[[silent:arts]]

For 115V they are wired in parallel, for 230V in series.

[zqone537]

Ok but in what orientation? I'm doing 230v.  Does it matter which pair I use first? Does the pair closeset to the ground wire go first?  Does yellow go to 1 or 1A? Sorry but When it comes to DIY this is the first power supply I'm buliding.

[[silent:arts]]

I think I forgot to mail you the EU picture pack, sorry.

The two windings are identical, the order doesn't matter (but polarity, sense the yellow / white coding)
If in doubt make four stickers with the colors Jeffs transformer uses:  brown, violet, grey and blue.
Take one winding and stick brown to yellow, and violet to white.
Take the other winding and use the grey sticker for yellow, and the blue one for white.
Now you can follow Jeffs wiring instructions using his colors.

And look in your emails for some helpful photos.

[rachansky]

Ive had some issues with finicky modules in my rack and after doing some digging I have narrowed the issue down to my floor box power supply. 15 pin rack, 120v canada power.

The situation is that as I load modules in my -16v rail voltage drops significantly. (Unloaded I get a balanced 16.7V across both rails)

I've reflowed solder and checked to make sure that the regulator wasn't installed too tightly but here is my scenario with 7 modules loaded (this is where the voltage really begins to drop off) and an output of approx. -14.5 V on the -16V rail, and +16.7V on the 16V rail

From the toroidal transformer into the board JP3-5&6  voltage =-2.72V
JP3 -7&8 are 11.67V
at the +16V regulator (starting on the side closest to the leds) voltages are 15, 21, and 23V respectively
 
at the -16V regulator (starting on the side closest to the leds) voltages are -1, 0 and 9V respectively
 
Beginnning inboard and working outboard ( I hope that makes sense) through c39 - c42 I have 11.6,  23.4, 23.4, 11.6, 11.6, 0, 0,
 11.6 (volts in all cases)

Beginning inboard and working outboard through c30 to c33 I have -2.72, 9, 9, -2.72, -14.5, -14.5, -2.72 again volts in all cases.

I'm really hoping this info is enough to give me some direction here. If not I may just bow out and buy another power supply.

[jsteiger]

I know you bought this 2nd hand and it is DIY so I would expect there were build issues/errors made by whomever built it. I would check the value of all resistors and every component. At this point, I would not trust the work that was done. Maybe a regulator was replaced by something not well suited for this PSU?

You can start with no load on the PSU and measure ACV at the secondary of the toroidal transformer.

[rachansky]

Starting from the outboard in pairs 19.13V(red wire) 12.57V(yellow wire) -4.24V (green) 36.83V (white) and 2.843 (orange)

Thanks very much for your time with this Jeff. I have already gone over the BOM to the best of my ability to check the placements.

[jsteiger]

Starting from the outboard in pairs 19.13V(red wire) 12.57V(yellow wire) -4.24V (green) 36.83V (white) and 2.843 (orange)

Thanks very much for your time with this Jeff. I have already gone over the BOM to the best of my ability to check the placements.

The ACV at the secondary are not referenced to ground. Make sure your DMM is set to ACV and then probe between the color pairs. Red to red, orange to orange etc.

[rachansky]

Oh mother....

OB to IB again 29.2, 19.5, 19.5, 55.5, 29.2

[jsteiger]

Oh mother....

OB to IB again 29.2, 19.5, 19.5, 55.5, 29.2

OK so you have the 51x PSU. The 48V leads are white not black.

These numbers are all solid and correct. I would imagine that its a problem downstream. I would suggest following the flow thru the schematic. After the bridge rectifiers it will be DCV referenced to the 0V star ground lug.

[rachansky]

So comparing the +16v and -16v areas with no load give me the following data:

+16v area:
C39 12.56V / 25.3V
C40 25.3V / 12.56V
C41 12.56V / 0V
C42 0V / 12.56V

IC5 PINS (starting from the +ve lead)
15.74V , 21V , 23V

-16V AREA

C30 -4.24V / +8.37V
C31 +8.37V / -4.23V
C32 -4.21V / -16.92V
C33 -16.95V / -4.20 V

IC4 PINS (starting from the +ve lead)
1.25V, 0V, 8.36V

CR7, CR8, R12 and R13 read identical to CR9, CR10, R14 and R15.

IC4 seems to be the contributing factor to me but I am interested in your opinion Jeff, hopefully I'm not driving you nuts just yet!

[jsteiger]

The results around the regulator seem very odd. Not sure how you could have -16V in the rack with no load. Have you verified that IC4 is the regulator that we spec? I think It's worth replacing that.

[rachansky]

Thanks Jeff I'll let you know how it turns out!

[rachansky]

I am a bit of an insomniac so I started disassembling the psu and found that the O.G. builder did indeed install the ICs incorrectly. He had IC1 and IC4 mixed up. I only wish my eyes were good enough to see that earlier! Pain in the butt for removals and reinstall but its alive!

This likely explains why I was having issues with phantom power on my 1073lb as well. Anyway loaded up the rack and the voltages move less than 0.1V with 11 units installed. Too tired now to try the problem modules but I am looking forward to the final tests tomorrow.

Thanks for the support Jeff Steiger!
 

[jsteiger]

I am a bit of an insomniac so I started disassembling the psu and found that the O.G. builder did indeed install the ICs incorrectly. He had IC1 and IC4 mixed up. I only wish my eyes were good enough to see that earlier! Pain in the butt for removals and reinstall but its alive!

This likely explains why I was having issues with phantom power on my 1073lb as well. Anyway loaded up the rack and the voltages move less than 0.1V with 11 units installed. Too tired now to try the problem modules but I am looking forward to the final tests tomorrow.

Thanks for the support Jeff Steiger!

Excellent! Sometimes its hard to imagine all the ways something can be screwed up! Glad you found it. Now get some sleep.

[rachansky]

Ok all my units are working as they should. Now please clarify for me as I have read what feels like contradictory notes in this thread.

Am I able to add another vpr rack with this psu?

[jsteiger]

Ok all my units are working as they should. Now please clarify for me as I have read what feels like contradictory notes in this thread.

Am I able to add another vpr rack with this psu?

It seems as though you have the 51x Floor Box? That will run one full rack on +/-16V and one full rack on +/-24V. So adding another VPR only rack would NOT be advised. You could change the transformer to the dual VPR version. It would also require changing 4 resistors on the PCB.

[rachansky]

Is there a breakdown of this mod posted somewhere? If possible  shoot me a link please!

Again thanks for the support.

[jsteiger]

Its not really a mod per se. The FB PSU can be built 2 different ways. The resistors values and part labels are shown on the BOM.

[rachansky]

One more thing monsieur Steiger! I see that you have the rack kits back in stock, I am unable to add a faceplate for the dual vpr box to my order unfortunately. Do you ever make exceptions to this? I would like to keep it 100% on the level. I'll even ship back my DIY one if you liken

[jsteiger]

One more thing monsieur Steiger! I see that you have the rack kits back in stock, I am unable to add a faceplate for the dual vpr box to my order unfortunately. Do you ever make exceptions to this? I would like to keep it 100% on the level. I'll even ship back my DIY one if you liken

Yeah man. I saw your email this AM but have been too busy to reply.

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