[time-nuts] PRS10 Lamp Module Needed

brucekareen at aol.com brucekareen at aol.com
Wed Aug 13 10:21:44 EDT 2014


Vasco,

As Brooke said it is unlikely there are spare PRS10 lamp modules found outside the manufacturer.  The probable reason is that when the PRS10 units are assembled certain adjustments to the firmware are necessary such as the starting level and final bias of the FET oscillator transistor.  As far as I know, SRS has not revealed how to access to these factory settings.

It might be possible to repair your lamp assembly.  One point of failure is the Tantalum capacitor found in the lamp assembly.  Another possibility is that the heater resistor may have changed value or opened.  Although it looks daunting, it is possible to replace the FET power transistor; however, after replacing the transistor in one unit, I found the transistor's characteristics were a little different than the original and the operating parameters were not right.  I considered adding some external resistors to shift the biasing, but finally decided to try another transistor with somewhat different characteristics.  But in this second try I damaged the board.

If the rubidium bulb assembly is suffering from old age, it might be possible to improve it with a heat gun as discussed on this listt several times in the past.  The bulb is cemented in place, but it might be possible to remove and replace it.

Bruce, KG6OJI



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