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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 21st Aug 2010, 11:03 am   #1
'LIVEWIRE?'
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Question NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

To explain-the mechanisms used in both these machines are (virtually)identical, and I am looking for information as to the correct settings
for takeup, ff & rewind torque, etc. The models in question date from the late '80s/early '90s, the mechanism used being a fairly typical mechanically operated servo, single motor type.
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Old 21st Aug 2010, 1:00 pm   #2
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

Without actually looking in the manuals, and i will if i have them, most Cassette Tape decks of that era had a Play Torque of 40g/cm and a FFWD/REW Torque of 80 - 120 g/cm.

I hope this helps.

As i say, if i have the manuals, i will look (probably Monday now) and get back to you with the published information.

Best wishes,

James.
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Old 21st Aug 2010, 7:42 pm   #3
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

Thanks, James. Meanwhile I have measured the take up torque of the NAD machine since treating the idler wheel tyre with fine grade glasspaper, at 45-50g/cm-a big improvement on the 20 or so it was before. There is another problem, which is that the fast wind/rewind
and pause functions don't always work, especially if the machine been left unused overnight. This is despite replacing all 3 drive belts and cleaning the cam gear shaft, and trigger lever shaft. Mind you, my workshop is in a cellar, so this may be temperature related
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Old 23rd Aug 2010, 7:33 pm   #4
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

I have now obtained a manual for the KX31, which goes into great detail about how the mechanism works in all modes, but gives no information about the torque or pinchroller pressure settings.
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Old 25th Aug 2010, 10:42 am   #5
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

Hi Livewire,

i am sorry but i don't have either of those Manuals.

The Torque settings i gave you should get you started as they seem to be quite standard for Cassette Tape Decks.

There isn't usually any pressure settings for the Pinch Roller, this is just usually held up against the Capstan with a spring 'around' the pinch roller 'bearing'. This spring could have become fatigued over time but i doubt you'd get an original now. A 're-tension' or making another might be the only options.

Sorry i can't be of more help,

James.
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Old 25th Aug 2010, 7:48 pm   #6
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

Thanks, James for your efforts. The NAD is now back with it's owner and wil hopefully give no further trouble, whilst the Kenwood(which is mine) is at the bottom of the 'to do' pile.
A torque setting of 45-50 pascals(g/cm) is, as you say, usually about right. Having spent 23 years servicing car stereos prior to 1995, I'm used to finding the settings for torque-and
pinch roller pressure-in service manuals. Blaupunkt being especially good in this respect.
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Old 26th Aug 2010, 7:23 am   #7
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

Ooh, Blaupunkt! You're a braver man than i !! We always steered clear of Blaupunkt, no offence but they always 'looked' cheap? However we did do Philips! (Remember the 751/752-Oh dear i still have nightmares about the sheer numbers we used to do of those. I suppose you get used to what you do?

There was a Blaupunkt model with a mod which was two pieces of plastic held together with what looked like a 'used' staple wasn't there?!!

None of the makes we did (JVC/Panasonic/Pioneer/Sony) offered a spec'n for pinch roller pressure.

When you get a 'round tuit' i hope the Kenwood goes ok.

Regards,

James.
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Old 26th Aug 2010, 11:09 am   #8
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Default Re: NAD 6050C &/or Kenwood KX31B Cassette Mechanisms

James,
for over 23 years I worked for a Blaupunkt main dealer, and for most of that time my boss wouldn't have anything other than Blaupunkt Radios or Stereos in his car, although in the last 4 or 5 he switched over to Clarion. I always thought, with one exception-a French made model called the 'Baden-Baden', all their products were of good quality, backed up by decent after sales service and spare parts supply. I know the model with the mod of which you speak, though-a cassette mechanism made by them called the 'mini7 mark II', used in several sets in the late 80s. They did also have
a problem with a 'white metal' flywheel in the later versions of their 'mini5' deck, which would work loose on it's shaft. This replaced a much better brass(or bronze)flywheel
used in the first version of the '5'-a cost cutting exercise no doubt. There was a 'bought-in' cassette mech.(made by EDI/RIEL in Italy) which suffered from splitting plastic flywheel rims, as did the P3 & P5 Philips decks used in the DC751/752 and many other models made by Philips. I, too, repaired many of those over the years, and got it down to a fine art, so much so, that I could change all the parts in those repair kits Philips produced in about 15-20minutes. Doubt I could fix one that fast now, though!
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