Hewlett Packard 606A
or
How I Found the Signal Generator of My Dreams

by Robert Shindhelm

Web Edition

If you own an HP 606A, you can relate to Robert Shindhelm's experience. The Model 606A is an overly engineered, rock-solid signal generator. For all other readers, here is your chance to learn more about this unit, as well as have a few chuckles. (Editor)

There it was, right in front of me on eBay, and located less than 25 miles from where I sat -- a Hewlett Packard Model 606A signal generator, shown at right. I couldn't believe it -- the picture was a little fuzzy, as many eBay pictures are -- but it was unmistakable. One of a kind! I had bid on several of these in the past, but right at the last second or two, some jerk with more money, or maybe more smarts than I, had pulled the rug out from under me, and I ended up with nothing. I resolved to do this very carefully so that nothing would go wrong this time.

I carefully noted the auction number and the date and time for the end of the auction. It had about two days left to run, and I sweated away every minute. At last, the time was here. It was about 11:10 p.m. and the auction would end at 11:21:07. I sat down at the computer, turned it on, got online, found my auction, reread the listing for the 47th time, synchronized my watch with eBay time, and went to the bidding area. I still had about seven minutes to go.

As I said before, I had been watching for one of these items for some time, so at least I had a fair idea of what they had been going for. I thought about it a little bit, so I bid the most I had ever seen one sell for; then, since I figured I would be able to pick it up and not have to pay any express, I added about 25 percent more. I really wanted this signal generator.

My HP 606A. The meters read "percent modulation" and "output." The unit has an oversized tuning dial and an easy-to-read dial scale.

I put the pointer over the bid button, looked at my watch, and still had over five minutes before the end of the auction. I sat there fuming and sweating with my finger poised for the longest five minutes I have ever known, hoping that the computer wouldn't time out or drop offline or something. At last, with 15 seconds to go I pressed the bid button, closed my eyes and slowly counted to 20. My heart thudded and my palms sweated.

When I opened my eyes, the screen said I was the high bidder! I couldn't believe it. I pressed the back button and then the reload button. Sure enough the auction had ended, and I was high bidder! And it cost me only about half the amount that I had bid. I was absolutely ecstatic. I was so excited that I let out a whoop that woke up my wife, and that quieted things down quite a bit. I did go ahead and send the seller a message that I was the high bidder, gave him my telephone number, and asked if I could pick it up, as I was anxious to conclude the transaction.

The next morning, I immediately put the computer online so I could regularly check my e-mail and took the phone to the garage so I wouldn't miss a call. I fretted and fumed all day with no calls and no e-mail that I cared about. Finally, about 7:30 p.m. I got an e-mail from the seller that said he had been trying to reach me by phone all day but kept getting a busy signal. I had been so excited that I hadn't thought about the computer tying up the line.

I did make contact with the seller the next day, and he told me, "Sure, come and get it." So I did. After I had paid the bill, he led me into a long building, and as we were walking, I could see the signal generator sitting by the back wall. The closer we got, the bigger it got!

Now I had seen many pictures of the HP 606A, and I guess I was vaguely familiar with its dimensions, which are about 15" deep x 21" wide x 13" high, but no one had prepared me for this sight. The thing was huge with a footprint of about 300 square inches. It was kind of like meeting the girl of your dreams and finding out that she was two feet taller than you. It was not only big, it was heavy. Luckily there was a sturdy fellow there, about 50 years my junior, who picked it up and put it in my truck with no trouble at all.

The Restoration

Since the trip home blew a lot of the cobwebs and surface dust off, most of what I had to do was clean off the residue of 40 years of smoke-filled rooms. I plugged it in, and it did work, as they said it would, but only on one band, which they hadn't mentioned. The band selector was frozen solid and wouldn't budge.

After removing the housing, I could begin to understand why it was so heavy. This thing is built upon a large aluminum casting which is bolted securely to a ¹/4" aluminum plate panel. There is a large 4-section variable condenser, as well as circuitry for 19 tubes mounted in various positions within this casting. The band selector knob drives a steel shaft into a geared rotary toggle arrangement with cams and detents which rotate to position the coils. The coils are mounted on two contrarotating fiber plastic gears, thereby changing bands.

Most of this stuff appears to be of a size more appropriate for pumping oil wells than for band switching. All of these shafts and gears are supported by bushing and ball bearings, and all of the moving parts were filled with dirt and the caked remnants of some sort of lubricant that had been placed there 30 or 40 years ago.

I clamped a pair of vise grips on the shaft behind the panel so I could wiggle it and went to work with WD40, a toothbrush, and a small wooden scraper. Two days, and half a can of WD40 later, I could rotate the selector shaft; in three days the toggle arrangement started working. Today, it operates like new on all bands with almost unbelievable accuracy. It tunes continuously from 50 kHz to 65 MHz in 6 overlapping bands, and it has a built-in crystal-controlled oscillator with a 100 kHz crystal and a 1 MHz crystal for "zero beat calibration."

As you can probably tell, even with the size problem, I'm reasonably well satisfied with my purchase. I've built a special "heavy duty" shelf for it over my workbench. I sure don't want to move it again.

(Robert B. Shindhelm, 5830 E 58th St., Tulsa, OK 74135-8131)

At age five in the early 1930s, Robert Shindhelm was given a Radiola III, which was soon reduced to junk, but still sparked a lifelong interest in vacuum tube radios. Though he worked in a radio shop before World War II, he did not start active collecting until retirement in the early 1990s. His primary interest is in collecting and restoring pre-World War II radios, especially early electrics and test equipment. A favorite radio is a Howard Junior from 1930.