2s to black. Proscan 32LB30Q

[culcuhain]

Ok. I have a Proscan 32LB30Q on the bench this morning.
I have all the correct voltages on the main board. (5vstby, 5Vpwron, have BLON and DIM)
I think I have narrowed it down to the Inverter Board or the Lamps.
I have attached a few pics with the voltages.
I am not sure how to test the primary side of the inverter. The secondary side (inner posts/bindings) I get 24.6V. I have 24.6v on all sides of the white fuses (F1-F4). I did not see a black Fuse anywhere on the board.
Inverter board is I315B1-16A-C302G.
All the voltages stay the same when going from standby to On except the error on the inverter, it spikes to 154mvish and then drops back down to the 50mv range.
If I need to test the inverter, please share a link (couldn't find one in the search) or walk me through it if possible.
I have learned a lot over the past few weeks and I appreciate everyone's help. Thank you!!!

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

If I use the cfl bulb tester that budm shows us how to make and connect it to test each output and the backlights come on then that means bad bulb and if not then bad board? Or is there a better to determine if the inverter board is bad or the bulbs?

[dick_barton]

Re: 2s to black. Proscan 32LB30Q

Here's a link to a thread on this site.

https://www.badcaps.net/forum/showth...sting+inverter

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

Awesome! That is what I am looking for! Looks like I will be starting at step 4 as I have already done the previous steps!

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

I think I have a bad inverter board.
I have 24.xVDC across all fuses.
I have 24VDV at the primary side input and output on all the inverters.
When hooking up a CFL bulb to each CFL connecter (keeping all others connected) it lights up but I still have 2s to black. Voltages steady on input side and output side.
I am getting a bad IC, shorted SMD Diode. Part order and we shall see....

[ReeceyBurger123]

Re: 2s to black. Proscan 32LB30Q

Sounds like a failed transformer to me, do you know how to test them ?

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

I read in the links provided earlier in the post. I have up to 20% variance betweeen all 8.

[dick_barton]

Re: 2s to black. Proscan 32LB30Q

From memory I believe that anything over 3% is considered as bad.

[budm]

Re: 2s to black. Proscan 32LB30Q

I read in the links provided earlier in the post. I have up to 20% variance betweeen all 8.

Can you show which pins you use for testing the resistance of the inverter transformer, and what reading did you get?
BTW, there are two high voltage windings for each transformer.

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

using this as a guide: http://www.lcdparts.net/TransformerD...ProductID=3497

P1-P2: 0.8 Ohm
P3-p4: 0.8 ohm
S1-S2: 1.022-1026 Kohms
S3-S4: 1.032-1.036 Kohms except 1... It was 1.154K ohms

Bad inverter?

[budm]

Re: 2s to black. Proscan 32LB30Q

Sound like you do have one bad inverter transformer.

[culcuhain]

Re: 2s to black. Proscan 32LB30Q

Inverter replaced and Backlights stay on. Victory!