[BUILD] 1176 Rev A - Back to the beginning...

[regularjohn]

Haha...what's the shipping cost for a keg?  Just happy to help, bro!!!   ;D
-Dustin

 

[stitch-o]

Haha...what's the shipping cost for a keg?  Just happy to help, bro!!!   ;D
-Dustin

Not too much.
Its the German beer fräulein that comes with it that's pricey...

THANK you once again, brudda  ;D

 

[Siegfried Meier]

Hey guys,

I'm just coming back to working on these after a long hiatus.  I bought a bunch of components for my pair last year, and can't seem to find some of the info I need.

I have 2 Farnell 953 0339 TA030/25 power transformers, and it appears they're no longer stocked.  But for the life of me I cannot find the actual wiring diagram for these.  Does anyone have them? 

These are the units:

http://export.farnell.com/multicomp/ta030-25/transformer-30va-2x-25v/dp/3068640

Thanks for any help.
Sig

 

[Siegfried Meier]

Anyone?  Or am I just missing the info I need on this Farnell page somewhere?

Thanks guys,
Sig

 

[Biasrocks]

Anyone?  Or am I just missing the info I need on this Farnell page somewhere?

Primary
Brn, Gry = 115V
Vio, Blu = 0VCT

Secondary
Red, Yel = 25V
Org, Blk = 0VCT

http://www.farnell.com/datasheets/79607.pdf

Mark

 

[Siegfried Meier]

Ahhh that's the site I was missing!!!

Thanks so much man!
Sig

 

[baadc0de]

I've built one rev a from a 1.1 board and wired it according to the last picture in this thread like this one:
http://img534.imageshack.us/img534/1859/1176wiring.jpg only for rev a (with blue board - can't find it now in this huge thread). I modified the output transformer wiring to match the 1.1 PCB though.

As I've quickly turned it on today, it passes no signal from input to output and the input and output t-pad/pot don't seem to make a difference. I'll measure voltages as described in this thread already for similar problems, but as a quick question, does the picture I worked from (skylar's rev a?) represent pots as they're looked at from behind (i.e. right hand side is ccw)? What about the input t-pad, does the picture represent it with the legs up, towards the viewer?

I should measure:
- AC/0 voltage on the power supply input pins on the PCB
- scope the input at the XLR, then input xfrmr in and then out

Any more ideas? I didn't ground my XLRs yet..

Thanks

 

[Rob Flinn]

The picture you're operating from is for the REV D board, which is sort of similar, but the blue stripe wiring is a bit different. There are some wiring diagrams relating to the Blue Stripe firther back inthis thread.  Although I found them a bit confusing & had to corssreference them to the Blue Stripe Circuit diagram, before I got mine working.


What are you using for the Tpad/pot ??    If you are using the black 3 deck attenuator from Hairball then you will definitely need the correct diagram.

 

[baadc0de]

Actually worked from this one (now I found it): http://i296.photobucket.com/albums/mm171/renbis/1176-RevA-Wiring_on-off---m.gif and it shows the attenuator. I'm using hairball's 3-decked t-pad and regular alpha pots-

 

[Rob Flinn]

Actually worked from this one (now I found it): http://i296.photobucket.com/albums/mm171/renbis/1176-RevA-Wiring_on-off---m.gif and it shows the attenuator. I'm using hairball's 3-decked t-pad and regular alpha pots-

The pic of the attenuator is correct when looking at the terminal side & it works.  Did you join the 3 middle legs of the HAirball attentuator ??

Do you have a scope so that you can check whether the signal arrives at the main board ?

 

[baadc0de]

Yes, I assumed it showed the attenuator from the top (that is, the terminal side) and that's how I wired it - I soldered the middle legs together with wire as shown on the picture. I'll check with an oscilloscope later, when I get my hands on one. Looking at the picture again, I might have failed to connect pad 16 from the board to the output pot, could this kill my signal?

That aside, can anyone confirm that from this wiring diagram, the pots are facing in such a way that the rightmost legs are on the ccw side? Also, I've searched, but maybe I'm a lousy searcher, what is the function of the  "NORM SHORT" jumper field? I think it has to do with the tracking adjust VR?

 

[Rob Flinn]

I might have failed to connect pad 16 from the board to the output pot, could this kill my signal?

Yes

That aside, can anyone confirm that from this wiring diagram, the pots are facing in such a way that the rightmost legs are on the ccw side? ?

The pots are looked at from the rear in that picture

Also, I've searched, but maybe I'm a lousy searcher, what is the function of the  "NORM SHORT" jumper field? I think it has to do with the tracking adjust VR

This is to do with setting up the meter driver part of the circuit.  It is documented in the setup procedure

 

[baadc0de]

Weird thing, looking at http://www.diyfactory.com/data/transformer_connections.gif, I assume I'd have to wire the Avel Lindberg Y236106 power trafo like this for 220V operation:

Gry-Violet linked, brown and blue for primary to 220V AC?
To the 1176 PCB, RED and ORAnge linked to center tap pad, black and yellow each on one AC pad?

This diagram is printed on the transformer:

BLU ------\ /------ BLK 0V
         *| |*
          | |
GRY ------/ \------ RED 25V
VIO ------\ /------ ORA 0V
         *| |*
          | |
BRN ------/ \------ YEL 25V

I get 60-ish volts on the AC-CT pads, so that's probably no good

 

[Rob Flinn]

That sounds like you wired it up right to me.    Red & Orange should be connected to ground.

Are you measuring this voltage from the centre tap to either side of the secondary or across the combined series secondary ?

Are you measuring the voltage with a normal load on the psu ?  If you have no load the voltage will be higher than the 50v ac you are expecting across both secondary windings in series.

Are you getting +30v & -10v in the right places on the compressor boards ?

 

[baadc0de]

It does seem right.. I'm getting -9.79V and +29.15V on the test points.. Also, the signal does arrive to the board from the input transformer and the attenuator. It's a drop of 1.1V->0.3V through both devices, but the signal is indeed present, though I haven't checked with the scope in what shape the signal is, since I have none available at the moment.

I have checked pad 16 and grounded the output XLR. The unit is now dead quiet, but that's the only thing it does, sadly. When switching modes (GR/+4/+8) the meter doesn't move at all. I've burned (and replaced) resistor r32 a few days ago, because I followed the wiring instructions linked above instead of what was written on the PCB, silly me (mine is v1.1). But the meter should move if I switch to GR mode even if the output trafo would be shot?

 

[Rob Flinn]

You could check to see that you have a signal on the output pot, which will tell you that the first amp stage is working or not, & then the brown wire of the output transformer & that will tell you if the signal is getting through output stage amp.

 

[baadc0de]

Nope, nothing on pad 15, and thus 17. Hmm, kinda stumped. What should I check now..

 

[Rob Flinn]

Getting anything on R5 ??

 

[Biasrocks]

Nope, nothing on pad 15, and thus 17. Hmm, kinda stumped. What should I check now..

Make one of these, trace your signal from the input, be happy.

http://www.diyfactory.com/data/mbsignaltracing.htm

The volume pot is optional.

Mark

 

[Rob Flinn]

Good advice