[BUILD] 1176 Rev F/G - new board, new transformer!

[moybm]

Hi, I think have a problem with my ref F and there is a transistor bad. I have the schematic from the rev J with voltajes but the schematic from rev F it´s different in Q5 (for example).

Where can I know the correct voltajes values?
How can I Know if any transistor it´s bad?

May not be the transistor, might be the resistors around the transistor (wrong value).

In the rev J have a resistor R28=>10k and R29 1M and make 4,98v .... in the ref F R28=>10k and R29=>6.8M and make 1,8v ...

the voltajes are diferents, but I don´t know if it's ok these, even so I will check the resistance I put.

 

[sktellis]

Thank for all of the help everyone! The Q Bias problem was I turned it way too much CCW and had to basically recalibrate it back to 0V. I have made it all the way through the calibration except the last step when you adjust the Tracking ADJ to hit -10. When I get it to -10 the Zero Adjust goes up to +2 1/2, so I turn that back to 0. Next I go back and turn up the Tracking ADJ but it will not go past -20... So I guess my question would be is there a way to zero the ADJ out before calibration or is this a bigger problem that I am looking over?

 

[sktellis]

Anyone have any ideas or suggestions?

 

[Echo North]

Not too sure about F as it has the IC meter circuit which I've never troubleshooted.

If you look at the F schematic, there are only a few components in the meter circuit.  Like 8 or so R's and the IC and FET.

http://mnats.net/files/1176REVFG_SCHEMATIC.pdf

Make sure those are the correct value an you have so shorts or bad traces.  Try setting the both trimmers mid way and then do the calibration.

Mike

 

[Finlaywatt]

Hi guys, pretty new to the whole DIY thing. I'm just starting to build the Hairball 1176 Rev G. I started stuffing the PCB's from mnats and didn't realise i'm not meant to use the mnats meter and ratio boards. I've put pretty much all the resistors in the mnats meter and ratio boards in following the BOM. Most of the resistors are in the main pcb too but apparently it is OK although my wiring will be different from the guides etc as it's a rev G.

Is this just a case of taking the resistors from the ratio and meter boards out and putting them in the hairball boards?
Is there anything else I should be aware of building this?

Any help would be appreciated. I'm wiring it for the UK if that makes a difference.

Cheers, Finlay.

 

[Echo North]

Hi guys, pretty new to the whole DIY thing. I'm just starting to build the Hairball 1176 Rev G. I started stuffing the PCB's from mnats and didn't realise i'm not meant to use the mnats meter and ratio boards. I've put pretty much all the resistors in the mnats meter and ratio boards in following the BOM. Most of the resistors are in the main pcb too but apparently it is OK although my wiring will be different from the guides etc as it's a rev G.

Is this just a case of taking the resistors from the ratio and meter boards out and putting them in the hairball boards?
Is there anything else I should be aware of building this?

Any help would be appreciated. I'm wiring it for the UK if that makes a difference.

Cheers, Finlay.

Welcome!

For the ratio PCB you'll need to carefully remove those resistors and put them on the switch boards.  Just follow the F/G column on this guide:
http://www.hairballaudio.com/docs/FET%20Compressor%20PCB%20Board%20Info%20V3.pdf

It'll tell you where to put them.

The input wiring for the G is different than the A/D/F because it does not use a transformer or a tpad.  I've never done it, but have a look at the top right of the schematic on the first page of this thread.

To me it looks like you wire the XLR in to the +/- at the IC Input section of the PCB.  Use shielded wire like the TPad version.  Then the "out" that is there goes to one side of your pot (opposite side to ground) and the wiper goes to the regular input on the PCB you'd use for the A/D/F.  I'd shield this again.

Mike

 

[Finlaywatt]

Thanks! I'm not really sure what you mean. So does the XLR input go straight to the PCB?

 

[Echo North]

The only "trick" to the input wiring is the shield.  You really want these connections shielded and you want a continued shield from input XLR to the PCB input (but not connected).  Basically you wont the shield to capture stray signal and short it to ground at one end (by the XLR).

Id probably do this using the concepts here:
http://mnats.net/1176_reva-d_hairball_wiring_input.html

1. Run your shielded cable from your input XLR to the IC input.
2. Connect that shield to the shield of a cable with the two inner conductors connected to the pot.
3. Connect that shield to a wire connecting the other side of the pot and wiper to the INPUT of the circuit and leave the shield unconnected (per the wiring pages linked above).

I've never done this, but this looks right and should keep the noise out.

Mike

EDIT:  POT IN DRAWING SHOULD BE 10K INPUT.

 

[Echo North]

The wire with the loops coming off it is the shield.

Rest of the wiring guide should be the same.

 

[Finlaywatt]

Ahh okay I think i've got it, the wee drawing helps a lot, thank you.

So for my main pcb so far I've just followed the BOM on the hairball site for placement. I'm guessing they'll all be fine?

 

[frazzman]

Hi all,

I'm just trying to finish up my first 1176 rev F build. I'm building with electronically balanced IC input and rotary switches.

I'm a bit confused about the input pot and XLR in & out wiring. Would someone be kind enough to check my attached diagram and let me know if I've got it right?

Most of the documentation on this build is surrounding push button assembly with Input TX so I am not entirely sure if my wiring for build with IC input and rotary switches is OK.

Appreciate if someone can take a look and let me know if theres any errors!

 

[frazzman]

Found what I needed with the transformer wiring ! Just looking for some advice on input xlr and pot wiring, is whsts in my diagram above right ? Thanks in advance.

 

[Echo North]

Did you see my drawing like 4 posts above?

 

[Finlaywatt]

Close to finishing my rev g build but while connecting the meter pcb Pad X popped off! Could I solder the wire straight to the back of the +8 switch?

 

[Echo North]

Close to finishing my rev g build but while connecting the meter pcb Pad X popped off! Could I solder the wire straight to the back of the +8 switch?

Ya just follow that trace and find the next connection point.  Or scrape away some solder by the open hole and feed the lead through and connect to the exposed copper.

 

[Finlaywatt]

Thanks, I followed the trace and got it fixed.

I followed your earlier drawing for the input wiring but where does it hit the input pot? The 100k pot is output.

 

[Echo North]

Thanks, I followed the trace and got it fixed.

I followed your earlier drawing for the input wiring but where does it hit the input pot? The 100k pot is output.

Opps that should say 10K on my drawing, that is the input.

 

[Finlaywatt]

Okay, thought so. Got that all done now. How do I wire the zero adj pot to the r55 pads on the main pcb. As in where does each leg of the pot go?

 

[Echo North]

Okay, thought so. Got that all done now. How do I wire the zero adj pot to the r55 pads on the main pcb. As in where does each leg of the pot go?

It's all in the wiring guide.

 

[Finlaywatt]

In the wiring guide it says "On the Rev F USA boards, use the pads for R55 - the "ZERO ADJ" trimmer footprint". But doesn't say where each wire goes on that footprint. Any help would be much appreciated.

Also, where do the grey, purple, green and blue output transformer wires go? The main pcb only has pads for the other four.