Pioneer m90 issue

Hi

I have a pioneer m90 , and there is a problem with dispay , display on the left side is lower than right side, sometomes left side disapire. Both chanels plays fine. I checked fuses they are ok

 

Welcome to AK... Might get lucky and just have a bad solder connection on the display board.

 

AWZ-2041 board Circuitry containing IC401,402 and 403.Check solder connections.

 

Do you think if this is broken thas may be the issue? Please check picture

 

That is the lamp indicating that the amplifier is not in protection mode. Even if open, it should have no influence on the meters.

 

Do you know where can i get this lamp? Unther this lamp it PL 402

 

In my recent M90 restoration I used successfully an 8V 170mA axial lamp (20mm in length). You can easily find it online.

 

Ok thank, do you think the meters are not working corectly becouse i didnt conect the speaker yet? I just plug the amplituner and conect the phone to check if both canals are working

 

if the input signal is the exact same for both channels, the meters should display the same signal level. I would not recommend trying that without a load at the speaker terminals. If you are worried there are issues with the amplifier that might ruin your speakers, then use an 8 ohm dummy load with adequate power dissipation (that amplifier can produce 200W per channel into an 8 ohm load, so you will need something very beefy).

With a load attached to the speaker terminals, if you don't have a signal generator, you can use your phone as signal generator; there are on YouTube videos that have frequency sweeps or individual frequencies (e.g. 440 Hz, 1 kHz) at a predefined output, so that you can be sure the signal reaching both channels is the same. With that, if you still observe differences in the L and R power meters, you have an issue somewhere.