Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, have you tried checking / swapping speakers and speaker wires?
And check the jumper plugs at the back of the Fisher X-202-B?
I understand and currently reviewing the Service Manual and schematic diagrams.
Are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even a soldering iron?
Equally important, would you be comfortable/familiar working with the inside circuitry and components? ...even perhaps live?
If I understand correctly; PHONO 1 and PHONO 2 works as expected BUT not AUX 1 and TAPE/AUX 2 where A Channel is low or missing.
Bear with me and for test purposes, can you please remove the RCA plugs from the PHONO input jacks and plug these instead to the AUX-1 jacks?
The sound may be low but the idea is to check if both channels A and B have about the same level.
Agree and appreciate the info on what has been tried. Likewise yes on using a known to be good source + 3.5mm to RCA cable.
Let's try and review the basic signal flow check. Based on the schematics, AUX-1 is fed through the LEVEL controls. Try to gently tap and exercise the A AUX-1 LEVEL rotary control.
Please post back results / observations of the above once tried.
in some instances, it may help to clean these level controls and even selector switches using compressed air or better yet, plastic safe / non-staining CRC 2-26, DeoxIT DN5 or LPS 03116 Contact Cleaner or equivalent to clean the insides of these parts but allow sufficient drying time.
Great! Good to hear that the issue has been resolved, congratulations.
Good luck and thank you too for the opportunity to be able to share the information.
Just checking if you need any more assist with the Fisher X-202-B ?