RA17 page 11

It is worth noting that Racal paid close attention to include appropriate filtering on the HT and heater lines. This was done per unit. The photograph on the left is that pertaining to the Harmonic Amplifier. The photograph on the right is the network associated with the 1st VFO. Note that here, as in the 2nd VFO, the 470R resistor (R55) has been replaced with two 1K resistors in parallel.

Even though the resistors in the input attenuator are unlikely to go too far out of spec., I went ahead and replaced them anyway. The photograph on the right is the meter rectifier. This is a very early solid-state rectifier from an age when valve rectifiers were still commonly used. As a consequence, the manual refers to this curious device as a metal rectifier, which I suppose is inherently accurate too.

Now this one had me scratching my head. I can’t remember where I read it, but I already knew that locking of the main tuning dials on the RA17 series was achieved by way of tiny brake pads. It wasn’t really a surprise either to find that they were a tad worn too (see the inset, right). One of the EMERs describes how these stick on pads can become loose and fall off if the dial is operated with the brake applied, and thus describes the procedure for fitting bolt-on rubber brake pads. I fully expected to read that the levers would require drilling to take the 6BA screws. But no, the holes are already there! One has to ask, why on earth were inferior stick-on pads fitted in preference to the bolt-on variety? Quite by accident, I found a source of rubber dial brakes on Ebay!