About Me

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Santa Clarita, Ca, United States
I work as a Technology Manager in the Entertainment Industry. My first film was Disney's Dinosaur and have been credited on several films since. I love working on old electronics, especially old radios. I am also passionate about technology and education. I have 4 kids and you can read about us on our family blog.

Saturday, December 8, 2018

Precision Apparatus E-200C Signal Generator

I needed a signal generator for my repair bench and was considering purchasing one. There are many good options under $200 that can be considered.  However, my dad had several old ones in his collection  that were in unknown condition.  I chose this one as a project.



Overall, it's a pretty nice unit with a vernier dial and large display.  It also has 400Hz audio output for testing audio circuits.  It clearly was going to require some physical cleaning as well as some electrical repair.


The inside is well organized and easy to service.



I was able to find the manual on the Bama site : https://bama.edebris.com/manuals/paco/e200c/  It wasn't an exact match, but seemed reasonably close.

There did not appear to be consistent RF output.  I suspected the electrolytic filter capacitor and decided to swap it out. It was an interesting multi-section capacitor with the elements in series.


I created a similar setup with modern capacitors.  I used shrink tube to emulate the original color configuration. 


I could have left it like this, but I thought it would be nice to keep the original appearance.


I always enjoy the challenge of trying to maintain original appearances on equipment so I hollowed out the original cardboard shell and placed the new capacitors inside. 


 I tested all the tubes and they all tested new.  Some of the dials were flaky so I cleaned them all with electrical cleaner and that brought them all back to life. I then tested it out.  My desktop multimeter has a frequency counter so I hooked it up to the Signal Generator.  The 130Khz setting (inner circle on dial) shows 130Khz on the meter. Looks good!


 Should be a useful tool for future projects. The next step was to work out the leads. This device has an old style Amphenol 75 series microphone connector.

I'd have to make a choice, do I swap out the connectors for something modern (i.e. BNC connectors), or try to find the old style plug?  I decided to quest for the original style plug.  Found one at Surplus Sales.  It's an Amphenol 75-MC1F.  There were also some good options on Ebay.  I was able to build a cable.


I then ran it through its paces with the cable in play testing from 90-200Khz. I would test more, but my tester only goes up to 200Khz. (200 Kilocycles).