Sound Skulptor forums
Build help and troubleshooting => CP4500 Stereo Bus Compressor => Topic started by: Jason on February 09, 2021, 04:04:01 PM
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Hi,
In switch lights up, but meter dosent and shoots up past 20db?
all voltage is correct in the first steps.
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also the Led lights up really bright ?
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Look for a short-circuit between Vu- and any other pin on CN2. Same thing for Vu+.
(https://www.soundskulptor.com/forum/index.php?action=dlattach;topic=44.0;attach=8;image)
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Sorry could you please explain in detail how to do that, I'm a novice and completely out of my depth.
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With your DMM set to ohms (or better set to ring mode if it can do) place one probe on the Vu- pin then with the other probe check all the other pins for a very low resistance (or a ring).
Repeat for Vu+.
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Thank you, no there is no short circuits
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Is it true with the front PCB and meter connected?
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Apologies,
Didn't have any power running through it. I've done another test and there is a sort circuit when the probe is on V+ and touching +12v All the other TP are fine.
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The short circuit test must be done without power but with the main and front PCB's connected together and the meter connected to the front PCB.
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No there is no short circuits and everything is connected as you said. when I probe CN4, the meter moves on everything apart from the red and on D3, k lights up and long shoots to 20DB, if this info is any good to you.
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also the Led lights up really bright ?
You have too much current in the LED. The current is limited by R104, RLY1, Meter LED.
- Remove the IC's until this is sorted out.
- Check the meter (unplugged): 600 ohms between the large terminals, infinite resistance between any 2 other terminals.
- Check the relay coil (in circuit), 2800 ohms across D19 (check D19 direction).
- Check R104 value (in circuit).
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- Remove the IC's until this is sorted out. Done
- Check the meter (unplugged): 600 ohms between the large terminals, infinite resistance between any 2 other terminals. 562 ohms large infinite resistance between any 2 other terminals. Short Circuit Small terminals when connected to PCB C
- Check the relay coil (in circuit), 2800 ohms across D19 (check D19 direction). 2.73
- Check R104 value (in circuit). .217
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It seems the short is on PCB C.
Check between the 2 center pins of CN4 when the meter and PCB A are disconnected.
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It seems the short is on PCB C.
Check between the 2 center pins of CN4 when the meter and PCB A are disconnected.
Yes, there is a short circuit ?
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Do you also have the short when the IN switch is off?
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Yes there is a short circuit when the in is off.
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You should be able to see the short on the CN4 pins. The track from pin 2 is very short, it only goes to the LED D3.
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I had 2 lifted pads on D3 problem is now solved
Thank you
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Congratulations!