I give up!!

tobyocc

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Just finished a pretty good recap on a wg k7600. Hooked it backup and still plays blind.New Caps, flyback HOT. But no fireworks or exploding caps, smoke, but the fuse blew on start up. I am ready to just sell the machine. I don't think I can fix this. Please motivate me to do this. I don't think I can afford a new monitor.

Toby
 
The horizontal output transistor must have a mica insulator between it and the metal frame. Plus it also needs a coating of silicone heat sink grease on both sides of the mica insulator.

You checked capacitor C36 for shorts and diode D18 for shorts, right? This monitor is also being run from an isolation transformer, right?

When you did the capkit, you carefully snipped off the excess leads and made sure you didn't solder splash adjecent foil traces?

The correct wires from the flyback are connected to the correct points on the neckboard?
 
I did put the mica insulator in place with some arctic 7. I did not check c36 and d18. Hate to sound like a noob but with my multi meter how do I check for shorts? I did carefully snip and watched for solder splatter and overages. And yes I did double check the new flyback wires.

Thanks Ken.
 
Arn't the Artic series of heat sink compounds Silver based? Therefore they're electrically conductive???? This doesn't matter for PC CPU's since everything is sealed by ceramic. However on a transistor with mica insulator use of any conductive compound pretty much nullifies the purpose of insulation. Just use plain old zinc oxide for these.
 
Jeebus I'm tired of the Arctic Silver being conductive comments. If it is then all 4 Amplifone deflection boards, 3 K6100's, 2 G07's, 1 K4901 and 1 K7000 that I've rebuilt using it should not work...... but they do. And here's food for thought. Arctic silver has been proven to drop 10 degrees off a processor. Imagine what it does for the surface mount transistors longevity. Just sayin......
 
Did you make sure the screen pot isn't turned down on the flyback?
Ooops, nevermind....I just noticed your fuse is blowing.

There's a diose that sets beside the yoke plug (sorry, I don't have it's designation handy)....check it.
Edward
 
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Though the OP stated "arctic 7" I couldn't locate that at their website. But for their others (original, 2, 3, 5) it had this stated:

"Negligible electrical conductivity.
Arctic Silver was formulated to conduct heat, not electricity. It is only electrically conductive in a thin layer under extreme compression."

"While much safer than electrically conductive silver and copper greases, Arctic Silver should be kept away from electrical traces, pins, and leads. The compound is slightly capacitive and could potentially cause problems if it bridged two close-proximity electrical paths.)"


While this may work well for many applications, if I need 100% electrical isolation I would not want to use this myself. Amps to heatsinks: Sure, but anything isolated with mica.. not sure.

Again, I've not used it myself and it may work well, but I was concerned that could lead to a problem for the OP. Just throwing out ideas.
 
If a person doesn't feel comfortable using it then don't, it's that simple. You are stating an observance and I'm stating real life scenario. It doesn;t make either one of us right or worng.
 
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You checked capacitor C36 for shorts and diode D18 for shorts, right?

Ok, I was wondering what the readings should be. I read that it should be infinity. Is this correct? If not what is the correct reading?

Thanks.
 
Jeebus I'm tired of the Arctic Silver being conductive comments. If it is then all 4 Amplifone deflection boards, 3 K6100's, 2 G07's, 1 K4901 and 1 K7000 that I've rebuilt using it should not work...... but they do. And here's food for thought. Arctic silver has been proven to drop 10 degrees off a processor. Imagine what it does for the surface mount transistors longevity. Just sayin......


Right from Arctic Silvers website:

(While much safer than electrically conductive silver and copper greases, Arctic Silver 5 should be kept away from electrical traces, pins, and leads. While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths.)

...but I agree... I've never had an issue with AS...that said, I prefer to use their CERAMIQUE product...
 
OK, So we are over the thermal paste issue. I test c36, d18 and get good readings. Tested legs 2 and 3 of the HOT ( I read that is how to test right?) Still blowing fuse and playing blind. Any other ideas would be much appreciated.

Thanks.
 
Put your meter on diode check. Start at the diodes connected to the fuse it sounds like one or both of those diodes could be bad, then go to the regulator. check your HOT. middle leg to outer legs should test like a diode. I have had diodes and mylar caps around HOT ciruit short out also. last should be your flyback. Take off board and power up and see if fuse blows. make shure HOT is good.
 
Thought I might throw some pics of the bottom of the chassis.
 

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I know it's hard to get pics to focus properly, but please preview them first and skip posting pics that are not focused. They won't help us.

As for that, I don't see anything there that I didn't expect to see...
 
Just finished a pretty good recap on a wg k7600. Hooked it backup and still plays blind.New Caps, flyback HOT. But no fireworks or exploding caps, smoke, but the fuse blew on start up. I am ready to just sell the machine. I don't think I can fix this. Please motivate me to do this. I don't think I can afford a new monitor.

Toby
You don't have to get rid of the machine if you can't fix the chassis and you don't have to replace the whole monitor. You can also pickup a working k7600 chassis or send yours out for repair to someone like Chad at Arcadecup.com.

I've never worked on one of these so I can't offer much help.

-VJ
 
Did you ever check to see if your voltage regulator was good? Or your C36 critical safety cap?
 
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