AC/DC & POWERSTATION KIT BUILD THREAD

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Joe Malone
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

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.

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