RCA L32WD22 No 15v No 24v no backlight

[budm]

Re: RCA L32WD22 No 15v No 24v no backlight

"Thanks could I check pin 8 on the fairchild pfc like that as well essentially using the capacitor like a common ground more or less?" Yes, the GND pin of the PFC IC should show low resistance to the Negative leg of that cap.
As you look at the primary side circuit GND, the negative legs of the main filter caps C919, C973, C915, pfc ic gnd pin, etc are all tied together, see the GND symbols.

[infringer]

Re: RCA L32WD22 No 15v No 24v no backlight

Yes I see this sorry I edited at the wrong time: Just hopped out of the shower off to bed but this is what I posted after that.

odd I get all low voltages through the whole thing putting the black probe to the negative and the positive to the points you mentioned .4 to .7 volts dc.

But I will note when I put the positive lead on the positive end of the cap and check the zener diode it is correct (looking at the photo I uploaded before) 20v on the right side and 14v on the left side so I think it is safe to say that the diode is an exact match and I checked pin 8 like this as well and it displayed 14v dc as well so the zenner has to be good it is somewhere somehow the voltage from the cap is not making it beyond the capacitor I don't understand what the heck would do this but I have learned a bit from this board thanks to you do you have a dogecoin wallet I'd gladly tip you for the help!

Still working at it but I have a full time job to attend I actually work with electronics for a living normally I can figure stuff out fairly well but getting down to the dirt of it all would be nice beyond board or part swapper.



Just got to figure out why there is no voltage beyond the cap really just all really low readings less than 1v... on everything you mentioned the zenner the collector the base and the emitter like .4v - .7v dc while I still do have 20v on the cap beyond the capacitor there is nothing it is just odd to me this is why I have been thinking of a way to test beyond it.

Hrmmm possibly a dry solder joint on the cap itself I think I will run a continuity check tomorrow and see what I can find gotta wake up in a few hours!

Thanks again it is a work in progress at least the zener is correct I know that much.

[budm]

Re: RCA L32WD22 No 15v No 24v no backlight

"But I will note when I put the positive lead on the positive end of the cap and check the zener diode it is correct (looking at the photo I uploaded before) 20v on the right side and 14v on the left side so I think it is safe to say that the diode is an exact match and I checked pin 8 like this as well and it displayed 14v dc as well so the zenner has to be good it is somewhere somehow the voltage from the cap is not making it beyond the capacitor I don't understand what the heck would do this but I have learned a bit from this board thanks to you do you have a dogecoin wallet I'd gladly tip you for the help!" That is not the correct way of testing the Voltage of the Zener because the Anode side is connected to GROUND, you have to test the Voltage with Black probe on Ground and Red probe on the Cathode.
You just cannot put unknown diode in its place without verification otherwise we can be spending the rest of the year trying to find out why the circuit does not work.What happen to using the power supply, resistor, and the suspect Zener to verify if it is good or bad.
Again, look up on how the Zener works on how it is used and how to test them. You have the tools to do it so you have to take an effort to test them.
It cannot have low Voltage on the Zener unless the resistor is bad or the Zener is bad, it is as simple as that, they are connected in series.
I do not know how much more I can explain to you, may be someone else can explain it better, this why I always say that you need to know the basic on how component works, skipping that step does not help.

[infringer]

Re: RCA L32WD22 No 15v No 24v no backlight

OK will do I just figured it would be correct reading it this way in circuit thanks for nagging at me I some times need the extra push I will grab it back out of circuit and give it a test and I'll pop the SMD resistor R944 and verify that the resistance is right out of circuit as well...

Will report back with out of circuit test results.

[budm]

Re: RCA L32WD22 No 15v No 24v no backlight

http://wps.prenhall.com/chet_paynter....cw/index.html

Simple Transistor/Zener regulator.

[infringer]

Re: RCA L32WD22 No 15v No 24v no backlight

The Zener was fine.

The Resistor was fine.

The trace was bad. No voltage at those points but more importantly no continuity a very tricky deal being a single sided layered board I presume it would be easy to spot a bad trace but fooled as I was save the maybes and check the things that are certain in the line lesson learned.

Fixed by Jumpering a wire from R944 The side that shares the leg with the collector of the transistor -> to the + side of C915.

What a beast thank you for all of your help BudM.

And thank you Dave as well for the help.

FINALLY!!!!