Bad Caps?

[oakdust]

Here is a link to the repair manual

http://www.4shared.com/document/BRu6u7FX/EMERSON_EWF2006.html

I discharged the CRT and all the caps in the power supply, been suprised before
I don't see any signs of burnt componets or spots on the board

 

[Resqueline]

What parts have you found to be bad so far? I didn't see where the resistor you were mentioning is.
Imho you'll need to measure voltages around at some point too.

 

[oakdust]

The Mosfet, the HOT and 330 resistor next to the Mosfet was bad. Can I do voltage checks when it won't turn on?

 

[(*steve*)]

The relevant page is 32 of the pdf, labelled as page 31 in the document..

As suspected the mosfet is in the switching power supply.

The word HOT refers to the fact that this part of the circuit is operating at mains potential and that you need to take appropriate precautions in working on it when the power is connected. If you don't *know* what those precautions are, then you really shouldn't be poking around with the power on.

I'm not sure which resistor the "330" resistor is. I see no reference to an R330 or to a 330 (k/M/)ohm resistor nearby.

We'll need a photo to be able to figure out which part you're talking about.

What parts have you replaced, and how did you determine that they were bad. And what anti-static precautions did you take?

Originally you said you replaced a 33 ohm resistor, was that a typo?

 

[jerryg50]

Power Supply Short & Failing...

I tested the caps in a TV power supply with an ESR metter and they all tested good but I did find a bad 33 ohm resiter and Mosfet. I replaced them, the TV worked for about 30 seconds and shut off. Now it just clicks when you try to turn it on (origninal problem). Can the caps be bad with a good ESR?

_________

Most likely the parts you replaced went defective again! You will have to find the original fault that caused the failure in the first place. These power supplies are very tricky to service!

Check if the switching transformer is shorted. Use an ohm meter on all the caps to make sure none of them are dead short. A dead shorted cap can fool an ESR meter!

You will have to manually check every component in the power supply to make sure everything is in spec.

Jerry G.

 

[oakdust]

The resitor is listed as R613 and is a 2w 0.33ohm metal oxide resistor, I ground myself to an earth ground and the board to the gegaussing springs on the picture tube. HOT= the horizontal output transistor should a short between base and collector and tested bad with an Elenco transistor tester. I did not find any shorts in any of the diodes, or oprns in the trace. I'll check the caps for shorts and let you know what I find.

 

[jerryg50]

The resitor is listed as R613 and is a 2w 0.33ohm metal oxide resistor, I ground myself to an earth ground and the board to the gegaussing springs on the picture tube. HOT= the horizontal output transistor should a short between base and collector and tested bad with an Elenco transistor tester. I did not find any shorts in any of the diodes, or oprns in the trace. I'll check the caps for shorts and let you know what I find.

You must remove the transistor to test it properly. The circuit resistance is too low. If the HOT is blown its sure there are other failures to be serviced.

 

[(*steve*)]

OK, I misread Q501 as Q601 on the circuit diagram.

But since nobody even bothered to point out that I referenced the wrong page, I guess my comments are being ignored.

If they're not being ignored, then perhaps pointing out the page of the service manual you're looking at might be a good idea.

I have noticed this resistor change from 330 ohms to 33 ohms to 0.33 ohms in the course of this thread. It would be useful to people besides myself maybe to know what actual value it's supposed to be.

 

[oakdust]

Steve, sorry for the problem. I guess I read it wrong too, I'll just figure it out. Thanks for your help.