[ted betley]

Tried adjusting pot 3 or 4 turns still read 0 volts. Any ideas on what to check?

I'm getting 16 volts ac out of transformers but 0 volts on other end.

 

[BrianDonegan]

It would probably be better to cover these issues on our support forum.

 

[boinger]

Quote:

Originally Posted by BrianDonegan /img/forum/go_quote.gif It could just be a bad trimmer pot. I can send a replacement. You can check with a multi-meter to see if you are getting and variation in resistance while turning it. Alternatively, it could be a bad/cold solder joint or a reversed diode.

upon your suggestions i carefully inspected the board against the layout and I did manage to reverse D4

Although I am going out of town tommorow so I will have to fix this when I come back. Will keep you guys updated.

 

[qusp]

are the pots on the power supplies isolated?? ie. can I adjust them with a metal handled screwdriver while they are drawing current?? or is it a matter of adjusting a quarter turn at a time power-up, test across +->ground, shut off power, wait for the power caps to discharge, rinse, repeat until the right voltage is found??

 

[johnwmclean]

Adjusting the pots whilst current is running with a screwdriver is the only way you’ll get exact measurements, if your worried insulate the screw driver with tape so only the tip pokes out - in case you should brush against something you shouldn’t, the pot screws are isolated from current.

 

[johnwmclean]

My enclosure,

Currently like this:

http://i30.tinypic.com/15wml9u.jpg

going into this:

http://i26.tinypic.com/ws2obb.jpg

http://i28.tinypic.com/2zjckgg.jpg

http://i30.tinypic.com/sb0l1l.jpg

http://i30.tinypic.com/t6a2p3.jpg

 

[aloksatoor]

@john very clean build... congrats

 

[Lil' Knight]

Very impressive case, John!

 

[qusp]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif Adjusting the pots whilst current is running with a screwdriver is the only way you’ll get exact measurements, if your worried insulate the screw driver with tape so only the tip pokes out - in case you should brush against something you shouldn’t, the pot screws are isolated from current.

yeah I figured they would be, but all the same I found myself wearing rubber gloves and doing the adjustments with them sitting on top of a plastic washing machine lid

before I saw this reply and checked the net for info, I did actually manage to match one of the LCBPS at 13v by turning a bit, then turning off power and repeating until matched

so its possible, but time consuming

turns oiut I did in fact kill the inductor as I feared when desoldering it, the other rail is fine though.

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif My enclosure, Currently like this: http://i30.tinypic.com/15wml9u.jpg going into this: http://i26.tinypic.com/ws2obb.jpg http://i28.tinypic.com/2zjckgg.jpg http://i30.tinypic.com/sb0l1l.jpg http://i30.tinypic.com/t6a2p3.jpg

nice work mate; i'm getting there too, had a couple of speedbumps, but its all good. soon as I get this bloody case sorted out i'll be able to get it all together.

 

[johnwmclean]

Quote:

Originally Posted by qusp /img/forum/go_quote.gif I did actually manage to match one of the LCBPS at 13v by turning a bit, then turning off power and repeating until matched so its possible, but time consuming

Congrats for your patience, even with a DDM and two probes it took me quite a while. Why 13v? Should it not be 15V, are you doing something different?

 

[qusp]

Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif Congrats for your patience, even with a DDM and two probes it took me quite a while. Why 13v? Should it not be 15V, are you doing something different?

yeah it took a bit of patience, the manual specs range between 12-15v, so I tried 13v to start with, if I can chew a little less power with good results all well and good. I can always pump it up a notch if needed.

 

[johnwmclean]

Quote:

Originally Posted by qusp /img/forum/go_quote.gif yeah it took a bit of patience, the manual specs range between 12-15v, so I tried 13v to start with, if I can chew a little less power with good results all well and good. I can always pump it up a notch if needed.

In the manual I can only see a ±15VDC spec for running the analog section.

 

[qusp]

huh; wonder where I saw that then; was definitely in the twisted pear stuff. gonna go search that out now and see

edit: its on the buff32 page noit in the manual



Quote:

Originally Posted by twisted pear The Buffalo module requires two power supplies. The digital section requires 5-7.5VDC and the two analog I/V sections require a ±12 to ±15VDC supply. We offer a combination of the Buffalo32s and our Low Current Dual Power Supply (LCDPS) and Low Current Bi-Polar Power Supply (LCBPS) below. Each supply requires it's own separate transformer. We recomend a 2 x 6-9V(15VA) transformer for the digital section and a 15V+15V (15VA or greater) transformer for the analog I/V sections. Suitable transformers are available here.

 

[DoYouRight]

I wonder if matching cases for B22 and Buffalo is necessary...

I have bought a few enclosures, but keep on changing my mind. I see stuff like dacs smaller and I cant make up my mind, very difficult. When its done its done, I dont want to unsolder everything.

 

[soloz2]

that would be personal preference.