eXStatA Build Thread II

[gilency]

T1 to ground: 332V
T3 to ground: 326V
High rail: 48V
Low rail: 291V
T1-T2: 360mV. It drifts down slowly a few mV.
T3-T4: 410.
For what is worth, the LED in the high rail looks a little brighter than the low rail.
I changed R15 because it was reading 1.5 instead of 475 ohms. The replacement measured 475 before I soldered it, now reads 1.5 ohms again. why?

 

[runeight]

Measure from the cathode of Z9 to ground.

 

[gilency]

Z9 to ground = 54V
Z14 to ground=203V

 

[runeight]

First guess is that the z9,z10,z11 string has blown zeners. Try replacing all of them.

 

[gilency]

I replaced Z9, Z10 and Z11.
Still get 48V in the high rail.
All other measurements (low rail,T1 to ground, T3 to ground) are fine.
z9 to ground is 45v.
z14 to ground is 198v

 

[runeight]

The 198V makes perfect sense given where you are measuring it.
 
We're going to have to replace components one at a time. If you are sure that the zeners are working then the next step is to replace Q9 and Q10.  I don't think that Q5 and Q6 would have been damaged by the two backward zeners, but Q9 might have been and it's just safer to swap out Q10 while you're at it.
 
The mosfet should be ok providing that its protection diode Z1 has the correct orientation.

 

[runeight]

While you're at it, what is the voltage from Z3 to ground?

 

[runeight]

gilency, how are you doing?

 

[gilency]

Fine, just need to order some parts. Unfortunately it will take a few days for them to ship and I get a few days and have to get back to work. I will let you know when I am able to work on it again.

 

[gilency]

Can somebody point me towards a specific 4PDT switch in Mouser? Thanks

 

[BoilermakerFan]

Quote:

Can somebody point me towards a specific 4PDT switch in Mouser? Thanks

For the inputs it can be a simple On-On switch:
 
http://www.mouser.com/ProductDetail/Mountain-Switch/10TC290/?qs=sGAEpiMZZMvudeGI7i40XMiFOdVKce2XfPMzx0bS%252bxY%3d
 
But, for a few bucks more you can have one of tthe best 4PDT, a TOCOS, from Michael Percy Audio. 

 

[gilency]

OK. Thanks.I am itching to start working on my PS but waiting for parts. 
One more question, How do I wire a loop out? I want to have balanced and SE in with a switch, but would like to have an RCA loop out. 

 

[spritzer]

You parallel connect the RCA sockets so center pin to center pin to the switch.  With a 4PDT switch you are using common ground so don't worry about that, just connect them all together. 

 

[gilency]

Thank you Spritzer.

 

[ujamerstand]

Finally able to case up my exstata hybrid:
 

 

 

 
This one uses toshiba 2SJ74BL as input jfets, 2sc3676s as output devices. Special thanks to BoilermakerFan for making the parts suggestions!