Author Topic: EEVblog HVP70 Differential Probe  (Read 29930 times)

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Online Dubbie

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Re: EEVblog HVP70 Differential Probe
« Reply #200 on: November 15, 2017, 12:51:08 PM »
Has anyone found any nicer probes for the thing?

I really don't like the ones that come with them. They are really hard to open up sometimes if you are in a tight space or funny angle.
 

Offline JonM

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Re: EEVblog HVP70 Differential Probe
« Reply #201 on: November 15, 2017, 04:34:27 PM »
Has anyone found any nicer probes for the thing?

I really don't like the ones that come with them. They are really hard to open up sometimes if you are in a tight space or funny angle.

probemaster.com has many choices for probe connections. For AC mains, I have a couple of banana to "big metal blade" that came with a Triplett wire tracer. I will probably keep them with my HVP-70 since I don't use the wire tracer very often.
 

Online Dubbie

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Re: EEVblog HVP70 Differential Probe
« Reply #202 on: November 15, 2017, 08:40:29 PM »
My favourite bench meter probes are probemaster so I did check out their site. They didn’t seem to have anything suitable.
 

Offline JonM

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Re: EEVblog HVP70 Differential Probe
« Reply #203 on: November 17, 2017, 09:17:52 AM »
My favourite bench meter probes are probemaster so I did check out their site. They didn’t seem to have anything suitable.

Upon further study it appears that I have only one Probemaster probe that fits the HVP-70 leads, and it it insulation piercing which may not be appropriate for HV work.

Because the HVP-70 leads do not have retractable sheaths (maybe a requirement of 1000V Cat III ?) only select probe adapter will work. In the photo, from the top:

 - "Big blade" mains probe from Triplett wire tracer
 - Big alligator clip marked 1000V Cat III, possibly from Fluke Scopemeter kit
 - The original HVP-70 probe, for reference
 - Minigrabber, probably from Franky: http://stores.ebay.com/99centhobbies
 - Probemaster 9174 Piercing Probe, marked 1000V Cat III

Looks like I may need a few more probes for the HVP-70.

 

Offline NiHaoMike

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Re: EEVblog HVP70 Differential Probe
« Reply #204 on: January 08, 2018, 10:13:37 AM »
I decided to finally do a teardown on mine and the build quality, while definitely not the worst I have seen, was nowhere as good as I was expecting. Three bodge wires that aren't even tacked down, a lot of other bodges, and poor soldering quality in general. There's also a trace routed under one of the switches such that tiny movements from use can cause it to short. The worst part is that I cannot touch it up (except the switch - very carefully bend the metal to give more clearance) because doing so will almost certainly affect the calibration.

Another odd part is that the chips were painted over in different colors. If it was to slow down reverse engineering, it was certainly ineffective since it only took a few minutes with a pocket knife to scrape it off and identify the important parts.

It looks like it uses basically two very well matched X100 attenuators with an impedance high enough to be considered isolated when used with mains voltage. It then goes to an AD8129, with a gain of 10, for the X10 mode and an AD8130, with unity gain, for the X100 mode. One switch selects which is used and a THS3061 drives the coax output. On the PSU side, there's a flyback converter with a very unusual transformer being driven by an unidentified chip with the markings 487D S18B. A common 393 drives the power LED.
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Offline bicycleguy

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Re: EEVblog HVP70 Differential Probe
« Reply #205 on: January 08, 2018, 12:31:52 PM »
NiHaoMike,

Wow, as you noted that looks surprisingly crapy.  I opened mine to see if the same but chickened out at the metal cans.  I really like the unit and didn't want to risk messing it up.

Up to that point it looked good although the tamper stickers were easily defeated, however, the solder joints I could see between the cans looked as dirty and cold soldered as your's.  I have gotten a little cocky about safety since I started using this but seeing your pictures will hopefully make me sober up.



 

Offline Hydron

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Re: EEVblog HVP70 Differential Probe
« Reply #206 on: January 08, 2018, 09:53:19 PM »
Thanks for the pictures, I was interested in how this probe was constructed. The use of the AD8130/29 is unsurprising, they fit the bill well for a diff-probe (I have played around myself using them in exactly the same way).

The J1 and J2 "bodge" wires are actually probably designed to be there (in order to make it possible to construct with a 2 layer PCB), rather than being hacked in afterwards. They are only being used to switch between the 2 input chips (go to the shutdown pins), so could definitely be tacked down without any change to calibration. I can't tell what the third wire does from your photo - is there any chance of getting a clearer, high-resolution picture of the top of the PCB?
 

Offline Zbig

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Re: EEVblog HVP70 Differential Probe
« Reply #207 on: January 09, 2018, 01:57:25 AM »
Kinda ironic, considering Dave's eagerness to point out any PCB's (or product's overall) quality issues or general nastiness on every occasion, in no uncertain terms. I definitely won't rush to drop my $350 (current Amazon list price) on one anytime soon, unless I need one badly. Well, that's the lack of competition at works, I guess...
 
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Online bitseeker

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Re: EEVblog HVP70 Differential Probe
« Reply #208 on: January 09, 2018, 08:32:22 AM »
Well, I guess Dave needs to take a look at the recent batch of them and open one up. If their QC has dropped, I'm sure he'll say something about it.

I haven't torn mine down, but now I'm getting curious.
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Offline TheSteve

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Re: EEVblog HVP70 Differential Probe
« Reply #209 on: January 09, 2018, 09:07:49 AM »
Hmmm, did Dave ever do a teardown on camera? It does look from the picture to be rather "how ya doing".
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Online bitseeker

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Re: EEVblog HVP70 Differential Probe
« Reply #210 on: January 09, 2018, 09:11:00 AM »
I don't recall, exactly. Might have been an actual Sapphire he took apart before?

Sent Dave a quick message to check out Mike's post. The forum is too big to keep track of everything.
« Last Edit: January 09, 2018, 09:13:21 AM by bitseeker »
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Offline The Soulman

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Re: EEVblog HVP70 Differential Probe
« Reply #211 on: January 09, 2018, 11:25:27 AM »
Construction quality and overall design of the Dave probe seems very similar to the lecroy (sapphire) from video 932.  :-\
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Offline EEVblog

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Re: EEVblog HVP70 Differential Probe
« Reply #212 on: January 09, 2018, 11:43:26 AM »
I don't recall, exactly. Might have been an actual Sapphire he took apart before?

Sapphire make all the probes, including this one, Lecroy, Keysight and many others, they all re-badge Sapphire.
 

Offline NiHaoMike

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Re: EEVblog HVP70 Differential Probe
« Reply #213 on: January 09, 2018, 07:03:00 PM »
Is anything being done to address the problem so that newer units will be built with better quality?
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