EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: alan.bain on September 02, 2022, 08:36:04 am
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Hi,
My Tek 2230 (which arrived here not working and had a bit of work done on the PSUs, usual sort of age related capacitor stuff and typical pre-regulator/crowbar fault) has an interesting artefact when the digital display is on that a row of small dots appears at the top of the screen (circled in pink). Photo here in analog mode as that is usually the easiest to debug. Turning off the readout makes the dots at top vanish.
I cannot really figure out what this is supposed to be; clearly Z-modulation is working (since the text at bottom isn't joined up and high speed sampling mode produces a field of dots) so if the beam weren't wanted I'd expect it to be cut off by the grid. Can anyone with a 2230 confirm that this isn't normal behaviour?
They are great scopes, but not the easiest to work on due to the packed innards and a storage board which seems to get in the way wherever it might be... I never did find where they hid the astigmatism adjust pot!
Alan
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It points to the SRQ description above the display ;). It is not an error. For more details you probably need to read the manual (personally I will try GPIB section), but it can have more meanings.
edit: Operator manual page 7-7 https://download.tek.com/manual/2230_Operators.pdf (https://download.tek.com/manual/2230_Operators.pdf)
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I recommend to go through the manual if you are not familiar with that device. It has a lot of features available by simply pulling the knobs out or in. Digitization mode have also a lot of adjustments. If you are using it at 230V check the power input filtering caps (they are hidden below the socket). Mine had blown up and it was nasty smell.
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Thank you. That now makes much sense! I have been going through the operator's manual but didn't look in the GPIB section as I wasn't using that (yet!). I agree that the acquisition modes section is very complex and surprisingly powerful (given the age of the scope) and very useful.
When you fix a scope you have used for years then it is clear that it is working, but when you fix one that was dead on arrival it can be harder to know what is "good behaviour" as I've had to deal with a whole series of display artefacts caused by hardware errors. When using one of these for the first time in analog mode with readout the slight gaps in the traces can be perplexing (you thing of ALT/CHOP) but it is a known behaviour which can be confirmed by turning off readout.
The exploding RIFAs have been replaced (one exploded....)