Film-Tech Forum ARCHIVE: ORC VS-250-NS Amplifier Manual

This is topic ORC VS-250-NS Amplifier Manual in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Tony Gallimore (Member # 5358) on 05-17-2010, 09:32 PM:

I am playing around with an old Optical Radiation Corp. sound amplifier VS-250-NS and would like to find a manual for it. Anyone know who actually made this for ORC? or have a manual? The name plate doesn't provide a clue. I would appreciate your input!

Posted by Don Sneed (Member # 955) on 05-20-2010, 06:24 AM:

when I was a RCA tech we had to fix these all the time, I sat in a hotel room repairing these, I had a test jig I made to power it (50vac), input & output test point, volume copntrol, & a spk connection. Most problems are the 10mfd & 100mfd axle lead capactiors, they normally open causing no sound, & the fuse link wire (most people don't know about that). The best way to see if the cap is open is to clip lead another cap on the suspected bad one, this works 90% of the time & I have repaired hundreds of these over the years & use to carry capacitors in my took kit just for these amps, I found these amps dead with no sound or weak sound, it all goes back to the 10mfd caps....good luck

Posted by Tony Gallimore (Member # 5358) on 05-21-2010, 02:38 PM:

Thanks Don,

I should have a few 10 and 100 mfd caps around. I used to work in a theatre with RCA sound. When the sound began to diminish, we automatically replaced the main caps throughout the amp, especially the filter caps on the power supply and the 868 photo cells. Maybe regularly replacing the caps would be a reasonable practice with this one too. And thanks for the info about the fuse link... although I've run into a few of those in automotive wiring, I would have had to hunt with the ohm meter for a while to find an open one, since the amps seem to be well fused individually. Thanks again.