AC/DC & POWERSTATION KIT BUILD THREAD

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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Miko wrote:Hey Joe. Kinda stumped. I'm hoping you can help. I'm trying to setup my V5. I have 30VAC unregulated, no CT coming off my power transformer. I set the doubler to D, and jumped C1 and C2 to drop the 48V to 24V as recommended in a previous post. When I connect one secondary to AC and the other to 0V it blows mains fuses. When I connect both secondaries to AC it doesn't blow fuses but of course doesn't produce the -voltages. I checked all component orientations, placements, and solder joints. Any ideas? Thanks!
HI Miko

Email me or attach up there some top and bottom photos of the built kit and wiring so I can check them over.

30vac is very high as it will give 42vdc unreg to each + and - reg but it should be fine except for heat under load.
Joe :-)
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cabbagerock
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by cabbagerock »

Hi Joe, Here is my sad tale: I built a v3 AC/DC with 48v and +/- 28v and it worked great for many months powering a DIY mic pre. Then one day it blew a mains fuse, I disconnected from the mic pre, replaced the fuse, and 48v had turned into 5v. I then replaced R7 because it was blown up and D10 because it looked possibly blown up, tested on the bench and 48v was back (yay). I repaired what I thought was a culprit short in the mic pre, powered back up and the fuse blew again because I had not actually fixed the short in the mic pre. Anyway, I replaced both R7 and D10 again and now instead of 48v I'm getting 68v. I replaced R2 because it looked a little stressed but still am getting 68v instead of 48v (+/- 28v still look good). Any advice on how to proceed would be greatly appreciated, thanks you!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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cabbagerock wrote:Hi Joe, Here is my sad tale: I built a v3 AC/DC with 48v and +/- 28v and it worked great for many months powering a DIY mic pre. Then one day it blew a mains fuse, I disconnected from the mic pre, replaced the fuse, and 48v had turned into 5v. I then replaced R7 because it was blown up and D10 because it looked possibly blown up, tested on the bench and 48v was back (yay). I repaired what I thought was a culprit short in the mic pre, powered back up and the fuse blew again because I had not actually fixed the short in the mic pre. Anyway, I replaced both R7 and D10 again and now instead of 48v I'm getting 68v. I replaced R2 because it looked a little stressed but still am getting 68v instead of 48v (+/- 28v still look good). Any advice on how to proceed would be greatly appreciated, thanks you!
If 48v LM317 is stuck at 68v then usually it will be the reg is short if the trimpot is not open circuit. If you mic pre 48v is likely to go short again add a tiny inline fuse between the 48v rail to the mic pre or a small value poly switch. Usually a 48v phantom rail will only draw 10 to 20mA per channel.
Joe :-)
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cabbagerock
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by cabbagerock »

Joe Malone wrote:
cabbagerock wrote:Hi Joe, Here is my sad tale: I built a v3 AC/DC with 48v and +/- 28v and it worked great for many months powering a DIY mic pre. Then one day it blew a mains fuse, I disconnected from the mic pre, replaced the fuse, and 48v had turned into 5v. I then replaced R7 because it was blown up and D10 because it looked possibly blown up, tested on the bench and 48v was back (yay). I repaired what I thought was a culprit short in the mic pre, powered back up and the fuse blew again because I had not actually fixed the short in the mic pre. Anyway, I replaced both R7 and D10 again and now instead of 48v I'm getting 68v. I replaced R2 because it looked a little stressed but still am getting 68v instead of 48v (+/- 28v still look good). Any advice on how to proceed would be greatly appreciated, thanks you!
If 48v LM317 is stuck at 68v then usually it will be the reg is short if the trimpot is not open circuit. If you mic pre 48v is likely to go short again add a tiny inline fuse between the 48v rail to the mic pre or a small value poly switch. Usually a 48v phantom rail will only draw 10 to 20mA per channel.
Thanks Joe! I have ordered some LM317, in the meantime I have both an LM7805CT and NTE958 lying around, are either of these a suitable replacement?

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

cabbagerock wrote:
Joe Malone wrote:
cabbagerock wrote:Hi Joe, Here is my sad tale: I built a v3 AC/DC with 48v and +/- 28v and it worked great for many months powering a DIY mic pre. Then one day it blew a mains fuse, I disconnected from the mic pre, replaced the fuse, and 48v had turned into 5v. I then replaced R7 because it was blown up and D10 because it looked possibly blown up, tested on the bench and 48v was back (yay). I repaired what I thought was a culprit short in the mic pre, powered back up and the fuse blew again because I had not actually fixed the short in the mic pre. Anyway, I replaced both R7 and D10 again and now instead of 48v I'm getting 68v. I replaced R2 because it looked a little stressed but still am getting 68v instead of 48v (+/- 28v still look good). Any advice on how to proceed would be greatly appreciated, thanks you!
If 48v LM317 is stuck at 68v then usually it will be the reg is short if the trimpot is not open circuit. If you mic pre 48v is likely to go short again add a tiny inline fuse between the 48v rail to the mic pre or a small value poly switch. Usually a 48v phantom rail will only draw 10 to 20mA per channel.
Thanks Joe! I have ordered some LM317, in the meantime I have both an LM7805CT and NTE958 lying around, are either of these a suitable replacement?
No it needs to be a LM317 to work
Joe :-)
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ahipkev
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by ahipkev »

