WG25K7501 ticking help

itobandito

Member
Joined
Feb 1, 2008
Messages
428
Reaction score
2
Location
Connecticut
Hey guys, so my monitor blew a cap the other day. (thing was really smoking) A buddy of mine happen to have the same cap from a bag of misc caps he had extra of and we replaced it however the monitor will not turn on, it now makes a ticking sound. After doing some research I see that this is usually caused by a bad H.O.T. In addition to finishing capping the board should I put a new Flyback in as well? Also I am having trouble finding what HOT part number I actually need. I searched bobroberts page but couldn't find anything specific. Again I have a WG25K7501 any help/advice would be appreciated. Thanks
 
The K7501 HOT is a C3686 transistor located at Q704. You can also replace it with an NTE 2324 equivalent. It needs a mica insulator between it and the wall it is mounted to...
 
This chassis is /really/ sensitive to B+. Try nudging the B+ pot down a hair. I mean the tiniest little amount possible. If that doesn't work, try again.

And of course actually TEST the HOT to see if it's bad.
 
This chassis is /really/ sensitive to B+. Try nudging the B+ pot down a hair. I mean the tiniest little amount possible. If that doesn't work, try again.

And of course actually TEST the HOT to see if it's bad.
You know, I am not 100% sure how to test the HOT actually since it has 3 legs. I did a continuity test with my meter and I got a beep when touching the first leg with the last leg however no combination of middle leg with any other leg gave me any beeps. Also on the right of the HOT there is another 2 legged transistor that for the heck of it I did a continuity test and I got no beeps either. Any help. I am not 100% familiar with monitor chasis and how they work, just good at capping/removing the chasis really. Any newbie advice would be appreciated.
 
Last edited:
oh forgot to say I tried to mess with the b+ but it was heavily glued to the board, thing can't move at all.
 
Sounds like you need to replace the 1uf cap by the pulse width modulator I.C. (uc3842).
If this is bad b+ goes up and starts to blow caps. among other parts. Replace that cap and the 22uf cap in the power section. Put your meter on diode check to properly check your hot and diode next to it. Also check the 68k ohm resistor at the top of the board north of the 1uf cap. to see if it is open.
 
Sounds like you need to replace the 1uf cap by the pulse width modulator I.C. (uc3842).
If this is bad b+ goes up and starts to blow caps. among other parts. Replace that cap and the 22uf cap in the power section. Put your meter on diode check to properly check your hot and diode next to it. Also check the 68k ohm resistor at the top of the board north of the 1uf cap. to see if it is open.

Actually, have some corrections to make, I replaced the battery in my meter and got different results. If I do a continuity test on the HOT I get tone with the furthest left leg and the furthest right leg as well as the furthest left leg and the center. However I get no tone with the 2 legged transistor labeled BD5F on the right of the hot.

As for the 22uf cap, do you know if that is that part of the cap kit sold by Bob Roberts? I planned on replacing the caps and place an order with him for a new cap kit for this monitor.
 
Pull that transistor and test it again. if you still get tone, then it's bad....
 
And don't rely on JUST listening for a tone... what does the meter actually read ? (.000 is a short)
Reverse the red and black leads..... same results ?
 
And don't rely on JUST listening for a tone... what does the meter actually read ? (.000 is a short)
Reverse the red and black leads..... same results ?

True. On a K7000 HOT (D1398), the outer legs will measure .060 both directions and that's the way it's supposed to be. Proper measurements for it are from the center to the outer legs.

If in doubt, come here with your results...
 
I do not know if it is in the cap kit. I have never bought a cap kit in my life. I buy caps in bulk as they usually are the same from monitor to monitor with a few exceptions.
 
Back
Top Bottom