Help for Building The S.E.X. 2.1,Impedance Switch and C4S

[Paul Joppa]

The plate choke goes between terminals 20 and 21, and drops about 40 volts when operatiing correctly. It appears that this connection is not happening. As always, check those solder joints first - its the easiest and most often successful test. Then measure the resistance between those two terminals; I forget the exact number but it must be around 1000 ohms.

The above is incorrect - see later post. I apologize!

[Paul Birkeland]

I forget the exact number but it must be around 1000 ohms.

IIRC, they are around 930 Ohms.

[i luvmusic 2]

Thanks! for the reply.

I reflow the solder T20 and T21 and measure the resistance the reading is 18.45M and dropping.

Thanks!

[i luvmusic 2]

While i'am at it i measured the resistor connected to T6 and T10 the reading is 674R and resistor connected to T16 and T20 the reading is 11.79M and going up.I don't know if this help because my electronic knowledge is limited.

Thanks!

[Paul Joppa]

Sorry, I mis-remembered the wiring, which is I admit complicated.

Your last measurement was extremely helpful. That resistor from T16 to T20 is blown. It probably happened due to the short circuit of high voltage T20 to the power triode grid T19 - this would cause the triode to conduct very excessive current, blowing the resistor quickly. I don't recall mention of a blown fuse, so the resistor probably went out faster than the fuse could react.

The plate choke I mentioned before goes from T16 to B2. It is probably OK, but measure the resistance to be sure.

The blown resistor means no voltage is supplied to the PC board, hence no LED glow. The board is probably OK - you won't know until the resistor is replaced and power is restored.

The tube is probably OK, the current surge would have been short and the tube is tough. Voltage checks after power is restored will determine whether there's a problem.

[i luvmusic 2]

I will check it tomorrow.

THANK YOU!

[i luvmusic 2]

Hi,
  So i measured T6 and A2 reading is 840R and 842R for T16 and B2.220R Carbon Comp. Resistor connected to T19 and B1 is cooked,Can i replaced this with Metal Film instead?

Thanks!

[Paul Joppa]

While carbon comp is theoretically better, there is evidence that metal film works well, and they are much sturdier. Do not use wirewound though.

[i luvmusic 2]

While carbon comp is theoretically better, there is evidence that metal film works well, and they are much sturdier. Do not use wirewound though.

Metal Film is the only type i can access in that value locally.

Thanks!

[mcandmar]

You can get them from Mouser -> http://www.mouser.ie/Search/ProductDetail.aspx?R=OD221JEvirtualkey58810000virtualkey588-OD221JE

[i luvmusic 2]

You can get them from Mouser -> http://www.mouser.ie/Search/ProductDetail.aspx?R=OD221JEvirtualkey58810000virtualkey588-OD221JE

yeah i just ordered it with some other sfuff.

THANKS!

[i luvmusic 2]

I didn't expect the SEX will drive my SANSUI SP-X6900,Not to the full potential of this speaker but it  sound darn good.