[BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread

[kante1603]

Udo, would you mind sharing the photos again? It seems they have disappeared. Thanks for the pdf with the colors "translated". I will probably manage with the help of that pdf, but it would be great to double check with your photos.

Greetings, Hans-Olav

Hello Hans-Olav,


sadly I had most of my pics on imageshack......and lost them two times meanwhile!
Will not do it this way anymore.
Also this was in 2012,so quite long ago.
I even can't remember which build my post refers to,was it a floor box or one of my big dual 51x types?
Best is to tell me which part(s) you want to see on what kind of build.
Then I might open up that device and do some new pics again.....if I can access it easily of course.
Shouldn't be too complicated to do on a floorbox,I have one here.


Best regards,


Udo.

 

[hanso]

That would be great! It's a VPR floorbox, with transformer from Volker. I'm unsure of both the input and output wiring to the transformer.

Cheers!

 

[kante1603]

That would be great! It's a VPR floorbox, with transformer from Volker. I'm unsure of both the input and output wiring to the transformer.

Cheers!

O.K.,seems to be the very same transformer on my floor box,it´s a "RONDO-MÜLLER" from Volker.
Here we go.


The mains wiring (please-as always- be careful with mains voltages):

 

[kante1603]

Secondaries:

 

[kante1603]

…and an overview.


Cheers,


Udo.

 

[hanso]

Thanks a lot! That's very kind of you. I'm new to this community, so I will consider this a warm welcome. 

I will get on with the project next week. Excited!

 

[hanso]

I'm happy to inform you that my build was a success!

At first the 48 V fuse blew. I had read here on the forum something similar regarding a Shadow Hills Mono Gama, so that module was quickly suspected. After I removed that module the 48 V fuse has held up. I guess I'll just sell the Mono Gama then.

Big thanks to Udo, Jeff, Volker and this whole great community!

 

[Patrik]

Hi,

I have an issue with my PSU floorbox.

A quick background to the issue.
I assembled it about 2 month ago and it has been working fine until I did some initial testing three days ago, on a new preamp module (Don NV73) and accidently shorted something with my DMM probes which resulted in the mains fuse blowing. Stupid me!
I dont know exactly what I accidently touched, but I replaced the mains fuse and everything was working fine afterwards. the PSU was turned on for about 30 minutes and I recorded some with no issues.
Two days later, after not touching anything since It was last working I turned the PSU on again but this time the mains fuse blew again, immediately. I disconnected the psu from the 511 rack and powered on but the fuse blew immediately again.

If I disconnect the 48V secondary windings from the transformer the PSU powers on. If I connect the 48V wires again the mains fuse blows. the 48v fuse on the PCB is fine. The powercord is disconnected from the PSU so the 511 rack and cable can be ruled out.
If i connect only one of the 48v secondary pair (the black wires on the rondo) the unit powers on and AC voltage between connector and ground reads 0.4V. The loose end reads about 55V.  If I disconnect both black wires and measure them one reads about 17,5V and the other 26V.

PSU is 511 24v version ordered from Volker. Rondo Müller transformer.

Any particular part that would be the first to check, and how?
I hope you can help me!

Thanks for reading.

 

[jsteiger]

@ Patrik, sounds like there is a short of some kind between the toroid and the bridge rectifier. You could verify this by checking DCR at the inlet for the 48V windings with those leads disconnected. NO AC power connected to the unit during this! If you get a low reading there, you can backtrace towards the bridge rect to find it. Might be a stray wire stand or something?

 

[Patrik]

I measured the resistance on the 48v connectors on the AC side to Mohm range. Values are moving on the DMM as I measure though, I guess its because of the capacitors in the circuit?
On the positive side of the Bridge it seems to move in the kohm range. Is this as it should be?

 

[Patrik]

The 48v fuse looked all fine and beeped for continuity on my DMM while troubleshooting.
It turned out when I measured the fuse that it had a 10ohm resistance (not to ground but internally) I didn't see that coming and I haven't seen that before, but I replaced it and after that the unit works.

