Jmb jtc012600102b

[Mtek325is]

Hi has any one had the pleasure of fixing one of the above tvs also the same as linsar 26led906t.
The set is stuck in stanby although i was told it would come on sometimes but not tested that yet.
Im thinking its the power supply which is 17pw06-2 has anyone tested one of these boards before? maybe there are some common problems to help me look for. One of the transformers is quite loud and the volts seem to be all over the place one side of it and a steady 66 on the other maybe this is faulty? Any help will be much appreciated.

[cashkennedy]

Re: Jmb jtc012600102b

Looks like an ultra thin set?

When you say you tested the voltages and got 66, that doesn't sound very realistic for a LCD set. There are 2 halves of a power supply, the primary and secondary. The primary is the side where the AC (wall socket) connects, the two halves are separated by a dark black line) You can set your meter to AC and test the 2 AC legs of the bridge rectifier for 110v / or 220v depending on your country. Then test the DC voltages across the series of filter caps in the center of the primary, your expecting something in the 160-400volts range.

The secondary should have a connector going to the mainboard, where you test for dc voltages between each labeled voltage and a labeled ground pin, and normal voltages on most TV's are 24, 12, 5, 3.3 or as labeled . The voltages should be within 2% of the labeled value for a working set.

[tom66]

Re: Jmb jtc012600102b

Hey, a fellow Basingstoke resident! Well, I live in Tadley (~10mi from Basingstoke), and go to university in Leeds, but I'm back in a few days time.

Anyway, I have a schematic for this board...
http://www.toms-service-manuals.com/...&Search=Submit

What mode is your meter set on? Volts AC or DC?

[Mtek325is]

Re: Jmb jtc012600102b

hi tom66 small world eh i think you was helping me with a samsung the other week on here. right so ive tested in ac and dc on the primary main connector and im getting 41ac and 24dc with the set plugged in but im not getting the standby light anymore but the buttons are still beeping.this is voltage right from the end of the cable plugged into the wall so it cant be right

[Mtek325is]

Re: Jmb jtc012600102b

thanks for the schematic ive noticed it has a fuse "f100" next to the connector could this still let voltage through or would it completely blow it says t3 15a 250v on top of it and its brown not your normal looking fuse to me anyway.

[tom66]

Re: Jmb jtc012600102b

24VDC sounds fine for the inverter. Always use DC scale from now on when testing the outputs.

So if you are getting 24V on PL201, check pin #11 and #12 for the DIM and BL ON/OFF.

F100 isn't going to be the fault for now.

[Mtek325is]

Re: Jmb jtc012600102b

#11 3.1v and #12 0.0v and 24v on pin 5

[tom66]

Re: Jmb jtc012600102b

Odd -- you have DIM voltage (brightness level) but missing on/off signal. Check pin 7, 9 and 27 of PL200 in the same way.

[Mtek325is]

Re: Jmb jtc012600102b

0.0v from all the above

[Mtek325is]

Re: Jmb jtc012600102b

sorry not checked 27 to secs

[Mtek325is]

Re: Jmb jtc012600102b

yeah pin 27 0.0v

[Mtek325is]

Re: Jmb jtc012600102b

sorry my bad..pin 7 and 9 are 3.1v and pin27 0.0v

[tom66]

Re: Jmb jtc012600102b

Double check #11 and #12 on PL201.

[Mtek325is]

Re: Jmb jtc012600102b

double checked pin #12 0.0v pin #11 3.1v

[tom66]

Re: Jmb jtc012600102b

Bizarre design for the BLON circuit but there would appear to be a fault with it as the main board is sending a signal and it's not making it to the inverter. Can you check if Q206, R245, C214 and D213 are installed? They will probably be on the bottom of the PSU board near the inverter connector PL201.

[Mtek325is]

Re: Jmb jtc012600102b

funny that i was just looking for them and getting the board off yeah there all there

[tom66]

Re: Jmb jtc012600102b

Check if C214 is shorted, it should appear open on ohmmeter (>100k)

[Mtek325is]

Re: Jmb jtc012600102b

saying that if there meant to be noticeable between the solder then no there not there

[tom66]

Re: Jmb jtc012600102b

No, check on an ohmmeter, the capacitor can fail shorted or leaky. If it does it will hold BLON low for the inverter.

[Mtek325is]

Re: Jmb jtc012600102b

the markings are there for them but the resistors aren't