ULTRA clean 9VDC Power Supply Project

[Peter_wadley]

The reason why the lm317 is getting so hot is that it has to dissipate the extra Watts. The regulator is reducing the output voltage to 9V, but if you have a 25V transformer it has to dissipate all the extra voltage and current. So it generates heat.

Just thought I'd clear that up for you, I did not notice anyone tell you why to go with a lower voltage transformer.

Hey Ambient,

The LM317 was getting hot with the 25v (actually it was @ 35v!!) transformer... Hero999 addressed this and told me to use the center tap (12v).. the LM317 does not change temperature while in operation now.

The reason I added the fan is because the heatsink would not fit inside the box.. just as a precaution .. and to ensure optimum life of all parts.

mneary: A suggestion: If the project is to go into an enclosure, you should begin there. It's easier to change the parts locations on the board before you etch it.

Point taken.

You could ditch the fan which will prolly induce electrical noise into the DC output anyhow.
It would reduce the component count and the cost too.

Yes you are correct, when the fan is turned on through my homemade (unfiltered pedal) you can hear noise.. that is why the red SPST button was added.. its used to turn the fan off when operating that particular pedal..

Thanks and keep up the constructive feedback - it will save others much time and money in the future
Peter Wadley

 

[Hero999]

I'm glad to see you're finishing it properly.

I suppose a fan isn't required but it's often a good idea especially if you want to use it to power higher current loads than your guitar pedals.

You could have probably purchased a cheaper supply for far cheaper though it's been well worth making it as the experiance you've gained it priceless.

 

[Peter_wadley]

Hey Hero,

Just wanted to let you know that I tried the Laser Copier PCB method you pointed out earlier and it worked GREAT!

I will NEVER hand draw a PCB again!

Ive added a few pics below.

It took 2 tries to get the iron temperature right.. I set it to about 50% and ironed for 5 minutes.. peeled off nicely..

I have a question about etching though..

This time I heated the ferric chloride (I HATE THIS STUFF) and the etching went alot faster.. On the bottle it says to not heat past 55c... I went to 70c at one point.. I was just wondering if anyone knows if I was breathing poisonous fumes at that point..

if that makes sense..

Can someone PLEASE show me an alternate to FeCl!!! I cant stand the stuff! It smells like metallic blood, stains everything yellow, etchs VERY slowly, and makes my sink look awful!!

I just want maybe like a powder that I can add water too and it will be ready

Thanks,
Peter Wadley

 

[Hero999]

Looks iumpresive.

I use Prees 'n' Peel etching crystals it says sodium persulphate and sodium bisulphate on the container but I'm not sure what proportions.

What paper did you use?

I use magazine paper because it's a free recycled material but I've been told that some of the more expensive proprietary papers are better.

 

[gramo]

Hmm, breathing that stuff is bad juju

Grab a etching tank like this
**broken link removed**


https://www.altronics.com.au/index.asp?area=item&id=T3201

That one is a little over priced, but you ge tthe idea..you could even build your own with a fishtank pump..

Put that near a window (where it wont get hit by curtains/pushed over by wind), and let it do its thang for a while

 

[Peter_wadley]

Looks iumpresive.

I use Prees 'n' Peel etching crystals it says sodium persulphate and sodium bisulphate on the container but I'm not sure what proportions.

What paper did you use?

I use magazine paper because it's a free recycled material but I've been told that some of the more expensive proprietary papers are better.

I designed the PCB with this program:

**broken link removed**

What programs do you guys use to design your PCBs? This one is alright but the trial version does not let you print! So I had to print screen and print it with paint. shhh

I printed it off on my inkjet canon primus then took it over to my mothers laser copier.. set the contrast to 100% to make the lines as toned as possible.. hit copy then cut it out .. placed it on the pcb then you know the rest.

The paper from the copier is just normal A4 sheets also!

As for the etchant.. ammonium persulphate is exactly the one I am after.. it is used in the tutorial I used for making my laser PCB:

**broken link removed**

That is exactly what im looking for ... no fuss and no cuss.. just add the powder and swirl around.. hopefully my electronics store carries this!

