Uher CR 240 AV Problem

[John K S]

Hi,
I just purchased a a UHER CR 240 AV casette player at the local flea market; no batteries, power supply, nor microphone.
I have arranged a 12 Volts direct current power supply, and when turned on (by the volume pot.), the VU meters light up, as does the orange LED.
After inserting a casette tape and pressing the rightmost push button down, I can hear the motor running - not noisy, but you can hear that something mechanical inside is at work.

When I then push the uppermost button(Pause-Stop-Start) to "Start", there is a sound of a relay clicking inside (I think) and the green LED (the one with the above arrow pointing to the right) lights up shortly - for less than a second whereafter it goes out.

I had expected that the thing would play after these maneuvers, but it does not. Does anybody have a clue as to why?

[paulsherwin]

I don't know this mechanism well, but at 40 years old it's likely to need a replacement main capstan belt at the very least.

[DMcMahon]

From my experience of my CR 240 there is a good chance that the belt that goes to the motor pulley is either well stretched or broken resulting in no drive to the flywheels

https://www.google.com/url?client=in...T3T3vzrKAuhXbd.

David

[DMcMahon]

The motor pulley is item A on the attachment.

Regards

David

[DMcMahon]

This video clip includes some good information on replacing the drive belts.

It is for the CR 210 but for the belts is basically the same as the CR 240

https://www.youtube.com/watch?v=H1ZiJdpKHKc.

David

[Uncle Bulgaria]

The broken belt gets my vote too. The 'click' is the play solenoid engaging, then automatically stopping as the drive reel is not rotating so the machine thinks it's at the end of the tape.

Look through the window on the top and see if the tape spindles are rotating. You can hold the joystick in the 'play' position to keep it running. If they aren't rotating then the belt's gone.

You can see the belt reasonably easily if you take the top cover off which is held with half a dozen or so screws (careful to disconnect the loudspeaker wires as you lift the cover away). You can also operate the machine with the cover off which makes it easier to see what's happening.

[John K S]

Thank you very much for your suggestions: the symptoms I have resemble very closely what DMacMahon has described in his link to the forum page.

I have ordered new belts. In the meantime I will scrutinize the video link suggested by DMacMahon, as it seems quite tricky to get near the main belt without using violence.

The belts will arrive in about ten days. Hopefully, I shall be reporting progress by then.

[Uncle Bulgaria]

The key part from the manual is attached.

[DMcMahon]

Originally Posted by John K S

I have ordered new belts. In the meantime I will scrutinize the video link suggested by DMacMahon, as it seems quite tricky to get near the main belt without using violence.

Depending on your experience with working on similar equipment it certainly is not easy to fit the main belt, mainly just very fiddly/awkward.

David

[Uncle Bulgaria]

Hooking it on pin 'B' is a must!

[DMcMahon]

I think I am correct in remembering that my CR 240 did not have pin B.

David

[DMcMahon]

Reference above Post I think I hooked the belt over a nearby capacitor.

David

[John K S]

Thank you very much for your advice.
I received the belts and managed to replace them; the main belt was in two pieces.

However, there were - and are still - mechanical problems. One of these concerns the casette loading mechanism. Although I did as suggested in the video (thank you for the link!), it did not quite work as intended. After many hours I saw the remains of a broken spring in the lower right part of the recorder. It was probably once attached to a pin fastened to the housing of the counter in one end, and the other end would probably have been mounted on an L-shaped moveable thing, whose function I have not yet grasped, but the function of the spring is probably to pull the top of L-shaped thing towards the front of the recorder.

When turned on the motor starts - sometimes. When it starts, which is not always, it moves the brass wheels in sudden steps of perhaps turning 20 degrees at a time, and after about 30 seconds the wheels are spinning at a steady pace - if you are lucky. I have not yet found out what makes an impact on this behaviuor

With the cassette loading mechanism out I thought I could just insert a tape, but the heads have to be retracted in order to do that. I assume that the loading mechanism is responsible for retacting the heads.
However, I managed to get a tape in place and start the tape rolling and playing: and it did not sound all that bad, so something is at least working.
I will try to get hold of a new spring and see if it helps, but at present the sleigh thing at the bottom of the resorcder seems to be stuck, and I do not like to use brute force.

