Tektronix 2432A noisy trace

[gerdy]

I have a TEK 2432A that works well, except for the trace(s) which are slightly noisy. This is as well on 1 of the channels as on on both channels, even if I ground the channel(s). Anyone having a clue where I have to start looking to repair this?

[TheDefpom]

Re-cap the power supply, I have done some videos on this unit.

Mine also had issues with Tantalum caps failing (because of the main power supply ripple getting excessive), so you may want to get onto that sooner rather than later.

A point to note, if you power it up without the cover on make sure you have a fan blowing air across the hybrid modules... you don't want them to overheat and blow up.

[Bud]

It looks normal to me.
@TheDefpom do you still have yours? Can you post a photo of yours traces?

[David Hess]

That looks about normal to me also, and reasonable for a 300 MHz bandwidth.  The 2400 series DSOs are known to be pretty noisy because of their design.

What does the noise look like at maximum sensitivity at the different bandwidth settings?

[TimFox]

How does the noisy trace change when you use the bandwidth-reduction switch?

[Bud]

These are hybrid scopes, there is digitization and multiplexing involved and part of the noise is because of digital artefacts. You can use averaging to smooth the trace but as it is it looks normal to me.

[David Hess]

These are hybrid scopes, there is digitization and multiplexing involved and part of the noise is because of digital artefacts. You can use averaging to smooth the trace but as it is it looks normal to me.

The 2400 series DSOs are not multiplexed.  In Tektronix terms they were "real time" with a separate sampler and acquisition record for each channel.  I do not remember if the digitizer is shared but it would not matter because it operates at low speed.

I am not sure what you mean by "hybrid".  They use hybrid circuits but these DSOs have no analog mode like the 22xx series.

[BradC]

I'm with everyone else. That looks pretty normal.

I did have a strange noise issue on my 2440 back in 2017 (it's archived on the Tekscopes2 list), but that was resolved by letting it warm up for a couple of hours and running an auto-cal.
That fault was characterised with extra noise on the Ch1 trace. Yours looks consistent on both and about what I normally see.