accutronics spring question

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Generally they either work or they don't. Measured resistance will always be lower than the published impedance. If you read something less than hundreds of K Ohms it's probably fine. If it reads open, it is. That being the case, check the coil leads to the jacks first; they are prone to breaking from bouncing around in the back of vehicles during transport, or being dropped off the back of a truck.
 
Funny how it is almost always the output coil that fails open circuit! Often they can be repaired - first of all check that the flexible wire from the coil to the phono socket hasn't broken - if it is - this will be an easy repair......

With the newer type of spring line, a push on connector is used between the coil and the phono socket. Pull off this connector and try and measure DC resistance now. Most common units found in Peavey, Marshall and similar amps usually measure around 50 or 60 ohms on a drive coil and about 200 ohms on the output coil.

If it measures open circuit, carefully examine (with a magnifying glass if you over the age of 30) - where the coil wires are solder terminated on the pins that the connector slides onto. A very common failure is to find a wire broken here - with care it will be possible to re-terminate this wire......

John Godsland
 
If it's a repair job - check tha actual connectors. Fixed an amp with a spring line - driver cct was ok - the phono sockets on the spring were different metal to phono plugs connected to it. This disimaller/bi-metal thing going on caused BIG oxidisation which in turn rendered it open cct.
I changed the plugs and sockets and BINGO - it worked a treat!
 
Thanks for the advice. The amp in question belongs to a friends brother in law. I now have my friends identical amp so I can swap the tank & see if the tank is duff. The tank has the push connectors but they check OK. I will get the microscope out (I`m over 40) & check out the coils. Thanks again.
 

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