Low frequency distortion is likely a capacitor failure.? First check
the power supply ripple, then the electrolytics in the feedback
signal path, then the main signal path.? I would start with A2C3,
2900uf, as it is only in circuit on the low range and is part of the
level feedback signal.? Next, A2C5 and A2C11, A2C13, etc.
Dave
On 10/9/2017 1:57 PM,
krizhz@...
[hp_agilent_equipment] wrote:
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Hi Alan Bill and Dennis. Thank you for your helpful
replies.Unfortunately, the attenuator switch is not similar to the
HP652a, it's a double 16 pole 10 way (balanced with 1 dB and 10 dB
steps). Today I've tried various cleaners and I think the problem
was old switch lubricant that had hardened. After soaking it in
Electrolube, and spraying it with a strong detergent (Power Force
kitchen cleaner) it was rinsed with boiling water. Now, after
drying, it looks good. The only problem is that? the waveform is
distorted when the frequency is below 50 Hz.
