Presonus Firestudio Project

[The Dude]

Hello all. I'm looking for either the power supply schematic for one of these or the value on what appeared to be a 1/4W resistor near the bridge rectifier. It was a black blob due to a couple of cap failures. Please don't advise me to contact Presonus. I've been battling with them for 2 weeks now- sent pics, asked for schematic, asked for part ID, etc., etc. and they still cant' help even though there are only 2 1/4W resistors on the entire board.

[Jazz P Bass]

That looks like a switch mode power supply.
Can't be that difficult a job to rough sketch it.
At least as far as the unknown resistor is concerned.

[Enzo]

I agree, it looks like the part was next to the mains rectifiers, and so I might suspect it was some low value inrush limiting resistor, probably not critical. Sketch out that part of the circuit and see if the resistor was in series with the output of the rectifier or one side of the input.

[The Dude]

Thanks fellas. That's what I intend to do if I can't get an answer soon. I found others who've had this problem via a Google search. I have yet to find an answer. As you say, the resistor is in series with the output of the rectifier, and I'm quite sure I could make it work. Just thought someone may have run into this before and have the "easy" answer.

Also, after further inspection, this is THE ONLY 1/4W resistor on the board. I fail to see why it would take Presonus 2 weeks to figure out what I'm talking about. My best guess is that they don't repair these boards and simply replace them. Don't know why else they wouldn't know immediately what I'm talking about.

[Enzo]

Because you are probably dealing with a customer service rep, not a technician, and quite likely he is not going to get up and go find the service department, if it is even in the same building, and then ask a tech to find out what part your pictures are looking at, then come back and respond with details for someone who is not looking to buy a product. Nothing against you wanting to fix something, but a request like that often falls through the cracks, especially in smaller companies. The photos are great for guys like me, but to your customer service rep, it is a photo of a transistor pizza. He won't know what he is looking at, he knows products from the outside - as whole things. If I showed a photo of a spleen or a pancreas to an auto mechanic, do you think he could identify it?

My guess is the guys who do the repair are not generally available to the phone people. As far as I can tell, they do not have a network of service shops, so all repairs are done there, meaning the guys are busy. I once worked at a good size music store, home store of a chain, as head of the electronic service department. The boss looked into efficiency and found that the sales people were getting me on the phone to help answer customer technical questions. He felt it was ineffective use of my time - couldn't bill anyone for it. His solution? Remove the phones from the service department.

MY general approach to something like this is to call them on the phone and talk to a human, and ask for a schematic. Chances are I don't need anything other than that anyway, and they are not going to talk me through the benchwork.


MY experience with Presonus regarding support was positive. I had some unit in here for repair and it needed some chip I couldn't seem to find. I know it was a 33079 in SOIC, because I just found the extra ones yesterday and filed them. Don't know why I couldn't find them then, Mouser has them today. But I called them and asked if they could recommend a source, or could they sell me the part, or even recommend a sub. They just threw a half dozen of them into an envelope and mailed them to me. Whatever year it was, it was around Xmas, because they were taped inside a company Xmas card.


KTB used to work there, if you see him posting, you might ask for insights.

[The Dude]

I agree with much of what you say Enzo, but it should be said that I work for a Presonus dealer (which they are aware of). We spend plenty of money with them. You'd think they might take that into consideration. I have called twice and started a support ticket over 2 weeks ago. I did ask for a schematic so that they wouldn't have to do the research for me....to no avail.

[robson]

bom dia alguem consiguiu resolver o problema da fonte da presonus firestudio project estou com mesmo problema mandei para autorizada para reparar a fireware e voltou om problema na fonte

[J M Fahey]

bom dia alguem consiguiu resolver o problema da fonte da presonus firestudio project estou com mesmo problema mandei para autorizada para reparar a fireware e voltou om problema na fonte

Amigo, por favor posta em Inglés ou nenhum aqui vai compreender o que voce fala.
Só por casualidade eu li o seu post

Could anybody solve the Presonus Firestudio supply problem? Sent it to officil Service and it came back with problems in "fireware" (Firewire? ... Firmware? ) It came back with supply problems.

Sorry but your only option is to send it back to the Autorizada (AWSC) , they charged you (or it´s still under Warranty) and they MUST solve it, who else?
Usa o google tradutor se for necessário mas primeiro corrige minha falta de acentos, cedilla, etc. (nao tenho teclado Portugues) ou o Tradutor fica doido.
Abraco.