RA117 serial number N0489 (/cont)

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!