Products > Test Equipment
Tektronix MDO3014 failure, MDO3000 series
kcbrown:
--- Quote from: GridWork on March 23, 2021, 12:23:40 pm ---The scope is still back at Tektronix, repairs are being finalized. The end damage was they are replacing the front panel board (I think) for $600, plus another $600 for Calibration (this one is required for any equipment going back) plus the cost of shipping. Half of what was originally quoted, which I can live with even though it makes me grumpy.
<Insert Grumpy_Cat meme>
--- End quote ---
Normally I would have thought you might want to get a parts unit and perform the replacement from that, but EBay doesn't seem to have any such thing and the used units are generally up in the $5k range from what I can tell. So considering that, $1200 doesn't seem terrible.
--- Quote ---I think that the speed things are moving is very much dependent on the times, capacity everywhere seems to be reduced.
--- End quote ---
Yeah, it's not unexpected given the way the virus has been handled.
Howardlong:
FWIW, my MDO3014 has started randomly hanging or resetting at boot time over the past few weeks. Occasionally the only way to get it to boot is to pull the AC out, let the caps drain (turn on with the AC unconnected speeds this up).
I hadn't used it for quite some time, maybe a couple of years, but occasionally it has the odd feature that is useful and unique on my second bench such as MagniView.
I've had it for about 8 or 9 years from new, and it's only done 546 power cycles. Typically it's lived in its Tek carrying bag for most of its life in a dry inside storage room.
Once it's up, now it'll stay working perfectly for hours until I finish for the day, but when the problem first started happening it did hang or boot two or three times while in active use. Restoring a setup or setting default setup would do this.
Anecdotally, there is a strong correlation between the hanging and the relays clicking away.
Also anecdotally, it seems to be getting better rather than worse (touch wood, cross fingers etc).
My hypothesis at the moment is that the problem may be due to a relay getting stuck, and that active use has re-wetted the relay contacts.
The scope's self test and SPC run OK.
Howardlong:
--- Quote from: Howardlong on June 09, 2024, 10:07:51 pm ---Anecdotally, there is a strong correlation between the hanging and the relays clicking away.
Also anecdotally, it seems to be getting better rather than worse (touch wood, cross fingers etc).
--- End quote ---
About three days ago the scope suddenly completely crashed again while using it, and it failed to ever successfully reboot, stopping at various times during the boot process. After at least half a dozen attempts to get it to boot (turn it off & on, pull the AC cord for a while to let the caps discharge etc), I gave up and put it away in the cupboard to look at later.
A day later, with a view to repairing it, I pulled it back out of the cupboard, and it booted fine. It ran a couple of dozen self-tests fine too. However I noticed that the relays don't click when running a self test. Furthermore, if I set up a semi-complex setup to save in an effort to get the relays clicking, apart from setting the 50/75 ohm termination on a channel, the relays won't click... unless you have the TPP analogue probes plugged in. When doing the self test, you are directed to remove all probes, so the relays aren't cycled.
I plugged the probes back in, and I haven't been able get it to fail again after 1.5 days of solid use.
I now have a new hypothesis... the TekVPI smart probe interface is suffering intermittent connections, leading to a 1-wire comms failure, thus rebooting or crashing the scope. (Previous analysis of these TPP probes show they use a 1-wire solution).
So the next time I get a failure and it won't restart, I'll try rebooting with the probes disconnected.
Howardlong:
--- Quote from: Howardlong on June 16, 2024, 11:23:03 am ---
--- Quote from: Howardlong on June 09, 2024, 10:07:51 pm ---Anecdotally, there is a strong correlation between the hanging and the relays clicking away.
...
--- End quote ---
About three days ago the scope suddenly completely crashed again while using it, and it failed to ever successfully reboot
...
I plugged the probes back in, and I haven't been able get it to fail again after 1.5 days of solid use.
I now have a new hypothesis... the TekVPI smart probe interface is suffering intermittent connections, leading to a 1-wire comms failure, thus rebooting or crashing the scope.
--- End quote ---
I've been using the scope daily for further 8 days, and (cross fingers, touch wood) it's worked flawlessly.
Unless it fails again, I'm going to put this down to dirty contacts & intermittent connections on the TekVPI probe connections causing a 1-wire timeout, crashing the scope. This correlates to the failures seemingly coinciding with when the relays on the input attenuator start clicking away.
So my advice is, if your MDO3000 starts hanging or crashing randomly, either at boot or while in use, the first step is to remove the probes and see if it works.
My unit had been in storage room for many months with the probes removed, so although it was stored inside its Tek bag with its front panel cover on, it's quite conceivable that the TekVPI connections had become a little tarnished, or one or more of the the TPP probes' pogo pin for 1-wire became similarly dirty. I haven't (yet) cleaned the connections, although that will probably be a next step if these problems recur.
When on the bench, typically it's set up for days if not weeks or months at a time with the same TPP probes left permanently connected, so it's a little strange this behaviour just suddenly started, but not beyond the realms of possibility.
stj:
interesting thread,
you should probably dump those 1wire devices and keep a note of their serial number and part id.
it's a bit lame though that a 1wire device-search failure didnt just result in a probe message on the screen!
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