Amcomm HB 140 "Penetrator" amp info?

[Robb]

Anyone one know much about these amps?
A friend of mine was given one of these.
10/15/20/40 meter switches on it.

 

[mrgumby]

I had one for years tough little amp but dirty as hell...AND THE FINALS AREN'T CHEAP EITHER

 

[Robb]

Thanks for that tip - Mr. G.

 

[mrgumby]

oh ya and not very good for ssb

 

[LeapFrog]

Hi Robb, did you ever get any more info on these?

HB-140 bi linear, push pull with TRW PT9784 transistors.
"Amcomm Penetrator", looks like a mid 70's CB amplifier.

I was hoping somebody has seen a Palomar or Gray amplifier that used these odd transistors.

I am considering swapping 2SC2879's or MRF454's into it and modifying/adjusting it for the input output impedance mismatch.

Thanks for any hints!

 

[Robb]

Nope; it wasn't my amp anyway.
Belongs to a local op.

The mods to an amp like this goes beyond the matching coils; some caps and resistors may also need changing to make the match work

Example:
http://www.cbtricks.com/Amp/txstar/dx250_dx350/graphics/ts_dx250_dx350_sch.pdf

 

[LeapFrog]

Nope; it wasn't my amp anyway.
Belongs to a local op.

The mods to an amp like this goes beyond the matching coils; some caps and resistors may also need changing to make the match work

Example:
http://www.cbtricks.com/Amp/txstar/dx250_dx350/graphics/ts_dx250_dx350_sch.pdf

Thanks Robb, & Merry Christmas!
I for sure want to make certain that the amplifier is biased above class C even @ the cost of power efficiency. This will likely require additional circuitry given the majority nature of amplifiers in the scene @ this era, but thermal tracking and controlled bias will be a focus for this project.
[I may just leave it "old-school cool" & buy the factory N.O.S. transistors from that trusted place we all use, and then go from there to ensure the bias is not class C.]

The blasted toy (HB-140) hasn't even been mailed out yet lol, I'm just digging for info that's all.
The Texas Star Schematic will definitely help out for sure, If I decide to perform a conversion.

I spent a few hours looking in English web results for a schematic of this obscure amp, to no avail laugh out loud.

 

[Robb]

The Texas Star schematic was just an example. You will notice that on it, it showed boxes for certain caps that change vales because they used different finals and therefore different capacitances - is all.

Didn't mean to rebuild your amp to that schematic.

 

[LeapFrog]

The Texas Star schematic was just an example. You will notice that on it it showed boxes for certain caps that change vales because they used different finals and therefore different capacitances - is all.

Didn't mean to rebuild your amp to that schematic.

So to make the 2SC2879 transistors work, I shouldn't have to gut the box and copy the schematic I could just change the "matching network" (I don't know what this means) and some resistors/capacitors?
Thanks

 

[Robb]

So to make the 2SC2879 transistors work, I shouldn't have to gut the box and copy the schematic I could just change the "matching network" (i.d.k.) and some resistors/capacitors?
Thanks

That board may have different traces/schematic than the TS.

 

[nomadradio]

Is this a mobile amplifier?

I'm pretty sure you'll find that the transistors are the dreaded stud-mount type.

Adapting it to accept flange-mount transistors will be a mechanical PITA.

73

 

[LeapFrog]

Is this a mobile amplifier?

I'm pretty sure you'll find that the transistors are the dreaded stud-mount type.

Adapting it to accept flange-mount transistors will be a mechanical PITA.

73

I am waiting this little mobile to show up in the mail, I will find out if they are stud mount. Thank You nomadradio. 73

 

[PA629]

I am waiting this little mobile to show up in the mail, I will find out if they are stud mount. Thank You nomadradio. 73

If they are TRW PT9784's, they indeed are stud-mounted. I have an old amp from the 70's with a pair of them in it.

 

[LeapFrog]

The amplifier I have contains the "non A variant" of the PT9784, looks like a Toshiba 2SC2879 in the case style of "211-07", is this the same size as the Toshiba part? (I'm having a hard time determining if the mounting flange is identical from comparing the two datasheets)
They look tiny in person, I was expecting these to look about the size of a quarter lol!

Toshiba Datasheet
TRW PT9784/A Datasheet
Source: RFparts.com

 

[LeapFrog]

AMCOMM
730 WEST McNAB ROAD
FORT LAUDERDALE, FLORIDA
33309

And it's made in Florida, like me!
.
. [photo="medium"]4408[/photo] ..
Too bad they placed the band switch module directly underneath the transistors (sacrificing most of the heat-sink in the process).

[photo="medium"]4407[/photo] [photo="medium"]4410[/photo] [photo="medium"]4409[/photo] [photo="medium"]4406[/photo] ..
Notice the statement mentioning: "Complies with FCC Regulations as of 4-15-77".

FCC Part 97.307 Emission standards

*(d)* For transmitters installed after January 1, 2003, the mean power of any

spurious emission from a station transmitter or external RF power amplifier

transmitting on a frequency below 30 MHz must be at least 43 dB below the

mean power of the fundamental emission. For transmitters installed on or

before January 1, 2003, the mean power of any spurious emission from a

station transmitter or external RF power amplifier transmitting on a

frequency below 30 MHz must not exceed 50 mW and must be at least 40 dB

below the mean power of the fundamental emission. For a transmitter of mean

power less than 5 W installed on or before January 1, 2003, the attenuation

must be at least 30 dB. A transmitter built before April 15, 1977, or first

marketed before January 1, 1978, is exempt from this requirement.

*(e)* The mean power of any spurious emission from a station transmitter or

external RF power amplifier transmitting on a frequency between 30–225 MHz

must be at least 60 dB below the mean power of the fundamental. For a

transmitter having a mean power of 25 W or less, the mean power of any

spurious emission supplied to the antenna transmission line must not exceed

25 µW and must be at least 40 dB below the mean power of the fundamental

emission, but need not be reduced below the power of 10 µW. A transmitter

built before April 15, 1977, or first marketed before January 1, 1978, is

exempt from this requirement.

I wonder if this unit was sold between April 15 1977 & Jan 1st 1978?