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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 2nd Jan 2020, 4:21 pm   #1
DMcMahon
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Default Uher 4000 Report Monitor Noisy

While checking out a 4000 Report Monitor I am repairing for a friend, noticed that it is very noisy on 19 cm/s tape speed, noise appears to be coming from the interface contact of the aluminium flywheel and the driving wheel. From reading various posts, sounds like it could be due to the hardened rubber coating on the flywheel which makes contact with the driving wheel (although it is quiet in the other 3 speeds).

While looking at this with the flywheel removed, I see that there is a metal clip at top end of the Sliding Control Member that looks twisted. In the Service manual the clip is identified as C in procedure 3.1.7.1 on page 23, the procedure does reference bending the clip to achieve correct (0.5mm) clearance.

Does anybody know please if this twist (as shown in attached photo) is normal/typical ? I should mention that in figure 17 that is referenced in the procedure it does look like the clip is twisted, i.e. its top long straight (somewhat tapered) sides are not roughly parallel with the long straight sides lower down the Sliding Control member.

David
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Old 3rd Jan 2020, 9:19 am   #2
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Default Re: Uher 4000 Report Monitor Noisy

Quote:
Originally Posted by DMcMahon View Post
While checking out a 4000 Report Monitor I am repairing for a friend, noticed that it is very noisy on 19 cm/s tape speed, noise appears to be coming from the interface contact of the aluminium flywheel and the driving wheel. From reading various posts, sounds like it could be due to the hardened rubber coating on the flywheel which makes contact with the driving wheel (although it is quiet in the other 3 speeds).
I have an earlier Report IC which is also noisy, or noisier on 7.5ips. The noise just seems proportional to flywheel speed.
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Old 3rd Jan 2020, 9:47 am   #3
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Default Re: Uher 4000 Report Monitor Noisy

Is it the part that is causing the noise? I would clean the rubber and see what happens. It looks to me like the part pictured is bent as it should be, which allowed the factory to take up differences in manufacturing between units. If you think the noise is coming from the flywheel it likely is.

There's a lot of information on here from people who have used various means to resurface rubber wheels in these situations. If it's entirely shot, it may be possible to replace the rubber, or get a new part from some of the German outfits that still have spares. Someone was on here recently mentioning they had bought a large array of Uher spares, too...
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Old 3rd Jan 2020, 10:05 am   #4
DMcMahon
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Default Re: Uher 4000 Report Monitor Noisy

It definitely appears to be the flywheel (rubber is not obviously in bad condition though), but seems a little odd that quiet on the other 3 speeds, although appreciate that it will be probably worse at higher speeds.

Have tried cleaning the rubber with no change. I do have some rubber restorer/cleaner spray that I also try later.

From another reply to another of my posts I see that SDS in Germany sell 4000 Report Monitor flywheels, i will ask them what condition they are (Used, Refurbished, NOS etc) and ask if the rubber on their flywheels is good/not hardened.

Many thanks for the various inputs,

David
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Old 3rd Jan 2020, 10:17 am   #5
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Default Re: Uher 4000 Report Monitor Noisy

My 4000 is in bits so I can't test if it's a possibility, but have you considered play in the wheel spindles? Perhaps at a higher speed any eccentric rotation or lack of lubrication is exacerbated? What if you put a fresh rubber band over the wheel as a test?
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Old 3rd Jan 2020, 1:08 pm   #6
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Default Re: Uher 4000 Report Monitor Noisy

I've tried rubber restorer without much success but there's no harm in trying. Eventually I had to bite the bullet and buy a new one -they are not cheap. The ones that SDS supply are new. There is also a Swiss supplier but it's much the same price.
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Old 3rd Jan 2020, 1:19 pm   #7
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Default Re: Uher 4000 Report Monitor Noisy

Do let us know how you get on with the new flywheel. I also have a noisy Report Monitor and it is due to a “groove” in the wheel caused by being left un-powered but with a speed selected.... I presume.
Good luck!
Peter
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Old 3rd Jan 2020, 5:25 pm   #8
DMcMahon
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Default Re: Uher 4000 Report Monitor Noisy

Hi All,

As always thank you for the various inputs. After email discussion with SDS (and revisiting the Service manual) I now realise that I was getting the Flywheel mixed up with the Drive wheel. The Flywheel is the Brass wheel, the Drive wheel is the Alloy wheel with capstan shaft + rubber bonding.

New drive belt has been tried with no change in noise level.

David
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Old 3rd Jan 2020, 5:27 pm   #9
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Default Re: Uher 4000 Report Monitor Noisy

Capstan shaft fine lubrication has been tried also with no change in noise level.
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Old 6th Jan 2020, 1:10 pm   #10
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Default Re: Uher 4000 Report Monitor Noisy

Information from SDS is that the 4000 Drive wheels (I mistakenly called Flywheel originally) they sell are original NOS, with new applied reformulated rubber bonding (added in Switzerland) with a quoted 5 year minimum life.
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Old 6th Jan 2020, 1:11 pm   #11
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Default Re: Uher 4000 Report Monitor Noisy

No obvious play in wheel spindles.
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Old 7th Jan 2020, 11:43 pm   #12
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Default Re: Uher 4000 Report Monitor Noisy

Noise has slowly but noticeable been getting worse over last few days and also intermittently some of the speeds will not always work (motor still running), spent quite a lot of time looking at it tonight but no real conclusions/progress.
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Old 10th Jan 2020, 4:17 pm   #13
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Default Re: Uher 4000 Report Monitor Noisy

Tried my rubber restorer spray, but unfortunately as half expected no obvious change to the rubber or noise level. My spray I think is not much more than a cleaner, not an aggressive product that attempts to roughen up the surface or add new rubber etc.

