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Ham Radio

Wavetek 178

[Yesterday: 5 miles, today: rest day]

A fellow ham had a ham radio garage sale yesterday, and I figured it was my duty to stand by him in his time of need.

So, we did our Saturday run really early and then drove up to his place in Smithville.  There I found other fellow hams helping this poor fellow.

I bought a box full of magazines, some electronic components, and a Wavetek 178 sweep generator in non-working condition.

I found the manual online easily enough, and he also sent me a copy as an email attachment.  I checked the voltages at the recommended test points and all looked ok.  The symptoms were:  the fan came on but no indication on the display and no life from the front panel, no output on the output ports and no 10 MHz coming out the back panel.

I studied the schematics.  It seems that the 4 MHz clock for the microprocessors is divided down from the 100 MHz which is the product of the 10 MHz crystal oscillator times 5.  So, no 10 MHz leads to no processors.  I plugged my external 10 MHz source in and I could see where that was on the circuit board.  I looked for the 100 MHz coming out, nothing.  Then I started looking at the internal 10 MHz oscillator.  I wiggled things around, gave the crystal a thump, and started seeing the 10 MHz.  I followed that through the x5 multiplier and could see 100 MHz.  I plugged the cable back into the 100 MHz connector , and give it a try with the power button.  It came to life!

So now I seem to have a working sweep generator.  I’ve never had one of those before.  I’m going to have to fool around with it to see what it does.