Replacing Tektronix 465 range bulb

[Boris Mohar]

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.

 

[Jim Yanik]

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.

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.

 

[Boris Mohar]

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.
http://www.sphere.bc.ca/test/tek-parts/tekpots.html
At first I thought that it was the socket but it turned out that the pins
become intermittent at the ceramic substrate solder junction. The gain and
the frequency response was all over the place. I unplugged them, removed
the lids and resoldered the pins from inside. I used some rather aggressive
water soluble flux because rosin flux just would not work wit those pins.
Washed them out with lots of water. It is rock steady now.

 

[Jim Yanik]

I think that you talked me out of it. Thanks.

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...

BTW I just finished repairing the 307 modules.
http://www.sphere.bc.ca/test/tek-parts/tekpots.html
At first I thought that it was the socket but it turned out that the
pins become intermittent at the ceramic substrate solder junction. The
gain and the frequency response was all over the place. I unplugged
them, removed the lids and resoldered the pins from inside. I used
some rather aggressive water soluble flux because rosin flux just
would not work wit those pins. Washed them out with lots of water. It
is rock steady now.

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?

 

[Boris Mohar]

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...


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.