Ameco PT-2 Preamplifier
The PT-2 is a RF preamp covering 1.8 to 54 MHz. It is designed for a transceiver but works equally well with just a receiver. I purchased this preamp online and it was advertised as working. However, it's getting to be a rare day I ever get anything online that actually functions as advertised. I replaced 6 components to get it back in proper working order: three burned resistors (R5, 6, 12), two bad 1N4148 diodes (D3, 4) and the power supply electrolytic filter capacitor (C9). I upped the working voltage of the cap as the original was only rated at 16-volts, but the power supply voltage is 15-volts. I changed it to a 25-volt cap. Also, half the split shaft of the gain control was broken off, so the knob would not stay put. Hey, but otherwise, it was in perfect operating condition.
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This is a MOSFET RF preamplifier and uses a 40633 MOSFET.
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The parts replaced to get the preamp working again. The little black lump below the two diodes is all that remains of resistor R12. It just crumbled when I unsoldered it. I measured its value before hand, but it's probably changed from the heat.
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A look at the inside of the PT-2.
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The PT-2 schematic with parts values added.
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Last updated 5/18/2022
