This is topic Help in repairing ORC rectifer in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Luther M. Spencer (Member # 442) on 07-05-2000, 11:14 AM:
Hello...I hope some one can help me...I have an Orc 1600 watt rectifer..that I have been working on,,,I finialy found the trouble...You couldn't control the Amperage....when you turned on the Lamp it pegged the amp meter...and wouldn't drop back..and the Pot control wouln't do anything....I first checked the Pot. It was within tolerance...100 ohms....I then figured it must be in the regulator transistor stack....9 hight current 2N4276's/NTE 27's in a row,,on a very large heat sink....controled by the pot.I took the regulator stack from a working Powewr supply and it cured the problem,,,,I then desoldered the transistors and checked each one ..One at a time..they were all shorted out....my problem is,,,I found the transistors from a local electronics house and theywere $37.00 each..times nine....That'over $300 for the stack...Does anyone know a cheaper source...Maybe a surplus house....Please help..Maybe some one has an old unit with the transistor stack..or maybe the transistors....again 2N4276 or ECG27 or NTE27....Thanks...MIKE
Posted by Gordon McLeod (Member # 33) on 07-05-2000, 11:20 AM:
The cost and availablity problems of that particular ORC rectifier are one of the reasons why there are so many of them for sale cheap
Posted by Ken Layton (Member # 133) on 07-05-2000, 08:30 PM:
Try Mouser Electronics at www.mouser.com and ask for the catalog.
Posted by Josh Jones (Member # 447) on 07-06-2000, 03:19 AM:
Well, If all else fails,
you could replace the whole stack with
cheap 2n3055's or MJ2955's(PNP) 
that way you'd replace the whole stack for
$18Sorry,
Josh
"Show me a mouse, and I'll show you a cat with bad breath" Garfield
Posted by Gordon McLeod (Member # 33) on 07-06-2000, 03:44 PM:
The regulator circuit and load sharing will not handle the inrush of ignition except with the original germanium stack
been there tried that
Posted by Josh Jones (Member # 447) on 07-06-2000, 11:50 PM:
Gordon,couldn't you add 2 or 3 more transistors to
lessen the inrush current through each device? If you have space, that would be an option in my book.
Josh
Posted by Luther M. Spencer (Member # 442) on 07-07-2000, 11:57 AM:
Thanks ....I guess I will reside myself to the higher priced Units...Mike