In the RA117, the 100KHz ‘strip’ is the fourth IF; the other three being 40MHz, 2-3MHz
and 1.6MHz … otherwise it is identical to that found in the RA17L
Here it is fully refurbished with the bandwidth switch shaft re-fitted. Note that
the shaft has been rubbed down with a fine abrasive. This was necessary since I had
a terrible time getting the gears off. The Allen grub-screws were, as usual, bonded
in place with locking compound. However the biggest problem was with the retaining
ferule between the rear bracket and the rear gear. In the end I simply drilled through
the aluminium ferule with a bit the same diameter as the ferule is wide. This enabled
me to ‘split’ it so that it would slide off the shaft. ALL the grub-screws had been
screwed in so tightly that their ends had actually formed ‘pits’ in the shaft. This
made it difficult to slide the gears off despite the screws being retracted. A hammer
and centre punch was necessary to effectively knock the shaft through the gears!
… hence why the shaft had to be ‘polished’.
This is the fourth IF strip reinstalled in the chassis. Note the extra RF-Choke at
the bottom of the picture. This is in the HT line to the 1.7MHz module. You can also
see, to the left of the choke, a 100K resistor on a ceramic stand-off. This is the
resistor, which in the RA17L is usually located next to the HT and heater decoupling
chokes. Finally … having destroyed the aluminium ferule, I replaced it with a piece
of brass tubing which just happened to be the perfect size … so no need for grub-screws!