Revox B285 no bass freq on a ch

[Bianca16]

Hello,

first time here and I hope you can kindly help me.
I have a Revox B285 and my left channel has no bass freq. I've tried to change inputs and even the headphones out has the same problem so I imagine it's a pre amp issue.
Do you have any tips how to fix it?
Plus, the front lamps are broken and it seems quite difficult to find the right ones. Any suggestion to replace them with LED lamps or else?
Thanks in advance.

Ste

 

[Binkman]

Welcome to AK!
No idea but here is the service manual. free to join and no nags.
Hope you can read German. I suspect a user manual would be in German, too if you can find one.. but may be some settings?
https://www.hifiengine.com/manual_library/revox/b285.shtml
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(complex s.o.b.) All face buttons look like soft touch so doubt any cleaning.