[BUILD] 1176 Rev A - Back to the beginning...
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Echo North
Well-known member
Djankies said:
What is you V AC between the CT and each of the AC terminals?
Mike
Echo North
Well-known member
Djankies said:
Between AC and AC?
Or between CT and AC, then CT and the other AC?
Echo North
Well-known member
Djankies said:
No you had it right.
We'll that sucks. If you're supply was testing 30/-10 then you stuffed the rest of the PCB and the 30 rail dropped, something is wrong/shorted/dead. Is your soldering decent?
Check ALL of your cap, transistor, diode polarities.
If you want, you can send the PCB in and we'll give you a free evaluation of the PCB. Like "oh man this soldering is hell this is junk" or "well this looks ok let's try it in our jig and see what happens".
Mike
I'm no soldering artist, but I'm fairly certain that the joints are secure. If all the the print on the PCB is correct then everything is placed in correct polarity.
I may send it to hairball eventually, but I'd like to exhaust all resources here before I spend more money to have it shipped out. Are there any other "tests" I can do within the board to try and pinpoint my issue? What information would a free evaluation give me other than an assessment of my soldering capabilities. I'm really just looking to be pointed in the right direction because it seems I'm chasing ghosts here.
Thanks,
Daniel
I may send it to hairball eventually, but I'd like to exhaust all resources here before I spend more money to have it shipped out. Are there any other "tests" I can do within the board to try and pinpoint my issue? What information would a free evaluation give me other than an assessment of my soldering capabilities. I'm really just looking to be pointed in the right direction because it seems I'm chasing ghosts here.
Thanks,
Daniel
Echo North
Well-known member
Djankies said:
That's the problem. If you're supply was right, I could walk you step by step through the signal stuff and get it working. But the supply is bad and that could be a million things.
Let's try this:
1. What is your DC voltage at the + side of C25?
2. What is your DC at the input of the 7824 regulator (check the data sheet for the pinout)?
3. What is your DC at the output of the 7824 regulator (check the data sheet for the pinout)?
I'm off to bed...we'll keep plugging away...
Mike
Echo North
Well-known member
The other problem is that sometimes components just fail. That's why companies do 48+ hour burn-ins, because components are prone to fail early. Maybe everything was right and your regulator popped. That's the thing with DIY. We'll get it....
Mike
Mike
The 30 VAC test point is back up!! Well it was always up, I was just an idiot and had forgotten that the other lead is placed on CT. It's probably pointless to give you this information now but here it is.
+ Side of C25 = 39.2 VDC
Input of regulator = 39.2 VDC
output of regulator = 29.2 VDC
The -10 VDC test point is also still reading as it should.
Apologies for my error, and thanks for helping me out,
Daniel
+ Side of C25 = 39.2 VDC
Input of regulator = 39.2 VDC
output of regulator = 29.2 VDC
The -10 VDC test point is also still reading as it should.
Apologies for my error, and thanks for helping me out,
Daniel
Echo North
Well-known member
Djankies said:
No worries, I did some pretty silly stuff early on. Glad to hear it!
Hook your compressor back up and let's see if we can move on.
Mike
Got everything wired back up this morning and ran a 1K signal through it at .775VAC as confirmed by my multi. There is power now, however no movement from the meter except when powering up and down. It hits really hard when the unit is powered on and then moves to 0 and stays there.
Thanks,
Daniel
Thanks,
Daniel
Echo North
Well-known member
Djankies said:
Slowwwwwww down. She's not calibrated yet.
Start by trying to set the QBias. How does that go? Remember those trimmers are 20 turn. Turn it so you get the highest output then set your Qbias.
Mike
Echo North
Well-known member
Djankies said:
I wouldn't recommend using your VU meter. It's easier for beginners to use known working instruments like a DMM and suss out issues in order.
Follow along with the text here:
http://www.hairballaudio.com/blog/d_assembly/reva/calibration/
Mike
Echo North
Well-known member
With your GR off and In/Out at 12 o'clock, you should see an output around 10-18dBu or (3-7V AC) when you have the Qbias full CCW or turn it to highest output.
Echo North
Well-known member
Djankies said:
1. So with a 1K 0dBu sine and GR OFF and in/out at 12 o'clock, what is your output V AC?
2. When you turn the GR on does the output go down?
3. Are you talking about the null adjust? You have moved the jumper and are testing between the TP's?
Mike
there is a confirmed 1khz, .775 VAC going into the XLR input. Output is at 2.44 VAC with gain reduction OFF, ratio of 20, input at 24, Attack clicked to off position and release fully clockwise. If it means anything, the output knob is at 48. With gain reduction on, the reading is still the same (2.44 VAC).
And yes, the null adjust, with the jumper moved to the position furthest from Q13. There was already a reading of 0 VDC between the test points with the jumper in position and the null adjust did not change the voltage.
Thanks,
Daniel
And yes, the null adjust, with the jumper moved to the position furthest from Q13. There was already a reading of 0 VDC between the test points with the jumper in position and the null adjust did not change the voltage.
Thanks,
Daniel
Echo North
Well-known member
Djankies said:
So the GR meter isn't working. If you switch to +4 or +8 with a signal dos the meter work?
Mike
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