The individual service data manuals on the DVD-ROMs,
USB Memory Sticks and available through the
Instant Downloads service will be one of the following types:
This is an original manufacturer's service sheet or manual. These vary from a large service manual at one extreme, to a preliminary data sheet containing little more than a circuit diagram and alignment information at the other end of the scale. Most are somewhere between the two extremes, and give adequate information for a reasonably experienced engineer to use.
Many restorers regard Trader sheets as the best source of information. Trader sheets generally contain a clear circuit diagram, separate parts list, alignment instructions, typical voltages, tuning drive restringing, production modifications and variations etc. Most have from 2 to 6 pages, televisions sometimes span 2 or more Trader sheets so could have more pages.
These sheets were published in a rival publication to the Trader. They are generally a little less comprehensive than Traders, and the layout is not so friendly. However they covered many sets that Trader did not, and the information is adequate for most purposes. Most are 2 or 4 pages, televisions sometimes span 2 or more ERT sheets so could have more pages.
These sheets were published in the 1930s and are quite similar in content to the ERT sheets. They cover some sets from an earlier period than Trader or ERT sheets. I believe this publication became ERT during or after the war. Most are 1 to 3 pages, with wartime data mostly 1 page.
These sheets were published in another rival publication - one which could not make up its mind what to call itself! The sheets were generally described as product reviews, yet they concentrated more on the circuit operation, adjust and alignment etc., than on the product performance. The information is a little more limited than ERT sheets. Most are 1 or 2 pages.
These famous burgundy books were published from the early 1950s. The amount of data included varies but it is generally fairly minimal, often just circuit diagram and basic alignment notes. I have generally included R&TVS data when nothing better is available - on the basis that something is better than nothing. The number of pages varies but the majority are 1 to 4 pages for radios and more for televisions (especially colour).
For a few sets, all I have been able to obtain is a circuit diagram. All circuit diagrams include component values (either on the diagram or in a separate table), because I feel that circuit diagrams without component values are not worth including.
This is used for data from other sources, such as magazines or books, redrawn circuit diagrams, etc.