SONY MZ-R5ST Portable Minidisc Recorder Tested Working

Description

What's included:Main unit,Dock,AC adapter.No other accessories are included.
Operation has been confirmed with AA battery and AC adapter.
There were several problems. 
The LCD backlight does not seem to work. 
When I released the unit from the dock and docked it again, the power went out. In that case, unplugging the wire and plugging it in again turned the power on.  
The main unit and dock can be docked and operated with an AC adapter. There is no dedicated lithium-ion battery, so it must be connected to an AC adapter to operate.
The main unit does not have a dedicated lithium-ion battery and external aa battery attachment, so the main unit alone will not work.
The recording function of the main unit has been confirmed to work with the microphone, but the dock has not been tested.
There is discoloration on some of the plastic as shown in the 19th and 20th photos.
There is one crack on the reverse side.
For people who do not mind the above points.
Although we pack them carefully and securely, they are old items, so even if they are working properly now, it is quite possible that a slight shock during transportation may cause them to stop working properly.
I appreciate your understanding.
Please see photos carefully.