Admiral 4A1, Issue B Schematic

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Product Information:
Model:4A1, Issue B

Schematics Content:

Page 1:

All readings made between tube socket terminals and chassis. Voltages indicated have been obtained using a Vacuum Tube Voltmeter. A second voltage reading is shown made with a 1000 ohm-per-volt meter, when use of this instrument would result in appreciable lower readings. Measured with a fresh battery, volume control full on, dial at the high frequency end, no signal,

Occasionally audio oscillation may occur in the 4A1 chassis with the volume control in an intermediate position. Should you encounter this trouble, reverse the leads of the primary of the output transformer or ground the speaker frame to the chassis. The speaker leads and the grid lead of the 1HS should be kept as far as possible from the 305 output tube.

Page 2:


1. IMPORTANT - Check to see that dial pointer reaches each end of dial scale when Station Selector Control is turned from one end to the other.
2. Volume control - Maximum for all adjustments.
3. Connect radio chassis to ground post of signal generator with a short heavy lead.
4. Connect output meter across voice coil of speaker.

5. Connect dummy antenna value in series with generator output lead, when needed (see below).
6. Allow chassis and signal generator to " heat up " for several minutes
7. Use lowest Output setting of Signal Generator capable of producing adequate Output Meter indication and then proceed in the following sequence.

Battery operated 4 Tube Superheterodyne with Single Tuning Range 535 KC. to 1630 KC. Covers standard broadcast band, using antenna and ground. Permeability tuning on Ant. and Osc. circuits. I.F. 455 KC.

Single unit " AB " battery pack. 90 volt " B " 112 volt " ALE Plug in connection. Use Ensign AB48, Burgess 17G - D60, Eveready 748, General 60DL - 11h, Ray - O - Vac AB - 82, or Bond 0528 Battery or Equivalent.

The battery economizer switch is located on the top of the chassis, right side.
Always have this Economizer Switch in the " NEW " battery position when first placing radio in operation or when installing a now battery.


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