HP 34702A Restoration and Repair
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- Опубліковано 11 вер 2024
- A huge thank you again for all that continue to Join us in the lab for repairs and alignments. The channel would not exist with out all of you so thank you again for dropping by!
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In this video we take a look at a equipment haul that we acquired recently. We have neet little HP 34702A DMM. This one needs a bit of help but we should be able to get some things moving. This meter if repairable is destined for a work bench that services UPS units and batteries. It will be used to monitor the voltages of batteries during load testing of the battery stacks.
** Repair exposes the Tech to mains electric and should only be done by trained personnel. Errors can be fatal. **
That's a cool series of instruments by HP. Meant to be more cost effective.
Strange how we have gone form "Remove this screw to open" to "Just toss it in a landfill".
wow and zamzam water
I’m currently working on a 34702A myself. Not happy with the linearity of the 10V DC (or higher) range(s) after calibration. Would be interesting to see the results of another 34702A calibration. I’m not even able to calibrate all the AC ranges at this time. Suspecting leakage currents.
I am waiting on the NP caps to come in then plan on doing a video on the calibration process. So more is on the way!
Well Curious Marc he isn’t.
A very unsatisfying video to watch. Specifically, for a 'restoration and repair' video, too much of the important detail is left out. And some of your nomenclature is well off.
The top half, isn't a DMM it's a meter. Not multi. 1:03
Those aren't full dot matrix displays, the are more like seven-segment displays. 2:07 Perhaps a fuller explanation of the operation of the display and its driver would have been helpful, especially given that that was where some of the problems lay.
At 5:34 you allude to interesting heatsinks and then don't show them.
You test the electrolytic capacitors at around 8:19, but don't zoom in on the tester for viewers to see. Frustrating.
At 10:20 you conclude there's a problem in the 'top unit' without explaining why or how you reached that conclusion.
At 11:30 we see some noise on the 'scope, but it isn't triggered and we can't see the vertical scale so it's pretty meaningless.
Lots of time to see an empty IC socket, but no footage of the test fixture where you were doing the testing of the 7474 ICs, or even what the tester might be.
It isn't clear to me why a floating power supply 12:29, would cause the 'scope a problem. Again a vague statement with no real explanation.
At 14:06 you start talking about specific signals on specific chips. But no sight of the schematic for us to understand the context of what you're saying and we're seeing. And, the view of the 'scope's screen is carefully obscured so we can't see what the settings are (which were on the bottom of the screen I would have hoped).
At 15:18 we see a chip that's quite the worse for wear, but we aren't allowed to know the part number or it's functionality. You call it the 'display driver' - is it the scanner or the character generator (HP's terms for the chips on A2)?
You 'have buffed the display' at 18:12 with no explanation of how, with what tools and/or products.
Thanks for the feed back there will be a follow up video to address some of these short comings.
Can't watch one more minute. This guys "speech" patterns are so annoy-YING ! He talks like he's auditioning for day-time TV commercial.