long shot Need diagams for BBC EMT 140 motor drive

[Rob Flinn]

I'm looking for BBC diagrams for the UN3/53/143 local control unit.  A long shot but if you don't ask .....

This is a motor drive to move the EMT 140 damping plate.  It's not a remote but operates locally like the buttons on a goldfoil.. 

 

[radardoug]

Just look for the EMT 140 schematics. Its not rocket science, just a motor and some relays wired through the  limit switches.

 

[Rob Flinn]

I have looked at them it's not the same as the EMT remote circuit which is simple in comparison.  The way it is point to point wired makes it quite tricky to  fathom out.

But thanks for your repsonse.

 

[radardoug]

At the end of the day if you cant find a circuit that is what you will have to do. There cant be that many wires in there, ohmeter is your friend! Bite the bullet and do it!

 

[Rob Flinn]

Thanks for your encouragement.    I promise you this is more complex than the EMT circuit.  In the end I may have to buzz it out, but since other things are a priority at this particular job. I'll haang out for a diagram for the moment.

 

[analogguru]

This is a motor drive to move the EMT 140 damping plate.  .... I promise you this is more complex than the EMT circuit.  .....

Really ?  I highly doubt that...

 

[Rob Flinn]

This is a motor drive to move the EMT 140 damping plate.  .... I promise you this is more complex than the EMT circuit.  .....

Really ?  I highly doubt that...

Sorry, but you're wrong,  I'm not really getting this, it's like I'm being accused of lying.  It is not the EMT circuit& if it was I wouldn't be asking anyone if they had it.    The circuit has about 14 germanium diodes , & the same resistors which all check out value wise..  It is wired on tag strips with laced wiring connnecting it all up with the motor & what looks like a position sensor.  The access to parts of it is not very good which makes it tricky to buzz out.  I may have to do this in the long run, but since it's not the biggest priority for the next few weeks I'll wait to see if a diagram turns up, albeit unlikely.

 

[ruairioflaherty]

People,

This is not Rob's first Rodeo, give the man a break.

Rob - have you searched here? - http://www.bbceng.info

I threw in a couple of obvious search terms but came up empty handed, maybe some creative searching will reveal something?

 

[Rob Flinn]

Thanks Ruairi.

I did look there.  I emailed some sites that specialise in old BBC info, & they pointed me there.  I couldn't find what I was after but it was suggested to me to email them, which I have done.  Still waiting on a response.

 

[analogguru]

This is a motor drive to move the EMT 140 damping plate.  .... I promise you this is more complex than the EMT circuit.  .....

Really ?  I highly doubt that...

It is not the EMT circuit& if it was I wouldn't be asking anyone if they had it.
......

Believe what you want - IMHO you are a lost soul which can´t be helped.

Before you start again whining and spreading BS maybe you want to compare it with the factory schematic of the EMT 140ST:
http://groupdiy.com/index.php?topic=44988.msg563170#msg563170

And now  smc and start tracing - obviously you have the unit in doubt in front of you.

BTW: Noone is guilty to do anything for you only because you are living.

 

[PRR]

{deleted}

 

[radardoug]

Maybe the bunch of diodes are so that you could drive it to a particular value of voltage and therefore a certain reverb time.
Why not just use the EMT schematic, and rewire it to that? Life is too short to make it complicated, its only a reverb remote!

 

[Rob Flinn]

Maybe the bunch of diodes are so that you could drive it to a particular value of voltage and therefore a certain reverb time.

That sound plausible.

Why not just use the EMT schematic, and rewire it to that? Life is too short to make it complicated, its only a reverb remote!

That's a possibility, but not at the moment , because I have other priorities & the owner has 2 other plate reverbs.    I will investigate this more when I have time available & it's in a place where I have better access to the insides of the unit.

 

[radardoug]

Yeah, access! Echo plates always end up in the worst places! And then you have to get the sides off. And its up against a wall!
Doh!

 

[Rob Flinn]

I managed to find the info I needed.  It is  different to the EMT version in that It applies a control signal down the audio send, in the same way phantom power is supplied down a mic cable.  You can switch on the Plate itself by stuffing 50v down it & by changing the current available you can open or close the plate.  The decay meter is fed down the audio return in a phantom power type way too.  Sounds over complicated...yes.    But it’s quite clever in that one can remote any plate without having to run any extra cables through the building.

 

[pvision]

There's a meter suitable for an EMT remote on eBay atm

http://www.ebay.de/itm/Siemens-seconds-meter-for-reverb-remote-nr-3/172121324045

Nick Froome

 

[Rob Flinn]

Thanks for the heads up

 

[studiochap]

Not sure why anyone hasn't posted the link to this info - unless I haven't spotted it?

http://www.bbceng.info/ti/eqpt/EMT140.pdf

Cheers,

Gwyn Mathias

 

[Whoops]

Not sure why anyone hasn't posted the link to this info - unless I haven't spotted it?

http://www.bbceng.info/ti/eqpt/EMT140.pdf

Cheers,

Gwyn Mathias

Nice Stuff,
thank you Gwyn

Thank you also Rob for bringing this to our attention it's quite clever the circuit indeed and really useful.

 

[Rob Flinn]

Not sure why anyone hasn't posted the link to this info - unless I haven't spotted it?

http://www.bbceng.info/ti/eqpt/EMT140.pdf

Cheers,

Gwyn Mathias

Nice Stuff,
thank you Gwyn

Thank you also Rob for bringing this to our attention it's quite clever the circuit indeed and really useful.

Yes it is,and it is more complex than certain people were telling me.    The inc/dec switching in the plate itself is stuck on in one direction (inc I think from memory).    A previous tech just disabled all of that circuitry with a switch,  so I have to get that working before I can start playing with the remote side of things