- BACKGROUND ON ZENITH - WHY THIS MODEL
In the 80's and 90's I became interested in shortwave listening and bought a digital portable and eventually graduated to better and better radios. However, I still remembered that Royal 3000 Trans-Oceanic gleaming of chrome and black vinyl. I happened to read about a book called "Zenith Trans-Oceanic: The Royalty of Radios" by Bryant & Combs, published by Schiffer Books. This book was totally entertaining and informative for a radio lover like me, explaining how Zenith came into existence under the direction of its passionate creator Commander McDonald. It explained how the Commander's personal desires led him to demand the finest possible performance from all of their products, most particularly their flagship line of Trans-Oceanic radios. There were 5 tubed models and 4 transistorized models of Trans-oceanics. There were many variants and subtle upgrades among these variants but these are the major models. The "T/O book" clearly outlined the development, design and characteristics of each model, showed glorious full color, glossy photos of the radios and their print advertisements. In short it was like reading a brochure for a new car I NEEDED to get a Transoceanic but which one?
My first two T/O'S were tubed models from the 600 series, and I will detail my experiences with those wonderful radios in a future Nostalgia Radio article. But my third acquisition was a solid state T/O, the Royal D7000Y. This is the third of the four solid-state T/O's and I chose it for several reasons. First, I opted to pass on the final T/O the similarly and confusingly named R-7000, because that radio was manufactured in far smaller quantities than the Royal 7000 which preceded it and would thus be more costly to obtain. Secondly, that last model did not follow the design concept of all previous T/O's the bandspread principal, which the Commander had specified on all the models he oversaw. Instead it adopted the continuous coverage design, which, while it did offer reception in some ranges skipped by the band spread models, nevertheless makes tuning of sw broadcasts much more difficult. That last model also marked the transition from the hand-wired chassis of all earlier models to printed circuit design. This model is often mistakenly referred to as The R-7000 Taiwan, but in actuality was built in the U.S. for the first year before production was moved overseas. Finally, the Royal 7000 (which Bryant & Combs refer to as the last "real" Trans-Oceanic") corrected many flaws in the design of the previous 1000 and 3000 series, and seemed like it would offer the most performance with enhanced circuit design and features.
Briefly, the Royal 7000 is a single-conversion, AM/FM/SW portable receiver that runs on 9 D cells or a built-in multi-voltage supply. As with most analog sets that run on D cells, by the time the batteries are exhausted you probably won't remember when you last replaced them battery life is measured in the hundreds of hours with modern alkaline cells. The radio offers a built-in BFO for SSB reception, a tone control, two bandwidths, lighted dial and map lights and a total of 9 reception bands, including VHF weather. Other improvements over the earlier 1000 and 3000 series included a stronger handle independent of the huge whip antenna, improved chrome plating to eliminate the pitting problems common on the earlier models, and an improved battery compartment design. There are still many good reasons to collect each of the T/O models, but these were my reasons for selecting the Royal 7000. There are three versions of the Royal 7000 but functionally they are identical except for the handling of the weather band. Also the map compartment cover was changed from silver to black in this final version and the logo on the front cover was re-designed.
- INITIAL ASSESSMENT AND CHECKOUT
I re-connected power expecting to find all the electronic problems resolved (as is often the case in solid state equipment) but I wasn't so lucky. Although all bands now worked and all the static and intermittent operation of the controls and transistor sockets were gone, the sound was still fuzzy, and seemed worse at low volumes. I also noticed lots of black flecks as I had mentioned earlier. I decided to pull the speaker and check it for a rubbing voice coil. When I did I discovered a foam mounting gasket around its edge had deteriorated and a pile of black dust fell out from the front of the speaker. I gently used compressed air to blow it out and the speaker sounded much clearer, but the sound still lacked the cleanness and power I had expected and the radio sounded weak and distorted even when another speaker was temporarily substituted. I did some signal tracing and soon discovered that one of the transistors in the push-pull output section was bad. These are matched pairs and replacing them with anything other than a matched pair will degrade audio performance. I didn't have a parts radio around and lacking a cross-referenced replacement pair, went to one of the internet groups devoted to these radios and quickly scrounged up a matched pair for the cost of shipping some $3 and change. A few days later they arrived; I plugged them in, and then heard the D7000Y sound "right" for the first time. Gone was that ripping distortion as I increased the volume. Confident that the radio was essentially working properly I turned my attention to finer details.
- COSMETIC PROBLEMS - CLOUDY DIAL/DENT IN GRILL
The other thing that bothered me was the dial glass it was cloudy and it detracted from that fresh, crisp look the dial had when it was out of the case. I was not able to reduce this haziness using the Novus Plastic Polishes, which usually work very well for this. I went to the auto parts store and bought a product used to clean the rear window of convertibles it was near miraculous. It left the dial clear and shiny absolutely amazing! I can't say this product will always work, but in this case it made all the difference. Since this is clear plastic with no lettering on it I didn't have to fear rubbing the lettering away. I've worked on that kind of dial glass before and it is a lesson in patience and care, using Q Tips to work around the lettering. Luckily there was no such issue here.
