Sanyo DP46840

[simplytrini]

Hi all, hope all is well. I am wondering if anyone here has had success in fixing this model Sanyo. I am having an issue where the the green led turns on but i cannot get the high voltage for the backlights working, the screen is black and I can turn the tv on/off with the remote and power switch but that is about it. the power supply has: 5v, 15v, 12v & 3.3v. however the HV circuit for the backlight is dead. also I know the inverter board works tried it on another set ant it worked. Any thoughts would be great. Thanks

[simplytrini]

Re: Sanyo DP46840

Also can anyone tell me where i can get a service manual for this set. Thanks again

[selldoor]

Re: Sanyo DP46840

Doesnt look like its been on the forums before.

We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed
https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

Have you tried electrotanya for the sm

Please can you update your profile with country and voltage.

[simplytrini]

Re: Sanyo DP46840

Here are a couple pictures of the powersupply and Main board. Any further thought would be much appreciated. Thank you!

[ben7]

Re: Sanyo DP46840

First you should check the resistance of the back-light inverter transformer secondary, which is on the bottom left of the PSU.

1. Can you take a picture of the whole underside of the PSU? Then I can show you where to measure for resistance on the transformer.

If the transformer secondary(s) is/are open circuit, then you will have to get a new PSU or get a new TV.

2. Take a bright light or a bright flashlight and shine it at the screen from close-up. Can you see an image on the screen? (TV should plugged into video source) If there is an image, your back-lights are dead. If there isn't an image, then something else must be wrong.

-Ben

[selldoor]

Re: Sanyo DP46840

Middle picture is ok but not great there is a small cap in the middle right looks marked on top but probably just shadow? The other two pics have too much flash & shadow. Please try again in natural light if possible. Try and get all the board in the picture. Please also do a close up of the power board at the back of the big transformer - looks a bit odd may need resoldering but cant tell from the pic.
Can you test the secondary winding resistance on the same big rectangular transformer in middle pic. (With set off for 10 mins)


When the set is on can you see a faint image of what should be on - perhaps use a pc as source so you know what to expect - try a torch.

[kevinm34232]

Re: Sanyo DP46840

(wrong thread)

[kevinm34232]

Re: Sanyo DP46840

I have this model TV too, it clicks on and the green LED lights up then clicks off a few seconds later, no backlight comes on. Have 120vac at bridge rectifier, 158vdc and filter caps. Not sure what to look for after that, and don't have a service manual... Could this be bad caps, nothing looks bad visually???

[selldoor]

Re: Sanyo DP46840

With it all connected up test the low dc out voltages on the connector.
It says on the board what they should be. Could be caps look for a small one on the primary side 50v 47uf or 68uf

[kevinm34232]

Re: Sanyo DP46840

Before it clicks off, all voltages are good at connector.

[kc8adu]

Re: Sanyo DP46840

got +24 at the inverter?

[kevinm34232]

Re: Sanyo DP46840

Checking off connector on power board that goes to inverter lableled 24v, I get 24.8v when switched on, grounded to chassis, clicks off and voltage drops away.

[kevinm34232]

Re: Sanyo DP46840

OK I just wanna fix 1 TV and I'll be happy. All voltages look good Ive followed the path thru the power supply, at the secondary side diodes I have 2 x 24v for the inverter, and a 5v and a 12v. It clicks on for about 5 seconds then clicks off, there is no backlight even though the invereter is getting 24v. What can I look for next?

[budm]

Re: Sanyo DP46840

There should be a pin on the inverter board connector labeled with BL_ON, see if you have >3Vdc at that pin. For the backlights to come on, it needs 24Vdc from power supply and BL_ON (the signal is generated by the main board routed from the main board through to the power supply board and out to the Inverter board).

[kevinm34232]

Re: Sanyo DP46840

Yes Sir there are 2 wires from the main board, bringing 2.9v volts to the inverter board before it clicks off.

[budm]

Re: Sanyo DP46840

Kevin, your TV does not use the same power supply setup as the original poster, his TV uses Power supply/Backlights inverter board combination.
Your TV has separated power supply and Backlights inverter board.
This will really confuse people when we try to answer the questions since they do not have the same chassis even though it has the same model number.
It may be better to start new post indicating the same model number with notes indicating separated PS/INVERTER boards.
We will need good clear pictures of all the boards (both sides of the board) so we can see how TV is wired up.

[kevinm34232]

Re: Sanyo DP46840

Here's a couple pics. I have a question, was checking voltage on the Power IC, I have 160vdc on pins 7 and 8, pins 5 ha 16.8vdc on standby, when I turn TV on it drops to about 13.6vdc. Is this normal?

[budm]

Re: Sanyo DP46840

Power IC on which board, I assumed the power baord, location and pictures, P/N? Not enough info to go by.

[kevinm34232]

Re: Sanyo DP46840

On power board primary side right in center of board A6051M SK071 04BP.

[budm]

Re: Sanyo DP46840

Please see the picture if that is the one you are indicating, if it is, that IC is for 5VDC Standby power supply, which is working since yoy can turn the TV on and off.