HP3478A Bench DMM... Good for a beginner starting out?

[metube]

Hi,

I've been teaching myself electronics for the past few months and I figured its time to get a multimeter.

I found a 'deal' for a HP 3478A bench DMM for $100. Waiting on a confirmation, but it looks like its been +10 years since the last calibration, wasn't sure if this was a big deal if I could find a way to test it against.

It's rated to 300V (1% DC accuracy?), but I'll likely be using much less...just experimenting with micro-controllers and learning as I go...

Do you guys think its worth it? I'm in Canada and finding decent quality seems to be quite expensive for someone just getting into the hobby.

Thanks!

 

[bountyhunter]

It's a good meter. We used them for many years. Assuming it's fully functional it's a good deal. You can get one that is fully refurbished and guaranteed calibrated for about $300.

https://www.testequipmentdepot.com/usedequipment/hewlettpackard/digitalmultimeters/3478a.htm

 

[Mikebits]

That is a very good meter, and the price is pretty good too. I used those meters for an ATE test station back in the late 80's.

 

[metube]

Thanks for the heads up!

I figured it would be a good place to start.... my only concern was for the CMOS battery... apparently the discharge curve is very flat up until the point when the battery is fully discharged (read 10-15 years). That, combined with the fact it is software calibrated worried me.

I will call some places in the morning, but for a reference, how much should I expect to pay to change the battery and/or have it re-calibrated if I dump the memory while trying to do it myself?

Found a detailed guide here: http://mrmodemhead.com/blog/hp-3468a-battery-replacement/

 

[Mikebits]

That is actually a Lab grade instrument, and has a lot more capability than a beginner really needs, but with that said, HP meters last a lifetime, and as your knowledge and experience grows, so will your needs. In other words, it is more meter than you need at this time, but if you think this is a hobby that you want to do for a long time, then as you learn more and develop more complex projects, the meter will be real useful. If this hobby turns out to just be a passing phase you may regret spending more than you needed as there are much cheaper meters available. This will have to be your call. Personally, the meter your looking at is great quality, and assuming it is fully functional, the price is right.

Now for calibration? I would suspect a calibration lab would charge you more than you are paying for the meter. An alternate solution if you do decide to go with this meter, would be to post on this forum, and ask for some ideas on how you can do some rough calibration test fixtures on your own. For example; you can purchase some very high precision resistors from a electronics surplus store on the cheap to calibrate your ohm meter portion. You would most likely need several values to check each range.

Well, be sure to let us know how it goes

 

[ModemHead]

The 3478A is indeed a nice piece of equipment, but you may wish to think twice if this really is your first multimeter. Its capabilities include 4-wire resistance and a GPIB interface, neither of which is likely to be of use to a casual hobbyist. It lacks a diode test range and continuity. It is huge, really deep, takes up a lot of shelf space. And it has a painfully slow update rate, especially in AC mode.

For $50 to $100 you should be able to find a nice new handheld DMM that you may find more suited to your purposes.

 

[metube]

ModemHead, thanks for chiming in. I was aware of the lack of continuity, but the lack of diode test caught me off guard. Desk space isn't an issue, but you make some really good points...

I've actually been mucking about in this hobby for half a decade now, using researched plans to build small circuits (headphone amps, stepper motor drivers...).

Recently, I've been learning the theory behind how these designs work and I feel compelled to turn what I've learned into a useful skill.

That being said I will take a second look at the multimeters available. After watching more tear-down videos of DMMs than I can count, its been hard to find a quality meter in Canada at the ~$100-125 mark.

 

[schmitt trigger]

I will echo what others have said; it is an excellent multimeter.

But since you are starting with your own lab, I suggest that you consider your overall startup budget.
For instance, you will require a benchtop variable power supply, and I would advise that it has at least two outputs.
Also consider a good, temperature controlled soldering iron.
If microcontrollers are your interest and you are not considering an oscilloscope, then consider a USB logic analyzer. It is impossible to see digital pulse trains with a DMM.

 

[spec]

Hi,

I've been teaching myself electronics for the past few months and I figured its time to get a multimeter.

I found a 'deal' for a HP 3478A bench DMM for $100. Waiting on a confirmation, but it looks like its been +10 years since the last calibration, wasn't sure if this was a big deal if I could find a way to test it against.

