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EQP501 Passive Equalizer
R14, R15 Started Smoking After Inserting SK25 DOA
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Topic: R14, R15 Started Smoking After Inserting SK25 DOA
February 12, 2021, 11:15:48 PM
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rob@roblanter.com
Newbie
Posts: 28
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R14, R15 Started Smoking After Inserting SK25 DOA
Hi JP,
R14 and R15 started to burn up when I inserted the SK25 DOA during the testing phase after the build. All the voltages checked out before I inserted the DOA.
I sent you an email asking for replacement parts.
Thank,
Rob
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February 14, 2021, 08:53:08 AM
Reply #1
JPK
Administrator
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Posts: 1085
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Re: R14, R15 Started Smoking After Inserting SK25 DOA
99% of the issues: https://www.soundskulptor.com/forum/index.php?topic=9.msg9#msg9
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JPK
February 14, 2021, 04:13:49 PM
Reply #2
rob@roblanter.com
Newbie
Posts: 28
Karma: +0/-0
Re: R14, R15 Started Smoking After Inserting SK25 DOA
Hi JP,
Is there a reason why a defective SK25 DOA would affect resisters R14, and R15 on the 501 Passive EQ? As soon as I installed the SK25 DOA, R14 and R15 started smoking.
Thanks,
Rob
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February 14, 2021, 06:42:11 PM
Reply #3
JPK
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Posts: 1085
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Re: R14, R15 Started Smoking After Inserting SK25 DOA
Yes. These 2 resistors are inserted in the +&- supply rails of the DOA.
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JPK
February 14, 2021, 09:30:48 PM
Reply #4
rob@roblanter.com
Newbie
Posts: 28
Karma: +0/-0
Re: R14, R15 Started Smoking After Inserting SK25 DOA
I was trying to be very careful when I built the SK25 since it was the second one I had built. Can you tell me what I might have done wrong on the SK25 to have caused R14 and R15
on the 501 Passive EQ
to burn up?
Thanks,
Rob
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February 15, 2021, 09:42:14 AM
Reply #5
JPK
Administrator
Hero Member
Posts: 1085
Karma: +35/-0
Re: R14, R15 Started Smoking After Inserting SK25 DOA
make sure R1 is not touching the vertical PCB and the diode D5,
check you didn't flip the power transistors Q9-Q10,
check that the 4 solders on each vertical PCB are making good contact,
check you didn't reverse the LED (it must light up),
check you didn't swap D4 (Zener) with one of the 1N914.
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JPK
March 08, 2021, 01:14:15 AM
Reply #6
rob@roblanter.com
Newbie
Posts: 28
Karma: +0/-0
Re: R14, R15 Started Smoking After Inserting SK25 DOA
My problem is solved. I had flipped Q9 and Q10...thanks.
I have another post with some other issues with the EQ501 unit.
Rob
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EQP501 Passive Equalizer
R14, R15 Started Smoking After Inserting SK25 DOA
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