IC is shorting/over heating in my protone body Rot build

[Belanger]

Ok so anytime I supply power to it the ic overheats. I'm assuming that means there's a short somewhere if anyone can possibly lend a hand and recommend some good places to check. I'm going to continue to scan it with my eyes and compare everything to the layout while I wait for everyone to have time to reply from all time zones.  Substitutions made were 330nf caps both are 220nf caps in parallel with a 100nf cap   430 k resistor is 470+33k in parallel and 43k was a 47k+3k in parallel everything else is as supposed to be. IC is a lm386N-1 and has the same printout. Oh sorry and I swapped the 2n5088 for a mpsa18 because I had no 2N5088

I can't give voltage readings obviously but once I get this sorted out if there's still a issue I'll post my voltage readings

I can't a schematic but it's a moddified krank Maximus

[Belanger]

I'm going to go over the schematic in the morning and try to use it to check continuity through out the circuit.  I'll also go back over there debugging page again. Any other tips are appreciated greatly

[Blitz Krieg]

that 100ohm resistor on the right side of the IC should go in the that hole in the row below the socket?

[Blitz Krieg]

and that 390ohm is moved in a similar fashion?  you have to post a pic of the other side of the board.  is this on strip board or perf board?  you observed the blue dot?  those are easy to overlook.

[bluebunny]

I can't give voltage readings obviously . . .

Take the chip out, apply power, then take readings.

you have to post a pic of the other side of the board.

+1

[antonis]

430 k resistor is 470+33k in parallel and 43k was a 47k+3k in parallel

Was there any specific reason for lowering voltage divider resistor values almost 15 times..??
(other than slightly altering bias - which should be obtained with a 500k trimmer..)

You have lowered input impedance almost 15 times and simultaneously kept input cap at 4n7 which results in raising HP Freq by the same ratio..
(not excactly, because the hfe X Re is constantly added in parallel..)

[bluebunny]

430 k resistor is 470+33k in parallel and 43k was a 47k+3k in parallel

Was there any specific reason for lowering voltage divider resistor values almost 15 times..??

Good spot - I glossed over that part without doing the maths!  @OP: you would have been better off just using your 470K in place of the 430K and your 47K in place of the 43K.  Both values are close enough for rock'n'roll until you get the "right" parts.  If you are going try to manufacture the right values with what you've got, you need to get the maths right!   

[duck_arse]

time zone checking in here - as they said above. resistors in parallel always total less than the lower paralleled value. resistors in series total the sum of the values.

and, you've got the IC out, so you can't damage it by bad volts, so that's the perfect time to get the voltage measures you would have wit der chip in circuit.


youse gots to stops the rots.

[Belanger]

Sorry I'll flip it and take a pic now.  Also yes I did the double link

and that 390ohm is moved in a similar fashion?  you have to post a pic of the other side of the board.  is this on strip board or perf board?  you observed the blue dot?  those are easy to overlook.

Also I used a X actor knife to make sure there was no Bridges as well. Obviously I messed up somewhere though. Appreciate the help guys

[Belanger]

Not intentional. What did I do wrong😳  Thanks for pointing that out. I'm still trying to figure out a lot of things. I know just enough to get myself in trouble obviously lol

430 k resistor is 470+33k in parallel and 43k was a 47k+3k in parallel

Was there any specific reason for lowering voltage divider resistor values almost 15 times..??
(other than slightly altering bias - which should be obtained with a 500k trimmer..)

You have lowered input impedance almost 15 times and simultaneously kept input cap at 4n7 which results in raising HP Freq by the same ratio..
(not excactly, because the hfe X Re is constantly added in parallel..)

[Belanger]

Ic 1,.6.  7, .3    8, .5 the rest are not showing any readings at all  and the transistor isn't showing anything either.  Obviously I made a pretty bad mistake somewhere and it's one I don't want to make ever again if possible.  Was my ignorance in the parts substitution or did I just put it together wrong do ya think. Again thanks for taking the time to help me out guys. I can't thank you enough

[Belanger]

I don't even know why I bothered building it lol. It's not really my fav circuit by a long shot . It's just hard to find any good high gain circuits with the components I currently have.  As I have no n channel j fets which are the majority
Of them.  There in the mail so as soon as they show up I can attempt a half decent pedal atleast. This I figured would be good practice, and making slight substitutions I could see how it would alter the sound. Really gooched that one lol

[bluebunny]

Was my ignorance in the parts substitution or did I just put it together wrong do ya think.

I vote for #2.  And it's not ignorance: rather, you're still learning.  You'll get there!    (BTW, go build an LPB-1 or a Hogs Foot or similar: just need a single NPN BJT.  Or if you have a MOSFET, try an AMZ MOSFET boost, or an SHO.  All very simple builds.)

[Belanger]

Thanks for all the help guys and I'll go back to the basics again. I'm trying to learn how to build from schematic on a breadboard so I can actually learn how certain blocks of circuits are typically constructed. I've been having a hard time though because the only 3 successful builds I've had were the zen drive, Andy Timmons od and the free the tone heat blaster. However I've found in not really learning a bunch this way about how the actual circuit works. I may be getting a little a head of myself though. I'm going to take your suggestion and really focus on some simpler circuits for now    If anyone sees a way for me to salvage this build just let me know

[bluebunny]

This is a well-known article from Beavis.  It shows the LPB-1 circuit and explains each part of it.  Very useful.

[antonis]

Just to mention a typo on the above schematic.. 

R1/R2 voltage on transistor's base is 818mV (NOT 8.1V as mentioned upright)..

(or else, Ve should be about 7.5V with Ie about 19mA and Vc around 200V...!!!)

[duck_arse]

Ic 1,.6.  7, .3    8, .5 the rest are not showing any readings at all  and the transistor isn't showing anything either.  ....

I'm afraid "the rest are not showing any readings at all" is not valid hereabaouts. please, if it reads 0.00V, put that as the voltage. not reading and 0V are two different problems. [also, it is easier for some old hacks *cough* to comprehend the measures if you put one per line, so a TL072 takes 8 lines to tell.]

otherwise, carry on. and your vero building method is different - mostly people poke the wire straight in the hole, and solder-cover the w/hole. why do you bend under and solder next-to?

[Zilla]

double check your components. it looks like the resistor and 2 caps on the left of the socket are going to the wrong holes - the lower legs should be going 1 row down from where they are. The 100R on the right looks like both leads need to move down 1 row. the 2k2 on the right needs to move the lower leg down 1 row also. can't tell about the caps and electros.

also looks like the purple wire in the bottom right (Mid 2) needs to move down 1 row.

[anotherjim]

I can't see anything new to help - sorry. The camera angle of the top side pic' is, I think, making it look out of line,. The socket pins are really one row up from what you see.