Complete view of ZM-2 with all internal components installed and wired except for L1.
L1 wiring.
L1 DETAIL.
L1 DETAIL.
LED - DIODE - 1K RESISTOR detail
L2 DETAIL. Notice that all of the leads are tinned before installation. This may seem to be a basic concept but I have learned from experience that people don't tin leads of torroids prior to installation.
When my father worked at Northern Radio he would bring home torroids for me to wind. Part of the job was to tin the leads. We did this with a solder pot. That was a nice way to do it. I, like most people, do not have a solder pot. But it is very easy to tin leads on torroids.
It is easy to do, just scrape a little of the varnish off with a knife or exacto. You just need a section of bare wire not a sparkling clean wire. Now, start at that cleaned spot and using lots of solder wet out the lead. You should supply a constant flow of new solder to the meltpoint during the process.