Westinghouse VR-4085DF wont power on & no lights

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

Ok yup that's the one with no continuity.
Ebay has 5 of them for like $5.50 Est Delivery is June 7
Is there something I can use to jump it to test ????
Thank you for helping with this

The million dollar question is what could have caused it to blow ?

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

ok if its just a fuse could I use one of these to see if the power supply comes back to life ????
Would you keep it 5amp or go a bit higher ?

RadioShack 5.0A 250V Fast-Acting 1¼x¼" Glass Fuse (4-Pack) or this
RadioShack 5.0A 250V 5x20mm Slow-Blow Glass Fuse

[budm]

Re: Westinghouse VR-4085DF wont power on & no lights

There may be shorted out parts that needed to be checked, such as the bridge rectifier, the power MOSFETs mounted on the heatsinks, etc. It is SLO-BLO fuse.

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

I found some 5amp 250volt glass fuses in my toolbox and swapped out the bad fuse and it popped instantly.
The power supply board had nothing connected to it just power in.
So like you said there is definitely something shorted...
I suspect mosfets are the cause.....
Q4, Q1 and is D3 one as well?

Do the power mosfets have to be removed from the board to test them ?
Also at this point is just easier to try and find a power supply ?
I hate to dump $50 or more in a tv that may still not work after replacing the power supply?

I found one for $42 w/ shipping included I'm going to give it a try.
Thank you for all your help.

[dick_barton]

Re: Westinghouse VR-4085DF wont power on & no lights

Get your multimeter out of the toolbox. You don't need the fuse in place to carry out some very basic checks.
Using you multimeter set to diode mode, check across the legs of all the Mosfets & diodes and see if any of them return 0 ohms or close to 0 ohms and report back your findings

[vinceroger69]

Re: Westinghouse VR-4085DF wont power on & no lights

I would expect that the OP would have test simple stuff like fuse already, but may be not.

Ive had this a few times now people seem to reconise a glass fuse etc and you can see if its good or blown a lot of the time so they can spot it and test it easily with these cylindrical type a lot of people i dont think have saw these before but once i point the marking out on the pcb to them etc they can see themselves its a type of fuse. But yes now we have found it blown more testing of parts required and maybe a dim bulb tester needs used to save fuses blowing.

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

Ive had this a few times now people seem to reconise a glass fuse etc and you can see if its good or blown a lot of the time so they can spot it and test it easily with these cylindrical type a lot of people i dont think have saw these before but once i point the marking out on the pcb to them etc they can see themselves its a type of fuse. But yes now we have found it blown more testing of parts required and maybe a dim bulb tester needs used to save fuses blowing.

When I first checked the Power supply for input power I did find it and even went as far as cutting of the heat shrink off it.
I didn't know what it was and therefore I didn't know to test for continuity across it.
I don't have much experience with electronic components other than say resistors and some capacitors.
I do my best to figure stuff out then turn to YouTube then forums if I cant find any info on YouTube.
I greatly appreciate everyone's help here.
I did google testing mosfets last night and know now how to do that but wasn't sure if they had to be removed from the circuit...
I was forced to sell my toolbox years ago filled with all my Automotive tools and Diagnostic equipment I accumulated over 20 years as a Ford mechanic and currently using a free but crappy Harbor Freight DVOM it does what its supposed to but is limited...

One question is what is D3 on the board?
Is it a Mosfet or just plain transistor ? It only has 2 leads ? How do you test it ? Continuity?

[vinceroger69]

Re: Westinghouse VR-4085DF wont power on & no lights

D usually means a diode test it in diode mode with leads one way and then the other and note the readings the mosfets etc can all be tested in circuit at first any odd readings i usually remove and retest but test the bridge rectifier first as these usually fail short circuit anything your stck on just ask and we will try too advise you.

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

D usually means a diode test it in diode mode with leads one way and then the other and note the readings the mosfets etc can all be tested in circuit at first any odd readings i usually remove and retest but test the bridge rectifier first as these usually fail short circuit anything your stck on just ask and we will try too advise you.

You're correct !
I removed the diode from the board and the diode tested ok.
Nothing one way and continuity the other.
I removed the 2 mosfets Q4, Q1 and one of them is bad it didn't pass the test I found a quick and dirty mosfets test on YouTube.
Could 1 bad mosfets be causing the fuse to blow ?

[vinceroger69]

Re: Westinghouse VR-4085DF wont power on & no lights

yes a shoted mosfet can did you test the bridge rectifier too?
try re testing both of those and use this method and post the readings for us

Mosfets
---------

If you have a manual range multimeter, set it to 200 ohms (two hundred). You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

yes a shoted mosfet can did you test the bridge rectifier too?

No I haven't I have to google how to test one.
That's the last one on the heatsink correct ?
Removing it from the board to test it and will post results.

[vinceroger69]

Re: Westinghouse VR-4085DF wont power on & no lights

No I haven't I have to google how to test one.
That's the last one on the heatsink correct ?

yes thats the one the oblong 4 pins usually and see me edit too above post
https://www.youtube.com/watch?v=dqkT6hF0O3E

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

yes a shoted mosfet can did you test the bridge rectifier too?
try re testing both of those and use this method and post the readings for us

Mosfets
---------

If you have a manual range multimeter, set it to 200 ohms (two hundred). You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

Of the board mosfet
a) black on pin 1- red on pin 2 - 120
b) black on pin 1- red on pin 3 - 120
c) black on pin 2- red on pin 3 - 002
Mosfet I think is good on board test
all 3 test are open no readings - off the board I passed quick and dirty YouTube Test

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

yes thats the one the oblong 4 pins usually and see me edit too above post
https://www.youtube.com/watch?v=dqkT6hF0O3E

Ok the bridge rectifier passes that test you sent me on youtube
So it looks like definitely a bad mosfets so far
Now to find a cheap one and try it along with a fuse.

[vinceroger69]

Re: Westinghouse VR-4085DF wont power on & no lights

budm may have some ideas of what parts if any in that circuit which may also of caused that mosfet to blow so wait till budm has a quick look at these results just incase theres more parts too order.

[dick_barton]

Re: Westinghouse VR-4085DF wont power on & no lights

Can you post some pictures of the power supply. What numbers are on the board eg BN44-xxxxxxx

Ignore, I can see them now in the earlier post.

[dick_barton]

Re: Westinghouse VR-4085DF wont power on & no lights

What is the part number of the IC marked IC1 on the underside of the board?

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

What is the part number of the IC marked IC1 on the underside of the board?

ok this is the best photo I can get of that chip
There is shellac or something on it so its hard to get a clear shot.
I think its upside down, I am not sure

OK it looks like L6562A 7/EZ012

[dick_barton]

Re: Westinghouse VR-4085DF wont power on & no lights

It looks like 6562x. Can't make out the last number. Can you scrape off the shellac carefully. I'm thinking it may be the IC that controls the blown mosfet so trying to find data on it.

[hackerjoe]

Re: Westinghouse VR-4085DF wont power on & no lights

It looks like 6562x. Can't make out the last number. Can you scape off the shellac carefully. I'm thinking it may be the IC that controls the blown mosfet so trying to find data on it.

I did scrape it but I don't have a strong enough magnifying glass.
It looks like L6562a