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Re: Sick Jamman ,HELP!!!!

In a message dated 5/8/98 3:38:04 PM Central Daylight Time, 

>  When I plug in the powersupply the led shows  18+  for a second or two.
>  It goes blank and the machine shuts down. This is not due to the 
> itself , I checked with the vortex  p.supply and it did the same thing. 
> this had gone on for a while I decided to let the Jamman (now a 
> rest , unplugged the patchcables and continued to work with the Vortex.
>   After about 15-20 minutes the Jamman miraculously turned itself on(!). 
> had left the
>  powersupply in the whole time on now the thing seemed to work. I hooked 
> the patch cables and played through the JamDude again. 

At this point, it sounds like a power problem.  Any time lights blink, the
power supply is being interrupted somehow.  Either you are shorting voltage
level to ground or there is a break in a circuit board of which an open
circuit is occurring.  Pull the cover off, you'll need torx screwdrivers,
then probe around on the back by jiggling anything that is attached to the
board.  If you can consistantly recreate the blinking, then you have found 
problem. Take a soldering iron and resolder that part.

>The sound that came out was very distorted
>  (i think you`d call it digital clipping). It sounded like Nine Inch 
> and I actually liked it. But we all know its not supposed to be a 
> unit so I got really worried. I turned the MIX knob all the way down and
> playing. Now the straight guitarsignal  sounded fine. Then , after a few
> minutes of this everything worked again. I played for maybe an hour or 
>  Then the problems returned and the whole cycle started over again. 

Not sure what would cause this, but if there is a voltage problem as with 
lights, perhaps there's a shunt to a part which is getting more voltage 
necessary.  Fix the blinking lights first and then see what happens.  

>  All this might be brought on by one particular change in the Jamdude`s
> Just before I hooked up the boys (Jamman and Vortex) and tried to play I
> them in a 2 unit rackbag from Rocktron.  This bag was a bit too small , 
> roof and floor" were leaning slightly inwards , making it necesary for 
>me to
> use force to fit the two processors to the screwholes.
>  Could this have made them "overheat" in some way ???

Not likely.  If you want to test for overheating, you can buy a can of 
which will cool parts you suspect of getting too hot.  Sometimes this will
allow you to zero in on a defective part. You may have to replace some 

>  Another thing I can think of is that the night be fore I rehearsed with 
> band and things got a bit loud. Could this result in a fuse blowing??  
> way out of my league here , only guessing..)

Unfortunately, a blown fuse would have a different symptom namely, no 
power to
the unit.
You only hope is to take the cover off and start wiggling components while 
power is applied.  Hopefully you'll be able to isolate the problem. 

Get a can of contact cleaner, and with the cover off, spray all of your
potentiohmeter's insides.  From there make sure your stereo cords are all 
and then take your footpedal apart and spray it heavily.  Let it dry and 
it all back together. 

I had a blinking light problem a while back which turned out to be a dirty
foot controller which was acting like a non-debounced switch.  

John Peters