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No element in bird 43p wattmeter?

805 california

805 california

Active Member
Jun 29, 2016
196
24
28
37
San luis obispo, ca
Yes yes I am a dumbass and didn't have an element in the bird 43p watt meter and keyed the mic. what happened was d8 in a cobra 29 smoked out. I ended up replacing d8 d24, 1000 uf cap and still blew fuses. so I replaced stock final and all is good. so obviously no element in bird 43p watt meter mucho problemo?
 

805 California, the way you wrote your post it appears that not placing the element into the watt meter did all the damage you listed.
Hopefully you meant to say you repaired a radio with all those parts being bad and then placed the radio in line and forgot the element for the watt meter.
Even with the element out of the watt meter, it wouldn't have done all that damage and no it shouldn't have hurt your watt meter either. JMHO's.
 
YUP. No element means nothing. Standard practice in commercial applications where a TX is run 24/7 is to run the line section without an element and only insert one when taking a reading. That avoids damage to the elements in the event of a lightning strike or some other "event".
 
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Are you sure it wasn't reverse polarity that did the deed? A 25 amp fuse would probably allow something in the radio to burn up (like the finals) before it blew. I have seen IC chips and finals blown before a high current fuse blew when the DC polarity was reversed.
 
OK D23 is the reverse polarity protection diode. I stopped there and didn't look for D8. You hooked the DC power up backwards. That D23 is supposed to short out the power supply and blow the fuse but since you had a 25 amp fuse in there it took too long to blow and smoked the diodes and since the capacitor was reversed polarity it said FU too. NEVER use a fuse far outside the current range the gear is supposed to draw.
 
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Captain Kilowatt said:
OK D23 is the reverse polarity protection diode. I stopped there and didn't look for D8. You hooked the DC power up backwards. That D23 is supposed to short out the power supply and blow the fuse but since you had a 25 amp fuse in there it took too long to blow and smoked the diodes and since the capacitor was reversed polarity it said FU too. NEVER use a fuse far outside the current range the gear is supposed to draw.
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The strange thing is I didn't hook the power up backwards. I have used the same power supply for months. yes I accidentally put a 25 amp fuse in, it happens. d8 was the only toasted componets. I just changed out d23 and the cap for good measure. Radio must have taken a power surge or the final went bad and instead of blowing the fuse it blew d8. I know the wires were and still are correct. if it was wired backwards d23 would have been shot before d8.
 
Well we were led to believe you changed D23 and the capacitor because they were bad. Why would you change them "just because"? Was the power turned on the radio and you simply flipped the power switch on the power supply? That's a sure fire way to drive a nasty spike into a piece if gear. With a grossly over rated fuse crap can happen before it blows especially when it is about ten times the recommended value.
 
Yeah normally I have the radio on and the power supply on and I ram the plug in the back of the radio. that might be it thanks. the first thing to check when fuses keep blowing is protection diode, so I pulled out d23 and it checked out fine but I had a new one so I figured why not. the cap I had no way of testing it so I replaced thinking it got hit with reverse polarity.
 

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