WG 13K7302 not come on

[kardenm]

I have a WG 13K7302.  Picture looks good but does not power up when first turned on in the morning.

Requires 3 or four attempts before it finally comes on.  Starts out then with a high pitched squeal which goes away after warming up. 

If anyone can point me in the right direction I'd sure appreciate it.

[grantspain]

caps or a dry joint

[kardenm]

Ten four grantspain.  I'll be checking such things today.

By the way, is grantspain from Grant's pain or Grant Spain? 

[grantspain]

Ten four grantspain.  I'll be checking such things today.

By the way, is grantspain from Grant's pain or Grant Spain? 

pretty crap user name reallly,name is Grant and at the timing of registration I was working as a tech in Spain-absolutely nothing to do with the American civil war btw

[kardenm]

LOL.!  Good user name though.  Can't stand names that are so non-unique that they have to use numbers.  Use your imaginations people!

[kardenm]

UPDATE: 

Have checked all except the smallest electrolytic caps.  All tested good.

Gone over most of the solder joints.  All look good under the magnifier.

Replaced the HOT even though the original one tests good. (just in case).

When first turn on get no picture, no HV, loud high pitch squeal, B+ tests at 190v (supposed to be 121v).

About the third time switch is turned off and back on, the B+ reads 135v then quickly climbs up to 190v again.

About the fourth time I get a picture but after a few seconds the pic collapses to a vertical line which also then quickly disappears.

About the fifth or sixth time the picture stays on, looks good and the B+ holds steady at 127v (again, supposed to be 121v according to the schematic), squeal fades almost completely, HV reads 21kv at the anode cap.

Can anyone shed any light on this?  Not sure what to try next.  I do have a couple identical, junk boards so I can swap parts if I know what to try.

[sarge]

Are you sure its a 7302 and not a 7203?  Just asking because I've seen several 7203's exhibit the symptoms you are describing, but not a 7302.

[kardenm]

Now that you mention it I can't remember.    

I know I did at first get it wrong (mixed up the numbers).  My cohort did (gleefully) point out my error. But now I don't remember which was correct and which was the error!! and I won't be able to check till tuesday!  BUT I think it is indeed a 7203 because I started this post before I was corrected.

I will let you know for sure on Tues.  Meanwhile, assuming it is a 7203 were you able to fix yours and do you know what the problem might be.

Thanks so much for your input!

[sarge]

Well if it is a 7203 I would change C009 and C013.  These are two small capacitors in the power supply section.

[kardenm]

Well I'll be 

It is indeed a 7203    I did check those two caps and they both tested well within spec. BUT, since it is an intermittent problem I will go ahead and replace them as per your advice.  I'll let you know what I find.

Thanks again for your input.

[kardenm]

  EUREKA !!!

sarge, your a genius  

I replaced those two caps as you suggested and the monitor fires right up. I must admitt, I did not believe that would fix the problem. Could hardley believe my eyes.

Thanks again for your advice. How did you originally diagnose this problem?