Uher 4000 Report Monitor Noisy

[DMcMahon]

Yesterday afternoon went to the South Coast Blues Jam where my friend used the 4000 to record sections of the various bands that were playing.

I say bands, I think the only actual band was the House band, the rest of the bands were made up from the various musicians that wanted to get up and play (like a music open mic event), which worked really well.

Will be interesting to hear the recordings.

[DMcMahon]

While borrowing my friends 4000 to check out why my 4000 was struggling with FFD & RWD, I swapped over the Drive Wheels between the 2 machines.

I had previously (earlier in this Thread) suspected that the root cause of the noise was maybe due to the Drive Wheel.

Swapping them over swapped the noise symptoms over, i.e. my 4000 then became the noticeably noisier one and his 4000 became the noticeably quieter one when playing at 7.5 ips.

No obvious difference in the rubber bonding coating condition between the 2 drive wheels.

Whether the noticeable noise improvement would warrant a recommendation to get a NOS Drive Wheel (with improved rubber bonding formulation) is debatable at around £100.

My 4000 although noticeably quieter, is far from silent, so maybe it also could benefit from a new (NOS) Drive Wheel ?

David

[DMcMahon]

While I was refitting the Drive Wheel back into my Friends 4000, I dropped one of the two securing shoulder screws for the Bearing rail and could not easily find it. When I shook the unit I could heard the screw rattling around somewhere but took a quite while to locate it.

It had fallen though a hole in the rear of the front panel metalwork and was rattling behind the actual front panel.

This was a bit of a nuisance as took time locating it but maybe a little fortuitous, as while searching for it I saw that a fairly large relay (large for the relatively small size of the unit) was very loose, its one securing was about to fall out from its hole, so tightened the screw down.

Have yet to work out what the relay does, it does not energise during normal operations ?

[DMcMahon]

Have deduced that the relay above is for Remote Pause control, the 4000 Pause lever just does mechanical pause by lifting the Pinch Wheel away from capstan shaft. The relay, energised from remote signal connected to pin 4 of the 6 pin "Accessory Input" D type connector (via some NAND gates and switching transistors) additionally removes power from the motor. Uher call this MIDE but I do not know what MIDE stands for ?

This relay appears to be designated as "A", the schematic shows a second relay coil also designated as "A" driven/energised from part of the same circuitry.

I cannot easily see any relay contacts for either of these relay A coils ?

[ms660]

I haven't got a schematic for this machine but the relay will be a mechanical relay, the two coils are for the actuating (initial inertia) and holding, the holding coil will have the higher resistance of the two, the holding coil will be on all the time the input to the 1st nand gate is held at zero and the actuating coil will be operated only for a short time after the 1st nand gate input has gone to zero.

Lawrence.

[barretter]

Originally Posted by DMcMahon

Have deduced that the relay above is for Remote Pause control, the 4000 Pause lever just does mechanical pause by lifting the Pinch Wheel away from capstan shaft. The relay, energised from remote signal connected to pin 4 of the 6 pin "Accessory Input" D type connector (via some NAND gates and switching transistors) additionally removes power from the motor. Uher call this MIDE but I do not know what MIDE stands for ?

I found this on eBay so perhaps MIDE is an acronym starting with "Mikrophon"?

[DMcMahon]

Originally Posted by ms660

I haven't got a schematic for this machine but the relay will be a mechanical relay, the two coils are for the actuating (initial inertia) and holding, the holding coil will have the higher resistance of the two, the holding coil will be on all the time the input to the 1st nand gate is held at zero and the actuating coil will be operated only for a short time after the 1st nand gate input has gone to zero.

Lawrence.

That is very good analysis Lawrence without a schematic !

Yes one coil is 260 and the other 11 ohms. Wish I could see the relay contact (s).

David

[DMcMahon]

Originally Posted by barretter

I found this on eBay so perhaps MIDE is an acronym starting with "Mikrophon"?

