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Need help with Power Transistor ID.

Robert132

Dec 30, 2017
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Got a Amplifier with what I think are Motorola Power Transistors, across the top it has 3800 and right under it says 8751 and under that it says MALAYSIA. Cannot find anything on the web about these transistors, are they obsolete and if they are what replaced them? Also would like to know what wattage they are, any help would be greatly appreciated. I went to rf parts and no help there.
 

kellys_eye

Jun 25, 2010
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Amplifier make/model?
Schematic?
Pictures?

Our collective crystal balls are broken......
 

73's de Edd

Aug 21, 2015
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Sir Robert132 . . . . .

Seeing that you only give me Rotomola and the rf clue . . . . . . . . now I DO " NOES " my Rotomola but apparently their rep DOES NOT ! . . . I now give you . . . . . .

upload_2017-12-31_10-31-53.png


73's de Edd
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Edd has amazing balls (crystal, of course)
 

kellys_eye

Jun 25, 2010
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8751 and 9110 are probably date codes (manufacture). 1987 and 1991 respectively.
 

Robert132

Dec 30, 2017
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Have I stumped the Class.........The Amp is called a Commander 2 all transistor, plug in wall, has own power supply.
 

(*steve*)

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Have I stumped the Class.........The Amp is called a Commander 2 all transistor, plug in wall, has own power supply.

Edd's answer wasn't sufficient?
 

Robert132

Dec 30, 2017
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Well it's the right series, but is the wattage the same? Has anyone ever seen or heard of this Amplifier, there is no information on the web I can find out about it "Commander 2 Transistorized Base Amplifier " it has modulation lights and swr warning light also on it, right now swinging over a Thousand watts.
 

davenn

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right now swinging over a Thousand watts.

well that is impossible., considering it is only a 50W transistor
there must be other amplifier transistors inside if it to anything near 1kW

please show an internal photo of the amp
 

davenn

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Has anyone ever seen or heard of this Amplifier, there is no information on the web I can find out about it "Commander 2 Transistorized Base Amplifier "

well there is some info on google, which would have been helpful to know in your opening post

http://www.hellotrade.com/palstar-usa/commander-ii-1000-watt-2-meter-rf-amplifier.html

The Commander II is a grounded grid, class AB2 linear power amplifier that operates on the Amateur 2 meter band (144 to 148 MHz). It features a single Eimac 3CPX800A7 pulse rated external anode triode with forced air cooling. Modern stripline circuitry ensures efficient and conservative operation.

so if it does indeed have a MRF492 in it, it must be getting used as a driver transistor, maybe ?

again ... show photos
 

davenn

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Got a Amplifier with what I think are Motorola Power Transistors, across the top it has 3800 and right under it says 8751 and under that it says MALAYSIA. Cannot find anything on the web about these transistors, are they obsolete and if they are what replaced them? Also would like to know what wattage they are, any help would be greatly appreciated. I went to rf parts and no help there.

well didn't take too much of an effort to find this .......

http://www.radiomanual.info/schemi/ACC_PA/Palstar_Commander_2_user.pdf

OK so the that transistor doesn't even exist in that amplifier

so time to find out from you what you are really talking about ????
 
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