x0x 122 power supply

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mome rath
 

x0x 122 power supply

Post by mome rath »

I'm working on #122 atm, but I've got a slight problem in the power supply. The voltage across J4 is supposed to be 5.333, but I'm getting it between 6.08 and 6.54 at either extreme of the potentiometer. All the other voltages are correct as per the fab manual.

Anyway, this is the first thing I've ever soldered, so responses should be as close to idiot-speak as possible.

Thanks!

Jonnay
 
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Joined: Thu Jun 02, 2005 12:28 pm

Post by Jonnay »

well, your first step should be to make sure that IC22 and D44 through D47 are all oriented correctly, and that R4 (5.6 Kohm) and R5 (2.4 Kohm) are the correct values.

Guest
 

Post by Guest »

OK I'm reading 4.6 and 2.8 across each resistor, respectively. The other components are mounted in thr poper orientation.

Jonnay
 
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Joined: Thu Jun 02, 2005 12:28 pm

Post by Jonnay »

Heh, Volts or ohms?

The next step is to test the voltage drop across the diodes. Connect the black lead to ground, and the red lead to the non-striped side of diode, and record the voltage. Then check the striped side. You should see a 0.6 Volt difference between the two.

while your at it, check the voltage on all three pins of the LM336 (IC22) and post the values.

Guest
 

Post by Guest »

When I connected black to ground and stuck the red on the non striped side of a diode I got lots of sparks.

Guest
 

Post by Guest »

So did I blow up my diode?

I built the whole thing but I have no sound... lights up really nice though. 8)

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subatomic
 
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Post by subatomic »

Anonymous wrote:So did I blow up my diode?

I built the whole thing but I have no sound... lights up really nice though. 8)
Could be your 6110 chip is bad (a lot of them were). does your VCA tests check out? If not, test your VCF and the VCO (see fab manual)...
If your lights are working right, (i.e. you're seeing the wonders of digital logic), then I'd guess your power is at least close to ok, then it's probably in one of the other sections...
Hopefully you tested the output from your PSU before plugging everything together. :lol:

Guest
 

Post by Guest »

I got a new chip when we all found out that run was bad.

What is PSU :wink:

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subatomic
 
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Post by subatomic »

Anonymous wrote:What is PSU
Power Supply Unit

Guest
 

Post by Guest »

OK I'm BANNED on this. Anyone near Columbus, OH?

Jonnay
 
Posts: 142
Joined: Thu Jun 02, 2005 12:28 pm

Post by Jonnay »

Post the voltages of the diodes and the LM336

mome rath
 

Post by mome rath »

Jonnay wrote:well, your first step should be to make sure that IC22 and D44 through D47 are all oriented correctly
These are all correct.

The voltages for the IC22 are:
  • 1: -0.56V, 2: -6.63V, 3: -6.63V, 4: -11.59V, 5: 11.78V, 6: 6.63V, 7: 6.62V, 8: 6.62V

    The diodes (black and silver ones) read -11.65 at the striped end of the first two (counting in from the edge of the board) and 0 at the non-striped ends. The other two are -12.65 at the non-striped end and the other end was also 0 for both.

    Hope that's what you needed?

mome rath
 

hah

Post by mome rath »

OK everything works now!

122 is up and running!

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subatomic
 
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Re: hah

Post by subatomic »

mome rath wrote:OK everything works now!

122 is up and running!
what was the problem?

Guest
 

Re: hah

Post by Guest »

subatomic wrote:
mome rath wrote:OK everything works now!

122 is up and running!
what was the problem?
I think I had a few cold joints... and the knob was on backwards. It was probably functional last night and I just didn't realize it.

I was showing my friend the radio trick (see above) and then he started switching a knob around and I heard notes play at random.

So it works fine overall, but the tuning is off by about a fourth.

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