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Old 9th Nov 2020, 5:55 pm   #1
orangethecolour
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Default Uher 4000-L - Number of issues

Hey everyone

I recently acquired a Uher 4000-L after wanting one for ages. The unit is in pretty good condition, however there are a few issues, that I believe could all be related in some way, that are inhibiting the use of the machine.

Upon receiving, the unit would play, record, fast forward, but not rewind. Also the pause button does not work.

In regards to the pause, pressing the button pulls the pinch roller back away from the capstan, but the take up reel continues to rotate, so something is obviously amiss with the way that the braking system should work here?

That's my first issue.

The second is that the rewind is very slow, if any at all. I believed this could be an issue with friction wheels on the see-saw but they don't appear to be very worn, unless of course they are supposed to be black instead of white and there for they are very very worn ? haha.

The third, and most pressing issue, is that the wow and flutter is crazy, the speed of the unit is here there and everywhere. Recording results in huge dips and spikes of pitch, the unit is obviously not running at a constant speed. Could this be caused by the wearing down of the rubber on the capstan fly wheel? It looks like this is very worn. I don't want to buy a new one yet though if the speed issue is not going to be caused by this.

I'm not amazing with these things but i've fixed a couple of B&O Beocord machines and don't mind getting my hands dirty.

Any ideas where to look, or how to begin fixing any of the above issues would be amazing. I've attached images of the fly wheel, friction wheels and the pause mechanism, but please let me know if any other images would be helpful.

Thanks so much,
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Old 9th Nov 2020, 9:17 pm   #2
DMcMahon
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Default Re: Uher 4000-L - Number of issues

Hello and welcome to the Forum.

Does rewind work with no tape loaded ? it should have a reasonable amount of driving torque if you try to manually hold the Supply reel table.

David
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Old 9th Nov 2020, 9:52 pm   #3
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Default Re: Uher 4000-L - Number of issues

Somewhere I have one with a knackered motor, think moisture had got to it. Does yours start up okay, run well with sufficient torque?
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Old 9th Nov 2020, 10:14 pm   #4
orangethecolour
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Default Re: Uher 4000-L - Number of issues

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Originally Posted by DMcMahon View Post
Hello and welcome to the Forum.

Does rewind work with no tape loaded ? it should have a reasonable amount of driving torque if you try to manually hold the Supply reel table.

David
Thank you and hello!

Rewind works with no tape loaded yes. It has quite a bit of torque.

I've just now tried playing a tape without the take up reel and the tape plays normal speed, without any issues. As soon as its got the take up real, it has drastic speed problems.
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Old 10th Nov 2020, 12:09 am   #5
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Default Re: Uher 4000-L - Number of issues

That is a good diagnostic. The driving torque in Play mode is fairly minimal just enough to collect/wind the driven tape onto the Take Up spool, so normally should not upset the playback speed.

Suggest you remove the top plate and check the brakes on both reel tables are releasing correctly and then check that both tables can be manually fairly easily rotated in both directions when Play, FFD & RWD selected. For RWD (Rewind) the Supply table rotation will be somewhat stiffer as it then will be driving against the see-saw drive and correspondingly for FFD (Fast Forward) the Take Up table rotation will be somewhat stiffer as it then will be driving against the see-saw drive.

If nothing obvious found then suggest you check things out to the service manual, like the clutch set-ups. Sounds OK from your results above but double check that the tape is making good contact with the capstan shaft in Play mode, the pinch wheel is not loose and the heads are really clean.

David
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Old 10th Nov 2020, 10:25 am   #6
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Default Re: Uher 4000-L - Number of issues

Quote:
Originally Posted by DMcMahon View Post
That is a good diagnostic. The driving torque in Play mode is fairly minimal just enough to collect/wind the driven tape onto the Take Up spool, so normally should not upset the playback speed.

Suggest you remove the top plate and check the brakes on both reel tables are releasing correctly and then check that both tables can be manually fairly easily rotated in both directions when Play, FFD & RWD selected. For RWD (Rewind) the Supply table rotation will be somewhat stiffer as it then will be driving against the see-saw drive and correspondingly for FFD (Fast Forward) the Take Up table rotation will be somewhat stiffer as it then will be driving against the see-saw drive.

If nothing obvious found then suggest you check things out to the service manual, like the clutch set-ups. Sounds OK from your results above but double check that the tape is making good contact with the capstan shaft in Play mode, the pinch wheel is not loose and the heads are really clean.

David
Cheers David. Upon checking this, the brakes are fine and are releasing properly. However, in play the take up table is not turning freely. It will turn, but with more force than the supply table, it seems like it might be touching the see-saw ever so slightly as this rocks a little when i turn the take up table. Does this sound like a clutch issue? Or shall i adjust the see-saw first to eliminate that as a potential cause?

Thanks!
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Old 10th Nov 2020, 1:07 pm   #7
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Default Re: Uher 4000-L - Number of issues

Quote:
Originally Posted by orangethecolour View Post

In regards to the pause, pressing the button pulls the pinch roller back away from the capstan, but the take up reel continues to rotate, so something is obviously amiss with the way that the braking system should work here?

The third, and most pressing issue, is that the wow and flutter is crazy, the speed of the unit is here there and everywhere. Recording results in huge dips and spikes of pitch, the unit is obviously not running at a constant speed. Could this be caused by the wearing down of the rubber on the capstan fly wheel? It looks like this is very worn. I don't want to buy a new one yet though if the speed issue is not going to be caused by this.

I assume when you say the Take Up reel continues to rotate, this is with a tape loaded, obviously this should not happen and may be linked/a clue to the wow issue but not sure what.

Worn or hardened rubber on the flywheel (Uher call it a drive wheel, they call the brass part the flywheel) could certainly cause W & F symptoms, but your symptoms possibly sound more serious than just W & F.

NOS drive wheels are expensive so is not something you can just easily try without great expense.

There are procedures in the Service manual under Speed selector that cover clearance adjustment of the drive wheel to the flywheel treads, this has to be correct for proper contact between the two when Play is selected. Cannot easily see it in the 4000L manual but in the 4000 Report Monitor (which I more familiar with) manual there also is an adjustment for the contact pressure between the 2 wheels.

David

Last edited by DMcMahon; 10th Nov 2020 at 1:14 pm.
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Old 10th Nov 2020, 2:55 pm   #8
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Default Re: Uher 4000-L - Number of issues

Hi David

Yes, this is with tape on the machine, the take up table continues to spin when the pause button is pressed. It also does the same when tape is not present.

I've checked the clearance between the drive wheel and flywheel and all looks good there.

I believe this has to be some kind of clutch issue with the take up table. I'm going to attempt to adjust this and see if it makes a difference.

I've added a video here that shows the problems a little better than just words and photos - https://youtu.be/LJQpKO9QCBs

Last edited by orangethecolour; 10th Nov 2020 at 3:16 pm. Reason: spelling
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Old 10th Nov 2020, 6:57 pm   #9
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Default Re: Uher 4000-L - Number of issues

Your video certainly clearly demonstrates your described symptoms.

It is normal for the Take up reel table to rotate with no tape loaded and Pause selected, I assume you can quite easily stop it rotating with a finger.

I think I am correct in saying that there will be contact between the underside of the Take Up reel table and the see-saw drive in Play, as this is what provides the Take Up drive.

I do not fully understand all the possible symptom causes but do think some of it could be reel table clutch/tension related. I assume you have checked your drive belts are not stretched/slipping.

David
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Old 10th Nov 2020, 8:05 pm   #10
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Default Re: Uher 4000-L - Number of issues

Thanks David. I have changed all the belts since receiving the machine so there shouldn't be any issues there.

I attempted to make some changes to the clutch system following the service manual today however the issues are still present. I will have another go this evening.

