No Raster with Sound ,Panasonic Tv TC-29V50R

[Jujeet]

Finally I decided to change IC805.Result is the same,still loading the voltage.What I did today , removed J115,J174 and disconnect IC806 pin 2(floating).Immediately IC805 pin 1 reads 13.69volts and pin 2 reads 11.95volts
Most voltage is lost when you solder back IC806 pin2 but minimum voltage loss with J115 and J174.Which path should I tackle first?


Best Regards

[jts1957]

IC805 is a three terminal 12 volt regulator.
Pin #1 is the input. You claim to have 13.69 volts there at the present time (This appears to be CORRECT).
Pin #2 is the GROUND pin (you claim to have 11.95 volts there at the present time (I presume you have Pin #2 confused with Pin #3 and vica-versa).
Pin # 3 is the output. (11.95 volts there would be CORRECT).

What is "Result is the same, still loading the voltage." Which voltage?

Let's start over at the Main power supply. With everything connected and power turned "ON," Yes or No. ...
Cathode of D807 is approx 140volts?
Cathode of D808 is approx. 86volts?
Cathode of D809 is approx. 15 volts?
Cathode of D811 is approx. 18 volts?

[Jujeet]

With the set "On"

Cathode of D807 is approx 140.5volt
Cathode of D808 is approx 86.7 volt
Cathode of D809 is approx 8.46 volt
Cathode of D811 is approx.18.3 volt

There is error in my schematic diagram for IC 806 and IC807
Pin 1 as input (correct)
Pin 2 as output (should be ground)
Pin 3 as ground (should be output)

For IC805 in my schematic diagram -
Pin 1 as input
Pin 2 as ground
Pin 3 as output

[Jujeet]

With the set "On"

Cathode of D807 is approx 140.5volt
Cathode of D808 is approx 86.7 volt
Cathode of D809 is approx 8.46 volt
Cathode of D811 is approx.18.3 volt

There is error in my schematic diagram for IC 806 and IC807
Pin 1 as input (correct)
Pin 2 as output (should be ground)
Pin 3 as ground (should be output)

For IC805 in my schematic diagram -
Pin 1 as input
Pin 2 as ground
Pin 3 as output

[Guest]

My current status for IC805 Pin1 reads 13.69volt and pin 3 reads 11.95volt,with J115,J174 jumper wire removed and IC806 pin 3 (floating)

I am able to get 11.95 volt at IC805 pin3 with the three things removed.I have not change IC806 yet.

Sorry for the confusion.

[jts1957]

Pull up dataheets for each. All three are standard (1=In / 2=GND / 3=Out). Schematic does show them (Pin numbers) either incorrectly (or Panasonic are trying to use them unconventionally?)
What about real-world? Do each pin 2 go to same ground "foil"?
Where are J115 & J174 on schematic?
I still think you'd be better off following the short resistance-wise (In & out pins of regs, if low float and read "foil" to see if lo no more).

[Jujeet]

I have replace IC806 and IC807.No solution to the problem. So I started at Switching transformer (T801)winding S4 and S5 reads 16vac this winding is for 15volt dc Rail. The S6 and S7 winding reads 25vac this winding is for 18volt dc Rail. L809 and L810 are disconnected . I see vast difference in the ac voltage.Both winding is using half wave rectifier and a reservoir capacitor.Base on calculation C819 should approx have 20volt dc, which I think is right.For C816 it is should be approx 18volt dc, not 13.69 volt dc.

Best Regards
Jujeet

[jts1957]

AGAIN: What about the real-world? Does pin #2 (center pin) of EACH Regulator go to ground "foil"?
Where are J115 & J174 on schematic?

With "everything connected" ... what is the RESISTANCE measurement at Pin #1 of P83?

With "everything connected" Except Pin # 1 of P83 ....
1) what is the Voltage on the "foil" (the right side of L822)?
2) What is the RESISTANCE measurement a) on the "foil" (the right side of L822)? AND b) on Pin #1 of P83 (Pin 1 of E83)?

[Guest]

Regulators Pin 2s are grounds, all three regulators reads 00.2ohms respect to ground point.

1) Resistance measurement of P1 ,P83 reads 0.395Mega Ohms.(Everthing connected)

2) Voltage at right side of L822 reads 14.00 volt (Except Pin1 P83)

3) Resistance measurement at right side of L822 reads 26.90Mega Ohms(Except Pin1 P83)

4) Resistance measurement at Pin1 P83 reads >4.0Mega Ohms respect to ground.


Best Regards
Jujeet

[jts1957]

If no low resistance ... what's pulling down voltage?