[BUILD] 1176LN Rev D DIY

[andydiy]

Hi!

ask the following numerical change capacitor ,Is it okay if?

Hi!

C8 = (MKP2-.15/100/5) change (MKP2.15/100/10A)

C9=(MKP2-.22/100/5) change (MKS2.22/100/10)

C22=(MKS2-.22/63/10)  change (MKP2-.022/250/10)

C27= (MKP2-.022/100/5) change  (MKS2.22/100/10)

Thx!

 

[number2]

HMPS, sorry I got lost in all the posts that came after mine. I'm still trying to resolve this.
I'm reading your posts over the last several pages and following your measurements and EN's tips currently

I'm showing similar numbers as you, how did you resolve this?

Hook up a signal to the input, use the signal tracer to see if the signal is present at the input to the pcb (output of the transformer). 
If it is, use the signal tracer to see if the signal is present at the input to the output volume pot.
If it is, then the problem is in the output amp.
Check the voltages on the components in the output amp. Check that the components are right. Post more info if you need help. Pictures of your build. Post the schematic with your voltages (listing all the voltages in text may be easier for YOU, but not for the person you are asking to help you).

checking voltages: Q13 seemed off.

Don't worry about the meter driver yet - get the signal preamp and output amp working first.

thanks so much dmp!
i signal traced and i have signal passing at all of the pots, input/output XLR's, output transfrmr and at input to pcb.

voltages:
signal preamp:
Q2: 1.05, 1.7 and 0.5
Q3: 1.75, 11.76 and 1.15  (11.76 should be closer to 12.5?)
Q14: 11.76, 29.6, 11.17

signal line amp: (is this the output amp?)
Q4: 0.98, 3.9 , 0.42
Q5: 3.2, 24.3, 2.6
Q6: 27.1, 2, 2      (this 27.1 should be closer to 28.9?)

GR control amp:
Q7: 14.82, 4.37, 3.8
Q9: 16.3, 3.38, 2.8

 

[HMPS]

What issues are you having?

The last transistor measurements i did were only off at a few places, and from what I read you have to have the controls at a certain setting to get the transistors to measure right *i think*

once you calibrate it, plug it it if it sounds good then....hey

 

[andydiy]

Hi!

I would like to ask,I'm starting to build 1176LN Revision D Boards PCB.

I downloaded hairballaudio site Mouser Cart Link. then to and  follow him buy .

https://se.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=cedcf00cfd

After find some capacitance values, ​​Bill of Materials-Mnats Revision D, differ.

ask the following numerical change capacitor .


C8 = (MKP2-.15/100/5) change (MKP2.15/100/10A)

C9=(MKP2-.22/100/5) change (MKS2.22/100/10)

C22=(MKS2-.22/63/10)  change (MKP2-.022/250/10)

C27= (MKP2-.022/100/5) change  (MKS2.22/100/10)

Expect someone to give me advice!

Thank you!

 

[sr1200]

I would go by the mnats schematic... i did for mine, havent had a problem.  it seems that only 2 of the caps are actually different values in the sense that the first two are just differences in amperage. and it looks as though the 2 that are different (even if they are incorrect) can be swapped to match the mnats schemo.

 

[rokus666]

Alright here you go....read this as well but note it's rev a so some values (DC and component) will be different.
http://www.groupdiy.com/index.php?topic=29981.msg615080#msg615080

Print off the rev D schematic from the MNATs site.  Now go to the rev A schematic and write in the pad numbers from there on to your Rev D schematic...20,21,18 and so on.

Now here is one of your issues....you have no DC voltage at pad 21.  Here is how you get that voltage.  Look at your schematic, R64 connects to your -10V rail and then to pad 20.  From here is runs up to the ratio board and feeds the R63, R62, R61, R58 divider network and back down to the Qbias wiper where it connects to ground closing the circuit.  Looking at the schem R64 is 1.5K and the rest of the R in the chain are like 2K all together.  So you'll a sizable drop across R64.  Rail on one side (-10V) and something like -6V on the other.  If you don't at least have this with PAD 20 disconnected you have a main board issue at R64.  Edit: With pad 20 disconnected you'll have no path to ground...so no voltage drop accross this R.  Just make sure you have that side of the R64 going to the raio PCB pad 20. [End edit] Now this 6V gets connected to that R network with pad 20.  Now if you follow those resistors in order you should see a stepped drop -6V -> -4V -> -3.2V -> -2V (real roughly) until you get to the other side of R58 where it should be near fairly low, like -1V.

Now the switch just taps off those stepped voltages 6V -> -4V -> -3.2V -> -2V and feeds them to pad 21.

You've got basically no voltage anywhere in that chain I just described.  If you have -6V or whatever on the on side of R64 and not at pad 20 on the ratio, then you have wiring issues.  Likely it's miss wired, which would also help explain your voltage sag.

Good luck.

