Re: TEK514 needs new 5V4G tube

Harvey White

Considering the cost for a 5V, which IIRC is a rectifier with an indrectly heated cathode (*many* years ago).  You might want to take some silicon rectifiers and put them in, substituting for the 5V4.  You may get a bit hotter B+ out of the combo, and I've heard that some people put some fairly large wattage resistors in series to limit the surge, but I'd certainly consider that fix for AU $45.00.  (which even at the last rate I remember is USD22.00 and that's a big bunch).  I suspect that 1N4006 might be a good candidate.

If you had an octal tube base you could build it into that.


On 1/26/2020 6:10 PM, Steve Hendrix wrote:
Okay, it's a "valve" for our limey friends!

Today I was able to do some more troubleshooting with my dad and my sons, on Dad's TEK514. I took along my thermal camera to help track down the short that was blowing the inlet fuse. Turned out i didn't need it, but it helped confirm. One rectifier tube right next to that monster power transformer started getting extra hot within seconds of power-on, and then started arcing and making a nice arc lamp. I've done a bit of searching and it seems the audiophiles like these tubes; the best I could find was AU$55 for a pair on eBay. Dunno how much shipping would be from down under. Fairly simple fix, to swap out a tube - if that's the only problem. But we checked all the electrolytic caps with an ohmmeter and none seemed to be shorted nor open. Looking for any thoughts on a good source for the tube, and/or whether it's a worthwhile fix.

Steve Hendrix

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