The Drake production change from the TR7 to the TR7A happened somewhere between serial numbers 11,500 and 11,800. The "A" version was just a upgrade of the then produced TR7 with a couple of additions and external differences. Those external differences being the front panel top section with model number and the rear panel spare jack wiring & labeling. We know Drake did perform factory TR7 to TR7A upgrades, however, that did not include the front panel top section indicating the "A" model. Drake stop short of replacing that panel so to not confuse the upgrade for a factory production version. Anyone with specific knowledge of the upgrade changes could perform the same upgrade changes outside of the factory. That same upgrade could be performed on the earlier low serial number models as well. However the earlier model probably did not have the later circuit board changes that the higher serial number radios had. Those TR7's with the stick paint case were some of the earlier radios produced usually found under serial number 6000.
Those TR7's with the BLACK textured finish case has a replacement case. The black was never an original production case, the original case was the dark gray texture. The black case came later and after Drake ceased producing the "7" line equipment. Drake did a run of black case because of a large demand for parts replacement cases for the sticky paint case. At that time Drake still produced the R8 receiver and the TR270 UHF/VHF radio which used the black case material, thus the reason for using black since it was a stocked material. When Drake ceased producing ham radio equipment they started selling off all their parts to everyone who wanted them. One of those parts was the TR7A front panel top strip which indicated "TR-7A" Drake had a few hundred of those which sold quickly. So now for the first time this made parts available that could make a TR7 upgrade look like a true TR7A production model. We all have seen a few of these upgrades on eBay which looks like a "A" production model. Prior to liquidating their parts, all parts which identified a radio by model such as a front panel were sold on an exchange basis only. This was Drake's way of security and to reduce the possibility of model misrepresentation. The process of ordering a new front panel for instance, was you sent Drake your old panel to them, in turn Drake would sell you a new front panel only for the exact model of the radio on the exchange. So the TR7 , or the TR7A production model, or the upgrade version, may be easy or difficult to tell the difference, all depends on the radio. In most cases the serial number is the best indicator since the transition between models was around the middle half of the 11,000 serial number range. If the serial number on the rear panel is missing or appears altered, Drake also printed the radio serial number on the chassis front panel behind the aluminum sub-panel. The Drake production change from the TR7 to the "A" version only included the following five changes. 1. A noise blanker ( <http://www.dproducts.be/DRAKE_MUSEUM/nb-7_noise_blanker.htm > NB-7) has been installed. 2. A 500Hz filter (SL-500) has been installed in selectivity position "A" 3. Selectivity "B" has been adapted to provide a bandwidth of 9kHz for AM reception. A resistor across the input and output terminals. 4. A surge protection device has been added to the receive antenna input to provide additional protection from static discharges from lightning. 5. The unused phono style tip-jack on the rear panel has been labeled "TX", and now provides an alternate audio input to the transmitter for sources other than microphone. This jack is connected in parallel with pin 1 on the front panel microphone jack. See below the pictures showing the connector labeling on the TR-7A rear panel. So determining the differences varies and can be a challenge all depends on the radio, the options installed and the ability of the person doing the upgrade. If you want more detailed information on the TR7 to "A" version differences, take a look at an article I wrote a few years ago on this subject. Here is the link <http://www.wb4hfn.com/DRAKE/DrakeArticles/TR7_Comparison_Ar ticle/TR7_Idenity-01.htm> http://www.wb4hfn.com/DRAKE/DrakeArticles/TR7_Comparison_Art icle/TR7_Idenity-01.htm 73, Ron / WB4HFN
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