I have a Model 630, and which is now working after recapping and replacing several out of tolerance resistors. Except for the Wave Trap adjustment all the other adjustments have worked fine. I am using a #20 wire, 26 feet to act as my antennae. If I attach the antenna to the ANT terminal of the radio, I can pick up several stations but with much static. See the attachment. If I attach the antennae to either the Black or Red terminal the reception improves but still has some static. If I attach it to the blue line, (see the attachment) direct input to the tuning condenser it works very well and tunes well with little or no static on the tuned station. While aligning the set I only experienced a problem trying to align the Wave Trap. The coil does ohm out at 17 ohms, but it seems like the variable capacitor has no effect.
Is the Wave Trap causing my static problem? the rotary switch seems to ohm out ok and has been cleaned. Any suggestions.
By connecting the antenna directly to the grid of the rf amplifier (blue wire) you have eliminated everything but the band switch and antenna transformer. The two most common problems at this point are dirty switch contacts (section one) and an open coil in the transformer (3). Have at it!!
The wave trap is to block signals at the IF frequency from ingress. This used to be a big problem back in the day when coastal marine services transmitted on or near that frequency. It could also be used to block stray IF output from the radio getting back around to the antenna inputs at the second harmonic.
Thanks to all. The problem was the antenna wire on the rotary switch was broke but just making contact. I
soldered the wire and all works good now. I left the Wave Trap connected.