EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Monolith on April 11, 2017, 01:19:32 pm
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I recently purchased a faulty Wavetek 395 Arb generator and found some time to investigate the fault. Device is responding well on front panel for all settings, but the output is heavily distorted. After removing the cover it is perfectly explainable why: Resistor R163 has been heavily toasted. Looks like the previous owner used this generator for inrush current measurements...
Can somebody identify this resistor R163? It's located near the output (see pic). Thanks in advance for this!
Kerry D. Wong made already a very nice review of this device last year: http://www.kerrywong.com/2016/06/26/wavetek-395-arbitrary-waveform-generator-teardown/ (http://www.kerrywong.com/2016/06/26/wavetek-395-arbitrary-waveform-generator-teardown/)
Unfortunately this resistor is not identifiable too in his pictures..
regards
Mono
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for comparison: output section of Kerry D. Wong's device:
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Don't know the box but wanted to point out R161 & R162 both look like they took some stress too... good luck with your fix.
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Just pulled mine out of the closet :)
Measurements didn't make much sense. Probably some components are affecting them.
R160 = 83.5 ohm (can't read the marking)
R159 = 83.5 ohm (301R) is 301 ohms
R163 = 83.5 ohm (150R) is 150 ohms
R161 = R162 = 75 ohms
From your picture it looks like R160 = 301 ohms
They are all 0.1% resistors
http://www.vishay.com/docs/31027/cmfmil.pdf (http://www.vishay.com/docs/31027/cmfmil.pdf)
They are Dale (now Vishay) Mil Spec resistors RN type
I hope this helps. :)
TTI wave generators look like the Waveteks. I think at one point they purchased them. FLuke has also some Wavetek looking function generators.
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@casinada: That's great! Thanks for looking! I did a temporary replacement with a 1% 150 Ohm resistor but still get the distorted waveform. I get an voltage offset and on sine wave mode i get only the upper half of the sine. So there is a good chance, that an active component is faulty too. Probing around i found many spots, where a correct waveform is present, so there is hope ...