Yes the Remote Pause signal control input at pin 4 of the Accessory Input D type is also connected to pin 7 of the Mikro/AV 8 pin D type and with a suitable microphone with a remote pause switch fitted, Remote Pause can be controlled from the Microphone.

So possibly M = Mikrophon.

David

[ms660]

Originally Posted by DMcMahon

That is very good analysis Lawrence without a schematic !

Yes one coil is 260 and the other 11 ohms. Wish I could see the relay contact (s).

The schematic I have is for the 4200 Report Monitor.

The manual for the 4000 Report Monitor that I have doesn't include the schematic.

Pull and hold circuits are quite common for solenoids.

Lawrence.

[DMcMahon]

I would imagine the 4200 schematic is the same for this area of circuitry.

I should have "latched" onto the 2 coil operation still trying to find the associated contact (s).

David

[ms660]

Why would there be any contacts?

Lawrence.

[DMcMahon]

I was assuming it was a relay with contacts and one or more of its contacts disabled the motor power.

You are saying it is a solenoid so somehow mechanically disables the motor, that would explain why I can see no contacts on the schematic.

Sometime later today I will energise it and see what it does.

David

[DMcMahon]

And of course you had said Lawrence at Post 45 that it will be a mechanical relay, at the time of first reading I had missed the word "mechanical".

[ms660]

Looking at the 4200 Monitor schematic I have in conjunction with the 4000 Monitor manual (that's minus its schematic) there is no connection to the motor, the solenoid just operates the pause mechanism by remote means, ie: by grounding the input to the first nand gate.

EDIT: Post crossed.

Lawrence.

[DMcMahon]

Hi Lawrence,

I do not disagree with what you are saying but from at least 3 different sources the MIDE operation reads as "stopping the motor" in addition to operating Pause mechanism. The Pause mechanism (at least from the Pause button) just lifts the Pinch Wheel away from the Capstan shaft and the motor keeps running when pause manually selected.

So the bit I do not yet understand is how is the motor stopped, hopefully later when I energise the solenoid things will become clearer.

David

[DMcMahon]

Tested the solenoid operation by linking pins 4 and 6 at the Accessory Input (also referred to as Remote Control) DIN connection.

Pause is actuated by mechanical linkage and tape stops (due to Pinch Wheel moving back off the capstan shaft), but the motor does not stop. The Remote Pause yellow LED on the front panel lights up.

So 3 main possibilities:-

1. Normal operation, motor should not stop.

2. Not normal, motor should stop so maybe a fault.

3. Normal operation, motor should only stop if extra MIDE hardware fitted.

Due to various Motor Stop references having been seen previously I am tempted to think #3 may be a possibility.

I will seek clarification on this and the meaning of MIDE from SDS.

David

[Uncle Bulgaria]

I believe the motor should keep running, presumably to keep speed wobble to a minimum as it's likely 'play' is going to be engaged shortly. On the CR 240 (even on battery power) the motor runs as soon as a cassette is inserted, and keeps running on pause and stop. It's plausible that this is a method carried over from the earlier Report models.

Does your friend's do the same thing, if you still have access to it? Is the external socket something to do with the F411 Akustomat or similar attachments used for remote stopping and timing of the recordings? Perhaps the motor indeed stops on some of these to save power on long monitoring runs.

[DMcMahon]

Yes my friends 4000 operation is identical, the Remote Pause just pausing the tape not stopping the motor, so largely ruling out my suggested possibility # 2.

Yes the Akustomat does connect to the Accessory Input DIN, I did wonder about how the Akustomat works in relation to motor stop but not really able to find the low level technical details for Akustomat working.

[ms660]

There'll be a relay in the unit, the contacts will be connecting pin 4 to ground when audio isn't detected.

Lawrence.

[ms660]

Update, connects pin 4 to 3 in a schematic I'm looking at (F411):

https://elektrotanya.com/uher_f-411_.../download.html

Description here:

https://worldradiohistory.com/hd2/ID...-Page-0011.pdf

Lawrence.