sync?

[cw]

really have no clue how it did what it did to the monitor but it did.  The only thing that was out of whack was the -5v was pushing -12.5 or so... After rechecking and installing a 7905 (the -5v reg) its fine.  We tested the wg4900 that he as on it and its working fine and is stable.

[grantspain]

very strange to affect the monitor,all i can imagine is the bu508a has gone faulty-but try all those test points as they will point towards the problem,it sounds like the flyback is not operating

[cw]

tp10 is at 85.6
tp14 is at 00.4      hmmmmm not looking good...
tp12 is at  2.8

that would explain the lack of neck glow

[grantspain]

check d15

[cw]

its good

[grantspain]

when you installed the bu508a it did have the plastic insulation sheet behind it?

[cw]

yes it does



the hot is getting really really hot.... sooo... I will check local for another one

thanks gs

[grantspain]

check +130v at r118

[cw]

can do


78.1  on the right side

[cw]

i am  going to pull the hot and check it...


the hot looks to be ok under standard npn transistor testing.

[ifkz]

I guess it's time to pull the bu508a and check it.  If that checks out then that leaves the flyback as the problem.

[cw]

thats the hot and its looks to be fine

[grantspain]

are you getting +130 at r105?

[cw]

tr22 is blown....


thanks again great spain

[grantspain]

so is it all up and running now?
and its grantspain not great spain,my spanish friends all call me Gran(great in spanish) but only because they cannot pronounce the "t" at the end of my name,not because i am great

[cw]

I hope to have the part needed today..   I will let you know..