Loophole help please(solved)

[danwelsh]

Hi guys.....i built the looper up and it worked for about 5 mins...then the 7805 i used fried(i thought i had it in backwards)....so i ordered up 10 78l05's and i put one in and same thing....about 2 mins and it crapped out, leds just kept getting dim, regulator got hot and it failed.....so, since i socketed this spot, i was like no problem, i'll flip it around and i'm all good.......well, same thing both ways, i fry them.  The only subs i did with this was used a 2590p(soldered pin 7&8 to ground plane beside the pins) and a 20ohm resistor instead of 22ohm on r15, would the resistor sub cause this?....I checked for bridges and can't find any anywheres(used a jewelers loupe)....when it works for the big 5 mins, it's awesome, everything works but i obviously have a stupid problem somewhere. Can anyone help me pleeeease before i rip my hair out.

[alanp]

I'm suspicious about the detune switch... sounds like you're getting a short on the +5V somewhere, and that's pretty close to what detune does (across 22 ohms, not 0, though.) I'm most likely wrong, though.

[danwelsh]

I'm suspicious about the detune switch... sounds like you're getting a short on the +5V somewhere, and that's pretty close to what detune does (across 22 ohms, not 0, though.) I'm most likely wrong, though.

so what would you suggest to try?

[blearyeyes]

don't know if this will help at all but I left out a resistor in a ZeroPoint DLX and had the voltage reg heat up and things go wonky on me. double check all the resistor values, sounds like the reg is getting to much juice, keeping it down to the proper voltage and dissipating the extra into heat and then volcanic ash....

Good luck..

[danwelsh]

anyone know how much voltage should be going in the 5 volt regulator

[danwelsh]

okay guys.....i found my problem i think...my 20r resistor i had subbed in for the 22r was black in the middle, i think i cooked it, i didn't have a 22r so i shoved a 24r in there and it seems to be working fine....but, i'm getting 9.4 volts to the in on the voltage regulator and it goes down to around 3.5 volts progressively on the out of the regulator, i don't know if this is normal or what...also i noticed when probing the pins of the regulator that when i press the detune switch the voltage jumps up to 5 volts on the output of it...Does this sound normal and the way it's supposed to work?. I rechecked all the resistors, caps and other components and they are correct but also wondering if i need to add a resistor before the input of the regulator to take the 9.4volts it's getting down a little bit, it's getting warm but i left it plugged in for 20 mins now and it's still going, i'm using a 78l05 regulator. Could someone shed some light on this for me please?

[danwelsh]

I'm suspicious about the detune switch... sounds like you're getting a short on the +5V somewhere, and that's pretty close to what detune does (across 22 ohms, not 0, though.) I'm most likely wrong, though.

You were correct and this was the problem....i disconnected my detune switch and no problems, regulator wasn't heating up at all. Thanks ....i might as well just leave the detune switch out as i won't use it anyways.