Just got this truck. Has Kenwood head (TDF 45R) and changer (KDC C504). I cannot get the changer to get power. Can't even eject the cartridge, that's with the head being powered on as well. Cable looks good and is plugged in tightly at both units. When I use the source button it will not recognize the changer, however I have found that when I tap the source button a bunch it will sometimes say CD for a second then goes back.
Is this a power issue? I tested each of the pins at the changer end of the cable and there are some signals in the 2.0 to 4.5 volt range coming out of some of them.
The research I've done leads to insufficient power, but I'm at a loss for how much is needed and generally how to test this. Is it possible to eject the cart with no power.