EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: Deepak on March 22, 2019, 12:21:40 am
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I picked up a Tek 492p that's about the same vintage as I am, and it seems to have some issues. I'm getting intermittent 'Error 60' messages, the trace seems to have a discontinuity it will either stop drawing halfway across the display (the peak/avg trace continues to make it) or there's a 2 or 3 division drop on the vertical scale depending on the setting I'm in.
https://i.imgur.com/7CHHNcM.jpg
https://i.imgur.com/2atUvJN.jpg
https://i.imgur.com/nIBkXss.jpg
The physical display is nice, with a strong beam, and the overall fit & finish is quite good. Opt 1, 2, and 3 are loaded.
I've pulled down the user manual as well as both service manuals and will be reading them tonight. The plan of attack is to pop the case this weekend, check the voltages, check all of the tantalum caps, then the rigid coax connections. 300 odd pages of replaceable parts sounds like fun.
This is my first spectrum analyzer so I don't really have any idea what I'm doing. Any traps for young players I should watch out for?
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Not necessarily related to the repair, but since you say this is your first SA, be sure to pay attention to the input capabilities. Some SAs cannot tolerate any DC level on the input. Others can tolerate some, just read the specs for yours. Inline DC blocks can help you out by ensuring AC coupling. If you're wanting to do something like look at your ham rig's key up characteristics, do not transmit directly into your SA. Use a sampling tee and a dummy load.
https://www.youtube.com/watch?v=E6P-R0C9ro0&t=458s (https://www.youtube.com/watch?v=E6P-R0C9ro0&t=458s)
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Not necessarily related to the repair, but since you say this is your first SA, be sure to pay attention to the input capabilities. Some SAs cannot tolerate any DC level on the input. Others can tolerate some, just read the specs for yours. Inline DC blocks can help you out by ensuring AC coupling. If you're wanting to do something like look at your ham rig's key up characteristics, do not transmit directly into your SA. Use a sampling tee and a dummy load.
Understood - there's a big red '0 V DC' marking right next to the input as well as a '+30 dBm max' warning that I'll try to be mindful of. I picked up a DC block which I plan to use until my beard is greyer and longer.
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Not necessarily related to the repair, but since you say this is your first SA, be sure to pay attention to the input capabilities. Some SAs cannot tolerate any DC level on the input. Others can tolerate some, just read the specs for yours. Inline DC blocks can help you out by ensuring AC coupling. If you're wanting to do something like look at your ham rig's key up characteristics, do not transmit directly into your SA. Use a sampling tee and a dummy load.
Understood - there's a big red '0 V DC' marking right next to the input as well as a '+30 dBm max' warning that I'll try to be mindful of. I picked up a DC block which I plan to use until my beard is greyer and longer.
There you go...I believe in many cases (at least with the HP SAs I'm familiar with) it will take +/- 7 Vdc without damage (despite the 0 Vdc warning), but personally, I try not to play with fire. :)
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Bumping this for the OP. Did you get a chance to pop it open yet?