Vintage DMM- Hioki 3200-50

An ebay find made its way into the lab- an industrial quality DMM from Hioki, made in 1984! The meter has some pretty good specs as shown in this datasheet:

  • 3.5 digit (1999 count), 0.5% on DC voltage
  • 20uA DC current range with 10nA resolution
  • 1G input resistance on 200mV range
  • Drop proof to 1 meter
  • Dust sealed.
  • 500 hours battery life using 2 AA
  • Neon indicator of overvoltage

The meter came in an original case, that looked a bit beat up:

Case front

Case front

Case back

Case back

Probes with safety tips included

Probes with safety tips included

Safety shrouded probes

Safety shrouded probes

The case feels very solid with no play

Stand works pretty well

Stand works pretty well

Original batteries. 2xAA is a bit unusual for the DMMs then

Original batteries. 2xAA is a bit unusual for the DMMs back then

1984 datcode!

1984 datcode!

The batteries held their voltage until I tried turning the meter on, then they sagged. Still remarkable condition and lack of leaks after almost 30 years

Back cover removed

Back cover removed

Two non-arching fuses (HRC?). though the smaller one was blown

Spare fuse to the rescue

Spare fuse to the rescue

Attempting to insert modern AA batteries is met with a bit of resistance. They seem to have grown fatter over the last 30 years?

Quite a force is required to fit newer batteries in

Quite a force is required to fit newer batteries in

Shielding cover removed

Shielding detail

Shielding detail

More shielding details

More shielding details

Top of the board with back cover removed

Top of the board with back cover removed

No idea who made the chip

No idea who made the chip

Binding posts are bolted to the board and loctited. Current shunt is in front

Binding posts are bolted down and loctited

Attention to details

An interesting switch gets pressed when the selector knob is in a particular position

An interesting switch that gets pressed when the selector knob is in a particular position

Unfortunately,further board removal would require desoldering multiple leads and I was not about to do that to a functioning vintage meter. So let’s put it back together and try to turn it on:

Measuring one AA cell- clear and crisp display

Measuring one AA cell- clear and crisp display

1Ohm

1 Ohm

9 Mohm

9 Mohm

5V DC reference

5V DC reference

1mA DC current

1mA DC current

To create low current, we’ll use a AA battery powering a large cap. Leakage should be pretty small:

Diode test- measures forward voltage and beeps rather loudly

Diode test- measures forward voltage and beeps rather loudly

Conclusion:

It’s a very impressive meter, especially considering the age. All functions appear to function with the exception of the AC voltage and current. It could be as simple as the mode button not making contact or could be more involved, but that’s a topic for another post.

An eevblog forum thread for this post could be used for comments

 

 

 

 

 

7 thoughts on “Vintage DMM- Hioki 3200-50

  1. I bought one just like in 1985. is very good, but unfortunately 2 years ago I put 230v AC input by measuring ohms and broke., I’ve had it running for 22 years perfect

  2. I have one since 1986 and has been my partner school and work throughout this time and still
    works perfectly.

  3. I by mistake, connected HV across the pins of the output capacitor of a racket insect killer to the V measuring input , but after that it is defected & doesn’t measure OHMs properly.Model of multimeter is 3200 Hioki

  4. This is my first digital multimeter, I bought in 1984, some years later I fall seduced by Fluke charming.

    Still I have thos meter and work like new.

  5. I have this since 1996 when i was 10 years old.very good multimeter.it works very well now. thanks to hioki

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