4002 5511 Started running very slow on 45 RPM Speed

8 replies
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bousie (archived2)
Bronze
Posted March 29, 2012 at 15:32 GMT
#2217209

Hi all, I apologise if I have posted this in the wrong section, first timer.

I have a 4002 5511 that I bought second hand about a year ago.  All the maintenance I have done has been freeing up the tone arm mechanism and drive scrrew.  It has been running well (with maybe some very slight speed fluctuations).

I recently played some 45's and although it started the first record fine, I noticed the platter slowed a few times then got back up to speed.

More recently it has significantly slowed to roughly half way between 33 and 45.  Starting and stoping doesn't seem to help.

33 still seems to work fine and the speed selector switches as it should.

I have downloaded the service manual but thought I would ask for advice before pulling it apart.

Any suggestions would be appreciated.

Thanks

YA
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yachadm
Bronze
Posted April 4, 2012 at 21:48 GMT
#2217210

Agreed, and don't forget the 45 thumbwheel potentiometer on the Keyboard panel - IIRC its a 1KOhm unit.

If that is the problem and it's non-repairable, it's very easy just to bypass it - it's really not necessary, if the speed trimmer poti on the main PCB has been set correctly.

Menahem 

Location: Jerusalem

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Electronics Technician in Jerusalem Israel. B&O fan for over 50 years.
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bousie (archived2)
Bronze
Posted April 5, 2012 at 05:26 GMT
#2217211

Thanks guys.  The Thumbwheel pots seem to be reading consistanly with a dmm.  (Not dirty) so I think they are ok.  Haven't pulled the relay apart to have a look yet.

Which pot is the speed trimmer on the main PCB?

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bousie (archived2)
Bronze
Posted April 6, 2012 at 11:09 GMT
#2217212

Ended up being a dirty R14 Pot.  Cleaned up with some fluid and enthusiastic adjusting.  All seems fine now.

Thanks again.

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Daveleeander (archived2)
Bronze
Posted January 5, 2014 at 03:24 GMT
#2217213

Mine was slow on 33 and varied from 31.577 up to 32.212. R15 pot took care of mine. Now running 33.014 - 33.118.

LO
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lostmyshoe
Bronze
Posted January 5, 2014 at 08:01 GMT
#2217214

How did you measure the speed so accurately?

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Daveleeander (archived2)
Bronze
Posted January 7, 2014 at 16:02 GMT
#2217215

I do balancing of fans, pumps, etc. as part of my living. In order to measure the phase of the unbalance, I employ a laser tachometer. So to measure the RPM of the turntable, I put a piece of reflective tape on the platter and set the laser to measure the tape.

Unfortunately mine has started slowing down again off and on. I'm thinking I will purchase a couple new pots and put them on the board. Does anyone know what the values are for R14 and R15?

Dave

YA
Offline
yachadm
Bronze
Posted February 4, 2014 at 14:58 GMT
#2217216

Once you've got the TT disassembled, do all 5 pots.

Use Piher PTC10 units.

Type 5513 DC

PCB1

4.7K R14, R15 (Can use 5K)

 

22K R56, R57, R88 (Can use 20K or 25K)

Menahem

Location: Jerusalem

My B&O Icons:

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Electronics Technician in Jerusalem Israel. B&O fan for over 50 years.
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