Can't choose new dmm, Arrrgh!

[JonSea]

Slightly off topic, but not too far....

I've always assumed DVMs pretty much work or they don't. The calibration may be off, but order-of-magnitude readings will be ok.

I visited a manager friend of mine the last day his RadioShack closed. He handed me a DVM that the store used for troubleshooting. Seems like a decent meter.

I needed to determine which terminals were which on a 5v & 12v AC/DC power supply and this meter was handy. One of the terminals measured 13.2v to ground and the other zero. This power supply was never used before and removed from a piece of new-in-box surplus gear. I've used some of these before and they've always worked, and the voltages were always close to 5 & 12.

I pulled out another one of these supplies. Exactly the same results! Odd that two would fail in the exact same way, so I grabbed a different meter. The rail that had measured 13.2 now measured 5.0 volts. The rail that measured 0 was now reading 12.1 volts.

I have no idea how the first meter could read high on one voltage and zero on another! Well, it's worth exactly what I paid for it! The test leads are nice at least.

 

[alec_t]

He handed me a DVM that the store used for troubleshooting.

Well if the first meter read erratically it makes you wonder how reliable the RS troubleshooting was!

 

[KeepItSimpleStupid]

The probes could be bad.

 

[JonSea]

Well if the first meter read erratically it makes you wonder how reliable the RS troubleshooting was!

Well, I don't think a crappy meter really made them any worse! That store certainly wasn't a knowledge trust.

 

[JonSea]

The probes could be bad.

I don't think so....there was a lot of movement and flexing of the cables between the two sets of measurements....and I don't see how bad probes could make a meter read voltage higher than it really is.

 

[throbscottle]

Took me a while to spot my old meter was badly off. Lot of head scratching in between times. I bet they had fun and games in that store!

 

[KeepItSimpleStupid]

Or maybe they designed it that way so they could see more batteries <G>.

 

[JonSea]

Well, it does take 5 D cells

Actually, it uses 3 AAA cells instead of the typical 9 volt battery.

 

[NorthGuy]

IMHO, there are small DMMs in $30-40 range which do most of what you need, then there's almost no imrovement (mostly cosmetical) up to about $300, then you start getting better ones.

I have good Fluke and it works great for me.

 

[chemelec]

throbscottle, Here is a Picture of it, Also sent to you in an Email.

 

[Tony Stewart]

I have many meters from $8 3 digit types with transistor test sockets, Fluke 96, 5 digit RLC meters, counters

But if I want to measure V,I,R in avg or RMS To 6 digits resolution with zero Cal I use my old HP meter.
10 uΩ to 100MΩ 2 or wire ..you might check used online Ebay.

 

[throbscottle]

IMHO, there are small DMMs in $30-40 range which do most of what you need, then there's almost no imrovement (mostly cosmetical) up to about $300, then you start getting better ones.

I have good Fluke and it works great for me.

Maybe there will be Fluke in my life too - have to wait and see

I watched Dave Jones £100 meter shootout - apparently this isn't true, because the build quality is usually better, also there's more to choose between brands - or rather, more things to pick up on to rule out a given meter as being worth the price. Brymen offer really well built, feature-full meters in this price range, and seem to offer more bang for the buck and quality than similar ones (many of which use Brymen chips btw). Also there are some really nice meters from Hioki, Sanwa and Kyoritsu. Dave rates the UEI meter he reviewed but the brand isn't available to me so I haven't looked into it.
I've seen a few offerings of the Sanwa pc510a, trying to find out more about it.
I'm tempted by this one though: **broken link removed**sorry I can't help it I just love vfd's even though I know Mastech are a bit naff - at least they are an OEM, not like most of the Chinese meter brands which appear to all come from one manufacturer... Grrr. Head going funny now, been looking at multimeters reviews and specs every day for a week
(edit) Well I think they are an OEM anyway. Maybe just another badge...

 

[throbscottle]

And so I look for hp bench meter on eBay, and there it is!
Thanks for the tip, Tony
But since I've discovered that modern handheld dmm's can do a lot of things I didn't know they can do, I want a meter that can do those things, since I don't have (and can't afford) anything else that can do them - or at least not as well as pretty much any multimeter with "features". Building my own equipment is the only real alternative, but it's a long slow process in which, for me, there are a lot of gaps that are hard to fill. But I'll keep an eye on fleaBay for one like yours too, once I'm sorted out with whatever I eventually get as a result of this little adventure.

 

[Ian Rogers]

The benchtop is a Fluke / Philips 2535.... I was comparing to my other, which is a solartron 7150 I have several 1% resistors knocking about.... The Fluke measures the 243 ohm resistor at 243.07... The solartron at 243.12...

I really don't need the accuracy but its nice to know it's still pretty accurate....
There are several comments about the Fluke/Philips DMM.. They say they are prone to temperature problems.... Mine has never shown this!!!

 

[throbscottle]

Well, if anyone is interested, I eventually got a Brymen BM867s from TME. That's an awful lot of dmm for the money, even though I did go over budget. It's even got a UL sticker on the back. Heavy beast.

 

[Ian Rogers]

Good choice... I have downloaded the manual to have a look see.... I see they are £100 ~ £125... The reviews are pretty good and its a good looking DMM..