L-R balance problem.
it's 75% Left and 25% right.
how to adjust the balance?

also, it's sounds a bit muted. less detail, not a "fresh or lively" sound. the head seems ok.

Serial number: 64959

does somebody know?

Have you checked the azimuth is correctly adjusted?

how do i check the azimuth?
i don't have any tech background.
perhaps tell step by step?

Below is an excerpt from the Sony WM-D6C service manual.

i've tested the adjustment screw. the sound is less muted, more fresh now. that's an improvement.
but the balance between L-R hasn't changed, so
do i need an oscilloscope for the rv101, 201?

The 'scope is required for the azimuth alignment where using a test tape, which I doubt the average person is going to have. However it is possible to make your own test tape recording onto a blank tape from a tape deck you know is set correctly and using computer software such as TrueRTA to generate the test tone required in the test. You can also use TrueRTA as a kind of poor man's oscilloscope as well.

For the L-R balance adjustment Sony recommends a VTVM, aka a voltmeter with a 47K Ohm resistor across the Line Out reading the playback from a test tape with a 315Hz sine wave @ 0dB.

looking at the service manual, i have to screw everything open. perhaps i'll contact someone who has an osciloscope and a tech background.

For 19lexicon78: first using a tape with a frequency 315 Hz and 0 db. Connecting the line output of d6c to an oscilloscope with double track. You adjust the trimmers so that the two channels have the same level and at the same time so that the corresponding LED lights up to 0 db. After successful calibration, you can switch to the recording (normal, chrome and metal) by setting both the level of the input bias (always with the help of an oscilloscope with a double track). If you add the setting for the wow and flutter you get a great recorder, able to match the best desktop recorder (Nakamichi, etc.).

i will let a tech check this. give the info which is written here. i hope he would be able to repair the d6c

also bought another one, just for sure. love this walkman.