VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

[pinballpuk]

Hello,

I recently acquired the subject TV at the swap meet for $20. It would turn on and then off. After reading similar posts & threads I checked out the PS and its working as advertized. I then read about the possibility of the TV being turned of last while using the PC input. I connected my laptop to the TV and then turned it on and it worked. I then changed the input to cable and attempted to perform a channel scan. The analogue channels scanned ok and when it finished I expected it the digital channels next.

However, the digital channel scan would not start.

I also noticed that the channels would not change when using the up / down buttons on the remote or on the tv side panel.

I could change the channels by pressing the number pad on the remote.

I tried to perform the factory reset steps but I wasn't successful. I didn't see an "F" on the menu screen.


These are the clues I've noticed so far.

Any help would be appreciated,

Best regards,

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

When I was trying to scan the channels the TV was connected to my TW Digital Cable.

[tom66]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

A regulator, 1.2V, on the main board can sometimes fail causing this.

[budm]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

"VIZIO VX37L" Does this one has two antenna input connections? one for cable and one for Over the Air Digital signal.

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Budm,

This TV has only one F connector and it is used for both the Analogue and Digital signals.


tom66,

Thanks for the input, would you be able to provide your best guess where a potentially faulty 1.2V regulator on the main board might be?

Thanks for your help guys,

[aaronwt6]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

A regulator, 1.2V, on the main board can sometimes fail causing this.

Tom,

This is the same TV I was working on a couple weeks ago. Unless I overlooked one, I don't recall any 1.2V regulators on the main board.

https://www.badcaps.net/forum/showth...ighlight=vx37l

Again, I could have overlooked one.

[aaronwt6]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

There were however a few 1.8v regulators

[tom66]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Tom,

This is the same TV I was working on a couple weeks ago. Unless I overlooked one, I don't recall any 1.2V regulators on the main board.

https://www.badcaps.net/forum/showth...ighlight=vx37l

Again, I could have overlooked one.

I think I'm getting confused with another model norcal715 recently repaired.

[aaronwt6]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

I think I'm getting confused with another model norcal715 recently repaired.

Gotcha. Just didn't want any confusion. I certainly have no idea on the actual issue though. Certainly sounds like a main board issue but I wouldn't know where to start.

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Hello aaronwt6,

Were you able to accquire a schematic for the main board of the VX37L while you were repairing one not too long ago?

Best regards,

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

I've removed the mainboard and I'm looking for an obvious problem and haven't see one yet. Perhaps I can get my hands on a known good mainboard P/N: 3637-0012-0150(3c), and install it to see if the problem goes away. I've been reading various post and there are some with similar issues of not being able to scan digital channels.

[Tvbob]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

firmware problem.

[aaronwt6]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

I've removed the mainboard and I'm looking for an obvious problem and haven't see one yet. Perhaps I can get my hands on a known good mainboard P/N: 3637-0012-0150(3c), and install it to see if the problem goes away. I've been reading various post and there are some with similar issues of not being able to scan digital channels.

Never looked for a schematic pinballbuk. I just found that it had no 12V/24V output on the power supply and changed it. I was going to attempt a repair but found the board so cheap I just bought the whole thing.

[budm]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Pictures of this main board and the list of the voltage regulators readings?

[ecking767]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

firmware problem.

I totally agree, I had an Vizio GV42LHDTV with the same problem. I replaced the mainboard. Also you may want to make sure your replacement board is at the latest revision before buying.

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Pictures of this main board and the list of the voltage regulators readings?

I can supply a picture of the mainboard later this evening.

Is there a list of the regulators by reference designator for the devices on the Mainboard?

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Here are the pics and the data. I noted on the LDS table when there was a resistor near the Adj pin on the regulator. I also noted on U10 where the Adj voltage was Zero on this main board and others I saw had a value of .33 for example.
I appreciate the help,

Best regards,





http://s1289.photobucket.com/user/pi...3ba7b.jpg.html

[pinballpuk]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Is anyone else able to see the pictures and LDO readings?

[gdblanford]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Wondering if this was resolved or found a fix. I have the same problem with the scanner. Here are my readings, I have no other issues with the TV just doesn't get any channels. Won't find any analog either in fact.

Readings with TV on
Name Reg Type IN OUT Ground Exp Specs/Tolerance
DU2 33L 5 3.28 0 3.27
DU3 25L 5 2.5 0 2.48
DU4 AMC1117 adj 3.34 1.24 0 1.25
U10 18L 3.28 1.8 0 1.78
U16 25L 5.02 2.49 0 2.48
U18 AMC1117 adj 3.27 1.49 0.25 1.50
U4 33L 5.05 3.27 0 3.27
U5 AMC1117 adj 3.27 1.95 0.7 1.95
U6 33L 5.05 3.27 0 3.27
U7 18L 3.27 1.8 0 1.78
U8 33L 5.02 3.28 0 3.27
U9 18L 3.28 1.8 0 1.78

I've done the Hard tuner reset and the RGP input attempt with no avail.

[Eagle72]

Re: VIZIO VX37L will not scan Digital channels or respond to up/dn channel changes

Same problem on mine
does everything except scan/display digital channels