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looking for RM italy kl 503 HD Schematic

KD2GOE

W9WDX Amateur Radio Club Member
May 30, 2013
952
220
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Buffalo
Any one have High Rez pics of the inside and a schematic of the KL 503 HD
it looks like for some unknown reason the adds say it is still 1 driving 8?
i am guessing they added more padding to get the "35 watts input drive"?
to me it seems like just removing the Driver like i have done would had been cheaper ¯\_(ツ)_/¯
 

I'm also interested in de schematic of the HD version. It is not published on the manufacturers website.......

Just found a recent review of the HD version on YT:
I was surprised to see the specifications on the front of the booklet at 3 min 29 sec.
It looks like the used transistors are the same as in the non HD version: one RM4 drives 8 RM3 mosfets.
Did they just add a fixed attenuator in the input to increase the max. drive to 35W?

Then another question that many may have: What are the RM3 and RM4 MOSFETs?
The IRF520 is mentioned often, nut I also read about the 13N10 (FQP13N10 I assume).
Any information here would be appreciated as I have one of these amps for repair on my desk.
 
I am interested in buying the KL503HD, but they are hard to find nowadays. Any ideas where i may find one new. Thanks in advance.
 
I'm also interested in de schematic of the HD version. It is not published on the manufacturers website.......

Just found a recent review of the HD version on YT:
I was surprised to see the specifications on the front of the booklet at 3 min 29 sec.
It looks like the used transistors are the same as in the non HD version: one RM4 drives 8 RM3 mosfets.
Did they just add a fixed attenuator in the input to increase the max. drive to 35W?

Then another question that many may have: What are the RM3 and RM4 MOSFETs?
The IRF520 is mentioned often, nut I also read about the 13N10 (FQP13N10 I assume).
Any information here would be appreciated as I have one of these amps for repair on my desk.

88 Radio has RM3 & RM4 for sale
 
Any one have High Rez pics of the inside and a schematic of the KL 503 HD
it looks like for some unknown reason the adds say it is still 1 driving 8?
i am guessing they added more padding to get the "35 watts input drive"?
to me it seems like just removing the Driver like i have done would had been cheaper ¯\_(ツ)_/¯
Look in back of Manual for schematic
 

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