Author Topic: Park barrel bypass works, no effect, lfo led not working  (Read 2526 times)

bigb1984yaherd

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Park barrel bypass works, no effect, lfo led not working
« on: March 15, 2012, 03:49:40 PM »
Ok so I built the pork barrel. It worked for awhile and then I bumped the box. I got a couple of pop noises and the lights went out. I replaced the leds. they both worked but the lfo indicator just went on and did nothing. Now the lfo indicator doesnt go on at all. I replaced both the 3207 and 3102 and still nothing. I will try to get pictures as soon as possible. Any guidance would help. Could it be the transistors? should I replace the other IC's?

Bypass works, and I get full sound when engaged, just no effect.

jkokura

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #1 on: March 15, 2012, 03:59:57 PM »
You bumped it and this happened? That's a bit strange.

The key is to find what changed. It sounds like either something grounded, or perhaps some other sort of issue arose. It's possible that a solder joint broke or something along those lines.

In this case, because it was working (I assume properly) we can likely rule out any part errors or wiring errors. This leaves us with either a new grounding issue or some sort of faulty soldering. Perhaps some high quality pictures and some voltages would help?

Jacob
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bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #2 on: March 15, 2012, 06:13:15 PM »
I will try to get photos up soon. When i bumped it i pretty much feel off the stool I was sitting on while adjusting the rate knob. I believe that the knob might have been loose enough that it moved and grounded out on something possibly. I was not sure if this would fry a pot or trannie. Ill make sure that when i get a change Ill go over the grounding again. Might the power supply be an issue aswell?

bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #3 on: March 15, 2012, 06:21:07 PM »
Ok so a few notes... the board looks like it may be touching the switch but it is actually sitting on wires. Im pretty sure it grounded out... im just not sure what it screwed up ...and if i can figure that out i could fix it.

Scruffie

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #4 on: March 15, 2012, 07:27:50 PM »
Voltages please!
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bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #5 on: March 15, 2012, 07:29:37 PM »
for trannies? Just making sure. Sorry still a little new here.

bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #6 on: March 15, 2012, 08:05:56 PM »
Q1
.46     .94     8.94
Q2
3.75    3.86      8.94
Q3
3.65      3.16    8.94
Q4
0       .28     7.17
Q5
.21     .53    8.07

I hope this is what you needed. If you need measurements on the IC's please give me a brief run down on how to do that.

Scruffie

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #7 on: March 15, 2012, 08:17:47 PM »
Ics indeed... Black to ground, probe each IC, pins 1 -8 and write down the measurements, that's it!

Notch or indent = the top, left side from the top 1,2,3,4 right side from the top 8,7,6,5 
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bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #8 on: March 15, 2012, 08:37:59 PM »
ok here we go!
4558             3207             3102             tl062
4.44              0                   8.07             8.27       (1)
4.43              3.93              3.92             .75           
4.37             3.74               0                 3.72
0                 7.54               3.94              0
8.94            5.09                7.54              8.94
4.42            5.09               2.18              .65
4.43            3.92               7.82              2.49
4.41            8.07               .19                .75        (8)

jkokura

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #9 on: March 15, 2012, 09:35:12 PM »
I don't think you have them quite correct. An IC goes like this:

1  |U|  8
2  |  |  7
3  |  |  6
4  |  |  5
    ---

Jacob
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Scruffie

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #10 on: March 15, 2012, 10:13:14 PM »
I don't think you have them quite correct. An IC goes like this:

1  |U|  8
2  |  |  7
3  |  |  6
4  |  |  5
    ---

Jacob
He did, he's just written them 1,2,3,4,8,7,6,5 instead of 1-8

Your TL062 aint right, pin 1 should not be voltage.
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bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #11 on: March 16, 2012, 08:36:35 AM »
Hmm ok. I have a socket in there. Do you think this is the IC itself or a component leading to it? Not sure if I remember correctly that it goes to theTL062 but i have a 1N4738 for the 8.2 zenner. Dont know if any of this helps. Just makes me wonder if I fried the Tl.

Scruffie

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #12 on: March 16, 2012, 11:47:47 AM »
Could be the IC, a cold joint, a solder bridge etc. you just have to check the area.

The 8V2 zener limits the supply voltage to the 3207 & 3102, seems to be doing its job.
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bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #13 on: March 16, 2012, 11:53:26 AM »
Thank you for the help. Ill check those tonight when I get some spare time.

bigb1984yaherd

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Re: Park barrel bypass works, no effect, lfo led not working
« Reply #14 on: March 18, 2012, 03:06:12 PM »
Ok so I have had zero time this weekend but i did get a few moments to atleast look at the area of the tl062. There are no solder bridges, Im goign to try and reflow the area. If this doesnt work could their be a faulty component in the path leading to the IC. And just a guess, Im probably getting no effect because the TL062 is the op amp which is not functioning would render the effect ....basicly noiseless, right?

Also, the fact that Im no getting anything from the lfo led, is that a concern? IF I blew out the led somehow would that create a problem like this? Does the fact that the led does not light up indicate another problem?