[sdiy] DC-DC converter problem

[mark verbos]

Solved!

It was the on/off pin. I had to suffer through desoldering 4 of these  
things, but once I cut that pin off everything started working fine.  
Thanks to whomever it was who suggested that should be floating and  
not tied high.

Mark





On Nov 16, 2009, at 2:26 PM, Barry Klein wrote:

> There are 3 variations of this regulator - each with unique input  
> voltage
> range.  Maybe you have a higher range part.  Hook a lab supply to  
> the input
> and play (while limiting input current).  Other than that, maybe  
> float the
> case?
>
> Barry
>
>
>
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tom Farrand
> Sent: Sunday, November 15, 2009 8:42 PM
> To: mark verbos
> Cc: Synth DIY
> Subject: Re: [sdiy] DC-DC converter problem
>
> It is possible the converter has a high inrush current.  That would
> potentially cause the 12V supply to go into fold-back current
> limiting.  Use an inrush limiter if Paul Perry's test resistor
> suggestion does not cause the 12V supply to cave.
>
> I recently put a DC-DC converter into a product and had such a
> problem.  The inrush current was listed by the (well known)
> manufacturer at 40A!  The supply only put out 800mA at less than 10
> watts of power.  The 40A figure stunned me.  Fortunately, I did catch
> that little "feature" before spinning a PCB.
>
> Peace.
> Tom Farrand
>
>
> On Sun, Nov 15, 2009 at 6:51 PM, mark verbos <mverbos at earthlink.net>  
> wrote:
>>
>> Hi there,
>>
>> Does anyone have experience using DC-DC converters? I have a couple  
>> Cincon
> CHB50 converters set up to take a 12 volt DC input and spit out +24,  
> +15, +5
> and -15. The outputs from the converters are fine, but the 12 volts  
> going in
> is dropping down to 6 volts even with nothing on the outputs. The  
> data sheet
> claims they use 50mA when not loaded. It happens the same on all 3  
> supplies
> I have here, so it must be something I'm doing with the converters.  
> I have
> the ON/OFF pin connected to the +input pin and nothing connected to  
> the trim
> and sense inputs. The case pins are grounded.
>>
>> suggestions? Thanks for any help.
>>
>> Mark
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy