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Bensdad 26th Jan 2020 8:53 pm

Tandberg 15-41 Woes
I have a Tandberg 15 reel to reel recorder , purchased in 2010 for a `minimal` price and serviced in 2010 by a chap in the London area , I know he replaced a few electrical parts , fitted a belt and presumably `greased` internals.
Admittedly , I have not been making as much use of these machine as much as I maybe should have in recent months and a few strange niggly problems have developed which leads me to believe it either needs another `service` or worst case `disposal`.
Basically ,yesterday there was a friction type noise coming from under the cover plate - as though there was unnecessary resistance or tension or something not moving as freely as it ought to be .
When I removed the cover plate to take a look , the noise was coming from the central pulley where the drive belt passes through in a figure of 8 , rotating the pulley by hand confirmed this noise which seemed to be friction from the drivebelt .
So , I removed the belt and cleaned around the grooves of the pulley using isopropyl alcohol soaked on a cotton bud , after I had done this the cotton bud was `black` - presumably from the rubber , but when I refitted the belt it did `appear` to cure the friction type noise which was coming from this area.
I ran the recorder yesterday for around 3 hours , to start with the audio seemed a bit `warbly` if that is the right word - but after 3 hours of use this was no longer apparent and the audio sounded perfectly normal.
When powering up the unit today and playing a tape , there was a different problem - the audio sounded dreadful due to erratic speed , when I removed the cover housing the playback head I discovered the pinch roller oscillating slightly at regular intervals.
I left the unit running for an hour or so and this problem went away of its own accord , the result being near perfect audio quality.
I know very little about the mechanics of these Tandberg 15 recorders but niggly problems like these and I begin to think does it need some sort of service or overhaul , the odd thing is that these niggly problems seem to disappear after the unit has been running for an hour or so !
Meanwhile , when it is working well , the audio quality of this particular machine remains consistently impressive , even at the slowest speed is still pretty damn good , using the middle speed or fast speed , the audio quality is very very good !

saxmaniac 26th Jan 2020 10:30 pm

Re: Tandberg 15-41 Woes
There is a setup procedure for the arm which controls the engagement of the brake and if it doesn't leave a clearance on play setting, it causes a bit of brake drag with the symptoms you describe. I think in play position there should be 1mm gap between the arm and whatever it pushes under the turntables (it's been years since I restored mine) The manual is available and explains this but if you can't find it I've got it somewhere. Also I get strange chirping noises from the large drive belt which go away after a while of running, I think due to a modern replacement belt made from old knicker elastic or whatever and not quite as per original. I live with that as it's a tiny issue

ricard 27th Jan 2020 11:03 am

Re: Tandberg 15-41 Woes
The idler between the motor and flywheel tends to get hard with age on these machines, but running them for a bit softens the rubber. In doesn't sound like something rubbing, though, more like a rumbling which goes away after a while.

I was thinking though that the figure 8 belt runs in separate channels in the pulley, if one gets it wrong and installs the belt in a single channel it will rub against itself when the machine operates.

These are fairly robust machine, but rubber parts, especially the pinch rollers, tend to deteriorate (harden) with time. The model 15 is also notorious for having scratchy rec-pb-switches although the later models updated the contact materials and have less of a problem than the earlier ones. This model was in production from 1968 to 1983 or so (i.e. even outliving the original Tandberg company) with a couple of minor variations over the years.

ben 27th Jan 2020 12:26 pm

Re: Tandberg 15-41 Woes
- The pressure pad and plate are clean.
- The pinch roller is not cracked.
- The capstan shaft is not wobbly (bearing trouble)
- Nothing is dragging on the capstan flywheel. ISTR a felt lining which may have come loose.

The main problem I find on these is hardened grease on the linkages which engage the clutches on the spool tables and also act as brake. You usually find a kind of yellowy tar all over the upper deck plate. The (largely inaccessible!) area below the joystick is always sticky too.

There are a couple of raised metal 'ramps' between the spool tables and the headbridge area which are how the clutches are shifted up and down (a most unusual design, heaven knows how they manufactured that to the necessary tolerances!) Backtension can also be affected. I suppose that could cause wow and flutter in your case, but I would also look elsewhere. I even had one fairly recently where the record lever would not lock down, there was a sticky linkage sandwiched between upper and lower decks.

A drop of light oil in the motor's upper bearing may be needed. As you have found, it is a good idea to clean the pulley of all black gunk.

A video might be a good idea if this continues after the above have been checked.

Paulus.d 27th Jan 2020 2:04 pm

Re: Tandberg 15-41 Woes
Is that the same machine we spoke about years ago , lol
Mine's long since dead … it literally fell apart...
Regards Paul

Restoration73 27th Jan 2020 8:03 pm

Re: Tandberg 15-41 Woes
I obtained a new manual for my 15-21 SL (language lab version) from the supplier
in this thread;

ricard 28th Jan 2020 9:03 am

Re: Tandberg 15-41 Woes
A good source of Tandberg documentation is, but if possible try to support the forum if the data is available on the Vintage Radio Service Data DVD-ROM (see upper right hand corner of every forum web page).

Bensdad 29th Jan 2020 12:26 am

Re: Tandberg 15-41 Woes
Very difficult to determine the problem this Tandberg has , it seems to be ok for the past two days - if anything there is slight `dragging` if that is the correct terminology , it is so slight it is only obvious on certain audio tracks where there are strings !
Maybe these units just have good days and bad days - as daft as it may seem !
Maybe it my fault for not using it as much as I should.
Not sure if I did the right thing , but I cleaned the pinch roller with a cotton bud and isopropyl alcohol , the bud was tinged black when I finished and the audio playback was perfect with no dragging - not sure if this was just co-incidence or because I cleaned the pinch roller :-/

ben 29th Jan 2020 1:36 am

Re: Tandberg 15-41 Woes
Be careful with alcohol. Usually I advise people to go for it, but I have had cases where the Tandberg roller was already borderline and alcohol accelerated its demise! Replacement is tricky on these, too.

Have you checked the items in the list I posted in #4 above yet?

ricard 29th Jan 2020 8:59 am

Re: Tandberg 15-41 Woes

Originally Posted by ben (Post 1211631)
- The pressure pad and plate are clean.
- The pinch roller is not cracked.
- The capstan shaft is not wobbly (bearing trouble)
- Nothing is dragging on the capstan flywheel. ISTR a felt lining which may have come loose.

There is a felt strip, but it's along the inside of the flywheel and nothing much happens if it loosens.

Another thing: the capstan bearings can seize up from old oil: check that the flywheel is turning freely. Since there is a brake on it in stop mode (unlike earlier models), I'd suggest the following procedure: take the top cover off, refit the pause control, set the machine to play mode to release the flywheel brake, and set the machine to pause to release the pinch roller from the capstan. Manually lift the idler from the flywheel, spin the flywheel and observe its behavior as it spins down. There should be virtually no braking tendency at all.

Unfortunately the lower bearing is a b*gg*r to get at; I usually just try to drop new oil into the bearing (by placing the oil on the shaft) using a long thin rod which is usually sufficient. Doing it properly entails separating the front top part of the deck from the lower part, with all sorts of mechanical linkages and electrical wires being in the way.

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