My 464 has no cassette motor movement on play

[Bignumbas]

My 464 boots up fine now.
But....
When I try to load/play a tape no movement.
FF and RW are ok. I have a good drive belt installed.
I have pulled the cassette deck apart. There is 5v to all the switches and out from them.
For Play the play switch opens and the other switch closes
For RW and FF the play switch is closed and the other switch is closed, direction is mechanically controlled.
This is what is indicated in the schematic.


It looks like a simple control circuit. All the components seem ok
If I manually activate the relay the play action of the motor works. Success!
The relay coil is not open circuit. I have 5v on both sides of the coil.


Anyway its all moot a bit 'cause now I find it needs a new idler wheel 'cause it slips when trying to turn the tape or not turn the tape at all, not enough friction.
Where to get one of them, part #20

[AMSDOS]

The motor won't move until you type load" or cat or run" followed by pressing any key, have you tried that?

[Bignumbas]

Thats what started this.
I typed run to test a cassette and it said press play and nothing moved when i pressed play.
So I think you are right, my problen is the idler wheel.
I just got carried away looking for an electrical fault and forgot about the run bit.

[gerald]

Thats what started this.
I typed run to test a cassette and it said press play and nothing moved when i pressed play.

it says "press play then any key" 

[Bignumbas]

Thats what I meant.
Anyway does  anybody know where I can source the part to refurbish the idler?

[gerald]

If I manually activate the relay the play action of the motor works. Success! The relay coil is not open circuit. I have 5v on both sides of the coil.

I am not sure what you mean by manually activate the relay.
Can you hear it switching when you use the RUN command and press a key ? The driving transistor may be dead.

Anyway does  anybody know where I can source the part to refurbish the idler?

Usually the tire just break and is easy to spot. However I do not know any source for replacement.

[Bignumbas]

Sorry but I made a mistake thinking I had an electrical problem, it is in fact a slipping idler wheel.
I have pulled it off and the wheel and measured it.
I make it to be 14.5mm OD x 10.5mm ID x 2mm thick.
Now the hunt is on.
I have found generic one online in Australia that is 14 x 10 x 2.1.
I downloaded a measurement chart from a US site and it measures as a nakamichi idler tyre, $5 plus freight
O-rings are maybe another option

[Bryce]

Have you tried just roughening up the rubber surface with sandpaper? That usually works.

Bryce.

[Bignumbas]

No I hadn't but it also has a crack.
Thought I might go ghetto repair like you with rubber band floppy drive belt Bryce.
I have suitable o- ring just need to make it a bit thinner.

[Bignumbas]

Finally received  replacement tape drive belt from the Motherland.
I have replaced the idler tyre with a fat O-ring that I shaved the thickness down so it fits in.

Loading tapes was failing about 5 blocks in now it fails near the end of any tape.
17 blocks in for fighter pilot. last block I think on the welcome tape.
These tapes load well on another 464 I have.
Maybe I will pull out the mechanism and scuff up the o-ring edge.

[Bignumbas]

I have now replaced the idler tyre with an 0-ring and put in a new drive belt so now the tape moves.
Now I find the jockey wheel does not push against the capstan drive.
The tape slips when in play mode so I get constant error a and b happening.
I have pulled apart the drive spindle and checked the fiber clutch pad and turned it over on reassembly
I have roughed up the wheel surface.
I have bent the spring to put more pressure on the capstan.
If I push the wheel with my finger it grips the tape properly.
The further the tape plays the heavier the drag gets so the slower it moves with the slipping clutch because the capstan is not pulling the tape at a constant speed....
When the tape gets to the end you can see the spindles starting and stopping or not turning at all if the tape is a long one like Fighter Pilot (17 blocks in)
What to do?
Is it possible to get a generic wheel somewhere?
Here is a photo of the spring tensioner  I bent and how I have to push the wheel to make it pull the tape through.

[Bignumbas]

All fixed, DUH!!!
It was the replacement drive belt for the counter being too tight. 


Took it off and all works perfectly. 


I have replaced it with a looser normal rubber band for the moment and now have a fully functioning 464 minus the "clr" key.


Kudos to Audronic for brainstorming with me over the phone.