I am not 100% confident that getting a NOS Drive Wheel from SDS will fix the noise issue. As this is my first exposure to the 4000 I am not really sure if I would recognise a good Drive Wheel from a bad Drive Wheel.

The rubber is not obviously damaged or worn, it is somewhat hard (all of this is somewhat subjective to me) but I do not know how soft, good rubber is on these Drive Wheels.

If the 4000 was mine I would have bitten the bullet days ago and got another Drive Wheel, but because it belongs to a friend, I am currently reluctant to get a replacement one until I exhaust all other possibilities. If the new Drive Wheel did not fix the problem I would then feel really bad asking my friend to fork out over 70 for it !

First still want to check out 2 other issues in case they relate in any way to the noise generation. 1. The inconsistent operation/selection of speeds and 2. When top speed is selected the flywheel makes contact and drives the Drive Wheel without "Start" being pressed.

For # 2 there is a set-up procedure in the manual but am struggling with that.
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Old 10th Jan 2020, 7:28 pm   #14
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Default Re: Uher 4000 Report Monitor Noisy

The drive-wheel-capstan shouldn't be in contact with the brass flywheel until the start button is depressed which tilts the brass flywheel to make contact with the drive-wheel-capstan. Perhaps there is a problem with the linkage between the start button and the brass flywheel. Perhaps the continuous contact has produced a flat in the rubber of the drive-wheel which would produce noise.

Last edited by barretter; 10th Jan 2020 at 7:32 pm. Reason: Spelling mistakes
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Old 10th Jan 2020, 8:23 pm   #15
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Default Re: Uher 4000 Report Monitor Noisy

It was only doing it (consistently) on the top speed, 19.5 cm/s, fine on the other 3 speeds, so I think linkage is good.

The set-up procedure for this states on speed 9.5 cm/s to adjust the C flap for approximate 0.5mm gap between the flywheel and the Driving Wheel with the Start key not depressed.

Personally I cannot see the actual gap or find any practical way of measuring it.

After numerous adjustments to the C flap now working OK in terms of the contact only occurring when the Start key is depressed, apart from occasionally/intermittently some speeds still not working. When this occurs can get them working (at that time) by light pressure on the flywheel assembly. Presently trying to measure the pressure of the flywheel onto the Drive Wheel as per procedure 3.1.7.2

The procedure says the pressure should be 75 p - 85 p, adjusting spring tension if required by bending strip F.

I assume p is pounds (lb) or more technically accurate pounds-force (lbf). I do not have an imperial spring balance, but do have Metric ones in Newtons/grams, so will do the conversion calculation required. Very difficult to hook in spring balance to measuring point E as described. There is a metal bracket (that the top of the amplifier board hinges on) in in the way.

Bracket can probably be removed but still think will not be able to hook on balance, probably will be able to secure some string/fishing line/ty-wrap etc at point E to connect the balance onto.

No real change to the high noise level on top speed during all adjustments.

Last edited by DMcMahon; 10th Jan 2020 at 8:25 pm. Reason: Extra information
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Old 10th Jan 2020, 11:37 pm   #16
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Default Re: Uher 4000 Report Monitor Noisy

Both my Uher Report and my Akai X4 machines have gone the same way: hard rubber ring leads to noisy drive.

That's the first stage. Next, when the ring goes even harder, drive becomes unreliable, but that takes a lot longer.

It depends on the use the machine is put to. Most would probably use such a machine to transfer old recordings. If the drive is still good, it will do the job perfectly. In the electrical audio signal the mechanical noise from the hardened rubber ring shouldnt be audible.
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Old 11th Jan 2020, 12:34 am   #17
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Default Re: Uher 4000 Report Monitor Noisy

Thank you for those inputs. Unfortunately my friend who owns the 4000 likes to do a lot of microphone recording and from a couple of microphone recording tests I have done, the recorded noise is noticeable.

I have not yet had a chance to do any more investigations, but having just done a quick conversion calculation from ibf to Newtons, realise that something is incorrect, as the average of 76 - 85 ibf is around 360 Newtons which is far too high (I thought 75 - 85 ibf sounded high) ?

It is certainly sounding like a NOS Drive Wheel may be the only way forward to improve the noise level. There are some second hand ones on eBay.de where they say they are good condition, but that is probably a large risk.

Last edited by DMcMahon; 11th Jan 2020 at 12:35 am. Reason: Correcting 80 to 85
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Old 11th Jan 2020, 11:59 am   #18
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Default Re: Uher 4000 Report Monitor Noisy

Grams....?

Lawrence.
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Old 11th Jan 2020, 12:10 pm   #19
DMcMahon
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Default Re: Uher 4000 Report Monitor Noisy

Hi Laurence,

Yes grams would seem the most logical but why do Uher give the units as "p" ?

I saw in the 4000 Report IC Service manual, one setting (a different procedure) of 20 p to 40 p where it was followed in brackets by (0.8oz +/- 0.1 oz).

Conversion of 0.8oz gives around 23 grams.

I will try and measure it later to see what it currently is, then try adjusting the spring tension to see if decreasing/increasing the tension has any effect on the noise level.

David
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Old 11th Jan 2020, 12:19 pm   #20
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Default Re: Uher 4000 Report Monitor Noisy

Pond...(kilopond) ?

When I worked for Sony servicing tape decks tensions given in the manuals were always in grams or ounces.

Lawrence.
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