Insignia NS-L37Q-10A - No power (no standby light?)

[alecjahn]

I agreed to work on this one today and upon first inspection, there's no response from the power button on the side of the TV.

I assume the front panel (where the power LED and, I assume, IR sensor are located) should have a standby LED (probably red?) but it does not.

There is a blue LED that lights up on the TCON board, though (never seen one there in other models... then again I haven't had my hands on very many). After plugging in the power cord, this light comes on for maybe... ~8-10 seconds, then shuts off.

All caps "look" fine. I'm headed across town to pick up my multimeter to check fuses but I assume since power is finding its way to the TCON that the main fuse is fine and probably the SM fuse (on the TCON) is fine as well.

Any closer/macro picture requests are very welcome.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I tested the following:
5v from psu (I assume standby voltage on this model) - OK
power switch - functions fine via multimeter
main fuse - good
SM fuse on TCON - good
Don't seem to be getting the (3.3v?) from the mainboard to the IR/Power LED board (obviously, it's not lighting up. )

[budm]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

If you haev any kind of indicator light, it means the standby power supply is working, it may or may not putting out the correct voltage. You will need to check the voltages on the connectors of the power supply, hopefully it will have some kind of labels on them to tell us what the voltages at the pins should be.
Please up load the pictures usuing attachment function, take good clear focus pictures of the boards and around the connectors.
The model number you hae posted 'Insignia NS-L37Q-10A', is there another number after it, that will show the year of the TV since Insignia uses the same model number for the TV, but added something like -09, -07 to indicate the year it is made.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I assume I won't be getting the 12v or 24v (on the PSU->Mainboard connection) until the unit is "powered-on", and only the standby voltage (5v?) will show anything. Right? So -until- the Mainboard gives the "OK" to the PSU to fully power on, these will read nothing?
The heatsink in the very center of the PSU gets fairly warm, and the one below it (center, bottom, two components on one heatsink) gets very slightly warm.
the 5v pins seem to show a steady 5v (5.0xx volts from my multimeter).

I think my problem is, right now, that the mainboard is not responding to the power button -at all- so it never even attempts to power-on (no relays clicking, nothing).

My apologies for the poor pictures, hopefully these new ones will help.
I'm afraid with the poor light in my current apartment I cannot get a clearer wide shot of the boards.
The plug on the mainboard (green) that I left plugged-in is just the speakers.

There's no designation directly following the model number, however a bit lower on the sticker is
MFD 9C19 Rev. A
MFG Date: March, 2009

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

Scratch that, the 5v (standby) line is ~5.17v. Should be within reason right?

I tested the 3.3v lines (from the mainboard to the IR/LED/front buttons) and read about 0.4v on both spots. (top+left plug on the second picture, first post)

So the PSU is giving the mainboard the proper voltage for standby, but the mainboard isn't using that voltage somewhere in the line?

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

(I know in most forums double, even triple-posting is bad... but I see no other way to add info to this thread and I apologize for this)

I shorted PS_ON with the 5V line and then tested the 24v and 12v lines, which put out a steady 25.1v and 12.02v, respectively. It appears the PSU is functioning correctly... however the backlight did not fire-up - should it, or is there another switching function I should apply?

[tom66]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

There is a BLON line which needs connecting -- safest to use a 100 ohm resistor between 5Vstby and BLON as it is sometimes 3V logic, the resistor will limit the diode clamp current to safe limits.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I'll give that a shot, too. I'll have to run and grab the appropriate resistor, a lot of my parts are in storage but they are acquirable.

From another thread (same model), it looks like it should in fact be 3.3v for that. ( https://www.badcaps.net/forum/showth...ht=NS-L37Q-10A post number 3).

Also, I happened to come across a thread for the 42" model... that -I- made last summer. Ha-ha!
https://www.badcaps.net/forum/showthread.php?t=20911
Anyway, it *looks* like that one uses the same mainboard (they look identical, at least and I'm not sure what numbers should be the same between the two...). Wish I still had access to that TV. They used different (larger in the 42", naturally) PSU boards, however.
Is it possible I might be able to source a mainboard easier by purchasing another size's board, or is that a big no-no-no(!) and I should feel ashamed for asking? (I remember having to be pretty specific on the TCON I bought for that 42").

[tom66]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

Any value 100 ohm to 470 ohm will likely work.
You can use different size main board in two possible cases:
1) the panel used is the same (apart from size... e.g. both LG Philips, Chungwha, Chimei, Samsung, etc...)
2) you are able to change the panel setting or mode from the menus.

I would look for (1) first, because not all main boards support (2) and they also don't always support all panels that may be added at a later time to a newer board's firmware.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

Hmmm. I guess it's a possibility...

How does the main board get its 3.3v? Since it is only being supplied with 5v at the lowest, I assume there's a regulator or similar on the main board - is this something I should look for? I probed around all the "regulator-looking" things (on the mb) and didn't find anything that was putting out 3.3 (though I didn't expect to, since I'm not getting 3.3 from the front panel connector or anywhere back to the PSU.

