Hitachi 3D5 problem left channel, he is booming when he is cold

Hi, I bought a Hitachi 3D5 in a beautiful external condition, no scratches. However, it does not play the left channel and booms from the speakers as it is cold, how a little after running it decreases. I am sending the service manual, if anyone has an idea where to start. I have already replaced the belts.

Hi,
I had the same issue with 3D30/3D88 (2x) - on one channel to low volume or "nothing".
1 .Check that all switches are clean and working correctly.
2. If that does not resolve it, can be a problem of the electrolytic capacitors (like it was in my cases).
You can bridge C506L as a first test. This is the most probable candidate. If it turns out to be a problem of the capacitors, it is recommended to change them all.

3D7...3D7 have higher quality capacitors and are usually not suffering from this problem.
Best regards
Helmar

Thank you for your answer. I checked in the service but there is no C506L capacitor in it. I will first try to assess whether the capacitors look ok.

Location of Capacitor C506L:
See your service manual page 6, coordinate C8, below leg #6 of IC501
also on page 7, coordinate C2, next to IC501

A visual inspection will not work. Sometimes they get bump/hunch on the top, but if they dried out you cannot see it.

Good luck
Helmar