Test Equipment Anonymous (TEA) group therapy thread

[bd139]

Look what I found. A Fluke 8505A for £100 about 30 mins from me. Someone buy it so I don’t: https://www.ebay.co.uk/i/282617106424

That’s 6.5 digits for £100! Plus it’s stacked with options.

[Specmaster]

Look what I found. A Fluke 8505A for £100 about 30 mins from me. Someone buy it so I don’t: https://www.ebay.co.uk/i/282617106424

That’s 6.5 digits for £100! Plus it’s stacked with options.

Go on, buy it, you know you want to.. its way to big for my small room.

[bd139]

It’s way too big for mine too. I’m trading off the week of frowning from the other half versus the fun factor

[Mr. Scram]

Bugger it! Just got outbid on a "flux multimeter"

Someone got a bargain due to someone else's incompetence!

http://www.ebay.co.uk/itm/122717474925

That's the stuff you dream of.

[Specmaster]

Ok then, talking about bench meters here, what in your honest opinion is the best bench multimeter that the average electronic hobbyist ought to get. Please take on board that I'm talking about people who may not  have much cash to splash around so I'm definitely thinking thinking well below £100 on Ebay or similar. Yes, of course we would all like to have 6.5 digits or higher (something about a lot of digits flashing up and down that looks impressive) but putting my sensible hat on rather then my ego hat, I'm thing maximum of 5.5 digits, so what you elect to opt for and why??

I'll kick it off with 2 that I own, Phillips PM2521, 5.5 digits LCD that also has a frequency counter and timer functions and a HP 3466A, 5.5 digits LED display that also does AC+DC together in volts and current mode, both are true RMS meters.

[bd139]

Fluke 8050a. Dirt cheap, not too big, reliable, true RMS, 4.5 digits, dB with ref impedance, relative measurements, good frequency response, good protection. Missing only auto ranging (meh I leave mine on 20v most of the time) and an emissive display (vfd or led) but you can’t win everything.

TBH the only time I use all the digits is trimming opamp offsets, something that you can do well with a 1960 differential voltmeter.

Most electronic design you’d be fine with a 200 count (yes two hundred). I could certainly be productive with that.

[STMartin]

It's finally here! After a horror story of an experience with TestEquity, the crown jewel of my lab is finally sitting on my bench.



I'm pretty stoked. Time to get crackin on some projects.


I also saved these guys from the scrap heap.

I don't have the transducer for the Panametrics. The Dana is in perfect agreement with my 34401, down to the least significant digit. Never heard of Dana before, but it seems to be a pretty good meter.

I've got more gear on the way too. 
Be back soon!

[bitseeker]

Ok then, talking about bench meters here, what in your honest opinion is the best bench multimeter that the average electronic hobbyist ought to get. Please take on board that I'm talking about people who may not  have much cash to splash around so I'm definitely thinking thinking well below £100 on Ebay or similar.

If budget is an issue, then unless you have need for long-duration logging, I'd even question the need for a bench multimeter. A handheld DMM will work just fine on the bench as well as around the house. In fact, you can then afford to get at least a couple of them for measuring power or for monitoring more than one measurement simultaneously.

Yes, of course we would all like to have 6.5 digits or higher (something about a lot of digits flashing up and down that looks impressive) but putting my sensible hat on rather then my ego hat, I'm thing maximum of 5.5 digits, so what you elect to opt for and why??

So, with the sensible hat on (though it doesn't like to stay on in the TEA house), a 3.5-digit handheld DMM will give you up to around 6V measurements with mV resolution, depending on the actual count. So, for general low-voltage analog and digital electronics (e.g., 3.3 and 5V microcontrollers, CMOS and TTL ICs), that'd work just fine. If you need to see fluctuations with a bit more resolution or would like to maintain mV resolution over a wider range, a 4.5-digit meter will do the job.

I'll kick it off with 2 that I own, Phillips PM2521, 5.5 digits LCD that also has a frequency counter and timer functions and a HP 3466A, 5.5 digits LED display that also does AC+DC together in volts and current mode, both are true RMS meters.

Those are nice ones. Note that the HP 3466A is a 4.5-digit meter. Still, it should work fine for general electronics. The HP 3468A or 3478A will do 5.5.

[bitseeker]

It's finally here! After a horror story of an experience with TestEquity, the crown jewel of my lab is finally sitting on my bench.



I'm pretty stoked. Time to get crackin on some projects.

That's a beauty. Is it from the recent multi-location auction?

Never heard of Dana before, but it seems to be a pretty good meter.

