NAD Cassette Deck 6040A

[SteveCG]

The belt on this machine has (unsurprisingly!) gone soft -so a search around for a replacement is under way. However I'm not entirely sure that the motor is operating as one might wish. A drop of lubrication on the only visible bearing might not go amiss, but the controlling electronics?? I've looked in the upper RHS of the site's web-page to see if there is any service/circuit diagram information on the machine but NAD is not mentioned. Also I've checked on NAD's web-site, but no joy.

Can anybody help please? PM me if you can.

Thanks.

[ben]

How do you know the motor is not right? I'd get a belt first, try it, then worry about the motor.

[SteveCG]

Ben, my concern for the motor was when play was pressed the shaft did not rotate, but could be persuaded to rotate by a manual twist - hence the drop of oil point of mine. However I fished about through my collection of belts and found a poor approximation, but sufficiently good enough for a cassette to be played. There was no problem with the starting of the motor. Not having a circuit diagram I could not/can still not tell how the motor speed is controlled. Nevertheless, given the belt I've used, I was impressed by the replay sound quality - rather to my surprise no discernable wow or flutter.

As an aside, I find the piece of cord and spring contraption connecting the record button to the system slide switches 'amusing' in what was sold as a hi-fi design! Heath Robinson would have been proud.

[SteveCG]

It's been a long time but I finally fitted a cpc brand replacement belt. The deck works, but I'm suspecting the tape speed is on the high side as a Dolby level test cassette recorded at 400 Hz plays back at 424 Hz. The replay levels are within 0.5 dB. Record is a different matter, but I'm not suprised given the differing bias level requirements and magnetisation retention characteristics of all the different tape brands. The user manual does not give any preferred brand.

So my earlier question still stands? Can the replay speed be altered on this machine? I don't see any pot to alter.

P.S. Ben, since I looked at this deck I found that a Linn turntable motor exhibited the same no-rotate action - until I loaded it with its platter, it then worked. Mind you I suspect a tiny drop of oil on the motor shaft bearing will not go amiss.

[DOFFERY]

Steve, many motors have a speed control in built , check if there is such a preset on yours.

Colin.

[SteveCG]

Colin,

Thanks for that tip - I didn't notice anything obvious on the motor - but I wasn't really looking for any small hole etc.

An alternative way to checking the speed I thought about was to see if a commercial cassette recording played back in speed sync with a CD version of the same recording.

[SteveCG]

I gave the motor a close inspection - no sign of any pre-set.

I then tried playing a CD version of a piece of music against the commercial cassette version. I found there was a little drift in relative timing, but it took a couple of minutes to slowly show itself. So I've concluded that the cassette tape speed accuracy is 'good enough'.

Quite frankly without a circuit diagram, service manual or reliable cassette test tape I'm probably better off leaving it all alone. Even with a service manual, circuit diagrams etc, trying to set up a semi-pro machine like a Revox properly takes care - without such info, setting up a machine properly can be an exercise in blundering about.

[Nickthedentist]

All decks of this age and quality had electronically-adjustable speed.

If there is no pot on the motor itself, follow the wires back and see where they go. There will surely be a pot nearby.

Best of luck with it,

Nick.

[julie_m]

Check for a little hole around the back of the motor, possibly with rubber flaps to protect against dust ingress. Insert a precision screwdriver (about 2.5 mm.), find the slot and adjust gently.

[SteveCG]

Nick and ajs_derby,

Thanks for your suggestions. There are only two wires coming from this motor and they go to a small pcb where there no preset pot. There is a small label on back the motor which I gently tried prodding with my finger, but it did not give, so I don't think it covers a hole. There are no rubber flaps covering a hole either.

I, like you, would expected some speed setting capability. The deck itself seems to live up to NAD's reputation of a good quality job - even the system slide switches don't have the bad contacts that nowadays write off many a rival of that era.

As I said I don't have any servicing information and with such a complex unit (quite a few ICs) I know that fiddling may just make matters worse - it is not as if it has an obvious fault where doing something to get it going is better than nothing.

[camper234]

Steve, that small label on the back of the motor, remove it, one speed pot. Very slight turn clockwise will slow motor. Hope this helps.

John

[SteveCG]

John,

Thank you for that information. I put the deck back together a couple of weeks ago, however when it is next convenient I'll lift that small label and see what's what!

BTW is that clockwise viewing the motor from its rear?

[camper234]

Yes Steve.

[SteveCG]

John - thanks.

[camper234]

Just a last tip if this helps Steve or others, I took mine out of the rack and positioned it on the kitchen table and used the headphone out to set the speed