Novice Rig Roundup is March 4-12 this year and is now underway. My Drake 2 Line, the 2-NT transmitter, and the 2-C receiver is my go-to novice rig. I used a Drake 2-C as a Novice Class ham in the late 60s. I get to recreate that novice experience using crystals for the 2-NT. It is challenging when you have a few choices of frequencies, and you can't move around with a VFO.
|The Drake 2-NT transmitter and Drake 2-C receiver work smoothly together like a transceiver.|
Sadly I let my original Drake 2-C go, so I bought a replacement from eBay. Phil N4STC now SK did a partial recap for me when I got the receiver. However, a hum developed that I lived with, but eventually, it was overwhelming the audio. The usual suspect is electrolytic capacitors, which was the case this time.
|This is the 12-volt DC power supply circuit board in the Drake 2-C. The large electrolytic caps were the issue.|
There is a sidebar to this story. I bought a digital storage oscilloscope for my birthday. The good news is you can get a lot of bang for your buck these days. I purchased a new Instek GDS1102B two-channel 100 MHz digital storage oscilloscope for less than $300. The scope is a great value considering we hams may spend $300 on an antenna analyzer.
|The Instek 1102B. Note I had not compensated the probe.|
The scope came in handy. Sure enough, the 12-volt DC power supply in the 2-C had a six-volt 120 Hertz AC component. There were two 1000 uF capacitors to do the filtering. One failed open they both had a cracked case. I ordered replacement caps from Mouser, and they arrived the day before NRR started. So a little soldering and mechanical maneuvering did the job. Yet the scope still shows one volt of AC on the 12 volts DC. That causes a minor hum, and I choose to go with it and get on the air for NRR.
|Before: This is a terrible output for a DC Supply.|
|After: Replacing the caps improved it, but there still is about a volt of AC.|