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*Solved Minerva Tropic Master model w117 "early"-crackle pop & no vol ****SOLVED
#3

(06-07-2018, 08:47 PM)jcassity Wrote:  here is the bottom of the set.

from my research the bare metal bar is what i "think" supposed to be the DC Buss.
right now i have no voltage on this bar.

i have also read that in nearly all cases the 50L6 tubes are wired in parallel,, so when there is a problem with one ,, all current passes through the other one and killing it by default.   This is only what i recall from early this morning reading up.  
there is a mod to rewire the 50L6's in series so that when one goes,, the other simply does not operate but it does not get killed.

You could rewire the parallel 50L6 to use 25L6 in series, all the tubes would then be 300ma. That's what every set I can remember used. Musta got a helluva deal on 50L6.

A 6SK7 doesn't draw enough current to get more than barely warm.

I suspect the buss is floating ground, B+ usually requires enough resistors to drop for various points that it's just a few wires. You need to check plate & screen voltage on each of the tubes., BUT start by verifying cathode voltage on 25Z6. Ground will begin at negative side of filter caps...

Tom


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RE: Minerva Tropic Master model w117 "EARLY" - by 35Z5 - 06-07-2018, 09:02 PM



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