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Old 22nd January 2007, 07:44 PM   #1
pjpoes is offline pjpoes  United States
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Default Repairing 805 tubes

Hey Guys, I have a set of the older style Sheguang (SP?) 805 tubes, the ones without the ceramic insulators on the anode cap. Today I went to check the 805's bias and also wanted to replace the coupling caps, and when I removed the Anode cap wires, the entire cap came off the tube. Inside was a brown crumbly stuffy I assume was used to secure this metal cap to the tube itself. The Metal pin that runs into the anode inside the tube is still intact and the cap itself seems ok, the problem is just attaching the too. Since I paid 45 dollars for each one of these, I would rather not thrown them away. I was wondering if anyone had any idea's. One I had was using a conductive epoxy, but I have never used that stuff. If you really feel that its a total waste and that I'm better off buying the new style ones, I will, but I hate to toss these tubes, which are perfectly fine other than the caps. Especially since, for a poorly made chinese tube, they aren't cheap.
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Old 22nd January 2007, 10:08 PM   #2
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I am not familiar with their 805 tubes, but loose to caps are common with older tubes. I have repaired dozens of 807's and 813's.

Scrape as much of the brown stuff out of the cap as possible. Use solder wick and a hot soldering iron to clean the solder off of the top of the cap. You need to expose the hole in the center of the cap. Verify that the cap will fit on top of the tube and the wire will come through the hole in the cap. Use JB Weld, (not JB Quick) from the automotive dept at Wal Mart or any auto supply store, to glue the cap to the tube. Apply enough glue to hold the cap securely, but do not get any on the end of the wire! Allow the glue to cure overnight. Solder the wire to the cap. DONE. This stuff works to fix loose bases on old octal tubes also.

I used this stuff to glue the oil pan on my Volvo back together when it broke in the middle of nowhere. That was 10,000 miles ago.
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