trinityamps.com

Since it didnt blow fuses when the 150R was pulled , and does when it is in circuit, despite it measuring OK, it is possible there is an intermittent fault. I would replace the 150R and see what happens. I would also consider replqcing th 50uf bypass cap.
Once the tubes warm up, amd start to conduct, they are running too much current. The amount of current is set by the cathode resistor and any plate resistors, so to me, this is the area to really inspect.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Finally had a few minutes to stop and get some parts... replaced the resistor and the cap... and no change. sigh...

Well, of you want to ship it, we will get it going again.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Well... a cold rainy labor day weekend affords the opportunity to try this again.

Double checked all the wiring on V4,5 and 6.. still seems good. Decided to go the other way and look at the speaker output.

As near as I can tell, there is no resistance to be found between anything involved. The positive and ground of the jacks are less <1 ohm resistance between them.. all the lugs on the selector knob are < 1 ohm.

If I disconnect the hot off the selector, there is no continuity between the knob and the hots on the jacks. There is continuity between the different tabs on the selector.

If I then disconnect the 16 ohm tab, there is no longer contintuity on the knob between hot and 16 unless the selector is on 16..

Is there that little internal resistance between all the taps on the output transformer that this makes sense?

Yes. All there is is a lomg lemght of copper wire, so R is typically low.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps