Msg Nr.     : 159413
Da          : EA7FHR
Per         : RIG   @WW      
Tipo/status : BF
Data/ora    : 0302/2040
Dimensione  : 4739
Bid (Mid)   : 21918_EA7FKB
Titolo      : Alcune modifiche per il TR7930

TR7950

Just found a Kenwood screwup on the tr-7950. On the power-output
board where the PA module is connected is a 470 uf Cap designated
C 1. The silkscreen on the board shows the + terminal going to gnd.
The origional cap that was factory installed was installed with the
positive lead going to the + on the board. This is obviously wrong
as the Gnd Foil is the minus lead not the + lead. The cap had swolen
up and burst due to incorrect installation. Almost blew another cap
till I verified that the MINUS goes to the foil, not the way its
marked on the PC board. 
If you have a 7950 or 7930 you would do well to pull off the back
and inspect the Cap installed at C1. Its the only large filter cap
on this board so its easy to locate. If the case looks bulged, better
get another cap and install it correctly. 73, N5WX @ N5WX.OK

RELAYED BY WB0SEN....&....N0KGX..GENE...&...GENE


TR7950.1

CIRCUIT MODIFICATION FOR KENWOOD TR7930/7950 TRANSCEIVER
              FOR PACKET/RTTY OPERATION
                      BY: WA4IXN

THIS MODIFICATION PROVIDES CONTROLABLE AUDIO OUTPUT
TO PIN 5 OF THE MIC CONNECTOR FOR SINGLE PLUG PACKET/
RTTY OPERATION.

REMOVE TOP COVER OF TRANSCEIVER AND CAREFULLY DISCONNECT
SPEAKER LEAD PLUG FROM "RX UNIT" BOARD.
LOCATE PLUGS"J-13" ON THE RIGHT FRONT OF THE "RX UNIT" 
BOARD AND "J-18" ON THE LEFT REAR SIDE OF THE BOARD.
NOTICE WHICH WIRE GOES TO PIN "8-M" ON "J-13" AND TO PIN #5
ON THE MIC CONNECTOR.
REMOVE PLUG "J-13" FROM THE BOARD AND LOCATE THE SPRING
TAB ON THE SIDE OF THE PLUG THAT HOLDS THE "8-M" CONN-
ECTOR IN PLACE.
USING A SMALL AWL OR POINTED TOOL, PRESS THE TAB DOWN
AND CAREFULLY PULL THE "8-M" CONNECTOR FROM THE PLUG.
WORK THE WIRE FROM THE HARNESS SO IT WILL REACH BACK
ALONG THE LEFT SIDE OF THE BOARD TO PLUG "J-18".
USING THE AWL OR SMALL POINTED TOOL, CAREFULLY SPREAD
THE "8-M" CONNECTOR A SLIGHT AMOUNT SO IT CAN BE FITTED
LIKE A SLEEVE OVER ANOTHER CONNECTOR OF THE SAME SIZE.
LOCATE TERMINAL "AP" ON PLUG "J-18".
CONTINUED IN FILE TR7950.3

TR7950.3
INSERT THE SPREAD TERMINAL "8-M" INTO THE TOP OF PLUG
"J-18" SO IT FITS AROUND THE TOP OF TERMINAL "AP".THIS
 IS A FAIRLY TIGHT FIT, SO  USE CARE NOT TO BEND
THE TERMINALS BY USING TOO MUCH PRESSURE.
ABOUT HALF OF TERMINAL "8-M" WILL STICK UP ABOVE
THE TOP OF TERMINAL "AP".  THE LOWER PART WILL BE
FIRMLY SLEEVED AROUND TERMINAL "AP" INSIDE THE PLUG.
DRESS THE WIRE AROUND THE LEFT SIDE OF THE BOARD.
REPLACE SPEAKER PLUG AND INSTALL TOP COVER.
PLUG TNC CABLE WITH PTT/AUDIO IN/AUDIO OUT/GROUND CONNECTONS
INTO MIC CONNECTOR AND IT'S READY TO GO ON PACKET/RTTY.
NO SOLDERING IS REQUIRED AND UNIT CAN BE RETURNED TO
ORIGINAL STATE AT ANY TIME IF NECESSARY.
THE END!          RELAYED   BY...N0KGX...GENE

   73S DE JERONIMO EA7FHR @EA7FKB.EAAL.ESP.EU.