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Old 10th Apr 2011, 3:06 pm   #1
n_r_muir
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Default Tektronix 545B vertical output amplifier

Hi,

I am repairing a Tektronix 545B and have traced the fault to a transistor in the cathode of one of the output valves. The transistor is marked with Tek part number 151-127. Can anyone tell me what the commercial equivalent is for this transistor or know what the operating parameters are?

thanks.

ross
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Old 10th Apr 2011, 3:14 pm   #2
oldticktock
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Default Re: Tektronix 545B vertical output amplifier

I found this

Tek Part Number...Type..Polarity.......Specs.......Equiv Part
151-0127-00........Si......NPN...........Selected....2N2369

on here
http://www.sphere.bc.ca/test/tekequiv.html

Info for 2N2369

on here
http://www.datasheetcatalog.org/data.../490431_DS.pdf

Like I know anything about such things, but I hope that might help
Chris

Last edited by oldticktock; 10th Apr 2011 at 3:21 pm.
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Old 10th Apr 2011, 7:09 pm   #3
n_r_muir
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Default Re: Tektronix 545B vertical output amplifier

Hi,


Thanks very much for the information, I now know what I need to get.

In the meantime I have found something in the junk box that works well enough for the time being but is not really good enough to give me the rise time that the scope is capable of.
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Old 10th Apr 2011, 7:57 pm   #4
ppppenguin
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Default Re: Tektronix 545B vertical output amplifier

The 2N2369 is a very common device for high speed switching and amplification. There are also plenty of other devices that use the same basic die, some in plastic packages though I can't recall any specific type numbers at present. Possibly ZTX314?

I don't know what Tek were selecting, possibly matched pairs to give good DC balance or possibly hFe to give low base current. I suggest you just get some 2N2369 or 2N2369A or other similar devices and try them. The results should be pretty good. I vey much doubt if Tek were selecting for HF characteristics so if you still have poor risetime after fitting a replacement then the problem lies elsewhere. Unless you have a very good test generator it is actually very tricky to get a decent risetime measurement.
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Old 12th Apr 2011, 12:20 pm   #5
John_BS
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Default Re: Tektronix 545B vertical output amplifier

Quote:
Originally Posted by n_r_muir View Post
Hi,


Thanks very much for the information, I now know what I need to get.

In the meantime I have found something in the junk box that works well enough for the time being but is not really good enough to give me the rise time that the scope is capable of.
I can send you a 2369 if you need one. Postage only.

John
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Old 14th Apr 2011, 7:15 pm   #6
n_r_muir
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Thumbs up Re: Tektronix 545B vertical output amplifier

Hi John,


Thanks very much for sending me the transistor. It is really nice to see just how ready people are to help each other out on this forum.

thanks everybody

Ross
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