It's rated to 300V (1% DC accuracy?), but I'll likely be using much less...just experimenting with micro-controllers and learning as I go...

Do you guys think its worth it? I'm in Canada and finding decent quality seems to be quite expensive for someone just getting into the hobby.

Thanks!

Hy metube,

Welcome to ETO.

Care to tell us where you are from in Canada and put it in your identity window at the left.

The Hp 3478A, while a fine instrument, would be a very bad choice for you. A hadheld digital multimeter would be a much more suitable instrument. There are a number of excellent models available, Fluke being the industry standard but a few other makes are just as good and considerably cheaper. Just Google the net and watch some of the evaluations on Youtube. You could also ask on ETO.

spec

 

[bountyhunter]

Personally I think it's mandatory to have a good bench top meter as well as a decent hand held. I use the bench meter most of the time. It's just more convenient.

I also agree 100% with:

"you will require a benchtop variable power supply, and I would advise that it has at least two outputs."

and that those two outputs be floating so they can be "stacked" when higher volts are needed.

 

[spec]

Personally I think it's mandatory to have a good bench top meter as well as a decent hand held. I use the bench meter most of the time. It's just more convenient.

Maybe, but you are hardly just starting out in electronics. I simply can't see how a bench multimeter could be more convenient than a handheld- I would say the reverse.

As you are an electronics design professional with a load of experience, I can understand how an instrument like the hp would be ideal though.

For an electronics newbee this is what I think are the bare essentials (costs notional):

(1) Handheld multimeter, with temperature measurement, transistor tester etc. (£70UK) (see ModemHead's post #6)

(2) Soldering iron (£50UK)

(3) Fine pliers (£22UK)

(4) Fine wire cutters (£22UK)

(5) Power supply, 0V to 18V minimum, 0A to 2A minimum (£50UK)

and you are set to go.

Later, consider another identical power supply and, later still, a second-hand oscilloscope (£200UK)

One of the major worries for private individuals is Through Life Costs (TLCs). If the second-hand hp multimeter went wrong it would cost a lot to have it fixed. If a new handheld multimeter went wrong it would be guaranteed for a year and possibly five and, ultimately, it would not break the bank to buy a new one.

Although comparable prices, when I bought a used Tektronix scope last year, I didn't buy the model I would have really liked with digital readout etc on similar reasoning: I could service/maintain the lower model but not the higher model (the essentials: bandwidth, number of channels etc were the same).

A prime example of the effect of TLC is motor cars: a pre-owned luxury limousine is relatively cheap, because even minor component failures can cost a fortune.

spec

 

[bountyhunter]

Maybe, but you are hardly just starting out in electronics. I just can't see how a bench multimeter could be more convenient than a handheld- I would say the reverse.

It's the battery thing. Seemed like everytime I would turn on a handheld the battery indicator would be flashing so I couldn't be sure it was reading in calibration. It was just a royal PITA to keep 9V batteries and have to change them. At National, the cal seal went over the battery cover so replacing the battery technically meant it had to be resubmitted back for cal. I currently have three handhelds but I only use them for data taking when I have to read multiuple things at once like Vin, Vout, Iload, Iin for efficiency or something like that. The other thing you must have a handheld for is car/motorcycle work.

The other major hate I had on handhelds was how they always sprouted feet. You go to lunch and come back and somebody would have grabbed them off your bench. Over time, all the good ones (HP - Fluke) just vanished. Anything that costs over $200 and fits in a pocket has a short life span.......

 

[spec]

It's the battery thing. Seemed like everytime I would turn on a handheld the battery indicator would be flashing so I couldn't be sure it was reading in calibration. It was just a royal PITA to keep 9V batteries and have to change them. At National, the cal seal went over the battery cover so replacing the battery technically meant it had to be resubmitted back for cal. I currently have three handhelds but I only use them for data taking when I have to read multiuple things at once like Vin, Vout, Iload, Iin for efficiency or something like that. The other thing you must have a handheld for is car/motorcycle work.

The other major hate I had on handhelds was how they always sprouted feet. You go to lunch and come back and somebody would have grabbed them off your bench. Over time, all the good ones (HP - Fluke) just vanished. Anything that costs over $200 and fits in a pocket has a short life span.......

I knew I was missing something.

