VC8145 thread ... It's here, finally

[T4P]

I'll post a preliminary picture first, i guess i got to do a teardown soon as i'm flying off to japan in a few days
But ... check out the built in temperature resolution!  (The thermocouple mode is entered by hitting "SELECT" and it goes to 0.1C resolution)

[Wytnucls]

Temperature to the 10th of of a degree...Whoa!...That will be real handy to keep the claret at the right temperature in that built-in wine cellar.

[videobruce]

Ok, there are 10 different pieces of equip. in that pic, which one is this VC8145?? 

[ciccio]

Does it measure dB?
I understand this reading the manufacturer's specifications, but they are absolutely NOT clear.
Does a forum member have a manual to share?
Thank

[alm]

The PDF manual is available from Aidetek:
http://www.aidetek.com/New_products_info/Photo/Vichy/VC8145_English_manual.pdf

It mentions dBm as a secondary function in AC/DCV mode with several choices of reference impedance. Unless you use it frequently, you might as well get out your calculator and calculate the dBm value from the voltage.

One thing I noticed in the manual is that the ACV accuracy is beyond terrible for values > 75% of each range: 8% of reading + 50 digits. Also note that ACV is only specified for frequencies >= 50 Hz.

[Rick]

Temperature to the 10th of of a degree...Whoa!...That will be real handy to keep the claret at the right temperature in that built-in wine cellar.

They could have made the box smaller, couldn't they?
Is it possible to fill that space with something useful for the multimeter?

[grenert]

Is it possible to fill that space with something useful for the multimeter?

You could tuck a Fluke 87V in there.

[david77]

What's the point of this meter?

[T4P]

Ok, there are 10 different pieces of equip. in that pic, which one is this VC8145??

The bench one 

So far i'm loving it, don't really like the boot time so much and not so much of the annoying startup sound, it's exactly like those nokia stock ringtones so annoying
But the built in square wave gen is pretty much quite accurate, down to 1% duty per step and yet it's very close except 90% onwards where it goes out nought-point-something percent

What's the point of this meter?

Bench? Don't need to worry about batteries when i'm logging to my PC neither do i need to worry about a backlight draining a battery (which i never had)

[Rick]

Is it possible to fill that space with something useful for the multimeter?

You could tuck a Fluke 87V in there.

Actually, when you think, it is better to buy a good brand new bench multimeter like that than buying a used Fluke or a HP 3478A from all sorts of crooks on ebay who never admit their device has some defect. And I notice people suffer to repair their old equipment. This is pathetic. I was planning to buy that VC8145 too but after they pointed out the inaccuracy in the AC range may be I shall go for the more expensive UNI-T UT805A with 5 1/2 digit resolution. After all it has also plenty of space in which I can tuck my Fluke 87V

[Rick]

Is it possible to fill that space with something useful for the multimeter?

You could tuck a Fluke 87V in there.

Seriously, I was thinking about some sort of hack or improvement...

[alm]

Actually, when you think, it is better to buy a good brand new bench multimeter like that than buying a used Fluke or a HP 3478A from all sorts of crooks on ebay who never admit their device has some defect.

I'm not so sure, if you call Vichy or Uni-T bench meters 'good'. Of course you might get a lemon HP/Fluke, but at least you know it was well designed and worked well at some point in time. The UI will be well thought out. The specs were probably much better, and many of the instruments are still in or close to the 1 year specs 10+ years after calibration. If it is still working after all this years, then it's unlikely to die anytime soon.

I wouldn't want to vouch for this meter being in spec right after being shipped from the factory. Depending on where you bought it (some shady outfit on eBay?) and where you live, warranty or returning may not turn out to be a useful option either.

[Rick]

All of the Chinese sellers I came across and bought items from turned out to be more or less good ones. When the items were defective I got at least a partial refund or a replacement was sent.
On the other hand when you receive a faulty product of a good brand it doesn't mean anything. You just lose your money.
I came across wonderfull sellers from USA but there are cheaters too. Especially those who sell used products. Fluke is a great brand, I agree as I have had the chance to try several of their handheld multimeters. But if the used product is defective and the seller does not tell the entire truth about his product, it doesn't mean anything. Now if someone wants to buy a new Fluke, that's great, but buying a used multimeter on ebay is not something I shall do again, just like I would not buy a used computer (I did it twice on the local market and in each case there was some defect).

[alm]

I'm not so much worried about a cheap DMM being outright defective, but more about it being unusable due to some stupid design issues. Sellers are less willing to give refunds for design flaws, and returning it is often quite expensive since shipping from at least Western countries to China is much more expensive than the other way around. Uni-T products have turned out to have a very variable quality, and I haven't heard of any good Vichy products yet. Opinions on the VC99 range from crap to OK for its price.

I have bought almost all of my test equipment used and have only had a few undisclosed defects that turned out to be fixable (all of the DMMs were fine and almost all were in spec). Of course I've had as-is/untested equipment that turned out to be defective. However, I'm not going to pretend to derive any odds from anecdotes.

With new equipment like this VC8145 you might either get an unusable piece of crap (ok, you might get a lunch box out of it) or a mediocre product. With a used HP 3478A you might either get a broken piece of equipment that may or may not be fixable or an excellent instrument. In both cases you might or might not be able to get a (partial) refund. Some Chinese ebay sellers are willing to give refunds for crap products, and some used equipment sellers also stand behind their products.