I have followed those steps up untill I disconected Pad 20 and measured R64 (voltage was 9.75 on both sides)
After I connected the wire back to pad 20, powered the unit and another fuse blew off. This is like the fourth fuse so far.

Another fuse blew when I replaced it, and after I disconnected pads 20, 18, 22, 21, 19, the unit powers on normally. I assume something is wrong with ratio board.

I am triple checking the wiring and I cannot find a mistake (it seems)
:'( :'( :'(

I am measuring voltages on pads. I am getting:

20  -6.61
18  -1.1
gnd  0
22  0
21  1.09
19  0.6

Lets do some further measurements...

Power rail- Good

 

[rokus666]

I am doing the third step of calibration process.

I got stuck at some point:

I have put back tracking adj jumper into action.

I shorted pad 22 to ground, adjusted output to 0 db with a sine wave.

Compression off, ratio 20:1

When I remove the shorting lead from ground, I SHOULD BE GETTING around -10db Drop, but I see no change in meter reading. The meter stays in the same place

I can't figure out what I am doing wrong...

 

[andydiy]

Hi!

You can write C8 / C9 / C22 / C27. with change Configuration ?

Thank you!

I would go by the mnats schematic... i did for mine, havent had a problem.  it seems that only 2 of the caps are actually different values in the sense that the first two are just differences in amperage. and it looks as though the 2 that are different (even if they are incorrect) can be swapped to match the mnats schemo.

 

[sr1200]

http://mnats.net/files/1176LN_REVD_V2.2_DOC.pdf
Its all in the doc linked above.

the only other change would be found on Mnats site which has nothing to do with the caps, but a resistor.

Revision D Version 2.2 26.01.09 (currently being supplied):

    R12 Value should be 1.8k rather than 920

 

[rokus666]

Why is my GR meter slow when I switch ratios? At some ratios it jumps up and comes slowly down again and at some ratios jums down and comes back up.

The unit passes the signal correctly.

The unit lets me go through 2 steps of calibration...


On pad 22 I am getting 0.3 V

On the third step, when I short pad 22 to ground, I am not seeing a drop in the GR meter reading.

I am not an electrical engineer and I don't think I can figure this out.

Will turning the attack off turn off GR meter ? because mine stays in place.

please someone help...

 

[Echo North]

Why is my GR meter slow when I switch ratios? At some ratios it jumps up and comes slowly down again and at some ratios jums down and comes back up.

On the third step, when I short pad 22 to ground, I am not seeing a drop in the GR meter reading.


Will turning the attack off turn off GR meter ? because mine stays in place.

please someone help...

All sounds normal.

When switching between ratios you should see a blip down or up and a reset to 0 depending on the direction you are going on the ratio switch.

When turning GR off and having GR meter button pushed in, your meter should just sit at 0.

 

[rokus666]

[/quote]

All sounds normal.

When switching between ratios you should see a blip down or up and a reset to 0 depending on the direction you are going on the ratio switch.

When turning GR off and having GR meter button pushed in, your meter should just sit at 0.
[/quote]

I don't think the meter should be so slow. I assume the problem is coming from either ratio or meter board...

I have thoroughly checked the scematic, traced every part, voltages (ratio board/PCB), wiring, I can not find a problem.

At this point I am ready to hire someone to help me

 

[sr1200]

Rokus where in NY are you?

 

[HMPS]

Rokus

your power is way to low you have something wacky -6.5 is too low


did you fix your power? you shouldn't be calibrating until you fix the power!

 

[rokus666]

Rokus where in NY are you?

I'm in the City...

 

[rokus666]

Rokus

your power is way to low you have something wacky -6.5 is too low


did you fix your power? you shouldn't be calibrating until you fix the power!

At the power rail I am getting the right voltages. -9.73 and 29.7
R64 measures -9.73 on both sides (all the wires from pads disconnected)

As soon I plug only purple to the pad 20, I get -6.5 on the other side of resistor going to the pad 20 and same -6.5 on the pad.

And, since this wire is going to the ratio board, I guess something is wrong over there and can't really see it

 

[Spendor]

Hi all

is it OK to use 2N3393 in place of the 2N3391 specified for the Rev D? They come up on the same spec sheet as the 2N3391 but have some different values.
Thanks!

 

[Mr_tea]

Hey guys,

Just put together the revision D and Im not getting signal through it when I put a sine wave through it. I think its something in the input stage. I'm getting grounding on the negative terminal on the input transformer (altran C-3837). Is this normal? any suggestions as to what it could be??

 

[Mr_tea]

Just wanted to add that it only becomes grounded with the signal coming through. If input xlr is unplugged then then theres no grounding.

Cheers.

 

[sr1200]

Mr_Tea, go over all the wiring. Start from the top and work your way back down checking everything.

Rokus if you ever want to do a comparison with one of my clones, let me know, im like 4 blocks from the LIRR station in westbury.