Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: TS-940 Power Supply Shooting 40 vdc (not 28) to Final Unit-Cause of No Output  (Read 3654 times)
N6QWP
Member

Posts: 261




Ignore
« Reply #15 on: November 24, 2017, 11:01:51 AM »

Thanx MIQ!  EXCELLENT VIDEOS FOR BOTH THE 930 AND 940!!!! 

THIS is what I was seeking.  Appears to be a "more modern" update.  Very straightforward.
Logged
W3AFC
Member

Posts: 2




Ignore
« Reply #16 on: November 25, 2017, 07:32:58 AM »

For those who aren't concerned about keeping their 930S or 940S "all original", the Phoenix Quint switching power supply option is the way to go. These are top-quality industrial power supplies with built-in noise filtration. This modification was pioneered by Paul Groothoff, PA2VC, but many have done it since. The Quint that I'm using has an adjustable output from 24-29.5 VDC, with a maximum through voltage of 32 volts in failure mode, so crowbars and other protection circuits are not necessary. In fact, when I rebuild a PA for a 930S that will have a Quint power supply, I remove Zener diode D1, which is supposed to protect the PA if the original power supply fails but it's rating is too small. By the time it shorts, the drivers are blown. From my experience, the only thing that blows are Zener diodes D1 and D5, and the MRF485 drivers. Seriously, I've blown up several PA's trying different drivers, and I've never damaged a Final output pill. In fact, one of the contributors to my web site sent me a PA in which he used 2SC1969's for drivers. They blew so violently that the cases exploded, and the 2-watt main buss resistor in the PA opened. But his output pills were fine, and his PA is purring again.


I experienced the same failure that most of you on this forum have. I was so upset when it happened that I threw a temper tantrum that would make a 4-year old blush. My AVR board also caught fire, almost triggering the fire alarm system in our house. But after a few days of sulking, I started researching ways to fix it, and the rest is history. All of this can be found at my www.w3afc.com page.

I'm up to the 8th revision of my Compendium of Repair for the Kenwood TS-930S, but I'm already working on Revision 9, which will include some tricks to repair other problems with the 930S, like the VFO and signal unit, without the need for sophisticated lab equipment.

By the way, the meter readings are set by adjusting potentiometers on the Signal Unit. So the meter could be set to read almost any voltage or current or SWR value. It's not absolute.

73, John
Logged
N6QWP
Member

Posts: 261




Ignore
« Reply #17 on: November 25, 2017, 11:17:07 AM »

Thanx John.....we're all following along and anxiously awaiting all of your updates.
Logged
N6QWP
Member

Posts: 261




Ignore
« Reply #18 on: December 08, 2017, 08:09:17 AM »

W3AFC's mod for the TS-930 appears to be the "Solution of the Moment" for me.  

For the TS-940, please refer to two other threads: TS-940 The Final Solution to Power Supply Problems?  and the one about the TS-930/ TS-940 Power Supply "CROWBAR" circuitry (see end of thread postings).  

(Again my apologies for misleading in the early stages of this here thread about the overvoltage.  Wasn't paying attention to the "obvious").   Roll Eyes

Great "new" strides are being made using the modern switching power supplies AND UPDATED INTERFACE BOARDS in the TS-940.....and soon to be introduced, for the TS-930.  

Take a look.
« Last Edit: December 08, 2017, 08:18:54 AM by N6QWP » Logged
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!