KL40 amp problems
 

I just bought a few of these for myself and friends. None of them
seem to be working. I have emailed RMITALY and am waiting for a
response.

They draw 180ma whether on or off. When driven with 3 watts AM into a
50 ohm dummy load, it draws 500ma (whether on or off) but has no RF
output.

An SWR meter shows very high SWR between the radio and the amp.

With the amp out of the circuit, I see 1.0 SWR and 3 watts on the
meter.

With power to the amp off, and 3 watts AM in, there is no RF out.

Three KL40's I've tested are doing the same thing.

Is it possible they switched the wiring to the PL-259's for a big run
of these?

Anyone seen this problem with KL40's?


Ken
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On Thu, 26 Feb 2004 17:40:40 GMT, Ken wrote:
Is it possible they switched the wiring to the PL-259's for a big run
of these?

Ooops. I meant SO-239's.


Ken
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remove "zz" from address)

From: (Ken)
I just bought a few of these for myself and friends. None of them seem
to be working. I have emailed RMITALY and am waiting for a response.
They draw 180ma whether on or off. When driven with 3 watts AM into a 50
ohm dummy load, it draws 500ma (whether on or off) but has no RF output.
An SWR meter shows very high SWR between the radio and the amp.
With the amp out of the circuit, I see 1.0 SWR and 3 watts on the meter.
With power to the amp off, and 3 watts AM in, there is no RF out.
Three KL40's I've tested are doing the same thing.
Is it possible they switched the wiring to the PL-259's for a big run of
these?
Anyone seen this problem with KL40's?
Ken
(to reply via email
remove "zz" from address)
_
Just a thought,,,,can your dummy load be bad?
NO RF output at all doesn't seem probable on all three units. Try keying
it in real time on the air,,,then report back with frequency and
results. I know an ambulance driver that owns one,,never had a problem
with his after he had it tweaked in south St. Pete, but man he sure does
bleed. I left a message on his answering machine and gave him your
email. Good luck.

On Thu, 26 Feb 2004 17:40:40 GMT, Ken wrote:

I just bought a few of these for myself and friends. None of them
seem to be working. I have emailed RMITALY and am waiting for a
response.

They draw 180ma whether on or off. When driven with 3 watts AM into a
50 ohm dummy load, it draws 500ma (whether on or off) but has no RF
output.

An SWR meter shows very high SWR between the radio and the amp.

With the amp out of the circuit, I see 1.0 SWR and 3 watts on the
meter.

With power to the amp off, and 3 watts AM in, there is no RF out.

Three KL40's I've tested are doing the same thing.

Is it possible they switched the wiring to the PL-259's for a big run
of these?

Anyone seen this problem with KL40's?


Ken
(to reply via email
remove "zz" from address)

Is this your amp?

http://www.rmitaly.com/download/manu...al_rel_300.pdf

On Thu, 26 Feb 2004 17:40:40 GMT, Ken wrote:

I just bought a few of these for myself and friends. None of them
seem to be working. I have emailed RMITALY and am waiting for a
response.

They draw 180ma whether on or off. When driven with 3 watts AM into a
50 ohm dummy load, it draws 500ma (whether on or off) but has no RF
output.

An SWR meter shows very high SWR between the radio and the amp.

With the amp out of the circuit, I see 1.0 SWR and 3 watts on the
meter.

With power to the amp off, and 3 watts AM in, there is no RF out.

Three KL40's I've tested are doing the same thing.

Is it possible they switched the wiring to the PL-259's for a big run
of these?

Anyone seen this problem with KL40's?


Ken
(to reply via email
remove "zz" from address)

http://www.rmitaly.com/download/inst...nstruction.pdf

On Thu, 26 Feb 2004 15:51:24 -0500, wrote:
Is this your amp?
http://www.rmitaly.com/download/manu...al_rel_300.pdf


As far as I know, Yes.

RM has three different PDF manuals for the KL40 and their might be
differences.


Ken
(to reply via email
remove "zz" from address)

On Thu, 26 Feb 2004 15:05:20 -0500 (EST),
(Twistedhed) wrote:

Just a thought,,,,can your dummy load be bad?
NO RF output at all doesn't seem probable on all three units. Try keying
it in real time on the air,,,then report back with frequency and
results. I know an ambulance driver that owns one,,never had a problem
with his after he had it tweaked in south St. Pete, but man he sure does
bleed. I left a message on his answering machine and gave him your
email. Good luck.

When the amp is out of the circuit, I have the radio going into the
meter and dummy load. The meter shows SWR=1.0 (as it should) and
approximately the same power as the radio meter.

One other oddity. Before I power up the radio, the amp is drawing
zero current. As soon as I power up the radio (on RX), the amp starts
drawing 180 ma, whether it is switched on or off.

I assume this amp has transmit sense and can be used with a
transceiver.


Ken
(to reply via email
remove "zz" from address)

One other oddity. Before I power up the radio, the amp is drawing
zero current. As soon as I power up the radio (on RX), the amp starts
drawing 180 ma, whether it is switched on or off.

Impossible. The amp has no input for the powered condition of the
radio (receive).

Do you have the coax in-out connected backwards?

In , wrote:


One other oddity. Before I power up the radio, the amp is drawing
zero current. As soon as I power up the radio (on RX), the amp starts
drawing 180 ma, whether it is switched on or off.

Impossible. The amp has no input for the powered condition of the
radio (receive).


Wrong -- it's very possible. That is a MOSFET amp with no power switch. A bad
combination to be sure, because as long as there is source-drain voltage, any
kind of signal can drive it to some extent. It's possible that C1 could be
shorted (after all, it's only rated for 50 volts) and the output of the radio
have a DC component. Or if D2 is blown (a 1N4148 passing 3 watts -- yikes!) D1
will hold a nice, steady DC bias on the MOSFET. There are a lot of possible
scenarios for what he is describing. What -is- impossible is for you to think
before you demonstrate your ignorance. Haven't we been through this before,
Tnom? Didn't you learn anything the first dozen times?

But hey, it's a cheap and crappy amp, and you get what you pay for.


Do you have the coax in-out connected backwards?


You have your brain connected backwards. Quit trying to act like you know what
you are talking about.







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On Thu, 26 Feb 2004 20:58:19 -0800, Frank Gilliland
wrote:

In , wrote:


One other oddity. Before I power up the radio, the amp is drawing
zero current. As soon as I power up the radio (on RX), the amp starts
drawing 180 ma, whether it is switched on or off.

Impossible. The amp has no input for the powered condition of the
radio (receive).


Wrong -- it's very possible. That is a MOSFET amp with no power switch. A bad
combination to be sure, because as long as there is source-drain voltage, any
kind of signal can drive it to some extent. It's possible that C1 could be
shorted (after all, it's only rated for 50 volts) and the output of the radio
have a DC component. Or if D2 is blown (a 1N4148 passing 3 watts -- yikes!) D1
will hold a nice, steady DC bias on the MOSFET. There are a lot of possible
scenarios for what he is describing. What -is- impossible is for you to think
before you demonstrate your ignorance. Haven't we been through this before,
Tnom? Didn't you learn anything the first dozen times?

But hey, it's a cheap and crappy amp, and you get what you pay for.


Do you have the coax in-out connected backwards?


You have your brain connected backwards. Quit trying to act like you know what
you are talking about.

I stand by my post. There is no voltage on the radios coax on receive
that will activate the amps increase in current draw. You should pay
more attention. Even if there was a DC voltage C1 on the amp would
block it.

"You have your brain connected backwards. Quit trying to act like you
know what you are talking about." I just couldn't resist.


http://www.rmitaly.com/download/inst...nstruction.pdf