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dom75011
Copper Member
France
19 Posts |
 Posted - 10/14/2009 : 21:48:45
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with the LED on, and a lead in the "direct" jack but no lead in the "out" jack, THERE IS signal on the direct out!
Other tests: at check point 2 Q6 C18-R23: input signal OK
at NE570 pin 2 & 3 : input signal OK
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dom75011
Copper Member
France
19 Posts |
Posted - 10/14/2009 : 22:49:59
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Following the input signal:
IC3b pin 5 : input signal OK
IC3b pin 7 - IC5 pin 2(check point 3) : no input signal, white noise.
Is IC3 dead ? |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/15/2009 : 00:50:06
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| Will take a look at these symptoms tonight when I get home from work... |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/15/2009 : 03:47:55
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quote:
Originally posted by dom75011
Following the input signal:
IC3b pin 5 : input signal OK
IC3b pin 7 - IC5 pin 2(check point 3) : no input signal, white noise.
Is IC3 dead ?
IC3 pin 7 has a "chopped" version of the input signal - the analogue signal is gated through IC4 by the SAH signal on the long-chip. White noise is probably OK. The only way to tell is with a scope. The good news is that white noise almost certainly means that the long-chip is working.
What do you get at TP4? (the emitter of Q9)
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dom75011
Copper Member
France
19 Posts |
Posted - 10/15/2009 : 08:56:45
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As already stated, test point 4 (Q9-R44) : no output signal.
The D14 diode is not referenced on the schematic. It has a high resistance (more than 700K) conducting
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Edited by - dom75011 on 10/15/2009 09:01:39 |
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dom75011
Copper Member
France
19 Posts |
Posted - 10/15/2009 : 14:33:34
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quote:
Originally posted by Laurie
quote:
Originally posted by dom75011
Following the input signal:
IC3b pin 5 : input signal OK
IC3b pin 7 - IC5 pin 2(check point 3) : no input signal, white noise.
Is IC3 dead ?
IC3 pin 7 has a "chopped" version of the input signal - the analogue signal is gated through IC4 by the SAH signal on the long-chip. White noise is probably OK. The only way to tell is with a scope. The good news is that white noise almost certainly means that the long-chip is working.
What do you get at TP4? (the emitter of Q9)
If IC3b had a "shopped" version of the input signal, this signal version should also be present on IC4a & b out pins 2 & 3 - IC3b input pin 5 , IC3b acts only as a buffer ! But the signal present is the clean (but compressed)input signal. The IC4a & b gates are always on.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/15/2009 : 14:43:12
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| Is there a clock signal on the long-chip pin 63? |
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dom75011
Copper Member
France
19 Posts |
Posted - 10/15/2009 : 23:15:37
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I can't check the clock, I don't have a scope.
I can only say that a very tiny noise seems to follow the d.time pot, as well as the 4066 generated clock.
Well, it's too much trouble, I think that this pedal is definitely dead.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/16/2009 : 00:49:23
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You could always send it to Canada for a holiday... (fix and return).
These things are impossible to fix without a scope. I've done I guess 10 of them now with faults ranging from broken mode switches to failed compander capacitors.
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Mesjoggah
Gold Member
Netherlands
595 Posts |
Posted - 10/18/2009 : 09:35:43
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| I am not 100% sure and i can't find the topic but i thought i had a dd-3 with the symptoms you described, i turned out to be a defective 74HC00 (ic8?) |
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dom75011
Copper Member
France
19 Posts |
Posted - 10/18/2009 : 13:55:44
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Some news:
I've just been to my favorite electronics components shop, 5mn by feet from home.
I've asked the boss if I could use their scope for 5mn. He agreed and I was able to see tha the 74HC00 clock was working, and that the SAH pin was all right, the 4066 too.
So the problem was around the ICs in the A/D D/A
I purchased the ICs and went back to home.
I've replaced the 5218 with a new one , and now the signal was going to the Z71 input, but the A/D D/A was not yet working.
Then I replaced the 271 to a new 311, not better, nothing was coming out the D/A
Then I replaced the 5534 with a new one and then BINGO!
The pedal, beside the BA634 not working (the wire point 1 is connected to the +9v) is working!
2 ICs were dead : IC3 and IC6
2 days ago, I've ordered 2 x BA634F, it's a 8 pins SMD that I will have to adapt to the 5 pins inline. I've found them at awatronic.fr, 1,90� each, their minimum order is 10� including shipping.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/18/2009 : 22:04:57
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| Ho ho!! Great job! Another one rescued! |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 10/19/2009 : 08:54:17
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dom75011
Copper Member
France
19 Posts |
Posted - 10/20/2009 : 19:52:11
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Do you know where I could find the serial number?
Mine has silver scripting and Fcc
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 10/20/2009 : 20:57:21
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quote:
Originally posted by dom75011
Do you know where I could find the serial number?
Mine has silver scripting and Fcc
The paper label in the battery compartment is probably missing... fairly common for that to happen. |
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Topic |
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Boss DD-2 not switching on
