Hey guys, having trouble finding info for diode D78. I can find it on a schematic but not on a parts list to tell me what it is. Anybody know this one??? It is inline with the MB 3756 regulator (IC4) HELP!!!
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Cobra 148 GTL PC 412 board D78
- Thread starter Bob Pyle
- Start date
D78 is NOT on the schematics
http://www.cbtricks.com/radios/cobra/140gtl/graphics/cobra_140gtl_142gtl_148gtl_tb1226.pdf
It is the SR1K2 diode from pin 1 to pin 2. This "bleeds" off the regulated voltage to the main input voltage to keep the regulator from being reverse biased after the power is switched off.
You could use any 1N4001 through 1N4009 diode in replacement. 1 Amp rating.
http://www.cbtricks.com/radios/cobra/140gtl/graphics/cobra_140gtl_142gtl_148gtl_tb1226.pdf
It is the SR1K2 diode from pin 1 to pin 2. This "bleeds" off the regulated voltage to the main input voltage to keep the regulator from being reverse biased after the power is switched off.
You could use any 1N4001 through 1N4009 diode in replacement. 1 Amp rating.
Last edited:
Radios made before that bulletin were supposed go get D78 added on the solder side of the pc board. It serves to prevent mysterious failures of the MB3756 chip. All radios built after 1979 came with this diode.
73
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