This is topic A70084 thyristor for Christie MUT speed control? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Jon Miller (Member # 163) on 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?
Posted by David Stambaugh (Member # 1102) on 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.
Posted by Gordon McLeod (Member # 33) on 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
Posted by Mark Gulbrandsen (Member # 72) on 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
Posted by Jon Miller (Member # 163) on 11-02-2009, 11:51 PM:
Thanks for the tips! ![[thumbsup]](graemlins/thumbsup.gif)
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.
Posted by Steve Guttag (Member # 268) on 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
Posted by Mark Gulbrandsen (Member # 72) on 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!
Posted by System Notices (Member # 2357) on 02-26-2013, 09:34 PM:
It has been 1211 days since the last post.
Posted by Stefan Rees (Member # 7497) on 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.
Posted by Louis Bornwasser (Member # 3063) on 02-26-2013, 09:53 PM:
Or you could buy the correct KB part. I have many in stock. Louis