Sea Pal Radio Co. 6P21 Series A Schematic

Sea Pal Radio Co. 6P21 Series A

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Product Information:
Model:6P21 Series A
Manufacturer:Sea Pal Radio Co.

Schematic Pages

PNG: Page 1 Rider Manual Volume 13
PNG: Page 2 Rider Manual Volume 13

Schematics Content

Page 1:



The tube complement of this chassis consists of the following tubes.
The type and function of each tube is as follows: 1 - Type 1.A7GT Mixer, First Detector-oscillator. 2 - Type INSGT Remote Cut-off Pentode, 1st and 2nd I.F. Amplifiers. 1 Type 1H5GT Second Detector, A.V.C. 1st Audio. 1 - Type 1TSGT Output Amplifier. - Type 11726GT Rectifier.

Page 2:


Volume control - Maximum all adjustments.
Connect generator ground to B.
Connect dummy antenna value in series with generator output lead.
Connect output meter across primary of output transformer.
Allow chassis and signal generator to " heat up " for several minutes,

The following equipment is required for aligning:
An alt wave signal generator which will provide so accurately calibrated signal at the test frequencies as listed.
Output indicating meter.
Non-metallic screwdriver.
Dummy antennas- I Mfd., 50 Mmd.

NOTE "A" - The loop may be connected to the radio when waking these adjustments. The ground of the signal generator is connected to the B, and the other lead from the signal generator in series with the proper dummy to the grid of the 1A7GT tube. NOTE. "B" - For aligning long wave band, countct a radiating loop consisting of 4 turns'of wire | in " Dia. in aerics with SPD, of condenser to terminals of signal generator. Place radiating loop 2 feet away from loop on receiver. The plane of both loop must be parallel,

View showing method of connecting batteries and the external antenna jack An external antenna will give maximum reception on distant stations but should be disconnected for direction finding operation.

View Showing Tube Layout

In any radio compass there may be a deviation from a true reading due to the motor or other metal parts around the boat just as there is with a magnetic compass. The simplest method to determine the amount of deviation is to select a broadcast or beacon station which you can can see from the ship Point your ship directly at the station and then tune the loop to the " Null " point. If there is no error the loop pointer should point to the station straight ahead, parallel with a line from bow to stern. If there is a deviation the pointer will not point exactly straight ahead. You can either note how many degrees the variation is and allow for it in future readings or you can turn the radio case so the loop pointer points straight ahead. This will correct for the error and you won't need to make any future allowance.

Check for deviation on several sta. tions and also with the boat turned 180 Degrees from the stations.