Hello,
The range bulb(s) 1x/10x (ch1) appears to be burned out. It looks like it is well buried under the switch. How much pain is it replace it and where can I get one. I might be tempted to replace it with LED and a resistor if I can get to it. Is that one bulb that has its light output steered or are there two? None of the pertinent positions on that channel light up.
Boris Mohar wrote in news: snipped-for-privacy@4ax.com:
you have to remove the vertical preamp board and attenuators to access those TWO lamps,a PITA. I definitely would consider LEDs and resistor in place of the lamps.I think you could get away with one resistor for both LEDs.
the original lamps had 50K hour lifetimes.
I think that you talked me out of it. Thanks.
BTW I just finished repairing the 307 modules.
-- Boris
Boris Mohar wrote in news: snipped-for-privacy@4ax.com:
I got pretty good at it while at TEK. I got to know what screws and shields to remove,and had a flex nutdriver for the nuts bolting the attenuator frame to the front casting. Of course,I didn't have the option of skipping the job... 8-)
Amazing that you could solder them at all,the plating/tinning on those ceramic substrates always seemed to vaporize under soldering heat. did you use ordinary solder,63/37?
I used 0.015" Kester 63/37 that contains organic water soluble flux. The flux is more aggressive that rosin flux. It is also conductive so everything has to be washed thoroughly. Having a Metcal soldering iron wit a tiny tip and stereo microscope made things rather easy. Time will tell.
-- Boris
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