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Re: [TenTec] 540/Triton Transmit Audio Distortion

To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: Re: [TenTec] 540/Triton Transmit Audio Distortion
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 13 Apr 2015 22:26:11 +0200
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Way to go, Bill.
I told you that you would find the problem!
Well done!

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Bill ACITO, 
W1PA
Sent: Monday, April 13, 2015 9:27 PM
To: TenTec@contesting.com
Subject: Re: [TenTec] 540/Triton Transmit Audio Distortion

Resolved.

After finally doing some real voltage checks per the manual rather than just 
the board swaps, I found the +8 (REG) line at 13.8V. I ordered and replaced the 
MC1723CL on the source logic board. Popped the board back in, and sure enough 
---13.8V.  What the heck?

Opened the schematic in my original manual, traced it around, and noticed the 
octal plug. Checked the wiring versus the manual, 2 to 4, 6, 7, and 8 together 
etc. Looks ok. Back to the schematic...   2 to 5 and....  huh?

The original 540 manual text is wrong (page 2-4)... says short pin 2 to 4. 
Schematic is correct: 2-5.  Previous owner had read the manual when they built 
the plug, not the schematic. 2-4 shorts and backfeeds the 13.8 line to the +8 
regulated line (which is used on the SSB board... no wonder my audio was “hot” 
and distorted). He must have been a CW-only guy.

Corrected the octal plug, full re-alignment, rig works and sounds great. Got 
several good audio reports on 20m this weekend.

I Googled this manual issue and found nothing; I can’t believe I am the first 
one to find this. The pdf version that is floating around the web is correct. 
The original hardcopy that I have is wrong. Anyone else heard of this?

I found an original resistor on the logic board that was also way off versus 
the schematic – 180 vs 4.7 ohm in the schematic. 

Bill  W1PA 
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