Power supply voltage:trouble shoot

Hi, Just got my kit and assembled the i/o board portion of the ps.
I get reading within spec on +15v and +5v but on -15v I am reading -17.2v(measured with two different meters to be sure)

Doubled checked all components going in, before and after solder.

Any suggestions? or should I continue with the build?

thanks for any help

Dear Ebbflo,

The negative regulator needs a slight load to begin regulating. Use a 2k7 ohm resistor between ground and -15v to check -15v.

Best regards,
e-licktronic

Thanks,
That is what I assumed but wanted to make sure. I am the guy that has the incomplete kit. I am sending pics now.
Best,
Neil

Hmm... Well I tried the resistor and it really did not knock it down by much. I went a head and built the noise and got the same readings on the "green dot" on u24. The trim pot will not trim down to 130mv after u24 soldered in either...

I've built kits before that behaved similarly and ended up fine when everything was in place but never built the yocto...

Thanks

ebbflo wrote:I went a head and built the noise and got the same readings on the "green dot" on u24. The trim pot will not trim down to 130mv after u24 soldered in either...

Hey Ebbflo,

Have a browse of this thread viewtopic.php?f=16&t=155 there is a lot of info about how to get the correct noise trimmer voltage.

lfo2vco wrote: viewtopic.php?f=16&t=155

Thanks, I have some 100k trimmers, so I think I will use that for the time.

e-licktronic wrote:Dear Ebbflo,

The negative regulator needs a slight load to begin regulating. Use a 2k7 ohm resistor between ground and -15v to check -15v.

Best regards,
e-licktronic

Atleast for me the 2,7k ohm resistor did the trick (Got -15.04V and +15.05 and +5.04). I have good 15 VAC 1,3A AC/AC Adapter: http://www.mascot.no/admin/common/getim ... ileID=1232

lfo2vco, your trimmer trick worked. I will probably just leave it in place...

thanks again,

When I measure voltage from power supply I get +15.05V, -16.30V and +5.04V and with 2,7k resistor i get -15.04 from the negative side.
Question is that is it ok that when I measure voltage from NOISE negative pin, I get the same -16.30V? Is the situation same that the regulator does not have enough load to start regulating?

ebbflo wrote:lfo2vco, your trimmer trick worked. I will probably just leave it in place...

Glad it helped. I decided to leave well alone and left the trimmer in place.