When looking that the pause mechanism, I can see what it's doing by pulling the pinch roller away from the capstan, however, what I don't see is how the mechanism would stop the take up table from spinning when pressing pause, it's almost as if something is broken or missing from the pause mechanism itself that would either engage the brake or lift the see-saw of the drive wheel of the take up table.
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Old 10th Nov 2020, 9:26 pm   #11
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Default Re: Uher 4000-L - Number of issues

As I said in Post 9 it is normal for the Take Up table to rotate (with Play/Start selected) with no tape fitted when Pause is selected. Normally there is not enough torque on the Take Up table when tape is fitted for the Take Up table to rotate with Pause selected.

David
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Old 28th Nov 2020, 12:25 pm   #12
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Default Re: Uher 4000-L - Number of issues

Hey everyone

Update on this. The issue with the pause not working has now be rectified. The felt was missing from the piece of metal that presses the tape up against the play head, because of this, there was not enough pressure to hold this in place when pause was selected. I replaced this and now the pause works.

I still have an issue with slow speeds.

If I play a tape without the take up spool, the speed is fine. As soon as the tape is feeding in to the take up spool then the speed is very slow. I have tried stopping the take up spool with my hand during playback, however the speed remains the same. It's only when the tape is not being fed on to this spool at all that the issue is no longer there.

Could this be an issue with the pinch roller? The pinch roller is rock solid and obviously should be soft. However, the fact that it plays at a normal speed without the take up spool being used leads me to think that it must be something to do with the take up spool. Obviously I have tried adjusting the clutch, and the brake mechanism to no avail.

Any ideas what to try next in order to remedy this issue?

Thanks so much
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Old 28th Nov 2020, 2:56 pm   #13
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Default Re: Uher 4000-L - Number of issues

Have you cleaned all the rubber parts thoroughly? I can't give first-hand advice as both my Report-Ls are inaccessible at the moment, but I know that the rubbers can provide all sorts of odd symptoms. Especially if your wow and flutter is crazy as you say, that's the obvious place for that to come in.

You could try roughing them up for extra grip as well. The rubber rejuvenator products have varying reports on here, and perhaps someone with more Uher experience like DMcMahon will be able to say whether the particular rubber used by Uher is receptive to this treatment.

I've just replaced the pinch roller on my Uher CR 240 which was the cause of my speed issues, despite the speed having been fine three months ago. I'd discounted it because of it working recently, and was chasing imaginary gremlins around the clutch and tension systems.

Some spares sources are:
SDS Consult
Johann Gruber's Uher Service
Uher Classic Service

I've bought parts from all these, from original manuals to the plastic spiral catch that holds the 4000 Report-L's bottom cover on. If investigations into the rubber parts prove they're the problem. perhaps between these outfits some new bits might not be out of the question.
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Old 28th Nov 2020, 3:21 pm   #14
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Default Re: Uher 4000-L - Number of issues

I've actually just received another uher 4000 in the mail that's working perfectly, so I used that as a guide to work out what the issue was.

Turns out, it was a clutch issue! I completely disassembled the clutch and the small felt disk that is inside had shifted (looks like the glue had melted and the felt disk had moved) so that the side of it was rubbing on the plastic internally. I cut away the access that was hanging over the side and put it back together and now there are no speed issues at all!

The pinch roller definitly needs some love so i will try some rubber restorer on it to see if that will bring it back to life. To be honest, the whole pinch roller assembly looks like a nightmare to remove in order to change the pinch roller

Anyway, thankful to report that this machine is now working almost perfectly. Just a rewind speed issue now but I can bear with that and give it a little help with my hand. Thank you for the website recommendations Uncle I will be sure to check those out for any spare parts needed!

Last edited by orangethecolour; 28th Nov 2020 at 3:23 pm. Reason: spelling
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Old 29th Nov 2020, 11:07 am   #15
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Default Re: Uher 4000-L - Number of issues

Well done on sorting the main issue.

David
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