Can anyone explain how a "half broken" fuse cause the mains fuse to brake?

Thanks for showing the way!

Regards
Patrik

 

[[silent:arts]]

Can anyone explain how a "half broken" fuse cause the mains fuse to brake?

No 
But mysteries sometimes happen. You might have fixed something else without recognizing.
Glad everything works again.

 

[andybaker28]

Hi there

I just finished a two channel power supply. Kind of strange thing happening and not sure where to begin. When I finished both channels were measuring correctly and seemingly there was no problem. So I put the unit together and tested it on my rack. When I plugged it in I noticed that my 4 channels of VP 28s all had an input kind of ringing sound. Low in volume but steady and clear. The VP 28s did not work, but the Helios and Chandler pres did still work but still with a bit of the same ringing tone. I unplugged the supply and tried channel two of the supply and no problem at all, nice a clean sounding. So I am not sure what might cause this? Anyone have a suggestion?

Thanks in advance!

Andy

 

[jsteiger]

What are the output voltages after final assembly? Remove all modules and measure DCV at one of the card edge connectors in the rack.

Maybe one of the regulators is fastened to strongly and shorting out to the heatsink, or maybe there is a problem inside of the cable connector.

 

[andybaker28]

What are the output voltages after final assembly? Remove all modules and measure DCV at one of the card edge connectors in the rack.

Maybe one of the regulators is fastened to strongly and shorting out to the heatsink, or maybe there is a problem inside of the cable connector.

Hi there! The final voltages were the same on both sides of the supply, I set them at + and minus 16.7 and 48.5. They seemed to adjust with no problem and were steady as I set them.. I saw many people had had the issue with the heat sink and regulator. I was trying to be careful there but I will check for shorts.. I will check the connector as well.

Thanks and I will get back soon

A

 

[jsteiger]

Hi there! The final voltages were the same on both sides of the supply, I set them at + and minus 16.7 and 48.5. They seemed to adjust with no problem and were steady as I set them.. I saw many people had had the issue with the heat sink and regulator. I was trying to be careful there but I will check for shorts.. I will check the connector as well.

Thanks and I will get back soon

A

I would check voltages at the card edge connectors inside the rack with no modules installed.

 

[andybaker28]

What are the output voltages after final assembly? Remove all modules and measure DCV at one of the card edge connectors in the rack.

Maybe one of the regulators is fastened to strongly and shorting out to the heatsink, or maybe there is a problem inside of the cable connector.

Hi there, I found it! It was indeed the connector! Thanks for your suggestion! Its up and running now!
Thanks so much!!!

Andy

 

[Unit7]

I've got two 51X PSUs each powering one rack with eleven 24V NV73 preamps. The other day one PSU started crapping out.

I checked voltages and it measured 24.5V while the working PSU measured 24.7 so I trimmed both to 24.7 and now all seem good (I also trimmed voltages at the 2N3055s in the NV73 modules). However further checks showed that the former faulty PSU went from 24.7V to 24.4V when powering all modules, while the other PSU only sagged to 24.6V. Is that normal?

 

[[silent:arts]]

What exactly do you mean with crapping out?
The voltages you are reading are all fine.
I wouldn't care about 0,2V difference.

 

[Unit7]

What exactly do you mean with crapping out?
The voltages you are reading are all fine.
I wouldn't care about 0,2V difference.

Thanks Volker!
The PSU sagged and voltage got below what the NV73s needed, causing the relays in all 11 modules to switch off, making the PSU to recover, making the relays open again. Over and over again in an approx 4 second cycle.

This only happened with the combination PSU #1 powering Rack #1, no other combination.

So I trimmed the PSU #1 to 24.7 and also fine trimmed the voltage at the 2N3055 in all modules and all now seem good.

I was just concerned that PSU #1 went to 24.4 loaded while PSU #2 only went to 24.6 loaded by the same 11 slot rack. But if you say it's fine I feel fine 

Thanks!
Paul