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

[rafael-sf]

Ah, so now I am betting that you have a newer style filtered rack/backplane?? I would check the polarity of the electrolytics on the backplane. Specifically C11 and C17. The two larger 1000µF caps. One of those is likely backwards.

I wish ! Removed all the caps, the inductors, split the two boards and tried removing the 5-pin plug (probably damaging it in the process, those things just won't come out) and the short only went away when I removed R1. Any idea what's going on?

Thanks,
Rafael

 

[jsteiger]

I wish ! Removed all the caps, the inductors, split the two boards and tried removing the 5-pin plug (probably damaging it in the process, those things just won't come out) and the short only went away when I removed R1. Any idea what's going on?

Thanks,
Rafael

R1 is between Chassis ground and audio ground. It has zero to do with the 48V rail.

 

[rafael-sf]

R1 is between Chassis ground and audio ground. It has zero to do with the 48V rail.

lol.. I should have stopped after 3am, I measured the wrong pins. Just re-tested now and the short is gone. I'll put things back together at a piece this time, the caps were all in the correct orientation tho.

Thanks,
Rafael

 

[PetezaSlice]

Hey, I've never measured card slot pins before?  Where do I put my ground probe? On the ground pin and then move my other probe down the other pins?

 

[rafael-sf]

Hey, I've never measured card slot pins before?  Where do I put my ground probe? On the ground pin and then move my other probe down the other pins?

Yup, check the last table on the assembly instructions.

 

[PetezaSlice]

Chassis or audio ground or psu gnd???

 

[rafael-sf]

Chassis or audio ground or psu gnd???

I don't have the schematics in front of me, but I think audio and PSU ground are the same (and you should use that).

 

[PetezaSlice]

I figured it out, thanks. I used my DBX560a to test all the slots after testing with DMM (most inexpensive module)  for some reason.. My Elysia Xpressor is allowing audio to pass  when THE POWER IS OFF.  Is this normal, why is this? Design of the Elysia? Other modules dont seem to be doing this.

 

[[silent:arts]]

My Elysia Xpressor is allowing audio to pass  when THE POWER IS OFF.  Is this normal, why is this? Design of the Elysia? Other modules dont seem to be doing this.

Hardwire (relay) bypass is a good design practice.

 

[PetezaSlice]

Hardwire (relay) bypass is a good design practice.

Yum. those guys at Elysia.

yay, lights and sounds:

 

[rafael-sf]

I finally found time to put things together and I see the short when C17 is in place. Same behavior with either one of the caps.
Any ideas?

Thanks,
Rafael

 

[jsteiger]

I finally found time to put things together and I see the short when C17 is in place. Same behavior with either one of the caps.
Any ideas?

Thanks,
Rafael

That is very odd unless there is an internal problem with C17, as long as you are 100% sure the polarity is correct.

 

[rafael-sf]

That is very odd unless there is an internal problem with C17, as long as you are 100% sure the polarity is correct.

Any suggestions on how to troubleshoot this or should I send it back to you?

 

[jsteiger]

Any suggestions on how to troubleshoot this or should I send it back to you?

I can mail you another cap but before I do simply measure DCR between the 2 thru hole pads for C17 on the PCB. You are looking for a very low Ω reading. You can also do the same thing on the cap's leads.

 

[rafael-sf]

I can mail you another cap but before I do simply measure DCR between the 2 thru hole pads for C17 on the PCB. You are looking for a very low Ω reading. You can also do the same thing on the cap's leads.

There's apparently nothing wrong with either the PCB or the caps. The PCB shows no short between the thru holes (infinite resistance) and both C11 and C17 start charging up (resistance increases the longer I measure their poles). This is the same behavior I see when I measure pins 5-15 on the card connector, which I've been assuming is the cause of the problem. That is, I don't see zero resistance between 5-15, but the same 'charging' behavior I mentioned. Makes sense?

 

[jsteiger]

There's apparently nothing wrong with either the PCB or the caps. The PCB shows no short between the thru holes (infinite resistance) and both C11 and C17 start charging up (resistance increases the longer I measure their poles). This is the same behavior I see when I measure pins 5-15 on the card connector, which I've been assuming is the cause of the problem. That is, I don't see zero resistance between 5-15, but the same 'charging' behavior I mentioned. Makes sense?

The caps charging is correct and as expected. I thought you said there was a direct short from card edge pin-15 tp pin-5 once you installed C17?

 

[rafael-sf]

The caps charging is correct and as expected. I thought you said there was a direct short from card edge pin-15 tp pin-5 once you installed C17?

No, 5-15 always show the cap charging (see a previous reply). What else could be causing the fuse to blow?

Thanks,
Rafael

 

[jsteiger]

I finally found time to put things together and I see the short when C17 is in place. Same behavior with either one of the caps.
Any ideas?

Thanks,
Rafael

Based on this statement I thought you had a direct short. No indication of just a charging cap.

To be clear, you are using the filtered backplane with a Floor Box PSU?? This is the Floor Box support thread not the one for the rack. Seems like you are indication a problem with the rack not the linear PSU.

 

[rafael-sf]

Based on this statement I thought you had a direct short. No indication of just a charging cap.

To be clear, you are using the filtered backplane with a Floor Box PSU?? This is the Floor Box support thread not the one for the rack. Seems like you are indication a problem with the rack not the linear PSU.

Yes.. is that not a valid combination? I can move the discussion to the rack thread if you'd like.

 

[jsteiger]

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.