[time-nuts] Adding adjustment pot to 5680
golgarfrincham at yahoo.com
Sun Jan 15 18:31:39 UTC 2012
>"Hardest part is attaching the 100K resistor to the ic. Boy thats small."
I didn't solder the resistor directly to pin 5 of the IC. I found that pin 5
was connected to a nearby SMD capacitor that was a little easier to
solder to. Attached is a photo of the correct location if you want to try
bringing the EFC out for analog control.
Where others had commented that the internal 7805 I added was running
without a heatsink and would be close to max ratings, I started to worry and
decided to mounted it on the heatsink that runs down the middle of the
5680A using an existing mounting hole that is used to mount a TO-220
device on the other side. The screw used to mount that device is too long
so I replaced that screw with one that doesn't go quite 1/2 way through the
heatsink and used an identical screw to mount the 7805 on the connector
side of the heat sink. I had to elongate the mounting hole in the 7805 so it
Wouldn’t interfere with the cover or the dimple in the cover where the screw
that holds the cover on screws into the heatsink. The photo linked below
shows the better way to mount the 7805 so you can use a single 15V supply
for the 5680A.
More information about the time-nuts