Modifications

What? Modify a Collins? If it needed modification, Art Collins would have already incorporated the modification.

Well maybe. Art didn't live in the new millennium.

Art intentionally made the 30S-1 cabinet large with lots of space so that ardent amateur radio operators could make enhancements to his design that he would be proud of. I'm sure.

He didn't include 160M into the 30S-1 because the KWM-1 did not have 160M and neither did the KWM-2. The 30S-1 was to be the companion to these two transceivers. Since they did not have 160M, why include it in the 30S-1? But he left plenty of room to include 160M as proven by Chris, KB3BF.

The following are the intentional modifications I incorporated into the rebuild:

1. Rewired the dial lighting so that the dial lights would turn on only after the 180 second cathode warm up cycle had timed out. This is convenient, knowing when you could apply the HV to the amplifier, but also aided in trouble shooting the circuitry should the occasion require it.

2. Replaced the stock 1500 RPM fan motor with a 3000 RPM motor complete with electronic speed control and bypass switch.

3. Replaced stock 4CX1000A tube with 4CX1500B tube.

4. Installed screen boost transformer to raise screen voltage from 200 VDC to 325 VDC.

5. Increased the voltage rating of C-204 to accommodate the increase in screen voltage.

6. Replaced stock RCA RF Input connector with N-type RF connector.

7. Replaced K-203 with a robust 4PST contactor. It will never fail!

8. Replaced 3B28 rectifiers with solid state equivalents.

All modifications, with exception of number 6, can be uninstalled to original factory condition. I intentionally did number 6 because of an unfortunate experience in 1970 with a failed RCA connector carrying 100 watts of RF. The result was a couple of 6146s that were destroyed. Using substandard connectors in RF circuitry cannot be excused. I'm sorry.