Insignia NS-46E340A13

[ngth82]

Good morning Badcaps!

I picked up an Insignia NS-46E340A13 TV yesterday. The original owner says the TV sometimes takes minutes to hours to turn on and it's been in their garage for 6 months.

I searched the forum for this particular model number. Looks like there are two threads, but neither have their issues resolved (one guy didn't post any information, and the other guy never replied after declaring the EEPROM could be bad).

This morning, I got the TV to boot after 3-4 power cycles. I took the back panel off and observed the following:


Power board: 715G5173-P02-W21-002M / (T)CR248XF3
Main board: 715G5738-MOD-000-004K / (T)TXCCB0K090000TOP:A MB:A v2.02
(see photos)

1. Upon applying AC power, the unit turns on.
2. The backlights turn on
3. The power ON_OFF signal is high (4.7V)
4. The power rails are up (12V, 5.2V). The LED driver voltage is also up (75V)
5. DIM is 2.56V (about 50% brightness according to the menu)
6. The TV power cycles itself 3-4 times (power LED blinks 5x times, the backlights turn on, the Insignia logo shows up, backlights turn off, and the process repeats)
7. After the 3-4 tries, the TV is up and running at this point. I can hook up my Chrome Cast and stream video to it just fine.
8. Interestingly enough the P_OK signal stays low. Is the P_OK signal indication active low?

The full list of voltages observed on connector CN902 are as follows (as observed from top to bottom when the board is installed):

• CN902: (Volts)
• ON/OFF 4.7
• DIM 2.56
• 12V 12.39
• 12v 12.39
• GND 0
• GND 0
• GND 0
• 24V 0
• 24V 25.02
• PS_ON 5.16
• 5.2V 5.23
• 5.2V 5.23
• P_OK 0

Its interesting that the P_OK signal is sitting at 0V.. I would have expected this signal to be active high vs active low. Any ideas here?

There are no visibly bad caps on the power or main boards.
The fuses on the power board are good; same with the T-con fuse
I have cranked the brightness up to 100% in hopes of inducing a failure faster (if it's related to the backlights) -- but unlikely since the background looks very uniform when projecting a white background.

The TV turned off once -- and was coincident with when i was measuring the PS_ON signal. I took that as a fluke.

Any ideas on where to go from here guys?

Thanks
-Thomas

[dskall]

Re: Insignia NS-46E340A13

What is voltage across one of your main caps when you press power button? Do you have an esr meter. Sounds like cap problem.

[ngth82]

Re: Insignia NS-46E340A13

What is voltage across one of your main caps when you press power button? Do you have an esr meter. Sounds like cap problem.

I read 386V across the main caps (C9801, C9802, C9804, C9805).

Is this a common failure among Insignia displays? I just haven't worked on these TV's much since they are the "$100 throw away when broken" type.

No, I do not have an ESR meter, but I'll end up purchasing one. Looks like they can be purchased for around $13 or so. I'll post back with ESR results when I have results in hand. Alternatively, I may just spring for a replacement main cap set.

Thanks!

[jetadm123]

Re: Insignia NS-46E340A13

Try heating up the power supply with a hairdryer to see it accelerates the turn on time. Heat the areas with the electrolytic caps first to see if you can narrow down
the area that's causing the problem.

[ngth82]

Re: Insignia NS-46E340A13

I will try that Monday. But generally, heating up components (caps especially) brings the part tolerances towards the high end. Wouldn't that induce failure more often vs accelerating (shortening) the turn on time? Wouldn't I want to cool them instead?

I ordered an ESR / Inductane / capacitance / diode meter from eBay. Should be here on/before Aug 9th.

I'll check local/eBay sources for caps after I get the ESR meter.

[culcuhain]

Re: Insignia NS-46E340A13

Is that a correct measurement for one of your 24v lines having 0v?

[ngth82]

Re: Insignia NS-46E340A13

Is that a correct measurement for one of your 24v lines having 0v?

Oh! No, sorry... Both 24V pins read as 25.02V.

-Thomas

[dskall]

Re: Insignia NS-46E340A13

I don't know if P_OK is like ac detect. May try freezing optocouplers

[ngth82]

Re: Insignia NS-46E340A13

I will try that when i get home from work this evening.

Out of curiosity, does anyone have the service manual/schematics for this power board? I tried looking for these items from the elektrotanya.com/ website, but it turned up nothing.

Thank you,
Thomas

[budm]

Re: Insignia NS-46E340A13

"After the 3-4 tries, the TV is up and running at this point. I can hook up my Chrome Cast and stream video to it just fine." So when it working does P_OK still staying LOW? if it is then LOW = normal.

[ngth82]

Re: Insignia NS-46E340A13

Thanks for the input budm. I'll just go with that assumption for now

[jetadm123]

Re: Insignia NS-46E340A13

If the cap (especially a startup cap) are high ESR, then heating it up might lower it enough to start the TV power supply more quickly. By the way, what brand are those caps?

[ngth82]

Re: Insignia NS-46E340A13

If the cap (especially a startup cap) are high ESR, then heating it up might lower it enough to start the TV power supply more quickly. By the way, what brand are those caps?

I don't have a picture of the backside on my phone (took it on my ipad).

As i recall, the caps are Elite branded 47uF 450V caps -- the labels said PET (C)1245 105degC. I can follow up after work.

[ngth82]

Re: Insignia NS-46E340A13

I don't have a picture of the backside on my phone (took it on my ipad).

As i recall, the caps are Elite branded 47uF 450V caps -- the labels said PET (C)1245 105degC. I can follow up after work.

Confirmed. Main caps are Elite branded 47uf 450V

[dskall]

Re: Insignia NS-46E340A13

You might try monitoring ps_on to see if it is shutting down the tv. If it stays on it would be power board problem

[jetadm123]

Re: Insignia NS-46E340A13

Confirmed. Main caps are Elite branded 47uf 450V

Actually, I meant the smaller caps as those are more likely to fail.

[ngth82]

Re: Insignia NS-46E340A13

Actually, I meant the smaller caps as those are more likely to fail.

I will have to check this on Wednesday. The low voltage output caps physically look okay... but I'll check the markings and report back when I get a chance to. A new project landed on my desk at work and I haven't had much time to devote to this TV.

If the lower voltage caps are suspect, i definitely have a lot of low ESR caps at my disposal in the parts box On a side note, my ESR meter arrives Monday.

Thanks for the input so far guys!

-Thomas

[ngth82]

Re: Insignia NS-46E340A13

The smaller output caps on the right are 330uF 25V caps. Funny since the same caps are used for Cbulk on the +24V rail. The capacitance measures around 340uF with my DIMM. The ESR meter arrives today (yay!) so i'll measure the ESR of each cap. I would suspect they are good. I tried replacing the output caps with what i had laying around (a couple of low ESR ruby con 470uF 50V caps) but the TV behaved the same way -- taking multiple attempts before turning on.

Does anyone out there have a service manual or set of schematics for the power board or the main board? I think it's time to dive in and debug this at a component / trace level.

Thanks!

[ngth82]

Re: Insignia NS-46E340A13

A couple of updtes:

The power-ok signal is not connected to anything on the power board. I didn't trace it on the main board though.

I received my ESR meter. The output caps have 0.09 ohm ESR. as a comparison, a known good 10 mOhm ESR cap reads as spec'ed.

I got rid of the tv for a few bucks. Oh well

[david.aaron.long]

Re: Insignia NS-46E340A13

Funny story. I bought the tv from him on craigslist, thinking I would be able to come to badcaps and find a way to fix it...