HELP!!!???

[shelby1420]

Ok folks, this has me upsidedown stumped!!!!  I have been using and enjoying my Stereomour for about a mnth now with no issues and loving it!!  This am  I swapped the two output caps for two different ones and now nothing, no sound.....I had a peak under and could see the LED were lit but still nothing, coulda swaor I smelled something funny so turned it off and took out the fuse to do a resistance check, here is where the confusion starts.......

Terminal - 1)3.0 k --should be infinity
Terminal - 2) 15.03 m --should be infinity but may settle around 486kohm
Terminal - 14) 15.3 m  same as above
Terminal - 15) 1.5 k --should be infinity
Terminal - 17) 2.7 k --same as above
Terminal - 19) 2.2 k --same as above

Four pin sockets

A2 3 Kohm should be infinity
C2 3 Kohm same as above

Also the big 10w 1,6k resistors between terminal 6-16 as well as 10 and 20 have the writing completely off of them, I suspect from heat............

What the hell have I done now?

[Grainger49]

There are only a few Stereomours out there.  So the community is a little slow to respond.  

The readings of ~15 M ohm, terminals 2 and 14, are the same as infinity, i.e. high enough.  I can't help you with terminals 1, 15 and 17.  I don't know where they are in the circuit.

The 1.6k resistors are in the cathode of the output tube, 2A3.  Losing the markings means it takes a lot of current.  Usually that also would discolor the resistors.  Try measuring the resistance of both.  It may be hard as there are capacitors in parallel with both of them.

Even if the capacitors you swapped were shorted I can't see where they would cause extreme current through the cathode circuit.  Check across the capacitors.  Measure resistance from one terminal to the other.  They should start at a thousand ohms or so and should climb.  That is normal.  A low reading would indicate a problem with them.

It is likely that you loosened an already loose connection when exchanging the capacitors.  Check all terminations closely.

[shelby1420]

There are only a few Stereomours out there.  So the community is a little slow to respond.  

The readings of ~15 M ohm, terminals 2 and 14, are the same as infinity, i.e. high enough.  I can't help you with terminals 1, 15 and 17.  I don't know where they are in the circuit.

The 1.6k resistors are in the cathode of the output tube, 2A3.  Losing the markings means it takes a lot of current.  Usually that also would discolor the resistors.  Try measuring the resistance of both.  It may be hard as there are capacitors in parallel with both of them.

Even if the capacitors you swapped were shorted I can't see where they would cause extreme current through the cathode circuit.  Check across the capacitors.  Measure resistance from one terminal to the other.  They should start at a thousand ohms or so and should climb.  That is normal.  A low reading would indicate a problem with them.

It is likely that you loosened an already loose connection when exchanging the capacitors.  Check all terminations closely.

Hey Grainger here are the measurements of output cap left 4.3kohm and coupling of same side is NADA......... From right side output cap the reading is 2.1 ohm and the coupling for same side is 16.5m ohm, what does this mean??

[shelby1420]

Well, good news and bad news.............. I swapped the old Solens back in and bob's yer uncle all is good in the world again, caps I took out were the Mundorf silver gold and oil..............

[Paul Joppa]

Sure looks like those caps were shorted. Those caps (according to the pdf from Mundorf) are rated 1200 volts, so there must be a serious problem with them. Since you seem to have the same problem on both channels, there may be a bad batch? Best to contact Mundorf directly, as well as the vendor - Mundorf may want to examine the caps to diagnose the problem, unless they already know about this.

[Paul Joppa]

Inspect the cathode bypass caps (220 or 270uF 250v, on the power supply PC board) for possibly bulging ends. They were exposed to the full B+ and may have sustained damage from excessive voltage.

[shelby1420]

Hey Paul, all caps look fine!!  I see that on both caps I had tucked the lead under so severely that the leads had actually burned into the metal can through the black outer coat, hoaping that was the issue...............