Digihome 32DLed906

[ronhayes]

Re: Digihome 32DLed906

Just retesting volts on power input connecter of driver board again and pin 14 now drops to 03.0v in 200v range.
I am leaning more to pin 11 B/L status as I have measured this pin in 20v and 200v ranges and sometimes I get 0.01v or 0.02v in 20v range and 00.0v in 200v range

[dick_barton]

Re: Digihome 32DLed906

I suspect that the led strips still have a fault and the mainboard may well be turning off the PWM on Pin14

You say you tested all the led strips using an external power supply and they all work so I would suspect an interconnection problem between the strips.
Can you use a piece of wire and bridge all the connections on the led strips where the strips join each other.

[ronhayes]

Re: Digihome 32DLed906

Just retesting volts on power input connecter of driver board again and pin 14 now drops to 03.0v in 200v range.
I am leaning more to pin 11 B/L status as I have measured this pin in 20v and 200v ranges and sometimes I get 0.01v or 0.02v in 20v range and 00.0v in 200v range

[ronhayes]

Re: Digihome 32DLed906

Yes as I stated in post #79 that I thought maybe the connecter strip could be the fault ?
I will have to strip the TV down again to expose the strip lights again would I need to remove the strip connecter board completely and then run a wire in and out of each strip then coming out with the two wires to the driver board?

[dick_barton]

Re: Digihome 32DLed906

Just retesting volts on power input connecter of driver board again and pin 14 now drops to 03.0v in 200v range.
I am leaning more to pin 11 B/L status as I have measured this pin in 20v and 200v ranges and sometimes I get 0.01v or 0.02v in 20v range and 00.0v in 200v range

Pin 14 drops to 03.0V in 200V range = 3V which is not a problem
Pin 11 0.01 & 0.02 again is fine because it says that Normal <0.7V

Do a search on the forum showing how to bridge the strips

Use the 20V range for your measurements

[vinceroger69]

Re: Digihome 32DLed906

coming out of the back of the metal tv chassis to your led driver board is it just two wires that go to the led strips? if so if can you remove that connector from the led driver board and use your led tester on those two wires that feed the led strips do the back lights light up.

[ronhayes]

Re: Digihome 32DLed906

Their is a long strip board that runs down the right side of the chassis and the four Led strips slot on to this board it has a connecter at the end and the two wire connecter plugs into this. I have started to strip it down when all is exposed I will take a photo of it and I will show a plan of how I intend to by-pass this board ?
Perhaps you could have a look and let me know if what I plan is right ?

[vinceroger69]

Re: Digihome 32DLed906

yes i have the same set up here its basically a thin board with one connector on and spaces for the led strips too slide on to what in thinking if you disconnected the connector to your led driver board and used your led tester to power those two wires if alls ok the whole backlight will light up saves stripping the panel down.

[ronhayes]

Re: Digihome 32DLed906

Yes I had already done that as I stated in post #78 that I pulled plug from driver board and powered up the backlights with the Led tester and the backlights came on this was while I had the TV on.
I have now stripped the TV down again now and here are some photo's of the Led connecter board and I have drawn on one of them to show how I intend to by-pass the board.. I will of course remove the board first and the wire will be a lot tidier than the drawing.

[vinceroger69]

Re: Digihome 32DLed906

so now if you retry powering the set up on the two wires that run through the back of the metal tv chassis do all the leds light up?

[ronhayes]

Re: Digihome 32DLed906

Here is a couple more pictures of me powering backlights .

[vinceroger69]

Re: Digihome 32DLed906

if the leds work like that i cant see it being a bad connection it has to be the driver board or mainboard ? and just saw your picture about the rewiring to rule out bad connections that should work fine in my opinion.
what i was trying too get you to rule out is the back of that connector your holding your probes onto in case theirs a bad connection there.

[ronhayes]

Re: Digihome 32DLed906

With these two photo's you can see me powering up backlights by the two wires coming out the back with Led tester.

[vinceroger69]

Re: Digihome 32DLed906

i personally dont think its a issue with the leds it has too be the driver board or mainboard in my opinion hopefully dick_barton or budm will chime in with there thoughts

[ronhayes]

Re: Digihome 32DLed906

Yes I am thinking that way myself !! But when I have checked the volts on the power input of driver board they seem correct from what dick barton was saying the only thing that seems strange on the driver board is the outlet pins to Led's comes on at 24.8v then after 5 seconds it rises to 140v then slowly decreases to 24.8v over a time of about 50 to 60 seconds then holds steady at 24.8v in the 200v range.

[vinceroger69]

Re: Digihome 32DLed906

your led tester is lighting up all the leds at about 100v so i guess one voltage from the led driver board should stay at about the 100v mark but like you say its dropping down too 24v hopefully budm will see this thread and advise us.

[ronhayes]

Re: Digihome 32DLed906

Yes hopefully he will ?
I don't think it is anything to do with the Led's but I will leave it stripped down until maybe dick barton or budm observe my photo's and hopefully point us in the right direction.

[vinceroger69]

Re: Digihome 32DLed906

budm is in a different time zone to us im sure he will reply if he has any ideas what maybe at fault here

[budm]

Re: Digihome 32DLed906

The only way to have 140V on the Anode end wire of the string is the open circuit condition due to no path for the Cathode return to GND through the PWM Control power MOSFET and the current sensing resistor to GND.
So check the Cathode end wire of the LED string to see if you get any Voltage that jumps up and come back down or not, if it does then that means the MOSFET may not be drven by the LED Controller IC.

[ronhayes]

Re: Digihome 32DLed906

How do I do this test do I need to reassemble the TV ?