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Main => Monitor/Video Forum => Topic started by: jconstanza on January 06, 2009, 12:52:45 pm

Title: Wells U3000 - no power up
Post by: jconstanza on January 06, 2009, 12:52:45 pm

I have a WGM2730 that does not power on. Did a cap kit prior to it not turning on. Checked for broken traces, replaced Q101, also replaced U101. I tried hooking up a light bulb on pins 1 & 3 of CN104 and my bulb does not turn on so I guess I'm pretty sure the problem is in the power supply. Wells doesn't have a troubleshooting guide on their site. Any ideas/help gladly appreciated!

Title: Re: Wells U3000 - no power up
Post by: qrz on January 06, 2009, 11:09:54 pm

normally, a smps isn't terribly difficult to repair.
http://www.wellsgardner.com/pdf/Schematics/U3000_27_inch.pdf

check c117 , c107, c108, r102, r103, r108

also check snubber components  c106,r104, d107

check for loading on secondaries ...


qrz

Title: Re: Wells U3000 - no power up
Post by: jconstanza on January 07, 2009, 09:20:55 am

Can those components possibly be bad even if they tested good or near good, I guess?

Title: Re: Wells U3000 - no power up
Post by: qrz on January 07, 2009, 03:36:06 pm

depending upon the testing method(s).... yes .

ESR ( effective series resistance) and DA (dielectric absorbtion) are two items most cap testers ignore.

in fact, my tester doesn't include DA... the next model up does .

i've had  old 'lytics test ok for value , but excessive esr.


there MUST be min of10v across c107 for the ic to operate.....

qrz

Title: Re: Wells U3000 - no power up
Post by: jconstanza on January 07, 2009, 05:16:38 pm

May I ask what tester you use?

Title: Re: Wells U3000 - no power up
Post by: qrz on January 08, 2009, 10:30:09 pm

sencore lc102...... i think  ?....will need to look   :-[    had it for many years of faithful service !

fyi, the majority of equipment i have is sencore.    and thankfully,  it all paid for itself !!

qrz