Leslie 145 motor disassembly disaster...

[Brazilla]

Hello there, first time post. I have an a100, mid sixties I believe with a 145 Leslie.


I have just been dismantling and lubricating all the Leslie motors to get rid of some motor noise. That went rather well but unfortunately I now have no sound at all. At one point I foolishly unplugged one of the motors whilst everything was running to test something out. This was a bad idea and threw the circuit breakers in my house. Since then the organ turns on fine and plays through its internal speakers, the tubes light up (except the oc3) and the rotors spin as they should. I have removed the amp chassis and inspected (oddly no internal fuse) and found the resistor 470 between the rectifier oc3 tube and the big silver tube next to it (capacitors?) has split in two. I am guessing that the current change I induced by unplugging a motor resulted in that burning out and that is why there is no sound. Hopefully I haven't damaged anything else.

Anyway, what i would like to know is, should I buy a particular type of resistor to replace it? I am aware of different types but unsure if I should replace with a specific one? Please advise! Any other suggestions for things to check out other than this are appreciated. Fingers crossed I can fix it myself! Pretty handy with a soldering iron!

[geoelectro]

It's a 1/2 watt 470 ohm carbon comp resistor. Don't over size the wattage. It acts as a surge protector for the OC3 and a fuse.
It's unlikely unplugging a motor had anything to do with this. I unplug and plug them in all the time while running, no big deal. However, you can accidentally touch the chassis with one prong of a plug while the other one is connected to the hot side of the mains while plugging in.

Recently, I had that resistor burned in a church repair. I suspected 6550's and changed them. The new resistor smoked. I changed the filter cap and again, the resistor smoked. I unplugged the relay (HS mini relay on circuit board) and the problem went away. I replaced the relay, plugged it back up and again, the resistor smoked. I pulled the 12AU7a switching tube out and problem solved. Installed a new tube and all was well. I should have started on that end I guess...
So a defective 12AU7 switching tube can draw too much current and burn that resistor.

Geo