Blowing fuses.

[ssssly]

Got my sex almost done. When I went to do the resistance checks I get 243ohm at a4. Thus is the exact reading of the resistor from a4 to 19. Looking at the schematic I don't see how a4 could make paths to ground without going through that resistor. The manual says that a4 should read 0ohm.

I have checked the wiring over and everything looks right. It does however immediately blow the fuse when powered on. I suspect that is the result of a bad cap which I am going to swap out tonight.

The a4 thing has me baffled though. Is a4 supposed to read 0 or is it a misprint?

 

[JC]

The resistor in question is the grid stopper on the A side driver.  With the volume control at one end of its travel, you would read just the value of that grid stopper from A4 to ground, or very close to it.

In any event, A4 is the control grid on triode that makes up that half of the tube.  Not really a fuse-blowing part of the circuit as a rule.

 

[ssssly]

I'm fairly certain that the fuse blowing is the result of a bad Cvd cap resulting from melting the side casing when I slipped while soldering something else. Hopefully I have a nother 220uf cap lying around someplace.

And thanks for keeping me sane on the grid stopper. From looking at the schematic the value I get there was what I thought it should be but the manual says "0Ω volume set to min, 100KΩ volume set to max". So I just wanted to make sure that I wasn't missing something since the value I get is the resister value to 100K + resister value.

Am also starting to wonder now if perhaps there is a bit of a clipped lead that has gotten into someplace it should not have.

Back to the hardware store for more fuses.

 

[JC]

you may want to do a search here about using slow-blow fuses in the SEX.  I seem to recall some folks having trouble with blowing fuses that cleared up by changing to a slow-blow of the same value.

OTOH, a "wounded" electrolytic can do some funny things;  Perhaps disconnecting the high-Voltage winding to the channel that it's in to see if the fuse holds will help you narrow it down further. 

 

[ssssly]

Found the culprit. Chunk of clipped was shorting. All is well and playing wonderful music. Thanks for the help.

 

[JC]

Congratulations! 

Good catch, BTW;  those can be a bear to find sometimes.