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

[rafael-sf]

If you are using the rack with only the Floor Box, the filtering is not needed. It is possible the inrush current to fill the 470µF caps is causing the fuse to blow. Its almost like leaving phantom on for 10 preamps and then starting up the Floor Box PSU.

Any workaround (other than putting the floor box on ebay) ? The long term plan is to have a second rack, hence the floor box instead of the other power supply on your shop.

 

[jsteiger]

Any workaround (other than putting the floor box on ebay) ? The long term plan is to have a second rack, hence the floor box instead of the other power supply on your shop.

If you only ever plan to use the Floor Box then no need for the filter components at all.

 

[rafael-sf]

If you only ever plan to use the Floor Box then no need for the filter components at all.

I got that, but what's a good workaround? Just bypass all the filtering section or use a higher current fuse?

 

[jsteiger]

I got that, but what's a good workaround? Just bypass all the filtering section or use a higher current fuse?

I would try a 160mA slow blow fuse.

 

[rafael-sf]

I would try a 160mA slow blow fuse.

Sorry for the delay in replying, but the short blow fuse worked purrrfectly. Much obliged, Jeff.

 

[PetezaSlice]

Okay, I've encountered a strange noise problem in a chain of gear.

I have a  Radial Komit in a CAPI VPR rack, into a Helios Type 69-500 pre/eq (line mode on) in a BAE 11 space rack. As soon as the Komit is engaged, I get a ground hum.

Now, I tested all the routing and cabling in a multitude of ways and configurations, bypassing different things and I'm pretty certain it is not a cable issue. bypassed the patchbay, etc, etc.  I'm fairly certain it is not cable related.

This is problematic signal flow:
Lynx Out (via patchpay normal) -> Komit In (CAPI VPR Rack) / Komit Out -> Patchbay w/ patch to Wall Tie In/Helios Type 69-500 ((I set these up because my preamp inputs are directly XLR connected to my wall snake, thus made patchpoints that lead to XLRs to my wall I can swap in when wanting to use my Helios  eqs))

I know, that's a lot of cabling to be suspicious of, but I'm pretty certain it's not cabling. I don't have the same noise problem skipping the Komit but still going into Helios same signal flow, and I don't have a problem skipping Helios but going into Komit signal flow - ie, they operate fine when individual. I also eliminated the patchbay a number of ways, and my wall tie ins.


I moved the Komit, out of CAPI VPR rack and into the 11th slot on my BAE rack, did the same chain flow and the problem was not there. then I returned it to the CAPI rack and recreated the same problem as before.

Then, back in the problematic spot in the VPR rack, I tried the same test, but reversed the order of the chain.., Lynx out -> Helios In ->  Komit In -> Lynx in. And the problem is not there.

So this problem only occurs when the Komit is in the VPR rack with the bypass out and is connected output to Helios input.

Helios output, to Komit input, no problem.

Any ideas? something I did wrong in the VPR build?  I'm wondering if the Helios just doesn't like line devices before it since it's -10db unbalanced (I'm pretty sure) - would that explain it? - not really,  because the specific gear chain works if Komit is in the BAE rack.

 

[Mylithra]

Make an XLR cable that has pin 1 cut on 1 end (make sure its not shorting about against the other pins).
Use that in between your Komit and Helios. You still get the noise?

 

[Mylithra]

Finished mine today. Had no real issues during the build. I too built the filtered rack because there will be times I will be on location and wont be able to take the larger supply.  I had to use a slowblo for the 48v rail. The initial in-rush current is too much with the extra filtering in. I toyed with putting an in-rush thermister between the PS and the Rack (probably between the phoenix connector and the cable would be the easiest place to put it) on the 48v rail to help deal with this but its working fine as it is.

 

[knadles]

I apologize if this has already been answered. I finished my power supply build and tested the rails this morning. All of the rails show the correct voltage except the 48v, which shows zero. The LED is also unlit.

I did an initial power up last night (without testing) and left it run for a while. When I returned, from a distance and the rear (looking through the box) it appeared as though the 48v LED was unlit, but when I came around to the front I saw that it was on. As I powered down the unit, I noted that the 48V LED turned off almost immediately, while the 16V LEDs all took a nice long time to power off.

This morning I tested the rails with the multimeter and found that 48V wasn't working. The fuse appears unblown.

I don't have a ton of experience troubleshooting from inside the box. Any thoughts on where I should start looking to track this down?

Thanks!
Pete

 

[jsteiger]

Pete, make sure you haven't over-tightened the mounting screw for the 48V regulator. You can test for a direct short by checking continuity between the reg's tab and ground.

Did you have a load or rack connected? If so which one?

 

[knadles]

I just checked it. The regulator tab is 48v from the star ground point. (Actually, 48.5v...since I took the opportunity to calibrate it based on your recommendation.) What's next? Look for a bad solder joint?

