[BUILD] 1176LN Rev D DIY

[edanderson]

during the GR tracking adjust process, r44 is the trimmer that you use to get the meter to read -10db in GR mode.  so yes, in answer to your question, r44 will change the amount of GAIN REDUCTION shown.

does that not directly answer your question?  i can't say for certain why it isn't working for you... but again, r44 is the tracking adjust trimmer and should let you move the needle to indicate -10db gain reduction.

you can try replacing the GR FET Q11, or the two transistors that make up the meter circuit Q12 and Q13.  i would suggest checking all the resistor values around those transistors and of course your wiring, but it sounds like you've done that already.  it is possible for extra solder flux around the FET to cause a problem, but usually that is only over time as it absorbs moisture.  still, if you haven't cleaned the flux away, that would be a good precaution.

the ratio doesn't matter that much; it is possible to do all the steps on any ratio setting, using 20:1 just makes it easier.  i don't think that is your problem.

ed

 

[college101]

Thanks Edanderson...  I appreciate your help  - I hvae not been able to get R44 to adjust the needle at all..I will start replacing....

One thing I need to mention that I did notice while doing the calibration( or attempting to do the calibration)....If you watch video Two-for the null adjust trimmer calbiration...when mnats takes R44 out of circuit, and then sets up his meter probes, the needle moves to the left....twoards the minus side of the VU...mine goes Positive...and goes twoards +2 and I have to adjust it from there!? Could this mean my null adjust is set wrong? or wires are flipped? 

I am telling you guys thou...inless the wiring guide colors are wrong...my wiring matches the pics taken on mnats site...

I order'd some new parts for Q1, and Q11 since they seem  to be the main and most important pieces...planning on replacing Q12+13 as well

I have the isoprpoyl alcohol, and clean with passion!!  I also use a heat gun on low heat setting to help dry the board after the thurough cleaning....I noticed that cleaning really does make a big difference!

 

[minor_glitch]

Hope you don't mind if I share a photo of my Rev D.  Finished it tonight and it works perfectly!  Even managed to calibrate it without any problems based on the mnats videos (any word on that distortion adjustment vid?).
All that's left to do is tidy up the wiring and attack the board with a cotton swab and alcohol.
Speaking of alcohol, I'm going to go celebrate 

 

[mnats]

(any word on that distortion adjustment vid?).

Answer is still the same, I'm afraid.

Finished it tonight and it works perfectly!

Thanks for restoring my faith! It's always good to be reminded that some people take the time to read the material available, build carefully and have success. Well done.

 

[spase]

hey mnats i want to ask you something about the payment?can i pay from my friend paypal account and put my adress in the comment field so you can ship the pcb on that adress not on that billing adress from the paypal account?Thank you

 

[minor_glitch]

Thanks for restoring my faith! It's always good to be reminded that some people take the time to read the material available, build carefully and have success. Well done.

Thanks!  I made one stupid mistake though.  Somehow while cleaning up I managed to throw away the 5W resistor for the meter, which is of course the very last component in the wiring guide!  Nothing like getting to the very end and finding out you're missing the last part! haha  Luckily the local electronics shop had a couple 220R 5W's in stock.

 

[mnats]

I made one stupid mistake though.  Somehow while cleaning up I managed to throw away the 5W resistor for the meter, which is of course the very last component in the wiring guide! 

Let me guess - that's why your forum name is minor_glitch? Seriously, the build looks great.

hey mnats i want to ask you something about the payment?can i pay from my friend paypal account and put my adress in the comment field so you can ship the pcb on that adress not on that billing adress from the paypal account?Thank you

Please post questions about sales to the White Market thread.

 

[minor_glitch]

Let me guess - that's why your forum name is minor_glitch? Seriously, the build looks great.

Haha sure that's as good of an explanation as any! If I ever change my name to major_fubar you'll know why.

 

[college101]

Its sad to report, but after installing the dip sockets and new 2n5457's at Q1, and Q11...there is still no change...

Something interesting though...getting -8.65 vdc at the -10 check point! Anybody else had this similar issue?

I still am not able to adjust R44 in GR mode with compression on...

 

[cybergolio]

College Could you check if each wire in the ratio panel arrived in the right resistor.

 

[college101]

Sure...Im gonna add a ground wire coming off the output transformer wiring as well....

I will check the wiring again and resistors in the ratio board...cybergolio

 

[college101]

Ok guys...took the day off work to go threw and check everything...AGAIN!!

Just checked the ratio board and everything matches

r58=150 ohms
r61=470 ohms
r62=560 ohms
r63=1.5k ohms
r45=10M ohms
r21=56k ohms
r20=56k ohms
r19=68k ohms

To compare locations on ratio board
1.5K  68K
560    56K
470    56K
150    10M

R22=47K
R78=56K  underneath ratio connector wiring

I then checked wiring locations of each wire from 1-6
All match and passed continuity test....

 

[college101]

from the wiring guide on Mnats site

Twist together the blue and red wires from the ratio board connector and the transformer secondary from the output transformer. Solder to the male output XLR as shown - a short, thick wire connects pin 1 to the chassis; the blue wires go to pin 2 of the XLR; the red wires go to pin 3 of the XLR. If you reverse these wires the polarity of the signal will be reversed in respect to the input. NOTE: If you are using an original or Hairball 5002 reproduction, you must also tie the yellow and orange output wires together to connect the secondary windings in series.

Pin 2 is supposed to get the Red wire, not the blue wire then...the picture shows it backwards then

MNATS-do you mean the Meter pcb board instead of the ratio board?

 

[college101]

Ok, after using an online resistor calculator to double check my visual readings of the resistor stripes...only one resistor seems to be suspect...which I will test now...which is R12

 

[college101]

Ok..so I am going to do this Today!!

re-check most of my capacitors as they seem to measure high or low--or maybe off...( even though I ordered them new from mouser...A few seem to be very suspect

c2 measured .086 nf

Can I assume, because my -10 Rail is low(-8.65)- this has to do with the capacitors?

 

[college101]

OK..I have added the ground wire from the output transformer board connections to chassis ground, and all the hum I was hearing has disappeared!

R12 did test at 1.8k- exactly to 1.761k ohms to be exact

My negative rail is still off...geuss I need to remove most of the caps next

My voltages for the 2N3707's is still High...will be replacing those

 

[Hank Dussen]

Something that's pulling down (or up) the voltages could be the polarity of the caps (or diodes) but it's more likely the transistors.
Do you check the pinout of the transistors? Sometimes transistors come in different pinouts (EBC vs. CBE, etc.)

 

[college101]

OK..I am still trying to get a grasp on the ECB pin out of the 2N3708's I am using...
I am getting confused because I flip from one side of the board to the other, and then have to process what I am testing...

I am having problems with Q2 and I know the voltages are wrong, I don't have a new c2 replacement yet, but I will order some and re-test

GOOD NEWS !!!

I now have -18db of reduction in the final step of the calibration! close but no cigar yet....Still cant get R44 to adjust...Think I need to pull it and test it again

 

[David R.]

Ready to go with my second build.  Everything ordered, and Mouser had all parts in stock!  See you when the smoke (from the soldering iron) clears.

BTW, thanks to all for the helpfull videos, posts, diagrams, and words of wisdom.  I completed the first one without posting once!

 

[college101]

I am going to replace the 2N3708's today!!  2n3708's are ECB by the way
Well I just compared to the 2n5088's which have the Base in the middle...

Replacing the transistors tonight...hoping for the best

Caps will be next, since I cant find my measurement sheet ...