Dana Laboratories was founded in 1961 and was known worldwide for high-end instruments such as voltmeters, function generators, and frequency counters. Racal Instruments acquired them in 1979. You may have heard of Racal-Dana (e.g., 1991, 1992, 1996, 1998, or 1999 counters) in various threads here or seen some of their products on eBay.

Be back soon!

Looking forward to it!

[tggzzz]

Most electronic design you’d be fine with a 200 count (yes two hundred). I could certainly be productive with that.

I certainly was, and people have been using such equipment very successfully until relatively recently, of course. Such meters also have the advantage of, for some measurements, being much more ergonomic and faster than standard multimeters. I am of course, referring to analogue multimeters.

During school (not university) physics lessons, we were taught how to increase their accuracy to ~0.1%.

We were also taught how to use them to measure charge, something I haven't seen on a DMM

[bd139]

That’s what the relative button is for on my 8050a. I was building a CW filter recently and wanted to calculate Q. Connect the 8050a to the output and a function generator to input. Peak the output and read the counter. That’s your centre frequency.  Then stuff it in dB and set relative mode. Then change the function generator frequency until you get -3dB. That’s your first Q measurement. Do the same the other side of the centre frequency, pop it in the calculstor and done.

[Specmaster]

Those are nice ones. Note that the HP 3466A is a 4.5-digit meter. Still, it should work fine for general electronics. The HP 3468A or 3478A will do 5.5.

You are of course correct, it is only a 4.5 digit and further checking also reveals the same is true for the philips PM2521, I got slightly carried away there  I suppose I took the ability to display - or + as the .5 digit  However they are a big step up from the average hand held DMM of the era that could show 4 digits max, eg. 1999 (2000 count?)

I just love multimeters and I cant help myself when I see one reasonably priced (typical TEA syndrom) and right now I'm eyeing up some more to add to my growing collection and I'll keep you posted on the out come.

In the meantime, be cautious of the 6.5 digit HP and Fluke old lab quality meters that seem to abound on Ebay at the moment, I saw a video and I'm looking for it to post here as a warning of things to look far as many of then require expensive repairs.

[bd139]

The problem with the really high precision meters is how to calibrate them. They're not easy and you need specialist equipment. You can do a reasonable job of calibrating a 4.5 digit meter yourself with a voltage reference IC. Just get someone you know with calibrated kit to write down the reference voltage output and you'll be good to a reasonable percentage for amateur use. After that it gets a little difficult.

I don't like Philips multimeters myself. They're incredibly difficult to get inside from experience and have quite fragile internal construction. Shame really because electrically speaking they're pretty good. Some of the older LED ones are a little scary. The current shunts are actually strips of metal clipped into the front panel plastic. One little accident and it'll go up in flames.

Really though TEA is not about what you need, but about what you want. I have a number of *needs*, one of which will hopefully be satisfied today. To fund this though, it will cost me £100 or so in a want from SWMBO and a trip to Westfield for some fancy face paints 

[alm]

In my opinion the Keithley 175(A) is a nice general-purpose bench DMM. 4.5 digit, the -A version adds a backlight. Has all the basics, including current to 10 A, diode test, auto-ranging, relative mode and data logging (though a GPIB interface is optional and rarely present). Downsides are no four-wire resistance, as I already mentioned no GPIB support by default and the fact that it uses an LCD screen, as opposed to a superior LED display or VFD. Should sell for well under $100.

Second would be Keithley 199. They are sometimes available for under $100. 5.5 digit, a nice big LED display, four-wire resistance mode, relative mode and data logging. GPIB interface is standard. They sometimes come with an eight channel scanner (relay) card that can be useful for some measurements. I like them for their simple UI and big, bright display. However, compared to some competitors, it lacks diode tests or continuity.

[bd139]

Fluke 45 is nice too. I just got outbid on one.

Having a bad eBay week

[Specmaster]

Everything I know about buying more test equipment, I learned from my wife.

Top 10 reasons for buying this:

10. it's a different color
9. it's a different brand
8. it's a different style
7. it's a different vintage
6. it goes with _________
5. I returned the other one
4. I lost the other one
3. one is for keeping in the car
2. I need a backup
.
.
.
1. It's on sale!

Copy that 

[Specmaster]

Fluke 45 is nice too. I just got outbid on one.

Having a bad eBay week

Join the club, I think we were both after same one    and I didn't get it either, the one that went for £96 by any chance? 

[bd139]

That’s the one!

