kante1603

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #460 on: April 19, 2018, 09:54:22 PM »
+1 on Jeff's comments!
Zooming in to pic 1 it looks like you clamped the insulation,not the wires.
Especially visible on the left green one.
Also the tinned leads don't seem to have any visible markings from pressure,they might have never seen the "force" to make a good contact.


Best regards,


Udo.



rafael-sf

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #461 on: July 24, 2018, 06:25:29 AM »
Hi folks, I just finished building another PSU and VPR chassis and all the voltages look good. But when I plug the DC cable and flip the switch on the PSU, the 48V fuse goes. I took the back of the chassis out and visually inspected the solders and they all look good to me. Any suggestions on how to chase this one down? I've built/repaired a few of these over the years but don't remember having these kinds of issues.

Thanks,
Rafael

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #462 on: July 24, 2018, 09:55:32 AM »
Hi folks, I just finished building another PSU and VPR chassis and all the voltages look good. But when I plug the DC cable and flip the switch on the PSU, the 48V fuse goes. I took the back of the chassis out and visually inspected the solders and they all look good to me. Any suggestions on how to chase this one down? I've built/repaired a few of these over the years but don't remember having these kinds of issues.

Thanks,
Rafael
Have you checked for shorts from 48V to ground in the rack with a DMM? Is the rack empty or loaded when this happens? Is it a 51x 18-pin rack?
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gar381

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #463 on: July 24, 2018, 07:22:09 PM »
Remote possibility but I have seen this happen.... :'( 

If you are firing up a rack full of pres and all the 48v Phan switches are turned on on the pres, 
The in-rush current charging up the 48v Rail caps on all the pres at the same time takes out the fuse.

Hope you find the problem  :)

GARY
RETIRED.....  from 51yrs in Show Biz

gar2520, gar1731,garAM10,gar918 DOAs at  http://capi-gear.com/catalog/index.php?cPath=71_72
NEW Sphere section  http://gar381interests.com/gar381interests.html

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #464 on: July 24, 2018, 11:42:25 PM »
These are the measurements I'm getting in the power supply

+48v: 48.2
-16v: -02.8
+16v: 02.8
+V#2: 02.8
-V#2: -02.6
+48v: 48.2


Why am I not getting 16v reading? only 2.8v.

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #465 on: July 24, 2018, 11:55:50 PM »
These are the measurements I'm getting in the power supply

+48v: 48.2
-16v: -02.8
+16v: 02.8
+V#2: 02.8
-V#2: -02.6
+48v: 48.2


Why am I not getting 16v reading? only 2.8v.
My first guess would be you have some resistors accidentally flipped/swapped around.
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Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #466 on: July 25, 2018, 12:16:51 AM »
what do you mean flipped/swapped around? ie, I have them in the right resistor position but their polarity is wrong, or do you mean I placed some resistors in the wrong position?

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #467 on: July 25, 2018, 12:21:41 AM »
what do you mean flipped/swapped around? ie, I have them in the right resistor position but their polarity is wrong, or do you mean I placed some resistors in the wrong position?
Direction doesn't mater for R's. I mean maybe 243R's got used instead of 2k43's.
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Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #468 on: July 25, 2018, 12:27:15 AM »
Yes I think that is indeed what happened. you are spot on, 243s for 2.43k

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #469 on: July 25, 2018, 02:53:25 AM »
Okay so 2.43ks are in the 243r spots, but in the 2.43k (red, yellow, orange, brown. brown) spots are 240 (red, yellow, black, black, brown).  I can't find 243 which would be red, yellow, orange, black... wouldnt it?


rafael-sf

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #470 on: July 25, 2018, 06:42:01 AM »
Have you checked for shorts from 48V to ground in the rack with a DMM? Is the rack empty or loaded when this happens? Is it a 51x 18-pin rack?
Hi Jeff, the rack is empty and it's the 15 pin VPR. I do see pins 1 and 5 are shorted, it looks like my DMM charges one of the capacitors when I measure between those two (either at the neutrik connector or any of the 15 pin connectors). I cleaned up any suspicious looking solders but still seeing this.

BTW, can I use a 250mA fuse instead of a 160mA? They're easier to find around here.

Thanks,
Rafael

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #471 on: July 25, 2018, 10:00:33 AM »
Hi Jeff, the rack is empty and it's the 15 pin VPR. I do see pins 1 and 5 are shorted, it looks like my DMM charges one of the capacitors when I measure between those two (either at the neutrik connector or any of the 15 pin connectors). I cleaned up any suspicious looking solders but still seeing this.

BTW, can I use a 250mA fuse instead of a 160mA? They're easier to find around here.

Thanks,
Rafael
You need to check from card edge connector pin-15 to pin-5. Make sure the 48V rail is not shorted. 250mA can work in a pinch but I don't think we can recommend it long term.
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rafael-sf

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #472 on: July 25, 2018, 04:27:02 PM »
You need to check from card edge connector pin-15 to pin-5. Make sure the 48V rail is not shorted. 250mA can work in a pinch but I don't think we can recommend it long term.

Sorry, that's what I meant. I see the same behavior when measuring pin 15 and 5 on the edge connectors. But I don't see anything on the board that would cause this. Any idea what could be doing it? Desoldering some of these things will take forever.

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #473 on: July 25, 2018, 04:39:15 PM »
is there a reason I have r240 and not 243?

[silent:arts]

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #474 on: July 25, 2018, 04:56:00 PM »
is there a reason I have r240 and not 243?
240R or 243R - doesn‘t matter  (but need to be in the right place on the PCB)

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #475 on: July 25, 2018, 07:18:50 PM »
Sorry, that's what I meant. I see the same behavior when measuring pin 15 and 5 on the edge connectors....
You measure a direct short between those card edge pins 5 and 15? With the PSU cable disconnected from the rack?
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rafael-sf

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #476 on: July 25, 2018, 07:28:04 PM »
You measure a direct short between those card edge pins 5 and 15? With the PSU cable disconnected from the rack?

Not a zero resistance short, it looks like the short is going through a capacitor (resistance climbs as I start measuring it).

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #477 on: July 25, 2018, 07:38:08 PM »
For the 5pin xlrs for VPR, numbers on the cable leads correspond to  xlr pin numbers? Or does green/yellow go to 1?

almost there. My corrections fixed problems, I was a little bit worried I wreck a couple of the PCB hole leads... but everything seems to be working, all LED lights are equal brightness and measurements then became 16.2 (adjusted to .7).


--
I  think I got it... Green/Yellow gets clipped as does 6, and then 1-5 leads goes to 1-5 pins, correct?
« Last Edit: July 25, 2018, 07:54:57 PM by PetezaSlice »

rafael-sf

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #478 on: July 25, 2018, 08:00:55 PM »
For the 5pin xlrs for VPR, numbers on the cable leads correspond to  xlr pin numbers? Or does green/yellow go to 1?

almost there. My corrections fixed problems, I was a little bit worried I wreck a couple of the PCB hole leads... but everything seems to be working, all LED lights are equal brightness and measurements then became 16.2 (adjusted to .7).


--
I  think I got it... Green/Yellow gets clipped as does 6, and then 1-5 leads goes to 1-5 pins, correct?

Yes, just follow the table at the end of the assembly pdf.

jsteiger

Re: [BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread
« Reply #479 on: July 25, 2018, 10:54:13 PM »
Not a zero resistance short, it looks like the short is going through a capacitor (resistance climbs as I start measuring it).
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.
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