[time-nuts] Repair of PRS10 Lamp Assembly
"Dr. Götz Romahn"
goetz at g-romahn.de
Sun Mar 17 16:50:42 EDT 2013
thank you for fast responses. As I wrote in my posting, heating seems to
be ok as reported by the PRS10 diagnostic tools. I agree with Bob and
Paul: RF seems to degrade with warming up, but how can I test this.
Remember, lamp and oscillator of PRS10 are not!!! accessible during
operation and what part of hte oscillator could be the culprit ( and why
do you think it is) ?
Am 17.03.2013 20:59, :
> My 2 cents and it is that. The FRS use a higher voltage say 24 V and on
> ignition that drops back. I have also seen on time-nuts older systems that
> actually use an ignition voltage to trigger the lamp.
> But I agree that it sounds like the RF might be low. The bulb does need to
> be heated to get to the right color temperature also.
> On Sun, Mar 17, 2013 at 9:03 AM, Bob Camp <lists at rtty.us> wrote:
>> Unless the PRS10 is very unusual in it's operation there are two things to
>> check early in the debug process:
>> 1) Is the oven heating up to roughly the right temperature?
>> 2) The lamp is lit by RF energy. If the oscillator / amplifier supplying
>> the RF isn't putting out as much as it should (or what it should) the lamp
>> will not stay lit.
>> I'd bet on number 2 in your case. There are many other possibilities, but
>> I'd check those two first.
>> On Mar 17, 2013, at 5:22 AM, Dr. Götz Romahn <goetz at g-romahn.de> wrote:
>>> dear all,
>>> beeing a silent reader of this list for a while, I now ask my first
>>> I have obtained a PRS10 that was declared faulty and it is. The problem
>> I located in lamp assy.
>>> Lamp ignites only after warming up and pushing by a voltage kick from
>> abt. 24V to abt 28V on the -24_heat line for some seconds. PRS10 gets
>> locked there after and rbmon shows a seemingly healthy unit (see
>> attachment). But... within some 15 to 45 minutes later light from lamp
>> degrades as seen through "LAMP VIEW" hole in top board as well as AD9
>> Photocell I/V going down from 1.68 after ignition to 0.158 and lock is lost
>> of course. Since all heating and voltage diagnostics do stay within
>> accepted limits I suspect some problem within lamp enclosure (see
>> attachment). Your help for further diagnosis and any hints for obtaining
>> spare parts would be appreciated very much.
>>> Cheers Goetz
>>> <PRS10 after
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to
>>> and follow the instructions there.
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> and follow the instructions there.
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
More information about the time-nuts