Best regards, John K.

[DMcMahon]

Unclear to me what the "sleigh thing" you reference is ? can you post photo (s).

David

[Uncle Bulgaria]

Have you made sure the pins on the cassette head mechanism were properly engaged with the unloading mechanism?

The white plastic spring-loaded head piece must hook over the pin circled in the photograph. This retracts it when ejecting a cassette.

The brass gate hooks over the pinch roller spindle to ensure it retracts as well.

There's a small spring on the lower right when looking at the front of the mechanism, circled in the photograph. Is this the one you mean?

The mechanism can be checked as per the attached service manual instructions section 1.2, by sliding 'A' and 'B' to make it believe there's a cassette inserted.

If you've taken out the cassette loading mechanism, make sure the lower right slider is pushed back to allow the mechanism to be seated properly as you reassemble. I think it's the part marked 'K' in the diagram.

[DMcMahon]

Yes looks like the spring in question is the one circled in photo 3 above, also looks like it is item F in the diagram above, which looks like it connects onto the slider K that is referenced above.

David

[DMcMahon]

Dug out my CR 240 and removed the cassette lift assembly to better see the spring in question, it does connect onto small pin at the tape counter and the other end of the spring onto the vertical piece of the slider.

Previous references in this Thread to the slider called it "K" but looking at the procedure it is actually "I", "K" being the Pawl, the Pawl is the piece to the right of the vertical piece of the slider that pivots a small amount and pushes down onto the flat black sprung plate when the slider is pushed fully forward (which as Uncle Bulgaria references needs to be done when refitting the cassette lift).

Pushing the slider forward retracts the heads assembly. The purpose of the spring is unclear, with cassette lift removed it does as stated above pull the slider towards the front of the unit, but the spring tension on the heads assembly mechanism is stronger and I think on its own (with cassette lift removed) would push the slider forward even when the spring is not fitted.

With cassette lift fitted it is very difficult see/work out what the spring might do.

I was very surprised and disappointed to find that my flywheel to take up spool and tape counter drive belts are broken and I think there are cracks in the supply spool drive belt. All these belts were renewed in July 2020 ?

David

[John K S]

Thank you very much for your responses, in particular for the images. I am afraid they do not quite match what I have. Perhaps I am missing a part or two. I try to attach pictures

Regards, John K.

[DMcMahon]

Generally looks the same as Uncle Bulgaria images.

Mine do not have the heads assembly removed so different view.

David

[Uncle Bulgaria]

What doesn't match, John? Your pictures look good to me. The plastic head piece appears to be correctly hooked over the retracting pin, and the pinch roller spindle is retained by the brass gate.

I see you have two problems: heads not moving as expected, and motor running intermittently.

Motor Only runs when a cassette is inserted and locked by pushing the eject lever down. You can get the motor to run at will with the ejecting assembly removed if you press switch bank K3 in the picture in post #15. The switch banks K3, K4, K5 operate the motor; solenoid(s) to hold the heads and pinch roller in 'play'; and, if 'record' is engaged, the motor will stop if you open switch K4.

Eject/Cassette Lift If the eject mechanism is still not working, the problem must lie with the front right bottom corner, where the small spring is. Can you post a picture of that, or better a video (use a file sharing service like wetransfer or a DropBox link)?

It won't work unless the linkages under the cassette eject slider knob are correctly engaged. The gold-coloured piece with the spring attached in the bottom right corner of the photograph must be pushed all the way back before inserting the cassette lift mechanism. I use a small screwdriver to push it from the front, then align the two holes and screw the chassis to the lift mechanism.