Tech Tips

Batteries for Tubed TOs       Cases for Transistor TOs       Battery Eliminators       Technical Information for Tubed TOs

All TransOceanics were designed to be operated from batteries (and most from ac as well - that the first Royal 1000 and Royal 3000s were not may have been since they were sold in parallel with the last of the tubed modes). The requirements varied from model to model.

Transistored TOs are simple as all use standard "D" cells in various numbers. For the Royals (1000, 3000, 7000, & D7000) one battery was dedicated to the dial lights and is the only source of dial light power. On the R-7000 only, line voltage could be used for the dial light making it possible to illuminate the dial without any batteries installed.

Batteries for the Tubed Trans-Oceanic

Tubed Trans-Oceanics require at least two sources (on -600 series a separate type "F" 1 1/2v battery was used for the dial light). All TOs were designed for use with a single combination A & B battery with 9v (A) and 90v (B) outputs. This battery nearly filled the lower compartment and was claimed to be good for 200 hours of listening (at low volume).

7G605 and 8G005 models required a higher A voltage for the increased tube compliment - 10.5v. All used series filament strings. In the 8G there are 8 tubes all of the same filament voltage. For the 7G one of the tubes required double the voltage as the others so both 7G and 8G have the same requirement). To achieve this a single type "F" cell (essentially double the "D" capacity) was used in series with the 9v section of the AB battery for these two models.

Today, neither "F" cells nor A/B batteries are available. Eveready does have a type 490 90v B battery available that is similar to the second stage but costs $33 from most sources and is obviously incorrect.

The most common solution today for -500 and -600 TOs is a combination of six series connected "C" or "D" cells for the A side (seven should be used for the A side of a 7G605 or 8G005). 10 9v transistor batteries may be clipped together for the B side. This is said to give reasonably good life.. A single "D" cell is adequate for the dial light in the -600 series

For those interested in specifications, the Eveready no. 752 was listed in 1971 as a replacement for the Zenith. It was rated for 9v @ 50 ma and 90v @ 12-15 ma and weighed 9 lbs, 6 oz. Life values indicate 220 hours theoretical and the total capacity of the A side was commensurate with a series arrangement of alkaline "D" cells (13,000 mahr/50ma=260 hr) while the 9v will have a somewhat shorter life (565mahr/15ma=38). - Note that these are theoretical vlaues - your mileage may vary.

Batteries and Cases for the Transistor Trans-Oceanic

The transistor TransOceanics all used the same batteries, nine of the common "D" cells, eight providing 12vdc for the radio and one separate batter for the dial light.

The problem is often not the battery but the battery case which, being integral in the first 1000s and the 7000 models may have suffered from leakage as the batteries of the '50s and '60s often did following long periods of inactivity. In this case the only solution is to clean the sufate off (CAUTION: the sufate is caustic/toxic - be careful).

A second problem exists if the leads have become corroded. In this case replacement is necessary. The use of 20 guage stranded wire is suggested for this purpose. If it is necessary to replace the springs, only spring material should be used though end loops may be replaced with 16 guage solid wire.

The major difficulty exists with later 1000s and all 3000s if the soft two-piece battery container is missing. In this case the best answer is to advertise for another (Newsgroups or are recommended) though these may be difficult/time consuming to find.

Unfortunately, while triple D cell holders are available, I have not seen any designed to fit in the confined space alotted to the batteries in a 1000 or 3000. However bearing in mind that originally the goal of a TO was 200+ hours life, three triple C cell carriers will fit is the space though battery life will be in the 80-120 hour range. While looking for a proper case, this will keep the radio usable.

Battery Eliminators

In the case of a 1000 or 3000 there is often the desire to eliminate the batteries entirely. In the case of a -1, this is not difficult as the radio is already designed for use with the proper AC supply such as those available from Radio Shack. Since the original was designed for 12vdc output at 50 ma there is a problem as the universal units are designed for higher loads (often 500-800 ma) and are generally poorly regulated. The answer is to try the next lower setting (usually 9v) and see if the radio operates properly. If it does, use that setting.

The next point is to make sure that the proper polarity is observed with negative (-) on the tip of the plug. Since the -1s used a 3/32" subminature phone plug for this and most universal supplies come only with a 1/8" minature phone plug, and adapter will generally be needed. These are available at Radio Shack.

The final note is if you wish to convert a non -1 unit to ac. In this case you will need not only a power supply, but probably also a noise filter (sold at RS as a 12v CB noise eliminator) and a connector.

Connections to the three pin connector are as follows or check the continuity against the battery case (better). Looking at the plug from the rear of the case, there will be two pins on the left. These receive the 12v with (+) on the top and (-) on the bottom. There is a third pin on the right at the same level as the left upper pin for the dial light. A 1 1/2v D cell is best used here connecting the two upper pins (polarity is unimportant but remember that one side is connected to 12v+). Like this:

	12v pos   O    O  1 1/2 v diallight ref to 12v pos

	12v neg   O

Technical Information on Tubed TOs

By far the best source for technical information on tubed Transoceanics is the Signal Corps Technical manual for the R520, TM 11-877. While specifically for the six tube chassis (R-520, -600 models), all of the basics are there particularly a good bescriprion of the bandswitch tower used since the firat 7G.

Recently this was scanned onto a web page by Mike Gasperi: TM 11-877 Chapter 4

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