Friday, November 16, 2012

Marantz 1200 Update

  When I got the Marantz 1200, both channels played through headphones, but only one through speakers. I had it fixed (never mind by who), and started to listen. The overall gain of the unit seemed low, and the whole unit hummed like crazy until the relay clicked in, after which things seemed to be pretty good. Then I got the Technics SL-1401, and mounted the SAE cartridge on it. Anxious to listen with a lower ambient noise level in the room, I shut down my computer, achieving dead silence, and making a residual hum from the Marantz glaringly obvious.
  Enter Joe. He's the new owner of an old school repair shop that I'd visited and written off as not into vintage audio. Joe doesn't feel that way, and set upon the 1200 with enthusiasm. I've known repair guys who don't want to work on equipment until it's not making sound. Joe tested each component, replaced many (with correct parts)and had it sounding great, and the really clicked in right away. The transformer continued to hum.
  I did some research, and know that the transformer was assembled using shellac, that dries and cracks with age (and use, especially improper use, like when capacitors start to fail). This allows the metal plates to move. Tightening all the assembly bolts often solves the problem. It didn't in this case. The transformer is failing.I just bought an exact replacement on eBay, and can't wait to hear my beautiful Marantz in all it's glory.
  Apparently Bullock Magnetics, the manufacturer, is still in business in California, and I may be able to have the faulty transformer reconditioned.

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