Denon DRM-22 issue

[Leicabimmer]

I’m having an issue with my Denon DRM-22 cassette.When there is no tape in the deck, play/ff/rw as well as record all work regardless if the door is open or closed. In both cases the head block(pinch rollers) rise up quickly and make contact with the capstans. When in play mode the take up/right spindle spins counterclockwise.It is very difficult to stop the take up roller. When I install a tape the head block does not respond at all, no clicks,no hesitation no indication at all the play button has been pressed. Same for rr/ff. The deck has only 1 belt which is attached to both capstans. Looking at the service manual I don't see a tire so I have to assume the rest of the mech is geared. I received this unit as-is which had clearly had been tampered with and appears to be hastily reassembled as evidence by the missing screws in the chassis and the eject assembly not being properly assembled. Is it possible to improperly mix up the electrical connections on the board? Any body have any ideas?

 

[duncan]

Looking at the service manual I don't see a tire so I have to assume the rest of the mech is geared.

On page 21 of the manual, it looks to me like part #31 is the upper idler, and that it has a rubber tire rather than a gear, and probably contacts the reels (labeled #25) directly.

When I install a tape the head block does not respond at all

I'm having some trouble making sense of this description. Are you saying you can make it go into play mode with no tape inserted, and then you can't when a tape is inserted? A video might be helpful. If you want to see more of the mechanism in action, you can try removing the plate labeled #76, same page in the manual.

 

[Leicabimmer]

Thanks for the input. Here are the 2 videos showing with and without tape inserted,

https://m.youtube.com/watch?v=oaWEbt17u1g

 

[duncan]

Look for a 2-pin connector near the middle (or the "elbow," since it's ell-shaped) of the power supply board, possibly labeled CN4. Is the plug jammed in there wrong somehow? Like, backwards, or off to one side or the other?

 

[Leicabimmer]

Look for a 2-pin connector near the middle (or the "elbow," since it's ell-shaped) of the power supply board, possibly labeled CN4. Is the plug jammed in there wrong somehow? Like, backwards, or off to one side or the other?

Hi- I found CN4 and all seems right with it, traced it back to the cassette module and seems ok there as well. I unplugged it while in play mode without a cassette and it had no effect.-

 

[Leicabimmer]

Look for a 2-pin connector near the middle (or the "elbow," since it's ell-shaped) of the power supply board, possibly labeled CN4. Is the plug jammed in there wrong somehow? Like, backwards, or off to one side or the other?

It seems like the 3 position switch above the cassette is somehow the culprit which makes your suggestion make sense as it’s connected to CN4

 

[duncan]

Okay, any chance you've got the cable for CN2 plugged into the CN4 socket and vice versa? If so, it would be misinterpreting the record-protect switch as the eject switch.

Not sure if it's physically possible to get that wrong, maybe they've got the plugs keyed to prevent it, but it's worth checking.

 

[Leicabimmer]

Okay, any chance you've got the cable for CN2 plugged into the CN4 socket and vice versa? If so, it would be misinterpreting the record-protect switch as the eject switch.

Not sure if it's physically possible to get that wrong, maybe they've got the plugs keyed to prevent it, but it's worth checking.

Dude! Dude! Dude! You nailed it! It’s working perfectly. When I received it I kind of suspected
there could be more issues than just the motor as the seller was very vague about the overall condition. Judging by the rats nest wiring it was bound be trouble. Again can’t thank you enough.

 

[duncan]

Aww shucks, 'tweren't nuthin'.