Presonus 16.0.2 power supply -- d16 burned

[clinkous]

I've got a Presonus 16.0.2 with a bad power supply. D16 is burned and I can't read the numbers off of it. There are also three bad caps C14, C28, and C16.

I can't find a schematic for this and was wondering if anyone can identify D16 for me if they have a schematic.

Thanks

Also D2 if anyone has a schematic.

[clinkous]

Sorry,

I didn't mean to post this in guitar amps section.

[Enzo]

First, did you CALL or otherwise DIRECTLY contact Presonus to ask if they would provide the schematic? Don't just look on their web site.

As to the diode, in a power supply, we mostly have only a few types of diodes. We have zener diodes to set some voltage, typically 15v, and many times we can see from the circuits around the diode that that is what it wants to be. 15v zeners tend to come in pairs, as there is usually both positive and negative 15v supplies.

There are diodes as plain old rectifiers. If this supply is an SMPS (is it?? I bet it is.) they will likely be fast recovery diodes. You can infer from the size often their current capacity. And from other circuit parameters, the voltage, or just use high voltage diodes in the first place.

Some diodes are there to protect other things, and rectifier types will work there too. We usually see the small glass type, 500mw sized, or the 1w sized like 1N4007.

A photo might help us. The photo in the following link is not very close, but you could point out which diodes if you can see them. Also note the whole supply can be bought.

PreSonus 410 PG2PWR Power PCB for StudioLive 24 4 2 | Full Compass

[clinkous]

No, I didn't contact them directly. Tried the forum but was not allowed to ask questions.

It is a 400SL16M and they have one for 95 bucks. I was going to take a stab at replacing the visibly bad components.

In the attached picture you can see the three bad caps (one is a taller 2200uf but fuzzy in the pic), and the melted diode.


The board is scorched as well on the bottom. Do you think I have a shot with replacing bad parts? I was told it just went up in smoke with no extenuating circumstances. My troubleshooting skills are very much beginner level.

If the board can't be fixed then I guess I have to buy one.

Any help or advice is greatly appreciated.

[The Dude]

That is a SMPS and could be difficult to repair if your "troubleshooting skills are very much beginner level"- as you say. No harm in trying, I guess. What have you got to lose but a few bucks in parts and a little time. You might try removing the diode without it falling apart and see if you can get some numbers off of it. Maybe even put some scotch tape around it first to keep it as intact as possible.

[Enzo]

This is a what is there to lose situation. Might as well try to fix it. a few bucks on parts, and if you win, great, if you lose, well you are back to replacing the whole board.

The diode looks from here like a 3A type, and on that SMPS is almost certainly a fast recovery type. Other than the burnt up part, are there other big diodes like that on the board? And do they all have the same type number? Good chance this one is just like them. Not guaranteeing that, but pretty likely.

yeah, get rid of any caps with tops bulging.

[Enzo]

And as it appears to be on the secondary side, you might remove the diode and caps and fire it up without. Some secondary voltage or voltages might be absent, but you could see if the supply will run. Does it blow fuses?

[clinkous]

I'm not sure if it blows fuses or not. I just disassembled it and tried to get part numbers.

This is the only large diode present and it looks like the trace to the transistor is blackened. I was going to replace the three caps, the transistor, the diode, and maybe run a wire across the burned trace.

So it is probably a 3A fast recovery rectifier diode? Got magnifying glass and I THINK it reads 6.8A 1243.

Sound familiar. I can look that up, don't want to waste your time with that. I think I will give it a shot and thanks to everyone for chiming in. I'm not sure what the voltages are supposed to be anywhere. I will read around some more in the forum and see what I can learn.

[The Dude]

This is only an educated guess from past experience working on those types of supplies. I would think something like this should work:

http://www.mouser.com/ProductDetail/...hhWiw22%2f4%3d

It's one example. There are several part numbers that would probably work.

As Enzo said, you can simply remove the bad parts and apply power to the supply to see if it will start up and run. Output voltages are labeled on the connectors in your picture. Test to see if any of them are there. Of course some will be missing because the diode will be removed. If any are there, the supply is running. Then, you just have to fix the parts of it that are not working. Get the supply working before you connect any of those connectors to the rest of the console.

[Jazz P Bass]

I'm not sure what the voltages are supposed to be anywhere. I will read around some more in the forum and see what I can learn.

The final secondary supply voltages are marked on the 5 pin header in your pic.

[J M Fahey]

Worst case, some local Tech used to repair computer supplies might get a shot at it.
Somehow they are both fast and relatively inexpensive, a necessary trait since PC supplies are so cheap, yet some people repair them.

[clinkous]

Thanks

So that large diode is probably not involved in rectifying the a/c like in a tube amp? I will call Presonus and see if they'll send me a schematic. I should probably read up on SMPS's. You guys have helped me immensely in the past and I've learned a lot here. Mostly tube amp stuff but I'm trying to learn to fix my solid state stuff as well.

I'll order some parts and be sure and let you know how it turns out.

[Jazz P Bass]

If this is your first SMPS adventure, a few words of caution:

The Primary half (the Mains Input side) & the Secondary half (the final voltage output) are two complete & separate entities.

The Primary is directly connected to the mains supply.
One slip & the sparks will most certainly fly. (if not your heart)
The Primary uses it's own zero volts (ground?) reference as opposed to the Secondary.
They are not the same point when used to measure the two halves.

Oh, and if you get it really wrong, the supplies can fail in such a way as to send shrapnel flying.
So it is a sound practice to wear safety goggles.

SMPS are a bear.
Not a tube amp or an effects pedal for sure.

[clinkous]

Awesome! Thanks for the warning. I've got a bunch of functioning computer power supplies and I'm going to see if I can rob parts from. I'll just measure the voltages listed on the pins going to the different sections and won't monkey around on the board with the probes. This should be ok right?

Each secondary group of pins going out has a 0v, +15, -15, etc. I can check each of these using the 0v pin for that group correct?

I'll call PreSonus tomorrow and see if a schematic is available from them. There are test points on the board but I don't know what they should read and using what as the ground.

Thanks

[vierneedator]

Hi
Do you still need the value of the diode? I just replaced mine