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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                     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                        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                     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                     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                     Thanks for the tips! 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                     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                     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                 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                        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                        Or you could buy the correct KB part. I have many in stock. Louis  |  IP: Logged

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