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Replacement Fan for Tektronix 2230 Oscilloscope

bcar11559

Oct 31, 2011
2
Joined
Oct 31, 2011
Messages
2
Folks,

I recently acquired a second hand Tektronix 2230 'scope. It powers up fine and reports no errors, the sound of the scope starts with a very high pitched whine and reduces after about fifteen minutes to around about the ambient sound of a TV CRT. I notice that the fan does not run continuously, in fact it doesn't run at all. The oscilloscope also makes a periodic knocking sound, about 2 beats per second. After approx. 30 mins. the scope will turn itself off. After about 5 mins you can turn it back on.

I took apart the scope and removed the fan. The fan turns freely but there is more friction than I imagined there would be. The fan is a 12 V DC Buhler 69-11-52, it has four terminations marked 0,1,2,3. The service manual quotes B9965EPL as the part number.

It is fed by another component also by Buhler, this has no part number marked and I was unsuccessful finding it mentioned in the sevice manual. It has 6 terminations, four to the fan and two from the power supply PCB board.

The thermal shutdown board has a pin soldered into it at one end which is designed to make physical contact with the metal chassis of the cooling fan. when everything is in place.

I can post photos tomorrow, my camera is not here with me today.

I have a few questions that I hope some people may know the answer to:

1) Should the fan run constantly when on?
2) What do you think, would this be a PWM controlled fan?
3) What could I replace the fan with?
4) What do people think about the chassis making contact with the thermal board, how would I emulate that with the replacement, any ideas?

I would be most grateful if anybody could help me with this.
 

shiekh

Oct 11, 2010
77
Joined
Oct 11, 2010
Messages
77
I often add a drop or two of engine oil to fan bearings; can free up even fans that don't spin.
 

MattyMatt

Mar 24, 2011
161
Joined
Mar 24, 2011
Messages
161
Well I can say that there are several places you can ask in addition to here, there is a yahoo group called TekScopes, I joined when I had a problem with my recently acquired 475A there were some good responses from there, and excellent ones from here. It may be a good idea to join that group as well :).

Now, my knowledge is limited, but I can tell you that my scope varies the fan speed based off the intensity I set for the trace, it does run all the time, but when I turn up the intensity the fan spins faster.

As far as the chassis making contact with the thermal board, it may be normal, it wouldn't be the first time I've seen it, but that was in other circumstances... not with a scope. I'll do a little digging around I may have a couple resources.

Good luck,
Matt-
 
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