troubleshooting a tv power supply

R!f@@

Joined Apr 2, 2009
10,004
when will you able to reply, as I will be away at my worktable. Have a circuit to built.
Give me a time, so I can check on you
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
check my previous post for information and question

a time would be in about 11 hours. 12 30-1 AM :D
Time Zone GMT -6

unless she brings her dog over i will be able to get it done real quick.
 

R!f@@

Joined Apr 2, 2009
10,004
You have the bridge soldered?
Those measurements dopes not make any sense.
Tell me do you know how to measure Voltage
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
no i don't. i did. but took it out before the test.

ok. said to ground to - of filter cap. and use red probe and probe around right

using a fluke 117 digital multimeter set to AC auto.

let me take a picture. got to take off back to gf's in little. but later on i will be back around 1 am GMT -6

let me know if want me to test it again before i take off
 

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johndoe45

Joined Jan 30, 2010
364
this is the cable

my solder job on the 2nd capacitor near bottom right (from fuse pin. go right one. and up to right. this pin) of image has a little hole or gap. not fully soldered. don't think that matters though

voltage kept increasing slowly on input i think. i have to take off. test again real quick and same way?
 

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R!f@@

Joined Apr 2, 2009
10,004
Look at the picture.

Plug in the PSU to Mains.
Put DMM in ACV, use two hands to hold the two probes and take the measurements after power up and confirm it is same as in the pic
 

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johndoe45

Joined Jan 30, 2010
364
i am not understanding where to put black probe.

i usually use an alligator clip to probe and clipped to negative capacitor terminal.
 

R!f@@

Joined Apr 2, 2009
10,004
That's why I said to use both hands to hold the probes.
When measuring AC Voltage across connectors, there will be no common point sometimes.
So you need to hold the 2 probes and measure them as shown
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
yep

122 VAC at jack pins

122 VAC at bridge pins

got to take off. sorry. let me know what to do tonight.

does that mean i was measuring it wrong this whole time with the regular cord???? so it would have measured 122 VAC without having to cut an old cable and soldering it

i used the original cable leaving the soldered one unplugged and got same results
:cool:
 
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R!f@@

Joined Apr 2, 2009
10,004
Ahh!! now we are getting some where.
Next step is
Remove that Big capacitor and solder a new Bridge together with a proper fuse
 

R!f@@

Joined Apr 2, 2009
10,004
I wasn't worried about the readings, I am trying to figure out why the fuse is blowing.
So If you have taken the measurements before in a wrong way then, the original cable is fine.
TSK TSK.., what were you thinking? :rolleyes:

With the FET & the Cap removed.
New bridge and Fuse installed.
Giving power should not blow the fuse and you can measure DC voltage at the bridge output.

Get it.
 
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Thread Starter

johndoe45

Joined Jan 30, 2010
364
alright about to get started.

so should i desolder the cable or just keep using it anyway???

CAPACITOR HAS WHITE GLUE ON BOTTOM!
how can i remove the cap safely without breaking pins from bending or damaging cap?????? FET still out. already discharged cap with 470 ohm resistor.

then solder bridge in. and check DC volts at what pins???

want the real fuse installed or slow blowing one that is still soldered
 
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R!f@@

Joined Apr 2, 2009
10,004
Keep the soldered wire for now
Solder the Bridge
Put a 4A fuse
Remove capacitor

Apply power
Measure the DC voltage at the capacitor solder pads.
Post the Voltage value
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
CAPACITOR HAS WHITE GLUE ON BOTTOM!
how can i remove the cap safely without breaking pins from bending or damaging cap??????

bridge is soldered in. so is slow blowing fuse 4A.
bridge passed diode tests. and fuse has continuity
so didn't burn out the bridge or fuse while soldering
 
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