Apart from early high end DMMs, which chewed juice, I never had a problem with flat batteries. I use rechargeable PP3s at home and have a few lying around anyway. If push comes to shove, you can always plug a handheld DMM in the mains, via a wall wart.

I'd forgotten about the legs. We lost a few heap expensive Flukes at work too, now I come to think of it. Never had much of a problem with the prior AVO 8s and 9s (like a Simpson) though.

What you say aside, I think handheld instruments of all types are a godsend, especially for a newbee (as in insect).

spec

 

[KeepItSimpleStupid]

Definitely not a good hobby meter. GPIB measurements is slooow. The LCD display gets annoying. It's better off as a systems meter that you don't look at.

Some things it might be good for: AC measurements at higher frequencies, 4 terminal ohms, large # of digits.

 

[bountyhunter]

What you say aside, I think handheld instruments of all types are a godsend, especially for a newbee (as in insect).

spec

Handhelds do give the most performance for the money because they are built on a single internal PCB with no point to point wiring or switches like a typical bench top meter does. I got so sick of the meter shortage when I worked at National, I ended up buying a couple of "no name" 4 1/2 digit handhelds for about $100 each that had true RMS AC, wide bandwidth and really tight accuracy. Always kept them locked in my desk.... still have them, they do give amazing performance for the bucks.

 

[spec]

Handhelds do give the most performance for the money because they are built on a single internal PCB with no point to point wiring or switches like a typical bench top meter does. I got so sick of the meter shortage when I worked at National, I ended up buying a couple of "no name" 4 1/2 digit handhelds for about $100 each that had true RMS AC, wide bandwidth and really tight accuracy. Always kept them locked in my desk.... still have them, they do give amazing performance for the bucks.

I remember now that the pool HHDMMs at work were a problem in some parts of the factory for the reasons you say. But most of us worked behind locked doors where there was no walking problems.

You either had pool instruments or 'your own' which were bought with project funds. Some of the engineers burnt their initials in huge letters into the plastic cases with a soldering iron to dissuade walking.

One of the department managers kept a top of the range Keithly/Fluke in his desk drawer and would only let selected engineers use it. I took it home to check a project. It was in my car ignition phase: I had a theory that a burst of 20KHz 20KV would give a better fuel/air burn, and other benefits. The circuit was built using a line output transformer from a large CRT TV, but it was playing up.

To cut the story, I was doing some measurement but hadn't realized that some of the high voltage high frequency signal was present. The whole PCB of the meter near the input terminals turned to charcoal within a minute. The manager was not pleased when I returned his coveted instrument.

Like you, I have a mid priced oriental clone which I bought when they first came out, in the 1970s I think. I checked the calibration at work and, apart from the resistance ranges which required a slight tweak of an internal trimpot, it was surprisingly accurate and is still going strong.

spec

 

[JimB]

Some of the engineers burnt their initials in huge letters into the plastic cases with a soldering iron to dissuade walking.

I have seen that trick go embarrassingly wrong.

One place I worked we had a lot of French guys (the site was owned by a French company), one day when I needed to do a quick measurement and my Fluke was a long way away, I asked one of the French guys if I could borrow his Metrix for a few minutes (The Metrix was the French "must have" DMM, in the same way as a Fluke was the "must have" in the UK).
A nice shiny new DMM it was and he had engraved it with a soldering iron.
Just one problem, he had done a literal translation from French and written "Theft to Emile T....."
He was quite crestfallen when I pointed out that the correct English phrase is "Stolen from Emile T....."

JimB

 

[KeepItSimpleStupid]

I solved the "borrow" problem. An RPN calculator that no one would borrow. or they returned it within seconds and a HHDMM with too many functions. They wouldn't borrow that either.

 

[schmitt trigger]

Metrix!
That brings long forgotten memories.
I once used one of their equipment, a LCR bridge, where one had to null out the L and the Q successively.

What I remember about it was that its operation was, how shall I say it....different. I had already worked with General Radio bridges, but the setup on the Metrix was different.
Plus some words were in French, there is where I learned that Tension is Voltage.

Similar to an aunt's Peugeot 403 with funny gages like "Eau".

 

[spec]

Our company was taken over by a French company. The site where I worked is now closed down. They think and behave differently to Yanks and Brits but some of their designs are excellent, my old Peugeot 406 for example.

spec

(where are you located ST?)