K7000 monitor troubleshooting help

[raventy]

hey guys, im trying to troubleshoot my WG k7184(no image and no heatercoil light) and am following Randy Fromms K700 flowchart. One of the first things it says to do is check R301.. however after looking at both a diagram and the board itself I just cant seem to find it! Could someone give me some hint as to where I can find this resistor on the board? Thanks!!

[Q*Bert_OP]

R301 is the big white ceramic resistor (220ohm@15watts)

[Ken Layton]

Yes, that resistor is mounted to the aluminum side frame with haevy blue and red wires going to it.

[raventy]

ok ive been following Randy Fromms flowchart and connected each end of that resistor to my DMM and I belive it read something like 97 before the resistor heated up REALLY hot and burned me!!! Anyone know why it got THAT hot? Could connecting it to the DMM wrong have done that? Or is this happening because of a failed part? Also for some reason I had mistakenly turned my DMM knob in the wrong direction and it sparked... in case u think that might have damaged something...

[censei]

You're suppose to connect one probe to the resistor and another probe (black) to the chassis ground/monitor frame to measure the +B voltage (+125v dc). You might have damaged some components but it's always good to check the chassis for faults. Check out the +B voltage and then you can move on to pin pointing the fault.

[raventy]

alright so I happen to have a K7000 chasis lying around(unsure if it actualy works) so i decided to hook that up. I hooked the red end of my DMM to the red wire on the 301 resistor on it and then hooked the black end of my DMM to the ground... however the DMM only read .1... whats that supose to mean? am i doing something wrong?

[Ken Layton]

Be sure you have your meter set to read "DC Volts".

[raventy]

whoops.. lol my bad.. .. ok I stuck the original chasis back in and its reading a R301 at 153V... which is TOO high... Disabled D10 diode.. nothing changed.. I swapped R301 with R301 from my spare chasis and R301 is still geting REALLY hot... Also.. in case this helps troubleshoot.. before this monitor stopped working it was acting funny and was showing LOTS of red on the screen at first then after a few minitues it would go away.

[Ken Layton]

Sounds like the flyback, horizontal output transistor, or capacitor C36 is shorted (or all the above).

[raventy]

hhmm well I replaced C57 and a few other questionable looking capasitors and it still acts the same... where is C36 located on the board? ive been searching all over for it but cant seem to find it. Also is the Horizontal output transistor the one thats attached to the bent metal plate by the flyback? thanks!!

[raventy]

OK.. I found C36 thoguh I am hesitant to reaplce it because....I just replaced IC4 on the chasis and the monitor started to WORK again!!! HOWEVER.... R301 is STILL reading around 153...is that bad?

[Ken Layton]

Move your meter lead to the other terminal on the R301 white resistor. One of the terminals in the power going into it and the other is the regulated output.

[censei]

You can adjust the +B voltage at VR8 but take caution while removing the factory paste so you don't break the VR.

[raventy]

hehe alright I took the Voltage from the other side and it read 128V.. a little bit higher than the expected 123V isnt it? Is that bad? Also... anyone think that whatever caused IC4 to die might happen again?

[Karetaker]

Did you put D10 back in? That's part of the protect circuit so you are going to want to put it back in if you haven't already.

[raventy]

yup yup! just resolidered it! thanks for the reminder though!!