Thanks Roy. This is very complete and easy to follow. Tacking the diode
across R 6 will be easy. I have a suggestion that will take care of that
mechanical strength issue for the additional resistor.
When you attach your wire to one end of new resistor, do heat shrink it up
the resistor to avoid contact with other components. When you attach your
resistor to the top of R3, position the resistor physically against the
circuit board laying between R2 and R3. Thread your wire through the
existing tie wrap that secures the J3 coax (or replace with wire tie if
yours is already too tight).
The solder joint at R3 secures the top and the tie wrap secures the bottom
of the new resistor.
Can we get a copy of the new schematic from Paul or an 800 B owner? Also,
Paul had a very detailed write up of the different ways to trigger the 800
in the original manual. It would be cool to have a copy of that text from
the new version too. Paul? Roy?
Thanks again Roy
Larry Hendry
----------
> From: Roy Tate <roytate@...>
> To: motm@onelist.com
> Subject: [motm] Modding the 800 up to 800b specs
> Date: Tuesday, January 25, 2000 12:49 PM
>
> From: Roy Tate <roytate@...>
>
> At 11:01 PM 1/24/00 -0600, Stooge Larry wrote:
> >Please supply the gory details. I have six of the old style.
>
> Sorry to convert private e-mail to public, but this is of interest
> to all, and several requested the info.
>
> First - full credit for the mod should go to Paul Schreiber, but
> any mistakes are my fault or your own fault. This has worked for
> me on 3 EGs, but I take no responsibility for any problems that
> may arise from your attempts. I reverse-engineered the mod from
> the MOTM-800B PCB, and discovered in the process that the new
> 800B schematic had a small mistake. I've already reported this
> to Paul S.
>
> Supplies:
> one 1K resistor
> one 1N4148 or 1N914 diode
> one 4 inch piece of insulated wire.
>
> Equipment orientation:
> Place the MOTM-800 module on it's side with the the power plug up,
> jacks at the bottom and the pots to the right.
>
> +---+
> |∗ |P
> | |P
> |RR |P <- R6 and R3 are here
> | |P
> +---+
> J J
> J J
>
> Step-by-step:
>
> 1. Locate R6, 1/3 of the way up the board. Our goal is to place
> a diode parallel with R6, with the band UP. I heated up the
> joints and SLIGHTLY lifted each resistor lead out of the joint.
> Then I laid the diode above the resistor, and bent the leads
> creating the two legs that would come into contact with the
> resistor. I then formed a hook part way down each leg. This
> hook will be wrapped around the resistor lead and soldered on.
>
> 2. Locate R3, to the right of R6 and the yellow Capacitor. we want
> to attach a 1K Ohm resistor to the TOP of R3. Once again, I
> formed a hook and tacked it on, leaving the resistor basically
> suspended in mid-air. I formed a loop on the other end of the
> resistor BEFORE I soldered it in place (to avoid breaking my
> solder joint). This loop is then soldered to a piece of wire,
> which should be threaded down to the switching input of the
> Trigger jack (and soldered in). You'll probably have to clip about
> an inch of excess wire off.
>
> Be sure not to leave any stray leads poking out anywhere, and
> make sure the in-air "loop" is very close to the resistor, so that
> the 1K resistor doesn't wander around much. Also, don't get your
> iron too close to capacitor C3, or it will start melting!
>
> Another thing - if you have multiple EGs to mod, do one of them and test
> it on a VCA.
>
> The only bad thing about my mod is that the 1K resistor above R3 is not
> very mechanically secure. I suppose a more professional approach would
> include a bit of shrink-fit tubing to cover up the resistor-to-wire
> "loop."
>
> Good Luck and you're on your own.
>
> Roy Tate
>
> Roy Tate
> roytate@...