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eHam Forums => Amplifiers => Topic started by: KJ6TSX on June 17, 2012, 02:51:40 PM



Title: CMI Power master RF Amp
Post by: KJ6TSX on June 17, 2012, 02:51:40 PM
Has any one heard of a CMI Power Master 100 amp? I don't have any specs on the unit. The label says 160 watts AM, 300 watts SSB there is no reference to frequencies. I assume it would work on 10 11,and 12 meters???  but what do you think about lower frequencies??
Thanks
George


Title: RE: CMI Power master RF Amp
Post by: W9GB on June 17, 2012, 04:15:03 PM
CMI (Chicago Musical Instruments) was GIBSON's Parent company, so AUDIO and Guitar / Music amplifier products were in their portfolio
==
Never heard of CMI for legitimate amateur radio HF amplifiers, for past 40 years.
There were countless garage businesses made illegal CB amplifiers, tube and solid-state in 1970s -- sometimes they would use any brand name to try to look legitimate.

EASY WAY to find illegal CB amps, the more of these that are true (more likely):

1. Unknown companies or no product/serial number plate with FCC ID.
2. RF switched, since CB radios did not have external relay contacts for external amplifiers.
3. No band switching (all) or low pass filtering (solid-state amps)
http://site.hfprojectsyahoo.com/low_pass_filters
4. Has very low power input, such as 5 watts.
5. Use the word: Bi-linear.
6. Bragging product or company names that reflect 1970s CB culture (Fat Boy, Texas Star, Dave Made, Bubbas Kitchen heater), or US patriotism (misdirection scam).

Quote
I assume it would work on 10 11,and 12 meters???  but what do you think about lower frequencies??
Why would you think that?  Known CB amp?
Photographs would help, but if it does not have a band switch for the low-pass filter -- suspect.


Title: RE: CMI Power master RF Amp
Post by: KJ6TSX on June 17, 2012, 04:33:51 PM
Wasn't using my head, tried it, smoked it..... input power to high  :'(
Trying to figure what i blew up no visible damage just smoke
Really ticked myself off

Found burnt resistor, Might get lucky.... Lesson learned


Title: RE: CMI Power master RF Amp
Post by: KM3F on June 17, 2012, 10:33:13 PM
Guess it had 259 type connectors if you hooked up to it and over drove it.
Advice is to chuck it.
Only place you could use it is between 28.3 and 28.5 SSB or 28.00 to 28.3 CW with a Tech ticket, then it would likely put out a dirty signal.
Bottom line it's not a Ham grade amplifier.
Good luck.


Title: RE: CMI Power master RF Amp
Post by: W9GB on June 18, 2012, 06:46:14 PM
Quote
Found burnt resistor, Might get lucky.... Lesson learned
You burnt more than resistor .... you really didn't learn anything ... transistors likely gone ...
You just bought a door stop.


Title: RE: CMI Power master RF Amp
Post by: WB2WIK on June 18, 2012, 07:32:09 PM
Quote
Found burnt resistor, Might get lucky.... Lesson learned
You burnt more than resistor .... you really didn't learn anything ... transistors likely gone ...
You just bought a door stop.

Probably true.  The known ham amplifier manufacturers are, well...known.  There aren't many, never have been many.

This isn't one of them.


Title: RE: CMI Power master RF Amp
Post by: KJ6TSX on June 18, 2012, 08:42:31 PM
The Lesson learned was think it out before plugin it in!! ;D
and you are right the power output transistors did bite the dust
George