Hi Joe,
Let me start by saying that this has been a real pleasure to build, so thanks for making it so easy and fun. I have run into a problem though, I am a noob afterall. I built it according to the instructions in this thread and have everything in place as directed, but the very last bit, the Bridge rectifier, seems to be giving me some trouble. From what I can figure where it needs to go has some diodes in the way. I have included pics to illustrate. Please advise the solution.
JLM3.jpg
JLM2.jpg
JLM1.jpg
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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ahipkev wrote:Hi Joe,
Let me start by saying that this has been a real pleasure to build, so thanks for making it so easy and fun. I have run into a problem though, I am a noob afterall. I built it according to the instructions in this thread and have everything in place as directed, but the very last bit, the Bridge rectifier, seems to be giving me some trouble. From what I can figure where it needs to go has some diodes in the way. I have included pics to illustrate. Please advise the solution.JLM3.jpgJLM2.jpgJLM1.jpg
OK you have several problems so lucky you have not powered up. All the regs are shorted to the heatsink the way you have installed the heatsink with no silicon tubes over them. You have the heatsink upside down. The 2 round pins in the air should be soldered to the pcb and all the regs should be in grey silicon tubes to isolate them from the heatsink so they don't short and the metal bar will clamp the thicker plastic part of the regs down to the heatsink.

If you want to fit the 10A to 25A bridge then the 2 diodes on each side covering the holes need to be removed.
Either heat with soldering iron and pull them or cut them with sidecutters from the pcb. NO NOT remove the outside pairs of diodes on each side as they are for the 48v pump rail.

See attached photo for more detail.

Let me know if you have any more questions
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Joe :-)
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ahipkev
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by ahipkev »

Thanks so much, did I miss the description for this version. I did search most of the thread.

ndinh
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by ndinh »

Hey there,

New to the community! I bought an AC/DC kit recently and have it all built up, but I have hit some snags along the way.

It is working fine on its own, but I am assuming that thermal shutdown is kicking in when I have it connected to my mixing console.

It is a Soundtracs Topaz, 24 channel board. When I start it up, all power rails are fine, but after about a minute, the -17 rail fades rapidly, shortly after followed by the +17 rail. 48V seems to have no problems though.

I'm assuming the two +/- V regulators are keeping up; I have all 3 regulators bolted to the rack chassis (it's a large steel enclosure. Should I be slapping a large heat sink on there instead? The chassis area around the regulators is very hot; is it this typical for the regulators to heat up this rapidly, or should there be something in the circuit I need to be checking as well.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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ndinh wrote:
Tue Mar 16, 2021 4:06 pm
Hey there,

New to the community! I bought an AC/DC kit recently and have it all built up, but I have hit some snags along the way.

It is working fine on its own, but I am assuming that thermal shutdown is kicking in when I have it connected to my mixing console.

It is a Soundtracs Topaz, 24 channel board. When I start it up, all power rails are fine, but after about a minute, the -17 rail fades rapidly, shortly after followed by the +17 rail. 48V seems to have no problems though.

I'm assuming the two +/- V regulators are keeping up; I have all 3 regulators bolted to the rack chassis (it's a large steel enclosure. Should I be slapping a large heat sink on there instead? The chassis area around the regulators is very hot; is it this typical for the regulators to heat up this rapidly, or should there be something in the circuit I need to be checking as well.
Yes sounds thermal. A metal rack case usually is only good for a pair of channels. Do you know the current draw on each power rail? And the size of the transformer VA?
Joe :-)
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ndinh
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by ndinh »

Hi Joe,

I'm not 100% certain of the current draw on each rail; I know the original PSU was rated for 1.5A.

The transformer is an avel lindberg Y236651, with a 250VA rating.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

ndinh wrote:
Wed Mar 17, 2021 2:43 am
Hi Joe,

I'm not 100% certain of the current draw on each rail; I know the original PSU was rated for 1.5A.

The transformer is an avel lindberg Y236651, with a 250VA rating.
Ok since running a desk I would have used our Kraftwerk or V6 as it has great capacitance for pre smoothing the dc and sync +/-v rails so they both power up and down together.

But if it is quiet when it first powers up before thermaling out then adding a large heavy base and mass heatsink directly to the regulators will fix the thermal problem. Something the size of the kraftwork heatsink 150mm x 75mm x 48mm fins.
Joe :-)
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ndinh
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by ndinh »

I unfortunately did not think of using a larger supply at the time, in retrospect that might have been a good idea.

I found locally a heatsink that's 130mm x 75mm x 60mm so I'll pick that up this weekend and try it out.

Would it be ok for me to mount it to the chassis or should I machine out a portion of the chassis and attach directly to the regulators?

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

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ndinh wrote:
Wed Mar 17, 2021 11:43 am
I unfortunately did not think of using a larger supply at the time, in retrospect that might have been a good idea.

I found locally a heatsink that's 130mm x 75mm x 60mm so I'll pick that up this weekend and try it out.

Would it be ok for me to mount it to the chassis or should I machine out a portion of the chassis and attach directly to the regulators?
It is best to have the regs with the silicon washers to be in direct contact with the actual heatsink so the thick centre core the heatsink and spread the heat quickly.
Joe :-)
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Thewotan
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Thewotan »

Hi there!

I intend to build a PSU for an 11 slot 51x rack (although it will be used mainy for 500 modules, I would like to have the option to add some 51x in the near future). I got the project second hand from a user in groupdiy. It came with a Kraftwerk PSU populated, but unforunately it was ruined when I tried to desolder most of the components, so I decided to use a Powerstation (Ver. 3) PCB that I had lying around with the Kraftwerk heatsink and with a 2x 25v 3.2 Amp transformer, but I'm going to buy new most of the BOM.


My question is: what wattage should the resistors be? Does 1/4 W suffice for all of them or are there any that should be higher?


Thanks for your help!

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