K4600 Blew Up... maybe...

[jasonsmith]

Well I posted on KLOV but no responses yet. Put it all back together again and fired it up and whoosh R504 blew up again. Thank goodness for the ceramic containment tube that's around that. Guess it's designed to blow and that's supposed to protect the rest of the stuff.

I'm at a loss, something is causing a massive current draw I guess and just frying that resistor. Since the voltage regulators and transistors check out it must be some sort of a short or something, I don't know. Tried measuring the B+ but all I was getting wasn't getting much of a reading plus it only took about 5 seconds for it to blow.

It's either something I did directly or a symptom of the fresh caps. Could it be like a degaussing coil short or something... bad ground... I have a spare K7901, not sure if I can use it or not but have been thinking of giving up. Sending it out for repair just doesn't seem financially viable.

Frustrated.  

[jasonsmith]

Went crazy and pulled everything off the power pcb, cleaned and stuck it all back on and the resistor no longer blows. My left side screen stretch issue is still there though, no idea what's causing that. Thanks to all for the help, wish I knew what it actually was though but was really losing my patience.

[John's Arcade]

So it's fixed? Great work! Who needs Klov?

[jasonsmith]

Yep, the weird blow up problem is fixed. The original issue and why I did the cap kit however is still there. I put in my spare k7901 and that problem wasn't there so it is the monitor for sure just don't know what. Gotta say though I was expecting more than one reply on klov...

[John's Arcade]

Yep, the weird blow up problem is fixed. The original issue and why I did the cap kit however is still there. I put in my spare k7901 and that problem wasn't there so it is the monitor for sure just don't know what. Gotta say though I was expecting more than one reply on klov...

Are you sure this isn't an adjustment? Did you adjust the horizontal hold and size pots?

[jasonsmith]

Gonna work the pots some more today. Noticed they haven't been responding very well. The horizontal width is doing nothing at the moment. Vertical size works nicely though.

[jasonsmith]

BINGO

I did screw up, I did screw up!! I shouldn't be so happy but I was looking at some before pics today and I noticed when I first stuck the two caps on the power PCB I swapped them. I stuck the big cap in the big spot and the small in the tight spot, seemed logical...  I remember jamming the big cap where it didn't want to go yesterday so started to think about it. Thought I did it wrong actually when in fact I did it wrong the first time. I checked and checked the caps over and over for polarity and soldering but never actual placement!

Man I feel like a turd, all I can say though is I learnt a hell of a lot. Thanks Ian for being a good teacher and making me do the right stuff.

[shaking my head]