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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WA1HZK on December 29, 2004, 10:45:30 PM

Title: DX-100 Problem
Post by: WA1HZK on December 29, 2004, 10:45:30 PM
I'm posting this to recommend that anyone that owns a DX-100 should replace the .001 mica cap that comes off of the 5763 plate & feeds the 6146 grids. While in standby & when I was outta the shack this cap shorted. If you look at the schematic you will notice that this puts 400 volts into the final grids and directly into the bias supply. Naturally the power transformer and choke self destructed to save the delicate fuse. Don't let this happen to you. Change that part or you will end up running TV transformers in the rig like me! I used the Voltage tripler circuit that is published for the Ranger to get the bias again & a 800 volt CT transformer running choke input delivers 320 volts for the low voltage. This is plenty to run the rig. I'll have the 833 transmitter that uses the DX-100 as a driver back on the air this weekend.

Title: DX-100 Problem
Post by: WA1LGQ on December 30, 2004, 12:42:56 PM
Yup, I had one of those caps crap out on me too once. But I caught it before it shorted. It changed value and I noticed a change in the drive level. .........Larry

Title: Yup
Post by: WA1HZK on December 30, 2004, 02:54:52 PM
It's a real weak point. If you own one of these you should unplug it and change that 12 cent part or your radio will emit the equal of a smoke bomb on the 4th of July!
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