Philips/ Marantz relays.

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The CD104 uses reed relays, reed switches actuated by an electromagnetic coil. They are a normally open type, and are in series with the audio output, so they must be energized and successfully close for music to be output.

Here are a few things I would check:
- Is the coil getting a drive voltage? It should be low when the player is off and should go high a short time after the player is turned on.
- Is the coil still intact? Check the resistance of the coil in case it has gone open.

If both of those checks don't shed any light, remove the reed switch. It may be corroded out or seized. Sometimes a sharp tap will free a seized reed (not to hard though, it is glass), but if it is badly corroded it'll need replacing.

At the end of the day, you can just bypass the reed relays. You'll get a pop and / or thump at startup and shutdown, but that's not a huge problem.
 
Sorry, I just checked the service manual, they are reed relays indeed. You can check them with a magnet, you should hear a clicking sound when you move the magnet over the relay. The deemphasis relays are the same so you can replace the kill relay with the deemphasis relay, the latter not being used only in very rare cases.
 
Thanks for the help.
The electronics are ok as I have tried other relays in the circiut.
The faulty relays work on one side when connected to a 9v battery (out or circuit), the other side is dead.
I have spares, but wanted to know if they can be repaired or if there is a suitable replacement, either old school or a modern eqivalent.
Many thanks
 
Okay, with this player a single channel fault is definitely due to the reed switch itself, as the actuating coil is common to both channels. I would remove the bad switch and replace it with a new equivalent. There are many types available from Farnell, starting from $1.70.

There are modern replacements, but they use different packages, so won't be nearly as easy to fit as one new reed switch.
 
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