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Author Topic: Info needed on Parks brand 432 MHz preamp  (Read 3063 times)
N4UE
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Posts: 711




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« on: February 13, 2017, 01:26:25 PM »

Hi. I know this is a stretch, but......
One of the items I collect are Parks brand equipment. Got a bunch. I just picked up a nice little Model
432-2P preamp for 70 Cm. It uses 2 external plug-in transistors. They look like dual gate fets like 2N4416s.
I would just like to get an instruction sheet.
Google/Bama had nothing........

thanks
ron
N4UE
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WB6BYU
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Posts: 17195




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« Reply #1 on: February 13, 2017, 04:27:36 PM »

The 2N4416 is NOT a dual-gate MOSFET - it is a single-gate JFET.

Metal can dual-gate MOSFETs would more likely be the 408673, 3N201, or other RCA types (there actually
are a lot of them, but most are rather similar.)

A 4-pin metal case could either be a dual-gate MOSFET, or a JFET with a grounded case.
The part number should tell you which it is.
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N4UE
Member

Posts: 711




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« Reply #2 on: February 21, 2017, 04:21:09 PM »

I guess you meant 40673?
The 'problem' was the markings on the plug-in transistors were NOT readable. How could identify them with NO markings? And no data sheets?

Actually, while packing up all my preamps and converters, I found another 432-2P. In the case of the 2nd example, one of the transistors did have a legible marking.
2N3399. Using my SA/TG, I found one of the transistors was inoperative, it was plugged in wrong. So, I purchased a small quantity of NTE-160s which is a sub for the 2N3399.
Although it is a 4 pin/metal case, it appears none of the 4 leads are (externally) connected to the case.

BTW, I have plenty of 2N4416s, 3N200s, 3N201s and many others, none of which operated as required at 432 MHz.

ron
N4UE
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W9IQ
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Posts: 1718




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« Reply #3 on: February 21, 2017, 04:49:05 PM »

For help with identifying unknown devices, take a look at this handy device:

    http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html



They make some very nice and reasonably priced instruments. I have a few on my bench and in my tool bag. They are extraordinarily handy gadgets when building or troubleshooting.

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
N4UE
Member

Posts: 711




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« Reply #4 on: February 21, 2017, 06:02:03 PM »

Hi Glenn, I agree with Peak. I have a ESR-60 I bought years ago. I have other ESR meters, but I like the Peak because it gives both ESR and Value.
I also have a DE-5000 but haven't done much experimenting with it, yet.....

ron
N4UE
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AA4HA
Member

Posts: 2384




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« Reply #5 on: April 02, 2017, 09:08:34 PM »

For help with identifying unknown devices, take a look at this handy device:

    http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html



I too have a DCA75, it took a few weeks to ship but it is a nice little instrument for identifying (good) semiconductors. At least it helps you figure out the pinouts.

You do need to plug the USB cable in to your computer to get the exact component readout or to do curve tracing.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
Free space loss (dB) = 32.4 + 20 × log10d + 20 × log10 f
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