[volt-nuts] Power Designs Precision Power Supplies

Andreas Jahn Andreas_-_Jahn at t-online.de
Wed Apr 25 22:04:08 UTC 2012

At least the 2N-Types can be found:


For the rest: did you really read the type number or something like the 
datecode (TI0421)

With best regards


> I looked up the transistors in the 2020B and 5020 and half of them are 
> unobtanium.  By chance, does anyone have the specs of these?  I've tried 
> the web based resources and located 2 transistor specs, and were barely 
> readable.
> Transistors:
> FS1700E
> 2N2219A
> IR4230
> TI0421
> FS2270B
> MS1700G
> FS1075
> 2N5416
> Does anyone know what these voltage references where?
> Voltage References
> A65555-1
> A65555-2
> A65555-3
> At 03:40 PM 4/23/2012, Dave M wrote:
>>I used to repair and calibrate lots of Power Designs supplies back in the 
>>late 60s and early 70s.  They were always top-notch supplies, very low 
>>noise & ripple, and seldom failed.
>>For instance, the ripple/noise spec for the model 5015 was < 250uV RMS. 
>>amd stability was 0.01% +5mV per 8 hours.
>>The model 2020 precision supply ripple/noise was 100uV P-P, and stability 
>>was 0.001% + 100uV per 8 hours.  Very nice supplies.
>>I have several of the PDI supplies in my shop, and use them often.  They 
>>are excellent supplies.  I love the constant current mode on them; that 
>>feature has saved more than one project from going up in flames.
>>I have a model C500 (0-100V/0.5V precision supply) that needs repair.  The 
>>reference assy is bad; haven't had time to get into it.
>>If you need manuals, I have PDF copies of a few models, (mainly models 
>>that I have in my shop).  Post your interests and if I have the manual, 
>>I'll send it to you.
>>Dave M
>>A woman has the last word in any argument. Anything a man says after that 
>>is the beginning of a  newargument.
>>volt-nuts mailing list -- volt-nuts at febo.com
>>To unsubscribe, go to 
>>and follow the instructions there.
> Sincerely,
> Marv Gozum
> Philadelphia, PA
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