So I finally got the Hammond in the house. Being the impatient kind I decided to switch it on. It worked – a little noisy with a few crackles but it made a Hammond sound. The bass pedals were shot but those were coming out anyway. Satisfied that I’d made the right purchase I switched it off.
The next day it was time to look inside the Hammond. I removed the back and the sight that greeted me was horrific. Not only had this instrument not been cleaned since 1969 but someone must have used the inside as a waste bin and a rodent family obviously thought it a spacious dwelling at some point. The circuit boards were completely covered in dust and dirt that had mixed with Hammond oil to create a sludge. Here’s the main amp board:
It soon became apparent that nothing could be done without stripping down the whole organ and cleaning it. That included places I couldn’t see such as the keybeds. I’d found myself in this position before with an old Range Rover when I decided to change a manifold gasket and ended up completely rebuilding the engine. A word of advice – label every wire with tape before unplugging from the circuit boards. Although there are circuit and wiring diagrams available there are several revisions of boards with slightly different pin connections.
So how to clean the boards – I needed something that wouldn’t damage them yet evaporated quickly. Enter Isoproyl Alcohol. It smells a little and is flammable but it certainly does the job and is cheap on eBay. Just make sure that it’s 99.9% pure. A couple of hours later the first board was done. The only issue I had was that the cleaning fluid removed the writing on some of the white capacitors on the board. No problem as I had circuit board diagrams – or so I thought.
I won’t bore you with the rest of the process as it involved more of the same on every wire and board in the instrument.