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Author Topic: RCA SoundHead Rebuild? Craig Hardy Film Handler Posts: 28 From: Barrington, New Hampshire USA Registered: Oct 2018 posted 02-13-2019 04:13 PM                     Louis, Thomas Mohr responded promptly to my email sending me three docs I'd already found and downloaded: instructions for installing the basement reader, and schematic for the AT-1200-PS Narrow Line power supply. I thanked him and wrote again last night asking what the AT 1200 looks like physically so I could search the old theatre that gave me all this stuff, and haven't heard back yet today. So now I'm going to bother you again about this matter! 1. Today I verified that the small brown cables from LED box were what they appeared to be: using a 3V button battery, I lit the LED's and tagged the cables "upper (Dolby)" and "lower (analog)". 2. From some of my reading, it seems the ATD-1200 is a 120 watt amp. I don't need that--have plenty of amps already. So I'm wondering if I don't need any more stuff, but just need to connect one of the existing cables into an amp like you mentioned. Or do I need to supply 12V to the card on back of lens B because it's a pre-amp? Or do I disconnect solar cell wires from that card and feed them directly to my own amp? The Super Simplex carbon arc lamp units I recently parted with had old WE sound heads with the old vacuum tube pickup. Parked a Radio Shack solar cell in front of the vac tube and fed signal right to a PA amp and they worked fine. I've included a few pics for this discussion.  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 02-13-2019 08:55 PM                     If you are serious about a pristine soundhead, then you need to go all the way with a complete disassembly, cleaning and refinishing! This includes repetitive medial blasting and overnight oven burn-out to purge the iron castings of oil along with washing the iron casting with phosphoric acid. You can then have the ferrous and non-ferrous castings either powder coated or use the authentic black Japanning available from Liberty on the Hudson. There are powder coating additives designed to eliminate bubbling caused by out-gassing, and they work quite well. For the interior white, I have a particular brand I use that does not go brown when heated, is oil-resistant, has excellent adhesion and mechanical durability and is easy to clean...and can also be easily touched up if needed. Refinishing is a lot of work, short-cuts don't cut-it! But the finished product is amazing! Door glass is reproduced thru graphic art software used to create a decal or mask used for either sand blasting or etching. I have reproduced RCA Photophone 1040 door glass and am also working on Century. The natural rubber isolator bushings are probably dry rotted. There are modern materials specifically designed for audio isolation applications that may need to be custom machined from bar stock or modified from available shapes. Gearbox gasket will need to be replaced. Auto parts stores normally stock gasket material, which you will need to cut by hand. Robbins and Myers motor may need attention...I have restored/overhauled and balanced a few of those! This is a process in of itself! Reputable electric motor service shop can help out. Keep in mind that the flywheel is a nickel-plated iron casting! Hope this gets ya going! Cheers! Kutler  |  IP: Logged Craig Hardy Film Handler Posts: 28 From: Barrington, New Hampshire USA Registered: Oct 2018 posted 02-14-2019 10:18 AM                     I'm all set now! Thomas Mohr just emailed me with more info, so now I know exactly where to supply voltages and take out signals.  |  IP: Logged

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