I can't remember any posts on MMD about the Busker Organ Forum.
It is a narrowly focused website, but very useful to anyone building or
repairing small mechanical organs. Discussions range over many topics,
including MIDI control technology.

The site was set up and is nominally moderated by Melvyn Wright, English
arranger and supplier of a wide range of mechanical organ music. It is
primarily focused on the John Smith organ family, which includes both
paper roll and MIDI organs, but Melvyn uses the term "Busker" to cover
all mechanical instruments suitable for transportation in an automobile
or carried by hand. Topics such as pipe, bellows, and tracker bar
construction are very popular. Production of parts with computer-aided
resources is also popular.

Posts may include photos and drawings and links to videos. The site
also includes listings of small organs for sale, parts and supplies
which can be useful on a broader range of instruments.

While offensive posts may be removed by the moderator, messages appear
on the site almost instantly, and there may be several responses to
a post within a single day. You have to be a member to post, but I think
that non-members are free to view the site.

https://www.tapatalk.com/groups/buskerorgan/ 

Wallace Venable