I have this dream in my head that whatever supplies the 3.3v to the front panel is toast and just replacing that component will bring it to life. I'm sure it won't be that easy... I'm not sure how separated the logic side would be from this circuitry but I could easily imagine a dead microprocessor (etc) being a culprit. In this dream the entire TV is just fine and that since the front panel isn't getting its 3.3v, there's no way for me to tell it to power on.

I apologize for talking out of my rear a lot, here. Just speculating/theorizing within my minimal knowledge. I'm learning more every day.

[retiredcaps]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

How does the main board get its 3.3v?

https://www.badcaps.net/forum/showthread.php?t=22231

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I'm still dissecting this information, but I figured I'd post it now while I try to understand it all.

Attached picture has components numbered and a diagram for how I counted the pins (basic left->right as described in the link above).
--------------------
1
L013
G1084-33
http://www.datasheetarchive.com/G1084-33-datasheet.html
-1. 0.2mv (0?)
-2. 0.732v
-3. 0.980v
--------------------
2
1804-18PE
995H8R
-1. 0.2mv (0?)
-2. 82.3mv
-3. 0.450v
--------------------
3
L031 (not to be confused with "L103" above, for #1 - I'm sure of this).
G9084
-1. 6.92v
-2. 8.16v - within spec (6.92v+1.25v=8.17v)
-3. 12.0v
--------------------
4
AZ1117D
902K77
-1. 0.4mv (0?)
-2. 4.96v
-3. 8.16v
--------------------
Thoughts:
#1, if following the link posted just previously, appears to be a 3.3v reg and is obviously not putting out anything near that.
#2, also does not match up with anything respectable. Definitely not correct if following this thread https://www.badcaps.net/forum/showthread.php?t=16780 (same model, same components, different problem, see post 5 for #1/#2, and 8 for #3/#4).
#3, looks good!
#4, at least matches the thread mentioned in #2...?
-----------
SHORT ANSWER - components #1 and #2 (labeled per my attachment) are way, way off - not even hitting 1v on any pins.
Should I replace these or be looking for something else that could be possibly causing the low numbers earlier in the circuit?
-------------

Hope this helps. I'm having quite a bit of fun working on this one. Love a challenge!
Thanks in advance.

[retiredcaps]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

4
AZ1117D
902K77
-1. 0.4mv (0?)
-2. 4.96v
-3. 8.16v

4 looks bad. Double check your readings for 4.

[pedro]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I'm still dissecting this information, but I figured I'd post it now while I try to understand it all.

Attached picture has components numbered and a diagram for how I counted the pins (basic left->right as described in the link above).
--------------------
1
L013
G1084-33
http://www.datasheetarchive.com/G1084-33-datasheet.html
-1. 0.2mv (0?)
-2. 0.732v
-3. 0.980v
--------------------
2
1804-18PE
995H8R
-1. 0.2mv (0?)
-2. 82.3mv
-3. 0.450v
--------------------
Thoughts:
#1, if following the link posted just previously, appears to be a 3.3v reg and is obviously not putting out anything near that.
#2, also does not match up with anything respectable. Definitely not correct if following this thread https://www.badcaps.net/forum/showthread.php?t=16780 (same model, same components, different problem, see post 5 for #1/#2, and 8 for
-----------
SHORT ANSWER - components #1 and #2 (labeled per my attachment) are way, way off - not even hitting 1v on any pins.
Should I replace these or be looking for something else that could be possibly causing the low numbers earlier in the circuit?

Those two regs are not getting source voltage so they can't put out their spec, and are *probably* fine. You need to look "upstream" from them to find out where their supply is and what is wrong with it.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

4 looks bad. Double check your readings for 4.

Double checked and that's exactly what I'm getting today, too.

Those two regs are not getting source voltage so they can't put out their spec, and are *probably* fine. You need to look "upstream" from them to find out where their supply is and what is wrong with it.

I was figuring this was probably the case. Guess I need to poke around. I'm not sure how well I'm going to be able to follow the circuit but I'll do my best. I've got plenty of time this morning.

As a little bonus info, I hear a faint buzz/hum coming from the main board, though it seems like it's coming from the RF/Cable box, which I could see being nothing notable.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I measured the impedance between each pin on reg #2 and it is shorted in every direction. (p1-p2=0, p1-p3=0, p2-p3=0). (this also concludes that all pins, 1,2,3, are shorted to ground)

[pedro]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

I measured the impedance between each pin on reg #2 and it is shorted in every direction. (p1-p2=0, p1-p3=0, p2-p3=0). (this also concludes that all pins, 1,2,3, are shorted to ground)

That is not consistent with the voltages you reported, unless it has died since then ....

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

You're totally right.
1-2=0.9ohms
2-3=1.3ohms
1-3=0.9ohms.
Looks like I had my multimeter still on the diode check function, whoops.

[alecjahn]

Re: Insignia NS-L37Q-10A - No power (no standby light?)

Overdue update:
I broke down and just ordered a new motherboard off of eBay. It fixed it right up. Bummed I couldn't manage to repair the original, but the TV is back in action in its new home.

Thanks for everyone's help.