The beast turned up at 5:30pm yesterday and we had a battle to remove it from the enormous crate before it got dark (and cold!). About an hour later my friend Patrick, my fiancee and myself successfully managed to carefully lift the top lid (quite heavy), bottom frame (heavy!), and generator chassis (Freaking Heavy!) into the house. This 70 year old, 163 tube (valve) monster weighs 1/4 ton!!
To my huge relief the instrument has not sustained any damage in transit at all!
After an evening of picking hundreds of polystyrene chips from between all of the tubes in the generator chassis (seemed like a good idea at the time!) and then going over the whole thing with beeswax and scratch cover it's really not looking bad.
The good news is that generally the sands of time have been very kind to this beast. Parts of her are in amazing condition - the front panel controls, and top wooden casing are in very good condition and the Bakelite & Plaskon keys (see note below) are practically mint and have not yellowed, chipped or cracked at all.
The bad news is that towards the end of the evening we identified the reason why the beast filled AG's house with smoke! It turns out that it's suffered an absolutely typical Novachord failure mode but was sadly not caught quick enough. There are two capacitor pairs potted in metal cans located in the pre-amp "channel" within the generator chassis. These caps decouple the HT supply and are potted in bitumen. They fail S/C and the bitumen melts and pours through the chassis holes. Unfortunately, in this case, the lack of functionality was not noticed until it was too late, as sadly Marc was away from the instrument at the time. This has led to much more serious secondary damage in the PSU chassis where, on first inspection, a prolonged dead short of the HT rail has caused at least one of the mains transformers, the supression choke, probably the valve rectifier and several resistors to fry. In short it's looking like the entire power supply, including transformers, will have to be completely rebuilt. I have a company lined up to rewind the transformers and all of the remaining parts are easy enough to get hold of - the issue is that everything will have to be very carefully noted before I remove all of the charred wiring and passives and rebuild the PSU. Assuming I can get the trnasformer and chokes rewound fairly soon this is about a months work (part time).
Here are some initial piccies of what is a truly amazing piece of vintage equipment...
The Base, Top Casing and Generator Chassis:
The next step is to carefully check the tube heater transformer (a big b$astard!), remove a rather frightening chassis mains decoupling capacitor, test for any any S/Cs on the filament output and then slowly attempt to wind up all 144 tube heaters in the generator chassis. At this point I will attempt to take a decent piccy of the whole lot running in the dark
Note on Plaskon:
The white keys on the Novachord are made of a substance called Plaskon. Like Bakelite, this is a very early plastic. Plaskon was developed and introduced in 1931 by the Toledo Scale Company to incorporate into their weighing scales. They began with the urea compound and used cellulose as a filler. They also made a few other chemical additions to keep the material from fading (they wanted a bright white color for the scale basin). Because of the superior properties and the help of a great marketing department, plaskon soon became the plastic of choice when a manufacturer wanted an end product to be a color other than the standard bakelite brown and black. Many pre-war radios in colours other than black or brown feature casings made of Plaskon.
Were the amp tubes damaged at all? They didn't seem like they were!
