Insignia NS-LCD47HD-09 Stuck in Stand by

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Ok. Here is an update.
I put the PS board back in after testing the parts based in the service manual. All tested good. I desoldered the VOL+ from the keyboard pcb and hooked that back up. Plugged it in with the new main board.
I get PS_ON at 3.3V no Dim and no No On/OFf and now I lost 24V and 12V. Ok. Weird. I plug in the old main board. I get PS_ON at 3.3V, Dim at 3.3V On Off at 3.3v Power button on keyboard turns set on and off. Still don't have 24v or 12v. Diode (SARS01) at D918 is shorted per my Diode Tester. I put in a 1N4007 I had laying around (close but not perfect). Tested it again. Same issue (but 1N4007 didn't short out).
PS_ON 3.3V
Dim 3.3V
On/Off 3.3V
12v: 0V
24V: 0v
5V: 4.95V
5v standby; 4.95V

I pulled the 1N4007 and she tested good. So I have an issue in that circuit. Time to figure this out and the kiddo is waking up from his nap... Any pointers would be greatly appreciated. I wont be able to get back to this until after 9pm tonight. I really appreciate everyone's help, I am learning a lot.

If anyone here helping ever comes to the DFW area, I will buy y'all some pizza and beer or BBQ and beer... your choice.

[CapLeaker]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

check the DCV on the main filter capacitor C908 and C907. Put both leads from your DMM to that capacitor. See if you get boosted voltage when the TV is turned on.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Since the SARS01 diode is toast and i took out the 1n4007 after testing, should I put that 1n4007 back in and then test or wait until I get the correct replacement?

[budm]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Where is this D918 on the power supply board?
Do you get 24V if you disconnect both inverter boards from the power supply board?
Per diagram, it is part of the PFC Voltage booster circuit.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

The D918 diode is fed from the + side of the bridge rectifier. See attached picture. The Diode in D918 (SARS01) tested fine the other night (removed from board and tested in my diode tester, today it shows unknown or damaged part which means bad). I put the 1N4007 in as it is close to the SARS01 spec and I had no changes (inverter boards were still connected) so I removed the 1N4007 diode.

So... Do you all want me to put back in the 1N4007 diode and do y'alls suggested tests or wait until I get one in next week? My kiddo has gone down for the night so I have time to test. Thanks!!

[budm]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Put the 1n4007 in place, then apply the power and turn the TV on and then check the dcv between the two legs of the main filter cap to see if you do have close to 400VDC or not.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Thank you. I put the 1N4007 in the board.
Fired her up.
My board has 2 mains filter caps. (C907 and C908) They are rated at 450V 150uf and I am showing 162.4VDC with inverter boards disconnected.

[budm]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

If that is all you get when you turn on the TV then the PFC Voltage booster is no longer working, the 12V/24V power supply needs that boosted Voltage to work.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Ok. BD901 Bridge rectifier shows 98.2vdv on the + side and -64.2vdv on the - side using + probe. D901 shows 99.4vdc. Q904 (using + probe) shows -64.2vdv on outside legs and 99.4vdc center leg. I assume the boosted voltage should occur between BD901 and Q904, correct?

[budm]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Ok. BD901 Bridge rectifier shows 98.2vdv on the + side and -64.2vdv on the - side using + probe. D901 shows 99.4vdc. Q904 (using + probe) shows -64.2vdv on outside legs and 99.4vdc center leg. I assume the boosted voltage should occur between BD901 and Q904, correct?

You use the wrong ground ref point for your meter! You are making the measurement in the primary DC side, the negative leg of the main filter cap is the GND ref for your meter, not the chassis.
Bottom line, there is nothing wrong with the bridge otherwise you will not have the 160Vdc on the main cap, it is the PFC Voltage booster circuit that you need to concentrate on at this point, see the diagram of the PFC section in your service manual.

[budm]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Check to see if D901 is shorted or not, if not, then you need to find out if the PFC IC901 is getting the VCC to run or not.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

well I appreciate everyone's help. I will be ordering a PSU board. While getting ready to do those test voltages using the - lead on the cap as the base my glass slipped off (stupid texas humidity and landed in the AC input side and saw some nice arcs. I have no 5v power now and I think no other power. Ugh. Stupid glasses sliding off. Time for a rum drink.

[CapLeaker]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Now that sux. Did you check the usual as for fuses, bridge rectifier, diodes etc?

[dick_barton]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

That's a bit of bad luck.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

I will take a look at it tonight..... i was a wee p!$$3d at myself last night....

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Update.
Got the new/used Power board in tonight and it does not have 5v standby. So bad board. Made my night. Will be asking for a refund on that one.

So that brings me back to step 1 on my power board. Fuse is blown. So I will place my Mouser order tonight or tomorrow for the fuse and some other associated parts.
Will post back once the parts are here.

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Another PS showed up. All is good in the world. The two other boards I got are being returned. Ordering my tactile switch from mouser tomorrow along with some stuff for some vintage stereo....
Thank you everyone for your help!!!!

[culcuhain]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Tactile Switch soldered in. The touchy feel is a little soft compared to the other buttons, but it fit perfectly in all 5 holes. Tv powers on and off. No issues. Thank you for all your help. This one might end up in the bedroom or the patio.... wife will let me know.

[vinceroger69]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Thanks for the update and glad the sets working fine now hopefully you will also get full refunds/and return postage costs on the bad psus

[dick_barton]

Re: Insignia NS-LCD47HD-09 Stuck in Stand by

Well done. Back in use not in the ground.