F5X -- the EUVL Approach - The Build Thread - Page 41 - diyAudio
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Old 6th February 2013, 07:27 AM   #401
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Use this method to trace?
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Old 6th February 2013, 11:57 AM   #402
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Quote:
Originally Posted by fitzfish View Post

For all of the bias work it is necessary to short the + and amplifier inputs to ground on the input board.
Do I need to connect the two input holes to the Gnd?

I measured the R18A, R19A, R24A and R25A and they are between 047.5mV to 050.5mV. Am I close?
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Old 6th February 2013, 12:27 PM   #403
NicMac is offline NicMac  Italy
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>Do I need to connect the two input holes to the Gnd?

If you have the input relay in place they will already be grounded by resistors (if I remember right via 1KR resistors R101 and R103). Measure the resistance between gnd and the inputs to be sure.
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Old 6th February 2013, 02:11 PM   #404
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> Use this method to trace?

Yes.


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Old 6th February 2013, 08:32 PM   #405
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Quote:
Originally Posted by NicMac View Post
>On the 'Degen Resistor Image' :
1) Is the regen resitors solder onto these pads?
2)Are the jumpers position for the Q11A, Q14A, Q10A and Q7A correct?
3) Is it okay if I didn't remove the tefron sleeve for the jumpers between Q6 and Q15?

Yes, yes and yes.

>On the 'Mute Connection Image':
4)Does the last hole on the Mute board extend all the way to the amp board or is just extended to the Input board only?
5) The holes right after R103 and R104, where do these goes to?

The wire does not go all the way to the amp board.
The two holes are the amp inputs and goes to the XLR sockets.
I'm a bit confused.

Regarding #1 - Degen resistors are also required at the locations pmchoong has shown? My understanding is they were only required at the (2) locations shown on Dave's build guide (first page of this thread).

Regarding #4 - I soldered this connection all the way down to the amp board, because it seems like there are no traces to this hole. I could be wrong though.
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Old 7th February 2013, 03:29 AM   #406
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Looks like Dave is too busy with work and I have to jump in.

1) The pads shown are not for degen resistors. Greg is correct, only 2 locations required at the source pin of the 2SJ74s.
Those pads were placed there for the cascoded version.

4) The daughter board is to connect the input of the XLR, after the 1k/100k divider, to the main board.
So other than Gnd connection, there are 4 wires going down to the main board (to the gate pins of the JFETs to be precise).

I don't want to spoon feed, so you can trace all these by following the schematics.
That way you will have a deeper understanding of what you are soldering, which is my goal.
So, if in doubt, compare the tracks on the PCB to the wiring of the schematics.


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Old 7th February 2013, 10:49 AM   #407
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Default Protection board

On the protection board :

What are the value for :

1) C18_L & C18_R
2) C20
3) C21
4) C22
5) C25
6) C28
7) C32
8) C35

For D10 & D11, which direction do the rectifiers face?

I think I am missing one 47uF capacitor for C20.

How do you test the board for errors?

Thanks.
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Old 7th February 2013, 11:44 PM   #408
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1) C18_L & C18_R - C1210-10uF
2) C20 - 1210-47uF
3) C21 - 1210-10uF
4) C22 - 1210-10uF
5) C25 - 1210-10uF
6) C28 - 1210-10uF
7) C32 - 1210-10uF
8) C35 - 1210-10uF

Correct? Thanks.
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Old 8th February 2013, 03:12 AM   #409
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Send ashaw a email and ask him.
He might not be reading.


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Old 8th February 2013, 05:57 AM   #410
NicMac is offline NicMac  Italy
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Quote:
Originally Posted by pmchoong View Post
Correct? Thanks.
Look in the BOM....
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