- ALIGNMENT CONSIDERATIONS/DIAL TRACKING
In the case of this particular radio the worst problem I saw was very bad AM dial calibration, although reception seemed good. AM is the first band to be aligned in the sequence, and that allowed me to experiment a bit before I proceeded to the shortwave adjustments. The problem I was having was that, no matter how I aligned the 7000 I could not get the dial tracking to be right. If it was correct at one part of the dial it was off at another by an unacceptable amount, 30 to 40 KHz. I discovered that when I started out with the tuning gang fully open (clockwise) and set the frequency for 1620 KHz as outlined, when I then turned the dial down to 1600 the radio was actually tuned to about 1615. In other words, as I tuned down from 1620 toward 1600 on the dial the actual tuned frequency was only beginning to decrease and at too slow a rate. What would cause this? My best intuition tells me that some component values have subtly changed. Attempting to measure these components would be a lesson in futility as most would have to be removed from the circuit to test properly. I could have gone crazy trying substitutions from a parts set (which I didn't have), but there are more practical ways to deal with these subtle changes. The most obvious would be to simply set the dial to 1600 and align to that frequency, but I avoid that method except as a last resort. This unit is supposed to top out at 1620 KHz when the condenser is fully opened and I wanted to start with that specification satisfied.
One way to deal with this symptom is to adjust the position of the dial pointer on the string. This is itself a calibration point in some, but not most, alignment instructions. It was more common in earlier days and now seems to be assumed rather than stated. Some radios have actual calibration marks say at the bottom end of the dial, where the pointer should rest when turned all the way in that direction. On the Royal 7000 you can assume the dial should point exactly to the "0" of the log scale and then it will reach the end of the dial scale markings at both the left and right extremes of its travel. My dial pointer was a bit to the left of what looked like the optimum position, so I loosened it on its string carefully and slid it a bit to the right until it seemed to span the dial scale properly. Now when I set the frequency to 1620 and aligned the radio with the dial all the way to the right, then tuned the dial down to 1600, the radio was very tuned very closely to 1600. Once I realized the dial was in the wrong spot on its string it all fell into place it is likely this sample was always this way from the day it was new. Unless it had sometime been tampered with I don't see how it could have shifted on its own.
One other part of alignment that is often misunderstood even by seasoned repair technicians is the concept of "rocking the tuning gang" or "making a rocking adjustment" at a specific frequency. Better AM radios have a so-called padder adjustment, generally performed at 600 KHz. When you are told to make a rocking adjustment at 600 KHz the procedure is this. Tune your RF generator to 600 KHz and tune in the signal on the radio. Hopefully the dial will indicate exactly 600 KHz, but for now just tune for maximum signal. Then align the adjustment point for maximum signal strength. Now, keeping the generator at 600 KHz, tune the radio higher in frequency just a bit, then re-peak your alignment point and note whether the signal is stronger or weaker than before. If it is stronger, turn the dial further in the same direction and peak the alignment point again. Keep turning upward and re-peaking until the result is a weaker signal, then turn the dial in the opposite direction and repeak. You are looking for whatever point on the dial yields the strongest signal after the alignment point is peaked. This is the proper adjustment, even if the dial does not indicate exactly 600 KHz. Generally the error will be subtle, and getting the maximum performance is the most important goal. Many technicians unfortunately simply put the dial at 600 and peak the adjustment for maximum, leaving a severely desensitized radio. Sometimes you have to start all over again to get all dial points closer while maintaining best reception, but when you are done you have the satisfaction of knowing your radio is indeed "peaked to the max," as we used to quip.
In the case of my particular radio the eventual dial calibration and tracking were excellent with very little deviation over the scale, and I know I'm getting the kind of performance this radio was designed to give. Alignment continued through all the bands without any further problems, and all the bands seemed to exhibit similar sensitivity and selectivity. I was confident it was working properly on all bands.
- RE-ASSEMBLY AND PHYSICAL RESTORATIONS
I also wanted to replace the lamps two of the three were working (two for the dial scale, and the third for the flip-up chart light. The eBay seller hadn't realized they required a D cell to work, even when the radio is plugged into AC. Unfortunately the lamps I bought were pre-focused and did not illuminate the dial scale evenly. I ended up ordering the correct #123 lamps from an online source they were inexpensive and arrived within less than a week. It is possible to change the dial lamps by simply removing the back cover, but it is easier when the chassis is out of the cabinet. I found the two drum-mounted lamp sockets were a bit dodgy I cleaned them as well as I could by hand then applied a light dab of contact cleaner before I put the new lamps in place.
VIII - FINAL
I then compared the Royal 7000 on AM and SW with my other portable radios and the Zenith acquitted itself very well. At the time Zenith radios were being aggressively marketed they were widely considered to be the very best in category. Nowadays we know there were some other excellent radios around which perhaps were more advanced, but they were also more expensive and less well known here in the US. Still, the Trans-oceanic holds up to comparisons and comes out smiling. While a few other radios were able to outpoint the T/O in various individual categories, taken as a whole package, the Royal D7000Y was a winner. Sensitive on AM & SW, good clear audio with some power behind it and built like the proverbial brick you-know-what, this solid package should have many years of dependable service left in it.
Final note: The Grundig Satellit 210 I wrote about in the previous column is one of the radios I was referring to when I discussed more expensive portables that out pointed the Zenith in some categories. That Grundig cost close to three times what the Zenith cost almost a decade later but it does have some design features lacking on the Zenith, such as double-conversion (for fewer images) and even higher shortwave sensitivity. But the Trans-Oceanic has some points in its favor. It is smaller, more rugged and far easier to service. It's much simpler mechanical design should pose fewer problems with wear and tear and shipping damage. I would bet the Zenith would be more likely to survive a "drop test" than the Grundig. And it has an audio clarity the Grundig does not. Clearly there is a place in this collector's group of favorite radios for both!
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