PK232.22
THIS APPROACH REQUIRES REMOVAL
OF Q6 AND REPLACING IT WITH THE PNP AND ADDING A "PULLUP" RESISTOR 47K
FROM +5V TO THE INPUT SIDE OF R150 THIS CAN BE DONE ON THE CKT BOARD
SINCE R149 HAS 5V ON THE END NEAREST THE FRONT PANEL AND THE PULLUP
SHOULD BE ATTACHED THERE AND TO THE END OPPOSITE THE FRONT PANEL ON R150.
IF YOUR PK-232 IS SOU PREFER NOT TO MODIFY IT YOU CAN
INSTALL A CKT EXTERNAL BY ADDING A 2N2222 TRANSISTOR AND 3 RESISTORS HERE
IS THE CKT :
PK232 PIN 3 ←- —————————→ +5V
# 5K RES.
# 47K RES
—–\
C \ 47K RES
2N2222 —–#——————->—-> TO KEY LINE
E / B IN 914
/
—- GROUND
THE ABOVE CKT CAN ALSO BE ADDED INSIDE THE PK-232 AND USE THE AVAIL
+5V SUPPLY . THE ABOVE CKT IS THE ONE I'M PRESENTLY USING AS IT PROVIDES
EXCELLENT ISOLATION FROM THE RTU'S TO THE PK232. I INSTALLED THE CKT
INSIDE THE 232 ON TOP OF TAddress any queries to JIM/W5IFP @ W5IFP
GW1NGL NA7KR Kevin Roberts Ham Radio
Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information
THIS APPROACH REQUIRES REMOVAL
OF Q6 AND REPLACING IT WITH THE PNP AND ADDING A "PULLUP" RESISTOR 47K
FROM +5V TO THE INPUT SIDE OF R150 THIS CAN BE DONE ON THE CKT BOARD
SINCE R149 HAS 5V ON THE END NEAREST THE FRONT PANEL AND THE PULLUP
SHOULD BE ATTACHED THERE AND TO THE END OPPOSITE THE FRONT PANEL ON R150.
IF YOUR PK-232 IS SOU PREFER NOT TO MODIFY IT YOU CAN
INSTALL A CKT EXTERNAL BY ADDING A 2N2222 TRANSISTOR AND 3 RESISTORS HERE
IS THE CKT :
PK232 PIN 3 ←- —————————→ +5V
# 5K RES.
# 47K RES
—–\
C \ 47K RES
2N2222 —–#——————->—-> TO KEY LINE
E / B IN 914
/
—- GROUND
THE ABOVE CKT CAN ALSO BE ADDED INSIDE THE PK-232 AND USE THE AVAIL
+5V SUPPLY . THE ABOVE CKT IS THE ONE I'M PRESENTLY USING AS IT PROVIDES
EXCELLENT ISOLATION FROM THE RTU'S TO THE PK232. I INSTALLED THE CKT
INSIDE THE 232 ON TOP OF TAddress any queries to JIM/W5IFP @ W5IFP
GW1NGL NA7KR Kevin Roberts Ham Radio
Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information