Tektronix 2901

[Docholiday]

Does anybody know where and part number for the neon power lamp indicator and the power switch too?

Thank you,

Nicholas

[Alex Eisenhut]

I can look into it, but they are probably Dialco lightbulbs, incandescent on my 2901.

They are like "grain of wheat" bulbs with a moulded plastic lens on top. The colored lens/bulb unscrews from the base.

[Docholiday]

That would help me! Thank you.

[Alex Eisenhut]

This is the thingy I mean, my plastic lens cap broke off years ago.

[Docholiday]

That is exactly what I need! Now where to find one? Or perhaps a subsitution? Can you check the voltsge on it?

[SeanB]

They will be 5V 50mA lamps, so you can replace them with a LED and a series resistor in those places where it is fed with a constant voltage, and with a shunt resistor added in those places where they are in series and driven with a current. Tip for the LED is to use a red or orange LED for those with red or orange caps, and green for the green caps, with white for clear ( or choose a LED colour) and run them at under 5mA, otherwise they will be too bright.

I used to replace a lot of soldered in dial illumination lamps, so still have a small box of the assorted grain of wheat lamps around, in 5V, 12V and 28V varieties. As it is a mixed box I test before using, using a variable supply and a 10R resistor.

If you really cannot get one you can transplant a LED and a 1/8W resistor into those little lamp units after taking the glass out. difficult, but doable using a very small 3mm LED.

[Alex Eisenhut]

That is exactly what I need! Now where to find one? Or perhaps a subsitution? Can you check the voltsge on it?

Patience, grasshopper. I'm pretty good at finding parts, but even I need to break for lunch sometimes...

It's gonna be a tough one, since these old companies no longer exist. You can try to fit a LED in there. I did that with a 191, but it's bigger.

I measure 3.3V DC at the bulb with a meter.

[Alex Eisenhut]

tek p/n 150-0045-00

http://sphere.bc.ca/test/tek-parts/tekleds.html

no pic though, email Sphere.

[Docholiday]

Thank you so much Alex and Sean! I am on my way to restoring this 2901. One last item is the power toggle switch. I just started to look for one but having a hard time finding one that small.nif you hapoen to know where let me know.

Again Thank You for your help and taking your valuable time for me Alex and Sean.

Sincerely,

Nicholas