9V 2A Guitar FX Pedal Power supply

[moody07747]

I ran into another small problem...this time with mounting the jacks...

I have ten 2.1mm panel mount jacks that i want to mount to the aluminum plate on the project box I'm using.

here's a photo link
(old link removed)

they fit great lined up as in the first pic but the second shows they are not really round so a few holes wont do.

I need to figure out a way to cut this shape into the aluminum so its a nice, tight, clean fit.

I was going to just drill some big holes for them but then the screws on each side of the jack wont work...there wont be any metal for them to go into.

Any ideas?

I was thinking the Dremel but those cutoff wheels are too big to use in such a small space like this.

 

[moody07747]

im hoping the parts will come in today, but even then...i have to wait on those other outlets.

btw, whats the maximum amperage output of this supply going to be after the changes?
is it the same max output of the 2A transformer?

 

[audioguru]

whats the maximum amperage output of this supply going to be after the changes?
is it the same max output of the 2A transformer?

The transformer is rated for 2A AC. The supply will make 17VDC peak at the main filter capacitor so its DC current is only 1.4A when the transformer is at 2A AC.
The LM317 is rated to regulate very well with no more than a 1A load but some can give 2.2A if it has a big enough heatsink.
If the regulator gets too hot then it shuts-down to protect itself.

 

[moody07747]

that should easily power 18 pedals for my new board

(old link removed)

thanks

I have decided to mount the power supply on/off switch on the pedal board as its got this neat green neon mounted next to it

its also easier than opening the back and searching for the switch in the pedal board.

 

[moody07747]

well i got those 2 resistors in place and im not getting any output voltage at all.

A step by step "how to use the meter to test where the fail point is" would be nice...

 

[audioguru]

well i got those 2 resistors in place and im not getting any output voltage at all.

When you removed the two extra resistors from the pcb layout, you shorted the output of the circuit.

 

[moody07747]

oops lol

ill try that one again.

 

[moody07747]

nope still no output...next step?

is it possable i burned up the regulator when testing with that short the first time?

if so i can replace it with another.

 

[audioguru]

nope still no output...next step?

is it possable i burned up the regulator when testing with that short the first time?

if so i can replace it with another.

The regulator with a shorted output gets hot then shuts down to protect itself.
Join a couple of spots on the pcb.

 

[moody07747]

my fault...i just noticed i forgot to solder a wire drom the bottom of those 2 diodes the the cap.

it hasnt been getting an power, let me fix that now

im not sure how i missed that link...

 

[moody07747]

fixed it, at first it didnt work...untill i took the green neon light out of the electrical path on the switch.

for some reason it wont work with it.

im getting 8.95DCV, plenty good enough

 

[audioguru]

fixed it, at first it didnt work...untill i took the green neon light out of the electrical path on the switch.

for some reason it wont work with it.

im getting 8.95DCV, plenty good enough

A neon bulb has a resistor to limit its current to only about 1mA. It doesn't go in the electrical path in series with the transformer, it goes in parallel with the transformer's primary.

 

[moody07747]

thanks once again.

 

[moody07747]

OK I'm back to this project once again.

I finished this build months ago but it never worked so I just did a quick supply in my board and put this DIY one aside for a while.

I'm planning on making a portable pedal board for Christmas and will need this to work as its the only thing just right to fit on the open space of the new board.

Whats happening is there must be a short somewhere in the line because its not putting out any power at all.

I have gone over the wiring sheet 5 times and its wired correctly so I'm not sure what's wrong.

wiring sheet:
https://www.electro-tech-online.com/attachments/ultra_clean_ps_layout-4-png.8742/

If I remember currently, I took the leads off the sockets on the panel and it was working...ill have to redo this as I'm not sure if this is true...I did this the day I finished it.

so somewhere in these output sockets I'm getting short for some reason.

The day I finished this project and it didn't work I thought I had wired the black (+) to the wrong lead on all the output jacks so I unsoldered each one and installed a wire jumping from output to output jack on the little switch terminal


Right now I have a black wire from the board to all the switch solder connections as well as all the ground connections...this way theres no way of messing up the connection...well its still not working...

I'm about ready to spend $140 for a nice new Trex FuelTank Power Supply **broken link removed**


edit
By the way. There's none of that magic blue smoke...(that's good)...so something must be kicking in and stopping the power flow. My thought is that this is the LLM317T voltage regulator chip in the circuit. The reason I think this is because after about 10 seconds of run time at no output or anything connected...the regulator chip gets really warm...

After getting that info I thought there was a short somewhere in the line...thats when I went though the circuit following the wiring sheet to see if I had something wired wrong. Nothing wrong at all....

 

[audioguru]

Somebody tried to make that crazy power supply project last year. Wasn't it you, Moody?

It doesn't need four 1% resistors, it just needs two ordinary 5% resistors to make 9V.

 

[audioguru]

The LM317 gets hot without a load?
Isn't the LM317 regulator installed backwards? Then it might be damaged. Replace it and install it correctly like it is shown in its datasheet.

 

[moody07747]

the regulators in place the right way.

checked the data sheet on it allready
This is under no load.

I have 3 more regulators. It may be i got a bad one...ill try soldering in a new one later today.

 

[moody07747]

OK i got to unsoldering the wires to the jacks...i just undid the 2 from the board.

im getting continuity between the leads showing exactly where my short is....the output jacks.

i have to figure out how I'm going to rewire these ...maby someone here can help.

I used part 15153 from jameco for the jacks, each has 3 pins...one goes to the center pin, the other to the switch in the jack, the 3rd to the outer case.

when i jack is plugged in the outer case and center pin are connecting to the male plug being used.
when i take the plug out the jack has continuity between the solder pins for the outer ground case as well as the switch terminal...theres no way to get continuity to the center pin.

as of now i have a wire from the board and that jumps to the board...then to the first jack and jumps to the rest of the jacks in line.
i did that as well for the board to center pin connection.

the ground connection is just a back wire going from each unit ...i tied this into the switched terminal yesterday which still left me with a short.

ill take some photos after dinner so you can get a visual on how i wired this

 

[moody07747]

Somebody tried to make that crazy power supply project last year. Wasn't it you, Moody?

It doesn't need four 1% resistors, it just needs two ordinary 5% resistors to make 9V.

If it was under my name, than yes it as me.
This is the original pedalboard power supply thread if thats the one you're refering to.

I got power to the board and its comming out at 8.97vDC,,,well enough for my pedalboard.

 

[Hero999]

It doesn't need four 1% resistors, it just needs two ordinary 5% resistors to make 9V.

But 1% resistors are the same price as 5% resistors so I used them anyway.