[Wytnucls]

Capacitance measurement accuracy is a joke, worthy of a 4,000 count meter only.
There is no cap discharge function, so you'd better make sure all caps are discharged before testing!
Also, I wonder how long it's going to last before the meter blows its mVolt range ADC:
What a P.O.S! 

[BravoV]

What's the point of this meter?

A benchtop meter with built in lunch box ? 

[Wytnucls]

Yes, all you have here is a mediocre 30.00$ DMM PCB, hooked up to an 8.00$ transformer, placed in a huge plastic box, selling for 140.00$. Vichy must be laughing all the way to the bank with this one. 

[T4P]

You came here just to knock the damn thing 
It's more than just 30$, it's not that SIMPLE god damn it
Do you have AutoHold with another chinese HH DMM? It works here for god's sake, DO YOU HAVE IT ON YOUR DMMs?
Mediocre? Does any of your meters have 10 digit frequency resolution? Rising edge duty cycle, falling edge duty cycle, rising edge time falling edge time so that you don't need a calculator on every reading! All covered. Oh how about 8Gohms capability?

Damn it, you guys came here just to knock it like SERIOUSLY?

[Rick]

... and returning it is often quite expensive since shipping from at least Western countries to China is much more expensive than the other way around.

Returning an item to USA from overseas is also very expensive believe me.
And they often set a 14 day return limit.
You may return it to the seller and not get a refund because of an equipment which arrives late at destination.
For people in USA it may be interesting to buy such multimeters or for those who sell in their own country like in Australia, UK, Germany, France or Netherlands.
When you buy a faulty equipment from USA and you live elsewhere it is always a pain to return it.

[alm]

Also, I wonder how long it's going to last before the meter blows its mVolt range ADC:

I don't understand this statement in the manual:

3.At millivoltage measurement mode in order to obtain DC+AC function , the input terminal o ADC do not employed coupling capacitor. Therefor please never apply more than double the dc or ac voltage of the rated value of this range.

Of course DC or DC+AC measurements are not AC coupled, and what does a coupling capacitor have to do with the maximum allowed AC voltage? Is this the result of the Engrish translation?

If the 80 mV range can only tolerate up to 160 mV, then this should be something to watch out for. Especially since the input is labeled just max. 1000 VDC / 750 VAC, CAT II 1000 V.

Mediocre? Does any of your meters have 10 digit frequency resolution?

Quantity of features does not equal quality. Admittedly your are probably the only one on this forum with access to this instrument, so the only information we have available is a few pictures and a crappy manual. According to the manual the 10 digit resolution is only for frequencies above 10 MHz with the high frequency accessory, is it included or do you have to pay extra? Too bad they didn't include a decent crystal oscillator time base, accuracy for frequency is only 0.05/0.1 % + 5 counts (so those other 5 digits are mostly for show). They don't have the power constraints of hand held DMMs.

Oh how about 8Gohms capability?

The manual just states larger than 80 Mohm. Do they specify accuracy anywhere? Interesting how the accuracy for the lower resistance ranges (0.3% + 5 counts) is much worse than DCV accuracy (0.05 + 5 counts for most of the ranges). On good meters these figures are usually quite close.

[T4P]

"High frequency accessory" 
Yeah i noticed the "Plus Adapter thing" Got to try it another time. i'll play with it another time and figure out the multiplier ratios

Of course this isn't a good meter by any shot but if you live in a country like mine you will not find a HP 3468 so easily (not that you would) or you have to pay shipping which costs about roughly how much a new VC8145 costs seriously stop comparing
Still has better accuracy than a UT61E  and of course bench DMMs don't come cheap in fact most of them of the same spec are considerably more expensive at least
Similar accuracy with a BK 2831E and yet wytnucls likes to knock it so much

Maybe when i tear it down i'll see if there's any oscillator module inside if there is, i'll hack in a better one (Or if it's a crystal ... Is it possible to hack in a osc module?)
You know what i really needed? AutoHold, i badly needed autohold without buying a fluke (110 series costs something like 200+$ here)

[nctnico]

Yes, all you have here is a mediocre 30.00$ DMM PCB, hooked up to an 8.00$ transformer, placed in a huge plastic box, selling for 140.00$. Vichy must be laughing all the way to the bank with this one. 

You could bash it as much as you want. I have one and I'm really happy with it. I actually prefer it over my HP3466A because of its features. It's accuracy isn't worse or better than similar instruments like the ones from BK Instruments. Besides that you won't find much benchtop multimeters capable of handling 20A with a backlit LCD display. There are loads of used HP and Fluke benchtop meters for sale on Ebay but their crappy LCD displays are hard to read and they can only handle a few amps.

@T4P: maybe you could use the min/max function as auto-hold.

[T4P]

Hold goes into autohold automatically ... 

[Wytnucls]

Slow auto-ranging too, perhaps?
https://www.eevblog.com/forum/reviews/question-about-vc8145-newbie/msg164949/#msg164949

[alm]

Yes, the unbacklit displays that Fluke used and HP used during mid to late eighties are annoying. I find the 7-segment LED displays much nicer than backlit LCD displays, though, because of their viewing angle. I don't care about the increased power usage for a bench meter, and I can live without an alphanumeric display or graphics. The more recent bench meters tend to use VFD, which is also nice.

Even many current bench meters don't go beyond 3A. Not sure what this is about. Maybe they don't expect bench meters to be used with such high currents? Of course external shunts are much more convenient on the bench than in the field.