[HAM] Leslie 900 Woes

[Paul Barrow]

It's been decades since I had my Leslie 910 but the
best of my memory is this.    With the Leslie sitting
idle for about 30 minutes (not playing through it but
turned on) feel the chassis around the output
transistors.   It should not be hot.  Maybe just
slightly warm at most.    If it's pretty warm or hot
them you most like have some leaking power
transistors.  Replace them and make sure the Emitter
current limiting resistor are not discolored from over
heating and replace them if they are.   I don't really
see how this could cause the amps to vut out though.
There is no Thermal protection built into those amps.
They either work or run hot until there is a
catastrophy (or tripped circuit breaker at least).
The only other possibility I can see is the
semi-regulated +28 volts for the power amp driver
stages which is supplied by that one transistor in the
power supply.  If that transistor was having problems
you could lost the DC tot he driver stages and thus
all 3 amps would drop signal and thus no bas or treble
or reverb output and maybe no tripped circuit breaker.
 So I would suspect that circuit in the power supply
1st.

Paul Barrow

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