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Albrecht AE55H / GRE PSR-255



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The discriminator IC of the Albrecht AE55H and the identical GRE PSR-255, a Motorola MC3361, is hidden below a crystal (marked 10.245). By bending this crystal carefully upright, the MC3361 can be reached. The unfiltered audio can be found at pin 9.

A 10 k resistor is soldered to pin 9, and mounted next to the IC. The resistor's other lead is isolated, e.g. with a piece of insulation stripped from insulated wire.

As usual with the 3361, the discriminator output contains a strong IF component at 455 kHz. This is filtered by mounting a 2.2 nF capacitor with one lead to the 10 k resistor, and the other lead to ground. The metal shield of the IF coil nearby can be used as a ground contact.

AE55H

PSR255

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The discriminator IC is hidden underneath a crystal

A 10 k resistor is soldered to pin 9

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Then the crystal is bent back to its original position. Put some isolating material below the crystal to prevent it from making contact with the discriminator IC

A 3.5 mm chassis socket is mounted in the back of the scanner. A piece of shielded wire connects this terminal with the discriminator output. The inner lead is connected to the junction of the 10 k resistor and the 2.2 n capacitor. The shield is soldered to the metal shield of an IF coil.

The disc-out connector is mounted in the back of the scanner



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