Rm Italy KL-503 watts vs amps

[Robert Foster]

Tall man please tell me with certainty what fets to buy for my kl503 please I'm hearing erf7030 irf520 please tell me I love my kl503 just made a mistake and didnt hook up my antenna after lightning store and transmitted..

 

[Tallman]

Your P.M. has been answered.

 

[William C. Colvin]

I repair KL amplifiers and the number one cause of failure is the amps are over driven. The second is over voltage. These are inexpensive amps and usually work well. The promise of 500 Watts from the KL503 is very optimistic.

What are common problems with the KL200P Amps when the receive dies when the amp is switched on.

 

[Tallman]

What are common problems with the KL200P Amps when the receive dies when the amp is switched on.

Nomad has an article written about how to fix that problem. That is why I always recommend not buying the "P" model amps. The fix is the same for either model.

 

[William C. Colvin]

Nomad has an article written about how to fix that problem. That is why I always recommend not buying the "P" model amps. The fix is the same for either model.

Do you have a link to Nomad's Article on the Pre-amp problem?

 

[Tallman]

Do you have a link to Nomad's Article on the Pre-amp problem?

I wish I did. He is on here all the time. You could PM him for the link

 

[William C. Colvin]

The 503 uses erf7030 fet's and the other uses the no longer in production MS1051. Rm Italy has re-biased the unit that uses MS1051 transistor to run the MRF 454.
The re-bias is necessary, RM Italy says it is not a direct drop in replacement. If the bias is left as is they warn of possible further damage to the circuits.
The kl-505 is more of a ham amplifier because of the frequency range 3MHz to 30 MHz.

Are they doing the same thing with the newer 200P with the MS1051?

 

[William C. Colvin]

I wish I did. He is on here all the time. You could PM him for the link

There are two Nomads listed -Nomad605 and Nomadradio only Nomadradio shows having any post and I did not see any information there under his posts.

 

[Tallman]

Are they doing the same thing with the newer 200P with the MS1051?

I don't think they are building the KL-200 anymore. If you go to my album that has the traces from the component tester those traces are from the MS-1051 that had not ever been installed or touched by a soldering iron. Brand new fresh from the packaging.

 

[Tallman]

There are two Nomads listed -Nomad605 and Nomadradio only Nomadradio shows having any post and I did not see any information there under his posts.

It is Nomadradio who has an active repair shop. He is the best in Louisville.

 

[William C. Colvin]

I don't think they are building the KL-200 anymore. If you go to my album that has the traces from the component tester those traces are from the MS-1051 that had not ever been installed or touched by a soldering iron. Brand new fresh from the packaging.

They are still selling the KL-200P on NEWEGG for $75.00 and Free Shipping.

 

[Tallman]

They are still selling the KL-200P on NEWEGG for $75.00 and Free Shipping.

Yeah they might still be selling them, but RM Italy most is not building them any more. Those are probably are new old old stock and have been sitting on the shelf in a warehouse.

 

[BammBamm]

I know this is an old thread but....would upgrading from a 203p to a 503 be worth it?

 

[w9cll]

Unless you are tripling your output no its not worth it.

 

[nomadradio]

Here's our preferred fix for bad preamp relays. Mostly this is to remedy loss of receive signal with the preamp turned OFF.

If your radio can't transmit barefoot through the amplifier when turned off, this will fix that problem.

But only if the preamp relay has the transparent top cover that can be popped off to expose the contacts. Remove the lever section and solder a thin wire across each side as you see here.

If the radio receives okay UNTIL you turn on the preamp, the relay is probably not the problem. If you only have trouble with the preamp turned ON, the trouble is probably with the preamp transistor and/or protection diode.


But if turning the preamp off causes trouble, this fixes that problem.

73