[Hallicrafters] SX-62A Alignment

[Joe Connor]

I'm in the process of reviving a very beat-up old SX-62A. An IF alignment did wonders for sensitivity. When I got to the RF alignment, however, the trimmer caps for Bands 1-4 do not seem to have any effect whatsoever. (On Band 6, FM, however, the trimmers made that band come to life). What could be causing the trimmers to be ineffective on Bands 1-4. 

Another question: a prior owner subbed 6L6s for the 6V6s. Is there any good reason to do that?

As always, thanks for your help.

                                   Joe Connor