Wharfedale LTF37K1CB Power Issue

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Hi Budm, Can you point me in the right direction to get the right Voltage Regulator.. everywhere I've tried has not got them.

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

3.3V regulator, right now the input voltage is too low for it to work
Variable regulator pin 1 voltage of 0.70V + 1.25V ref then the output should be 1.95v but you are getting 3.22V, so it is bad. Variable regulator pin 1 voltage of 0.70V + 1.25V ref then the output should be 1.95v but you are getting 3.22V, so it is bad. The voltage between pin 1 and pin 2 should always be 1.25V for 1117 series variable regulator.
)11 8CW -> line 1 of the IC
1117L -> line 2 of the IC
pin 1 = 0.70
pin 2 = 3.22
pin 3 = 5.03

Now changed this regulator and getting

Pin 1 = 0.71
Pin 2 = 1.37
Pin 3 = 0.84

Still not turning on.

[budm]

Re: Wharfedale LTF37K1CB Power Issue

Pin 1 = 0.71
Pin 2 = 1.37
Pin 3 = 0.84

That cannot be right, you were getting 5.03V input voltage and now you are getting 0.84V input and the output is higher than the input, so that is not right at all. 1.25 +.71 = 1.96V, you are getting 1.37V.

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

http://www.ebay.co.uk/itm/1110761250...84.m1497.l2649

Thats what I ordered.

[budm]

Re: Wharfedale LTF37K1CB Power Issue

That is the right one, you need to find out why you are not getting the 5V on pin 3 (last pin on the right as shown on EBAY).

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Bah ballsed up on my original numbers.... dont know where the last one came from.

Heres the correct details from my paper that I wrote the values down.

)11 8CH -> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 0.14
pin 3 = 0.85


LD18 -> line 1 of the IC
Y437 -> line 2 of the IC
pin 1 = 0.00
pin 2 = 0.00
pin 3 = 0.14


L780SC2T -> line 1 of the IC
GK1BN VW -> line 2 of the IC
CHN 815 -> line 3 of the IC
pin 1 = 0.39
pin 2 = 0.00 Cut pin
pin 3 = 0.00


)11 8CH -> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 0.10
pin 3 = 0.85


AZ10845 -> line 1 of the IC
-3.3E1 -> line 2 of the IC
751K99 -> line 3 of the IC
pin 1 = 0.00
pin 2 = 3.30
pin 3 = 5.03


)11 8CH -> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 3.22
pin 3 = 5.03


)11 8CW -> line 1 of the IC
1117L -> line 2 of the IC
pin 1 = 0.70
pin 2 = 1.35
pin 3 = 0.82

Gah dont know why I wrote that down before wrong...

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Replaced the cap next to it too, No change.

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

RIght, got a 2nd hand main AV board from ebay and fitted it today.

The set now turns on but before it does the blue LED at the front of the set blinks red a few times then the back light comes on. I however dont get any display from the menu or a source.

Any ideas?

[Rtech]

Re: Wharfedale LTF37K1CB Power Issue

Have just received the same model.Different fault,in that it took a long time to come on,LED flashing then going back to Standby.All the caps looked good,But using my ESR meter, the Capxon one( where the Green one is shown in the photo)was 47uF @35v,but with an ESR of 18Ω.Replaced and now excellent.

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Ahh will check that out tomorrow Rtech. Hope this is it

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Right update on this, Replaced all the caps on the power board and still the same issue. The board powers up and back lights fire up but no picture.

/me thinks it will be the av board that I got from Ebay is faulty

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Got some spare time jumped back on this.

Checked the board that I got from eBay and here are the values for the fets. Set turns on but no display. Back lights fire up.

8FL-> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 3.27
pin 3 = 4.81


6H8L -> line 1 of the IC
17-18L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 1.79
pin 3 = 3.27


CHN -> line 1 of the IC
L780SC2T-> line 2 of the IC
pin 1 = 10.25
pin 2 = 0.00 Cut pin
pin 3 = 5.05


8FL -> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 3.28
pin 3 = 4.79


AZ1084S -> line 1 of the IC
-3.3E1 -> line 2 of the IC
744k76 -> line 3 of the IC
pin 1 = 0.00
pin 2 = 3.28
pin 3 = 4.93


8FL -> line 1 of the IC
17-33L -> line 2 of the IC
pin 1 = 0.00
pin 2 = 3.28
pin 3 = 4.92


8DK -> line 1 of the IC
1117L -> line 2 of the IC
pin 1 = 1.37
pin 2 = 2.62
pin 3 = 4.81

Caps look fine could be a Con
issue now?

[Atomical]

Re: Wharfedale LTF37K1CB Power Issue

Got a tcon board yesterday. Same outcome..