[NJARC] Knight KX-60 Amplifier

[Chuck]

Thanks for the warning! I will take those transistors out!
All of the diodes tested good. That was one of the first things I checked. 
And I completely recapped the amp, so it is getting there.
I forgot what made me think those IRF-240 transistors might work, or why I 
tried them, but you can hear that they are not what the amp needs.
I understand what you are describing about eliminating the transistors all 
together.
It sounds like a great idea, but the amp belongs to a friend of mine and I 
don't think I should change anything in it.


-----Original Message----- 
From: Mike Feher
Sent: Friday, June 10, 2016 10:48 AM
To: 'Chuck' ; 'Al Klase' ; njarc at mailman.qth.net
Subject: RE: [NJARC] Knight KX-60 Amplifier

Another BTW, check the diodes in the supplies as well. 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960


-----Original Message-----
From: Chuck [mailto:cpaci1 at verizon.net]
Sent: Friday, June 10, 2016 10:26 AM
To: Mike Feher; 'Al Klase'; njarc at mailman.qth.net
Subject: Re: [NJARC] Knight KX-60 Amplifier

You are spot on Mike...
Both filter caps were totally dried up and causing the power transformer to
cook.
I am sure that also caused one of those transistors to open and the other to
short.
I re-stuffed the filter caps then replaced the Bendix 660032s with a couple
of Motorola IRF-240s I had in the shop.
The amp came to life after that, but not quite fixed yet.
Those transistors have built-in diodes and do not seem to be quite right,
since they introduced a hum.

Thanks again,
Chuck

-----Original Message-----
From: Mike Feher
Sent: Friday, June 10, 2016 7:44 AM
To: 'Chuck' ; 'Al Klase' ; njarc at mailman.qth.net
Subject: RE: [NJARC] Knight KX-60 Amplifier

Chuck -

BTW, something caused those transistors to fail, and, you should try and
find out what that is prior to just replacing them. I also believe that it
is much earlier than the 1073 that you mention. By that time most amps were
using Silicon NPN transistors. In 1973 I bought a Pioneer SA9100 amp that I
still have and use. 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960


-----Original Message-----
From: NJARC [mailto:njarc-bounces at mailman.qth.net] On Behalf Of Chuck
Sent: Friday, June 10, 2016 4:40 AM
To: Al Klase; njarc at mailman.qth.net
Subject: Re: [NJARC] Knight KX-60 Amplifier

Just remember
Reply = Poster
Reply All = Everyone

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