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Old 09-12-2009, 06:09 AM
jshorva65's Avatar
jshorva65 jshorva65 is offline
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RCA 621TS Alignment Tips

Many DIY Collector/Restorers seem to find the RCA 621TS (Chassis KCS-21) very intimidating when the diagnosis of a technical issue points to a need for Alignment as its cure. Since Sams Photofact provides only a Schematic for the 621TS (on the Servicer pages of Set #78) rather than an entire Folder dedicated to it, there are no Alignment Instructions, Chassis photos, etc. in Sams for the 621TS.

Alignment should NEVER be attempted without the proper tools, test equipment, and significant experience with their use!!! The following paragraph assumes that the reader is equipped with: a set of TV/Radio Alignment Tools; an Oscilloscope; a Sweep Generator; a Marker Generator; a VTVM; appropriate test leads and other accessories (adaptors, impedance-matching pads, etc.) for proper lead terminations; and Intermediate experience with Alignment of other equipment. Readers lacking a properly-equipped Service Bench and/or who have not previously performed successful Alignment of several receivers for which Sams provides full Alignment instructions should NOT attempt to align a 621TS without first obtaining the proper tools and equipment and acquiring the proper experience. Such readers should consult a Professional Restoration Facility to have such a procedure performed or arrange to have a fellow Collector/Restorer having suitable tools and experience supervise and guide them.

Having gotten that out of the way, the 621TS is very similar to early-production (27.25 MHz Trap omitted, shown as "Some Models" in the RCA Service Manual) RCA Chassis KCS-26 (model 721TS) aside from those differences specific to the use of the 7DP4 versus 10BP4, the absence of Horizontal AFC, and the use of a type 6H6 tube as Video Detector versus 6AL5. These differences are mainly related to Power Supply circuitry for Electrostatic versus Magnetic Focus and Sweep circuitry. The Sound IF, Picture IF, and Tuner are otherwise nearly identical. RCA Chassis KCS-27 (models 730TV1, 730TV2) covered in Sams Set 70 Folder 7 is also nearly identical except for the differences previously noted and those arising from KCS-27's lack of self-contained Audio Amp/Output stages (audio output from the TV chassis is coupled from the Discriminator stage to the Radio chassis in these Combination models).
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