The Tascam CD-500B is one of a sadly quickly dying breed — a professional grade CD player, with balanced audio output (and AES/EBU digital) as well as RS-232 and contact closure remote control. Unfortunately, it features some very non-professional grade buttons on the front panel. I don’t even understand what on earth they were thinking.
Symptom: Buttons “fall” into front panel. Operation of button is impossible.

Problem: Thin plastic hinge section of button has broken.
Solution: Wedge button in place from below so it’s trapped between the front panel, the wedge, and the switch on the circuit board.
Disassembly of the player: This player is truly and sadly built like total BPC (Black Plastic Crap). You have to remove the rack ears, top cover, and the entire front panel. Carefully release the wires going to the front panel and unscrew the one visible grounding jumper. Unplug the two multi pin connectors (they cannot be mixed up – different number of pins). Remove all the silver screws around the front of the player and release the tabs on the right and left sides, then drop the front forward. Remove two screws holding in the LCD, then you can unscrew and remove either button board as needed.
Wedge the broken button(s) from below, then set them into the front panel with it tilted downwards and reassemble.
It is worth noting this player uses what appears to be a standard slotload SATA cd-rom drive as its transport! I have not tried substituting drives yet to see what happens. The buttons break before the transport 🙂
Do you know the manufacturer’s part number for the pushbutton switches themselves, and where they might be had?
Sorry, I don’t – however they should be a pretty generic tact switch if I remember right.
Okay I’m sorry, I should have said “oops, they’re weirder than hen’s teeth”. Some custom looking round tact switch with two through hole leads??
I’d say order a few of these, file down the plungers as needed.
I found this part with the Digi-Key mobile app. https://www.digikey.com/product-detail/en/Panasonic+Electronic+Components/EVQ-11U09K/P8085STB-ND/259538