[Specmaster]

Yep, I never got round to bidding on it, I was watching it within minutes of it being listed. I was a bit dubious of it actually working correctly seeing as it was photographed during its 4 second self test routine only, I would have liked to have seen a photo taken after that as well in case it showed any errors.

[bd139]

The other pictures showed it in low mV range. You have to watch out for faded displays on them otherwise they are usually good.

[Specmaster]

Those are nice ones. Note that the HP 3466A is a 4.5-digit meter. Still, it should work fine for general electronics. The HP 3468A or 3478A will do 5.5.

You are of course correct, it is only a 4.5 digit and further checking also reveals the same is true for the philips PM2521, I got slightly carried away there  I suppose I took the ability to display - or + as the .5 digit  However they are a big step up from the average hand held DMM of the era that could show 4 digits max, eg. 1999 (2000 count?)

I just love multimeters and I cant help myself when I see one reasonably priced (typical TEA syndrom) and right now I'm eyeing up some more to add to my growing collection and I'll keep you posted on the out come.

In the meantime, be cautious of the 6.5 digit HP and Fluke old lab quality meters that seem to abound on Ebay at the moment, I saw a video and I'm looking for it to post here as a warning of things to look far as many of then require expensive repairs.

I found the video and here is that link as promised.

[alm]

Please do not take what Martin says as about this topic too seriously. I remember cringing while watching his videos about bench DMMs due to the large number of mistakes. For example, why would a high calibration count be a warning? Customers sending a meter off for calibration every 90 days are more likely to take good care of it than customers that put the meter on a shelve collecting dust. Feet will often be missing for equipment that was rack mounted. Does not look like a good reason to skip it either. My impression is that Martin bought a single defective meter and a single good meter, and from that concluded that any difference between the first and the second meter was related to the first meter being defective.

Just apply common sense: look at physical condition (may or may not be indicative for electrical condition, but clear trauma is a warning sign), look for errors / test results. Look at the service manual to see what is and what is not being tested in a self test. Look for damage to connectors. Look at the condition of the display (if VFD, segments may be faded).

[Specmaster]

I don't take anything too seriously but I thought that he makes some valid points during that video. Where did you glean that he had purchased 2 of these meters? I understood that he purchased this meter, knowing that it needed calibration and I thought the point he was making was that the seller stated it passed self test, had a battery fitted but now needed calibration. There was no mention of the fact that it had the error and also the service request flags showing on the display at all!

I also thought that Martin had tried to do the calibration and that it failed to accept it, despite following the service manual procedure and that I'm guessing is why the SRQ flag was flashing because it has a problem that only the service centre could fix.

Whats the point of a meter if it is miles out of calibration, could have purchased a cheap chinese meter for $25 and been closer to the resistance value.

Anyway, I took it as a cautionary tale and he was trying to give others some useful tips on how to try and check that any meters that there are trying to bid on is worth the price.
 

[xrunner]

I found the video and here is that link as promised.

I've seen that one before. First of all, you can replace the battery without needing to re-cal it. I have the same meter in perfect working order which I got off Ebay. I replaced the battery and attached a voltage in parallel with the battery so it wouldn't lose it's cal memory for the short time I had the old battery out of the system.

Second - he keeps going on about the "SRQ" indication as meaning it needs "servicing" as in it needs to go to the shop. The "SRQ"  is a HPIB control function and pertains to the operations on that bus. Not sure where he got that from.

[Cerebus]

I also thought that Martin had tried to do the calibration and that it failed to accept it, despite following the service manual procedure and that I'm guessing is why the SRQ flag was flashing because it has a problem that only the service centre could fix.

I'm sorry to say that just by watching the first five minutes or so of that video that I know one thing about the maker, that he cannot read a manual.

• He botched the calibration by slapping 10.01Mohms on the front and then entering 10 when the manual says, and I quote "Enter the value of the input resistance (in ohms)" - i.e. 10010000 (if he's right about the actual value of that resistor). (Page 5-8) So the meter rejects this off by a factor of one million error and returns a cal error.
  
• The SRQ light is, as someone else has pointed out, a GPIB interrupt and has nothing to do with faults.
• He is wrong about what CALNUM? reports. It is the number of calibrations and the manual clearly and categorically says this (Page 5-2).

I gave up at that point and double checked my understanding with the manual just in case I'd lost my mind - I hadn't.

So more than a pinch of salt is required to be taken. I'm not going to bother watching any more of that video but, judging by the litany of errors in first 5 1/2 minutes or so, the only thing you have to gain from watching it it misinformation.