Grab a etching tank like this

No more FeCl for me please

 

[Sceadwian]

I suddenly feel about 30 years older because the focus on those pictures is so bad =) Nice results though.

 

[Peter_wadley]

Could be worse.. could be a camera phone :|

Edit: Aren't wolves supposed to have keen senses?

 

[Hero999]

The paper from the copier is just normal A4 sheets also!

No special paper, just normal A4 copier paper!

I'm not surprised at all. I had a feeling that it would work with normal paper but I suppose I'll carry on using magazine paper because it costs nothing and plain A4 paper is relatively expensive.

 

[Peter_wadley]

No special paper, just normal A4 copier paper!

I'm not surprised at all. I had a feeling that it would work with normal paper but I suppose I'll carry on using magazine paper because it costs nothing and plain A4 paper is relatively expensive.

Sorry if I seem over excited, I am just happy I dont need to spend extra money on this hobby ... its suckin my wallet dry by the day

 

[audioguru]

Could be worse.. could be a camera phone

My son's camera phone has a very good image sensor that rivals the clarity of my digital camera. The camera in my cheap (free) phone is crap.

 

[Sceadwian]

I'd agree with audioguru =) Though you have to watch distance, most camera phones are fixed focus. When you're takeing pictures up close with a decent digital camera you have to remember to switch to macro mode because it changes the way the autofocus works.

 

[Hero999]

Sorry if I seem over excited, I am just happy I dont need to spend extra money on this hobby ... its suckin my wallet dry by the day

Your exitement is justified, you're lucky it worked so well the first time.

Many people hear swear by various types of paper, some of them are proprietary and quite expensive. I myself swear by magazine paper and I've thought about trying normal paper but I'll just stick with what works for me, it's not like it's expensive.

 

[Peter_wadley]

I'd agree with audioguru =) Though you have to watch distance, most camera phones are fixed focus. When you're takeing pictures up close with a decent digital camera you have to remember to switch to macro mode because it changes the way the autofocus works.

Wow! embarrassing...

I just found two options on my camera.. 1) close up and 2) super close up

My mistake!

I'll just stick with what works for me, it's not like it's expensive.

Yes, I also tend to stick with things once they work I am going to try magazine paper also.. the normal printer paper was very hard to remove after soaking.. id think that magazine paper would be a bit easier in that department.

 

[Peter_wadley]

Just purchased a 1kg bottle of ammonium persulfate crystals. Costed me 28.00 CDN !!!

This stuff better be damn good!

Will share my expierence after test board.

 

[Hero999]

I wouldnt use boiling water with that stuff, if decomposes and gives off poisonous gass. You're better off sticking to the maximum rated temperature of 50 degrees C.

 

[Peter_wadley]

Results

These are the results of using the ammonium persulphate and MAGAZINE paper.

I called the company who manufactures the ammonium persulfate and they said to mix the crystals into boiling water (not the other way around)

They also said to either wear a fume mask or keep clear of the fumes.

The magazine paper works alot better then regular A4.. next i am going to try A4 Photo paper to see if there is any difference.

The etching took about 20-30 minutes. And was ALOT less messy then FeCl3, thankfully.

Here are some pics:

Note: Used Eagle to make PCB layout.

 

[gramo]

What type of magazine paper did you use? Like a silicon chip magazine, and you ripped(well cut cleanly) the pages apart to print on?

 

[Peter_wadley]

I used my sisters' Cosmo magazine.

I just gave it a quick tug and the sheet came right out.

(I think thats what your asking)

I made sure to print it right on Jessica Simpsons' huge forehead : )

The only think I dont like about using the magazine paper is that it is hard to decipher the PCB from the mag picture.

Probably best to use a page which has a mostly white backround

 

[Hero999]

I'm glad it worked for you.

I've often found that the coloured areas work better though it does depend on your printer and the kind of paper.