[moonboy403]

Dr. Gilmore, is that Extreme in the picture from Nate? If so, I believe Shelly and I were two of those unlucky owners that lived through the edge with it.

 

[spritzer]

It also looks like that resistor cooked every part close to it. The electrolytics for the filament supply have nearly burst...

 

[Born2bwire]

I think the standing operating procedure at this point would be to yank out all the amp innards with a claw hammer and then stuff the shiny casing full of used pinball machine parts.

I mean, everybody loves pinball.

 

[n_maher]

Quote:

Originally Posted by moonboy403 /img/forum/go_quote.gif Dr. Gilmore, is that Extreme in the picture from Nate? If so, I believe Shelly and I were two of those unlucky owners that lived through the edge with it.

No, it's yet another shining example of ineptitude unfortunately. Every time I think this can't get worse I'm proven wrong.

 

[Happy Camper]

Singlepower amp model "Extreme", board "Extreme Rev. A/ Feb. 2007"

Immediate hazard warning.

 

[kevin gilmore]

http://gilmore.chem.northwestern.edu...ourextreme.pdf

This is absolutely the first example i have seen where mikhail has biased
up the filaments.

If he had done this with the ES1/ES2...

By the way, on most of the ES1/ES2 with the plitron transformers, there was
already a 40 volt winding that was abolutely perfect for the C- supply, and
there were dual filaments...

Most of them were cut short and heat shrunk, but a few are long enough to
actually use...

 

[immtbiker]

Another proud product built by the Singlepower team, "Pursuing excellence at every corner." Quality is Job 1!

 

[The Monkey]

Just imagine what's Job 2...

 

[atbglenn]

Unbelievable

 

[mrarroyo]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif ... The electrolytics for the filament supply have nearly burst...

I saw that, scary job to say the least. Dr. Gilmore is that raffy's unit?

 

[00940]

Actually, those threads are very informative for tube amps building safety. Should be stickied in the diy forum

 

[mikeymad]

Thanks Kevin for giving us more things to look out for...

Never thought that I would have to know so much EE just to own an amp...

Cheers,

 

[nurxhunter]

"So its obviously time to remove the circuit board.
But wait, the side board is soldered in from the backside

and no way to unsolder it without brute force.
Sweet."

I was puzzled by the side board, which seems to be completely unnecessary. Who uses a side board simply to attach RCAs input to PCB?

1) Does this 'side board' serve any purpose some wire would not ? Would seem straightforward to dispense with without undue force or hassle--toss it--and wire the inputs to the board?

2) All the pics I have seen with resistors in place at position R54 --show two 5W stacked resistors at R54, not one resistor in that position. Was this unit maybe an early one, and then a correction was made in later units.

 

[kevin gilmore]

No useful purpose in the sideboard, other than making it almost impossible to remove.
Obviously the ground on the backside did not work, hence the extra set of blue
grounding wires.

I had to specially machine a tool with .060 sidewalls to fit into the circuit board to
get to the nuts that hold the tube sockets to the chassis. Without that tool the
circuit board would never survive unsoldering all of the tube socket pins. This tool
is not going to last long with sidewalls that thin.

Notice the 2 big filament electrolytics and the huge holes for screw mount caps.
Yet the caps installed are not screw mount and are just soldered to the side
of the holes.

I've seen many units with 2 filament resistors, some with one, and some with
none. Still don't understand the first high voltage cap in series with the 15 ohm
resistor. Does absolutely nothing except waste parts.

The resistance of the circuit board lands causes a loss of about .4 volts from the
diode bridge ground to the tube ground. So that is heating up too.

 

[nurxhunter]

Extremely great answers. Thanks.