Electronic/electrical guru help needed??

[omegaspeedy]

Beeman and myself are about to re-plinth and revive two lovely Denon broadcast TT's he stumbled across that date back to 1962. The motors are Synchronous and have a selector to change the Hertz rating between 50 and 60 which is because different parts of Japan run the two different ratings. The big stumbling block though is they are 100v units.

Have a look at the photos. I don't know much about synchronous motors. From looking at the photos, is the electronic circuit shown a power supply of some sort or is it something else like a soft start. Part of it is a solenoid for the electric brake I think.

With these sorts of motors, if I was to wire it to a 100v step down transformer, should it just run, or does it need a power supply circuit of some sort?

Any help would be much appreciated and hopefully someone with the skills of looking at a circuit will be able to answer some of these tough questions.

Cheers James.

[cloth_ears]

It would appear that you only need an AC supply of the correct voltage.

[omegaspeedy]

It would appear that you only need an AC supply of the correct voltage.

That would make life much easier cloth_ears. Thanks for that. Can you make out what all the electronics are. May be it's just the circuit that coverts the acceptance of 50hertz or 60hertz depending on what region of Japan you live in and the solenoid for the electric stop/brake.

[cloth_ears]

My answer is based on the motors requirement for a 100VAC supply, which is unlikely to come from anywhere but an AC wall outlet.

Some of the capacitors will be for noise suppression.

There must be some way of changing the gear ratio for 50/60Hz operation. The motor will clearly rotate at different speeds on the 2 frequencies. Perhaps that's what the solenoid is for.

[davyboy9]

Am I correct in believing that Japan has 2 frequencies; 50Hz in some part and 60Hz in some other so could not the differences be accommodated by the use of difference pulley sizes?

[omegaspeedy]

Am I correct in believing that Japan has 2 frequencies; 50Hz in some part and 60Hz in some other so could not the differences be accommodated by the use of difference pulley sizes?

Yes your right. 50hz in some regions and 60 in others. If I was the government I'd make it one frequency.....

Believe it or not it's 'the flick of a switch' on this puppy. That's why I was wondering if all those caps and resistors were part of that mechanism.

[Jon]

Lovely decks these from the very few pictures I've been able to turn up... and I've seen some comments like "poor man's EMT"!

A direct connection to the mains is the place to start. You will need to ascertain which frequency it is set to since if you supply 50Hz when set to 60Hz you will get odd behaviour and stress the motor. If you have picked this up in NZ then you would have good grounds to believe it is set to 50Hz but as ever YMMV.

I would suggest you have the electricals checked thoroughly anyway since the caps will be well past their lifetime.

Blog on the build as you go!



.

[beeman]

A direct connection to the mains is the place to start. You will need to ascertain which frequency it is set to since if you supply 50Hz when set to 60Hz you will get odd behaviour and stress the motor. If you have picked this up in NZ then you would have good grounds to believe it is set to 50Hz but as ever YMMV.

They have a 50hz/60hz switch so thinking all the gear is an electronic speed controll? Hopefully making the selection easy. There are 2 x simple pin plugs one labeled "Remote" & the other "Power supply" Jon if you have found pics or links could you share them please as so far I have found nothing. Cheers

[Owen Young]

How about trace & draw a wiring diagram? I've traced a preamp, so this should be reas. simple!

Then, I'd say a Variac would be a good place to start when applying AC power.

[MosfetMainac]

That's true, I have a variac floating about over here, Mr Beeee knows where my beer fridge is...

[beeman]

Mr Beeee knows where my beer fridge is...

Im off next week - that could work ;-)

[MosfetMainac]

Oh crap, Now I'll have to clean up the man cave....

[omegaspeedy]

How about trace & draw a wiring diagram? I've traced a preamp, so this should be reas. simple!

Then, I'd say a Variac would be a good place to start when applying AC power.

Not a bad idea Owen. I might give it a go. Looks like all the caps and resistors are well labelled.

Whats a variac??

[DodgyConnection]

Have you tried contacting Denon in Japan? May have an archive with some info on this?

Especially as this is their 100th anniversary - and they just released a direct drive TT to celebrate it!

[fisher X 100 A]

7825


varies a voltage to your desired voltage .......

[Papa Hemi]

Or perhaps you could use Mosfet's dim light set-up? I would think though that firstly you need to get a 100v ac supply going, the frequency should not matter too much at the outset? You can switch in the machine for that?
I may be tempted to do motor maintenance even prior to feeding any volts into it..
Still eagerly awaiting details as to how you came by these.
Rock on!

