Re: Problems with 1147 XB-2 preamp

[mwolk@awod.com (Michael Wolk)]

Mike Sues wrote:
>
>  last weekend I was have a grand time playing my M3 through my 145 and
>  decided to switch to my XB-2. Well, my XB-2 was already turned on as I
>  had been using it as a MIDI controller. The 1147 preamp was plugged
>  into the XB-2 but its power cord was not plugged in. I took my 6-pin
>  Leslie cable and connected it to the preamp. When I did this I heard a
>  small pop from my Leslie. I unplugged it, not because of the pop,
-------------------snip---------------------------------------------------
>  I presume the problem is with the 1147 preamp but maybe I'm wrong. Any
>  ideas ? Has anyone else had a similar problem ? I'd like to figure out
>  which component (Leslie, XB-2 or 1147 pre-amp) is damaged before I take
>  anything anywhere for servicing.
>
>  Thanks in advance.
>
>
>Mike Sues
>http://www.magi.com/~dragonmn
>================================================================
>The world is a raw waveform, waiting to be sampled and filtered.
>================================================================

Mike:

I'm not a Hammond/Leslie service tech, but I do a tremendous amount of
electronics repair work in my regular job (I&C Tech) and this is probably
what happened:

By not grounding your 1147 preamp (by plugging it in) when you tried to use
it, a hot signal or DC went through there looking for the quickest path to
ground. On it's way either to or from the Leslie, it smoked a component in
the 1147. Look fro a charred zener diode in the 1147 Power supply output.
Otherwise it will be in the audio output driver section of the 1147.

"Walkin' Wolk"