Film-Tech Cinema Systems
Film-Tech Forum


  
my profile | my password | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Film Handlers' Forum   » A70084 thyristor for Christie MUT speed control?

   
Author Topic: A70084 thyristor for Christie MUT speed control?
Jon Miller
Jedi Master Film Handler

Posts: 973
From: San Diego, CA, USA
Registered: Sep 1999


 - posted 10-31-2009 08:00 PM      Profile for Jon Miller   Email Jon Miller   Send New Private Message       Edit/Delete Post 
I am trying to resurrect a faulty speed controller from a Christie MUT. The controller is a KB Electronics KBVC-14, apparently an older design. Two of the four diodes are shorted, as is the thyristor.

Try as I might, I can't find a replacement for the Teccor A70084 thyristor...

 -

Littelfuse/Teccor does not list that number on their website, and I cannot find a cross-reference.

Does anyone know of a suitable replacement for the A70084, or is the part — and the controller — truly obsolete?

 |  IP: Logged

David Stambaugh
Film God

Posts: 4021
From: Eugene, Oregon
Registered: Jan 2002


 - posted 10-31-2009 08:15 PM      Profile for David Stambaugh   Author's Homepage   Email David Stambaugh   Send New Private Message       Edit/Delete Post 
Some possible variations on that part number to search on:

A7-0084
A7 0084
A70-084
A70 084
A700 0084

I found that here. Could be a clue. Could be sales BS.

 |  IP: Logged

Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 11-01-2009 06:01 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Some of those speed controllers used a Quadrack rather than a Triac
Just get the highest voltage/current available in that package
If it was a quadrack which can be difficult to find put a Diac in serries with the Triacs gate lead

 |  IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 11-01-2009 10:39 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Dude, check the motor brushes and commutator! I don't even bother repairing/replacing the christie speed controller. I install the variac used on the SPECO platter into them. They never fail and it doesn't actually cost any more for the variac parts then it does for a new Christie speed board!! You just need the variac, a 40 amp bridge rectifier and a 4 amp push to reset circuit breaker. I also replace the wimpy light under the window with a screw in type socket that will accept a screw base flourescent 25 watter. Except for possibly the cable you'll never be making another repair to the table again.

Mark

 |  IP: Logged

Jon Miller
Jedi Master Film Handler

Posts: 973
From: San Diego, CA, USA
Registered: Sep 1999


 - posted 11-02-2009 11:51 PM      Profile for Jon Miller   Email Jon Miller   Send New Private Message       Edit/Delete Post 
Thanks for the tips! [thumbsup]

The Variac idea sounds great, Mark...next to finding the correct one, I just need to see if the theatre manager will go along with the idea.

 |  IP: Logged

Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 11-03-2009 06:36 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
SPECO uses the STACO 221-B variable transformer (Variac) for both the MUT and the Take-Up speed.

They are available from a great many places.

Steve

 |  IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 11-03-2009 09:17 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Again, be sure to check commutator and motor brushes. Worn out brushes and or an arcing commutator are the main reasons those cards fail... aside from iddiott kids using the table incorrectly!

 |  IP: Logged

System Notices
Forum Watchdog / Soup Nazi

Posts: 215

Registered: Apr 2004


 - posted 02-26-2013 09:34 PM      Profile for System Notices         Edit/Delete Post 

It has been 1211 days since the last post.


 |  IP: Logged

Stefan Rees
Film Handler

Posts: 1
From: Johor Bahru, Johor, Malaysia
Registered: Feb 2013


 - posted 02-26-2013 09:34 PM      Profile for Stefan Rees   Author's Homepage   Email Stefan Rees   Send New Private Message       Edit/Delete Post 
This comes probably a bit late, but can be used for general interest.
Our cotton candy machine broke down with a blown A70084, used in the heater control. After searching everywhere and unable to find anything, I contacted the manufacturer of the unit for some details. To my surprise, within 24 hours, I received the reply posted below. A new controller, without shipping and customs duty in Malaysia would have cost me US$ 350.00 A new Triac, bought from my supplier was a whopping US$ 7.00, a bargain!
Important seems to be that the part has an Isolated Tab.

Cheers,
Stefan

KB's reply:
The number A70084 is KB's inventory number and not the component manufactured part number. That is why you could not find a replacement part.

A70084 = Q2015L manufactured by Teccor. ( www.littelfuse.com )
However, this part is listed as obsolete on the website. Replaced By Q4015L5

You can also use Q4015L, Q2025L or Q4025L as a substitute for the Q2015L.

 |  IP: Logged

Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005


 - posted 02-26-2013 09:53 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Or you could buy the correct KB part. I have many in stock. Louis

 |  IP: Logged



All times are Central (GMT -6:00)  
   Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



Powered by Infopop Corporation
UBB.classicTM 6.3.1.2

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.

© 1999-2020 Film-Tech Cinema Systems, LLC. All rights reserved.