MX7000 will not show the picture

8 replies
K(
Offline
Kilaasi (archived)
Bronze
Posted January 24, 2009 at 16:44 GMT
#1866971

Hi

First of all sorry my bad english.

I am repairing a MX7000. First it wouldn't come out of standby. But now the standby problem is fixed.

Now i can turn it on and hear the sound normally, but the screen is completely black. It seems like the CRT is missing some power somewhere....maybe. But I can also hear the energising sound when I turn the TV on.

I have measured the different voltage points in PCB 4 (8V, 15V, -10V, -20V, 20V, 154V, 190V) and all of them is there. But there is a deviation for 190V, I measured 167V.

Does anyone outthere knows if there is a typical failure for a problem like this?

Klaus

A(
Offline
A14BEO (archived)
Bronze
Posted January 24, 2009 at 17:30 GMT
#1866972

Does the television have the correct Tuner type for the country you're in? Does it display a picture via SCART?

K(
Offline
Kilaasi (archived)
Bronze
Posted January 24, 2009 at 18:04 GMT
#1866973

Yes, it is the correct tuner. We have used this TV for many years before. And it doesn't display picture via scart or antenna.

TO
Offline
tournedos
Bronze
Posted January 24, 2009 at 18:06 GMT
#1866974

A long shot, but have you simply checked that the tube has power to the heater (does it glow)?

K(
Offline
Kilaasi (archived)
Bronze
Posted January 24, 2009 at 20:54 GMT
#1866975

I have checked the 154V (measured 154V) and 190V (measured 167V) that goes to the print where the tube is mounted. But don't have tool to check the 27,5kV.

The tube doesn't glow.

N(
Offline
nickyg63 (archived)
Bronze
Posted January 25, 2009 at 03:32 GMT
#1866976

you could always have my mx6000 for the tube!!

 

see in the sales section

DI
Offline
Die_Bogener
Bronze
Posted January 25, 2009 at 05:12 GMT
#1866977

No, not the high voltage... the heater line for the tube (pin 9 on the tube) "Filament"=connector P89-3 shown in the manual page 2-14 I76 

K(
Offline
Kilaasi (archived)
Bronze
Posted January 25, 2009 at 20:44 GMT
#1866978

Very interesting point. There is no power (voltage) to measure. And the connection from connector P89-3 to P14-3 in the PCB 4 is fine.

But in the other side, I really don´t know what to expect to measure in that line. I followed the line for P14-3 in the diagram and this is connected to a coil and again to ground = 0V ?

But an accident occured while I tried to measure this connector P89-3. P89-3 and P89-4 (190V) touched together and made a huge spark. But luckily the before measured voltages is still there :) And the TV can still turn on.

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