Surface Roughness Tester Kosaka Laboratory SE-4A

Surface Roughness Tester SE-4A manufactured by Kosaka Laboratory Co., Ltd.
Analog measuring instrument for surface roughness.
Consists of three parts: tracer unit, amplifier/indicator unit, and pen recorder unit.

Item requires repair. Operation was confirmed in December 2024.
After that, it operates when the power is turned on, but the operating time gradually became shorter (with the passage of days...).
As a layman, I suspect a loss of capacitance in the power supply circuit capacitors of the amplifier/indicator unit...??
When the pickup is brought into contact with the workpiece and the RJ-41 is set and the power is turned on, it operates. The tracer and recorder are moving.
It's impressive that a measuring instrument made in 1977 is still operational! That's Kosaka Laboratory.

No repairs or overhauls have been performed. The original price was over 1 million yen, so repair costs would likely be high?...
Therefore, this is for someone knowledgeable in electronics who understands surface roughness testers.

The main ICs used are four 709HC and three 741HC. Please refer to photos 12, 13, and 14.

Power and Amplifier/Indicator Unit: SE-4A
Pen Recorder Unit: RJ-41
Tracer Unit: TR50Y6
Tracer stylus tip: 5μmR diamond, Skid: 40mmR x 2mmR sapphire

Accessories:
Measuring probes (unit price at the time was 100,000 yen): 2 included, including a spare.
Recording roll paper: 10 rolls (5 boxes of 2 rolls each, totaling 10 rolls). Calibration standard sample, instruction manual, etc.

The ink is still usable. The ink was removed from the recording needle after each use, so there are no nozzle clogs. It is an eyedropper-type ink pot.

Please make your decision after carefully considering the details in the photos.
No claims, no returns, please.