Voltage drop on my PS

Started by Agung Kurniawan, February 27, 2017, 06:53:04 AM

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Agung Kurniawan

Hi guys..
I have finished my regulated PS a week ago. It work best.

I have a delay pedal using one of  PT2399. Yesterday I just change the enclosure then when I step on it, the delay doesnt come, there just clean signal.
The 7805 become warm and there is voltage drop from one of the output PS from 18V ito 6V. And also the 7818 just geting warmer.
This is the diagram

Please guys help me solving this problem
Multiple gain stage followed by some active EQ is delicious.

GibsonGM

It sounds to me as if something is shorting out.  Is there any place in the path the power is taking that could touch the enclosure, or another component, to cause this?   

Sometimes when we put the circuit in an enclosure something changes - a part is bent or something - and bad side effects like this can occur. 
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Kipper4

Ma throats as dry as an overcooked kipper.


Smoke me a Kipper. I'll be back for breakfast.

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anotherjim

Power short when stomp switch pressed may suggest a problem with bypass indicator LED wiring (if 3PDT switching).

GibsonGM

Quote from: Kipper4 on February 27, 2017, 08:12:10 AM
Check your data sheet for the part
This suggests a min input voltage of 26-35v

http://uk.farnell.com/stmicroelectronics/l7818cv/ic-v-reg-18v-7818-to-220-3/dp/9756175


One would like to ask:   * did it work when it was all connected, and out of the enclosure?  No issues?  The Assumption is that the problem started after it was boxed up but that it worked before...  because if the 7818 requires a higher input voltage, perhaps the 2nd circuit is not operating due to drop on the 1st regulator?   

Step back through your 'blocks' - insufficient input voltage would certainly cause the 7805 to drop out.  If all was good before placing in the enclosure, however - a short is indicated.
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MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...

Agung Kurniawan

I put the delay on plastic enclosure now, I was add the AMZ LED delayed circuit to prevent pop.
gonna check it tomorrow
Multiple gain stage followed by some active EQ is delicious.