I don't have it connected to a rack yet. Waiting for the CAPI to come in. [UPDATE: they're in and I just ordered one!] I do have a Radial and a Heritage here, but I'm not sure if they're the same pinout.

Thanks,
Pete

 

[jsteiger]

Check if you have 48V on the right end tab of the 48V fuse holder. If you do, then look for a short at the output screw terminals or inside the XLR.

 

[knadles]

I agree the screw terminals seem to the likely culprit. I actually had it running yesterday morning for about 2-3 hours and all lights were functional and all output terminals measured the correct voltage. The fact that it's an intermittent issue suggests a bad solder joint. I installed the first cable to the screw terminals, fired up the unit, and watched the 48V LED turn on, fade off, followed by the entire unit as the mains fuse blew. If nothing else, I know the mains fuse is working correctly. Ha.

I haven't had time to take the unit apart yet, but I did notice one thing. I don't know if it's a clue or normal behavior, so I figured I should ask. I decided a quick way to test for a short would be to check resistance to ground at the screw terminals. I found that the ground and chassis terminals were zero ohms to ground (as expected); the 16V rails ranged around 2-3K ohms, and the 48V rails were "open." Is that expected, or should there also be a measurable resistance on the 48V?

 

[jsteiger]

I agree the screw terminals seem to the likely culprit. I actually had it running yesterday morning for about 2-3 hours and all lights were functional and all output terminals measured the correct voltage. The fact that it's an intermittent issue suggests a bad solder joint. I installed the first cable to the screw terminals, fired up the unit, and watched the 48V LED turn on, fade off, followed by the entire unit as the mains fuse blew. If nothing else, I know the mains fuse is working correctly. Ha.

I haven't had time to take the unit apart yet, but I did notice one thing. I don't know if it's a clue or normal behavior, so I figured I should ask. I decided a quick way to test for a short would be to check resistance to ground at the screw terminals. I found that the ground and chassis terminals were zero ohms to ground (as expected); the 16V rails ranged around 2-3K ohms, and the 48V rails were "open." Is that expected, or should there also be a measurable resistance on the 48V?

Your 48V output is likely measuring open circuit due to the fuse being blown.

The main thing you would be looking for when measuring DCR from the output rails to ground would be a direct short or extremely low resistance. Its hard to measure them because the caps will be loading. A direct short will be evident though.

Check DCR on the circuit side of the 48V fuse. It should be fine.

 

[knadles]

Okay, I thought I had found the problem and fixed it. Putting the unit back together, I've apparently munged things further. I'm now blowing the mains fuse every time I turn it on. 

On a whim, I checked for continuity between the regulator tabs and the screws that hold the regulators. I'm "open" on three, but showing a non-open resistance on the 48V (approx. 5.5K) and the +V#2 (approx. 1.5K).

In addition, checking resistance from regulator tabs to the star ground point, I have 0 ohms on -16V and -V#2, but positive resistance (in the K-ohms range) on 48V, +16V, and +V#2. I don't know what the preferred behavior would be, but it seems to me it should be similar across all regulator tabs. Certainly across all the 16V regs, so I figure something is grounding out somewhere.

At this point, I'm wondering if it would be easier and more straightforward to just pull all the regulators and replace them from scratch. Can I purchase them, plus pads, insulating sleeves, and screws from you? I've half a mind just to buy the whole circuit board and components and start over. I'm pretty confident in my toroid and mains connections, since it was working before—at least until it wasn't—but that's about all I know. I looked over my solder connections and they actually seem pretty textbook for the most part, so I'm assuming a mechanical connection is the issue.

Any thoughts? I'm happy (well not happy, but willing) to spend what I need to. I just want to get it working. I realize this is my problem and not yours, but if you can offer any advice, I'd appreciate it.

Thanks,
Pete

 

[jsteiger]

Pete, the resistance from the tabs to ground you posted is correct.

 

[knadles]

Okay. Well that's good to know, at least!

 

[Mylithra]

can you post some detailed pics?

 

[knadles]

I found the issue, and I have to say it's right up there with the old "using the CD drive as a cupholder" trick. 

1.25A fuses for 230V mains; 2.5A fuses for 115V mains. Guess what I had in there? What's the emoji for bashing your head into the wall and stepping on your own foot?

Funny thing is, it worked at first with the 1.25A. Maybe with the 48V rail not working the unit overall didn't draw as much power. I dunno. Once I solved the 48V issue, I blew my fuses. Looked over the build docs again late yesterday and I'm like WAITAMINIT!!!

Almost too embarrassing to point out in public, but I figured I should cop to it in case someone someday makes the same mistake. When I got home last night, I put a *2.5A* fuse into the slot and voila. No issues and all the rails tested correctly. Live and learn, right? In my case, learn to read. Don't quit school, kids!

Thanks to you both!

Pete

 

[zqone537]

Hey guys,
I've got one these RONDO-MÜLLER Volker transformers. The 2 pairs of cables for primaries are yellow/white and yellow/white. Sowhich one's are for 115+?
Thnaks