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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 on eBay and it was advertised as working. However, it's getting to be a rare day I ever get anything off eBay that actually works 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; the original was rated at 16 volts but the power supply voltage is +15v. That's too close for comfort so 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. But otherwise it was in perfect operating condition.
Picture
This is a MOSFET RF preamplifier.
Picture
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 kinda crumbled when I unsoldered and removed it. Good thing I measured the value before trying to remove it.
Picture
Inside the PT-2
Picture
Schematic with component values added. Click to enlarge
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  • Home
    • Contact
  • Astrophotography
  • Observatory
    • New Observatory
    • Lancaster Dome
    • ExploraDome
  • Equipment
    • Accessories >
      • RA Drive Corrector
    • CCD Cameras >
      • Orion Starshoot Pro
    • Mounts >
      • Orion HDX110 (EQ-8)
    • Telescopes >
      • 1956 Questar 3.5
      • Astro-Tech AT6RC
      • Celestron C-11 XLT
      • Zhumell 152mm Refractor
  • Projects
    • C11 XLT Mods
    • Dome Automation
    • Orion SSPRO Camera >
      • Disassembled Views
      • Noise Reduction Mod
      • Temp Controller Mod
    • Ultima 8 Mods
    • Zhumell Refractor Mods
  • Non-Astronomy
    • Amateur Radio >
      • Accessories >
        • Station Boom Microphone
      • Ameco >
        • Ameco AC-1
        • Ameco OCM
        • Ameco PT-2
        • Ameco R5A
      • Vintage Equipment >
        • Knight Kit T-60 Transmitter
        • Heathkit SB-102 Station
      • Yaesu FT-817 >
        • Yaesu FT-817ND
        • LDG Z-817 Autotuner
        • Windcamp LiPo Battery
    • Antique Radios >
      • Building A Radio Workbench
      • Radio Dial Neon Clock
      • Radios >
        • Boat Anchor Radios >
          • BC-348N Receiver
          • Collins 51J4 HF Receiver
          • R-392 HF Receiver
        • Echophone EC-1
        • Eltz Radione 2
        • Knight Kit Span Master II
        • Panasonic RF-5000A
        • Silvertone Model 4465
      • Test Equipment >
        • Hickok >
          • Hickok 19X RF Generator
          • Hickok 225K VTVM
          • Hickok 288X RF Generator
        • Simpson >
          • Simpson Genescope
        • Supreme Instruments >
          • Supreme Model 385 Automatic
          • Supreme Audolyzer
          • Supreme Vedolyzer
        • Military Test Equipment >
          • BC-221-AF Frequency Meter
          • LM-21 Frequency Meter
          • TS-323/UR Frequency Meter
          • TS-465 C/U Sweep Generator
          • TS-505D/U VTVM
        • Other Test Equipment >
          • Tektronix 326 O'scope
        • Radio Analyzers >
          • Rider Chanalyst
        • Tube Testers >
          • Alternating Current Sink
          • Drug Store Tester
          • Hickok 550X
          • I-177 Tube Tester
          • MX-949 Adapter
          • Precision Model 10-12
          • Supreme Model 385
          • TV-3C/U Tube Tester
    • New Homestead >
      • 2015 - 17 Getting Started
      • 2018 - Log Home Progress
      • 2019 - Finishing Up
    • Star Trek Communicator