[Jon]

Here it is (http://translate.google.co.nz/translate?hl=en&sl=ru&u=http://xn--80aaaoubmcg2a0bas.xn--p1ai/phpbb/viewtopic.php%3Ff%3D13%26t%3D5266&ei=og0dT6jtMcqYiAeFqsyDDA&sa=X&oi=translate&ct=result&resnum=3&sqi=2&ved=0CD4Q7gEwAg&prev=/search%3Fq%3Ddenon%2Brp53%26hl%3Den%26client%3Dfir efox-a%26hs%3DPBa%26rls%3Dorg.mageia:en-US:official%26biw%3D1918%26bih%3D968%26prmd%3Dimvn s)

And also here (http://translate.googleusercontent.com/translate_c?hl=en&prev=/search%3Fq%3Ddenon%2Brp53%2Bsergei%26hl%3Den%26cli ent%3Dfirefox-a%26hs%3DvTF%26rls%3Dorg.mageia:en-US:official%26biw%3D1918%26bih%3D968%26prmd%3Dimvn s&rurl=translate.google.co.nz&sl=ru&u=http://blog.goo.ne.jp/kuiren/e/15f0f238fdf223bd650ad57044a2fcf0&usg=ALkJrhhdkinrj4nGfxrqvgtFEEpzaswI3w)

[wrecker]

1st - get a 230-100v step down transformer - say 150VA would be a good starting point - this would be a special order but you may get away with a 230-110V tranny which should be off the shelf from an electrical wholesaler. You may have to wait a coupe of days dependeding on were you are in NZ. Alternatively get hold of a variac to do your trials with but ultimately you should have a step down transformer when you ultimately get to using theturntable.
2nd - A synchronous motor is frequency dependant based on the formula f=np/120 where f=frequency, n=rpm p=number of poles (in this case 4 poles, just believe me) and 120 is a time constant for number of poles. You can do the rearrangenent of the formula but 4p @ 50hz is 1500rpm and @ 60hz is 1800rpm
A synchronous motor will have two windings with a common point which is usually connected to to 0V or neutral. One winding will be connected directly to the supply and the other via a capacitor which is most probaby the big one. Guesing most probably in the region of 15-40microfarad. This results in a phase shift between the windings and will determine the direction in which the motor will rotate.
If the motor can be switched between 50 and 60hz there will be some upstream circuitry to change the frequency but this was most often done in the past by altering the size of the capstan. Does the frequency change do something physical or does it switch some ciruitry around?
As mentioned above a good look see and a with a sketch of the control circuit a we can make some calls from there.
This reply may be a bit long winded but this is what you are dealing with.
Be carefull as you are dealing with lethal voltages - be warned!!

[beeman]

Great start thanks guys - something to go on with - cheers

[beeman]

info still thin on the ground - had this site forwarded from OS. if you can get it to translate. Look like they do replacement idler wheels which could be usefull. Some ubber cool gear as well ;-)

http://translate.google.co.nz/translate?hl=en&sl=ja&tl=en&u=http%3A%2F%2Fwww.soundlabo.co.jp%2Ftube%2Ftube.h tml

[beeman]

Some pics at last

7826782778287829783078317832

[omegaspeedy]

Nice!! Any written info on them?

[DodgyConnection]

info still thin on the ground - had this site forwarded from OS. if you can get it to translate. Look like they do replacement idler wheels which could be usefull. Some ubber cool gear as well ;-)

http://translate.google.co.nz/translate?hl=en&sl=ja&tl=en&u=http%3A%2F%2Fwww.soundlabo.co.jp%2Ftube%2Ftube.h tml

Some nice big horn systems there - Japanese audiophiles never let room size get in the way of a good horn system :)

When are you going to spill on where you got these Denons Mr Bee?

[beeman]

Um nope - suffice to say from a very nice older gentleman who has other things I would like to purchase in the future

[beeman]

Cool here is the manual & circuit diagram - just need a translation now

7858

[Owen Young]

Cct diagram?... That could answer some Qs.

[beeman]

Bump on this thread too some useful links in it

[audionut]

Hi Beenman,
I asked my better half to translate that funny looking page ... hope it helps :)

If you wish to start/stop the turntable, you need to move a shift lever either “ON” or “OFF” position.
If you wish to change a turnover speed (rotation speed?), turn “OFF” position first then moved a knob(?) to pointing line. However, if the shift lever wasn’t right on the “OFF” position, knob won’t turn.
Please beware that when a pointing line wasn’t on the turnover speed correctly, shift lever won’t turn on.
If you wish to shift lever on the hold position, use the lock lever in front of the knob. Push the lever to “ON” position, a screw push the plate to lock it. It’ll unlock when you move to “OFF” position.
To operate Slip turntable: If you leave it “OFF” the toggle switch at the “T.TABLELOCK’ on the left top of the motor board, Slip Turntable will rotate together with Turntable due to the weight of the felt and frictional force.
If you leave the toggle switch on, Turntable will rotate together with Slip Turntable. However you can stop operating the Slip Turntable by using the Catcher on the remote control.
When you start, you can operate optionally by remote control.