Yokogawa Bench Meters, Slim Pickings.

[Muttley Snickers]

Greetings People,

I came across a listing on Ebay for a Yokogawa bench multimeter and figured that I would do some further research on them only to find that they are not doing bench multimeters as such anymore, they do have a couple of other bench meters as can be seen by the link below but these do not appear to be dedicated multimeters, more along the lines of temperature and resistance measurement.

They still carry a large selection of handheld meters and other test and measurement equipment again linked below, but no current bench multimeters to replace the previous models that I could find unless they are looking at a new series which could be the case I suppose, this is just pure speculation of course as I have no clue.

There is very little available in regards to online manuals that I could see including on the forum, are they worth keeping an eye out for ?

Any thoughts or experience with these meters would be most welcome.

Bench Meters
http://tmi.yokogawa.com/au/products/other-test-measurement-instruments/

Handheld Meters
http://tmi.yokogawa.com/au/products/portable-and-bench-instruments/digital-multimeters/

Discontinued Products
http://tmi.yokogawa.com/au/service-support/discontinued/

Picture 1.  The listing I found on Ebay for a 7552, the price seemed fair but I was slightly discouraged after finding what appeared to be the same unit elsewhere, I doubt that he knows it's history, no disrespect intended to the seller and I suspect he is just an equipment dealer. 

Picture 2.   The listing I found elsewhere for a remarkably similar unit, looks like the same unit above to me.

More Pictures.   Just some other Yokogawa bench meters and I did like the look of the 7555 but it's now discontinued as well.

[tautech]

What's the slot bottom of the front panel for Pete?

[coppice]

I've never used a Yokogawa multimeter, but their bench top power meters are almost the industry standard. A number of specs, like Intel's server power specs, specify Yokogawa meters as the reference.

[Muttley Snickers]

What's the slot bottom of the front panel for Pete?

I read on another product that it may be a memory card slot, I could be mistaken of course otherwise it's simply a cockroach entry point. 

Here's more pictures of a 7552 from another site, and the slot looks too big for a compact flash and too small for a floppy, one document indicated an optional custom memory IC card and another showing an interface similar to a PCMCIA to compact flash adapter, I've added the PDF below and I suspect others will know what it's for, also added some basic specs on a couple of meters, unfortunately few and far between I'm afraid.

[tautech]

What's the slot bottom of the front panel for Pete?

I read on another product that it may be a memory card slot, I could be mistaken of course otherwise it's simply a cockroach entry point. 

Yep

[crispy_tofu]

What's the slot bottom of the front panel for Pete?

I read on another product that it may be a memory card slot, I could be mistaken of course otherwise it's simply a cockroach entry point. 

Yep

Could be a designated magic smoke escape point... 

[enut11]

Hi Muttley Snickers
Just purchased a Yokogawa 7552 DMM on eBay and waiting for it to arrive. Joined the Forum yesterday and this is my first posting so I hope I get it right.
There was no manual in the listing and I now see that documentation is hard to find on the net.
I saw that tinhead has a 7552 and presumably a user manual but I have not been able to contact him.
If anyone has direct contact details for tinhead would you please ask him to contact me (enut11) at his convenience regarding the 7552.
I would appreciate any support on this matter.

[Muttley Snickers]

Welcome to the forum,

Was the unit you purchased the same as listed above, I was so tempted by the way but soon realised that they were phased out in 1996 and with possibly no history available on that particular unit it was enough for me to steer clear, the lack of information didn't help much either.

As yet I have not found the 7552 manual but only conducted a brief search, they may be out there somewhere and one will turn up I'm sure, I did find however the full PDF manual for the 7555 which was the successor to the 7552 but it's in Japanese.

In the interim here is a link below to the 7561/7562 full manual in English, PDF is 8.72 MByte and these are a 6 1/2 digit meter as opposed to the 5 1/2 digit 7552 which you have, some features and functions are most likely the same, also please let us know how you get on and if you dont mind a review or opinion on the meter would be fantastic if you can spare the time.

Best regards

Muttley


http://www.yokogawa.co.jp/ftp/dist/ks/eusers/basic/nbqc1/im/IM7560-10E_04.pdf

[enut11]

Hi Muttley. I purchased the 7552 from an Aussie dealer. There were only two listings at the time. It arrived just as we were leaving for a week away so only had a brief look at it. Needs a good clean! Looking forward to checking it out this coming weekend.
I just purchased a dmm calibrator online from the USA.
I had previously owned a HP34401 6.5 digit unit which was very nice. It was part of my dedicated workshop which was dismantled and sold off when we moved into a smaller flat. Now slowly buying more equipment as I  need it.
The 7552 looked to be an afforable quality instrument. Time will tell. Unfortunately the Japanese are not very generous with their manuals.
Regards

[enut11]

Hi all
Just back from leave and unpacked the Yokogawa 7552 that I purchased on eBay a couple of weeks ago. This is a 5.5 digit bench DMM with a best DC V accuracy of 0.0035% over 24 hrs or 0.008% over 1 year. These are fairly good specs and I will be giving the unit a thorough check over the coming weeks.
The unit was purchased from an Aussie eBay dealer who said that he got it from a local (SA) laboratory.
First impression is that it looks in good condition and needs a good clean-up. It had a number of (compulsory?) stickers on the case including one claiming it was tested on 19/02/2015 by Testel, which sounded encouraging.
Powered up the unit after checking that the AC voltage selector was correct. Nice red LED display. Did a quick check and volts and ohms produced expected results. DC A did not work. Blown fuse and easily replaced. This model also has a handy 20A range.
So far so good. More tests to come including a peek inside the case. Thanks for the user manual Muttley I will be reading it soon from cover to cover.

[deadlylover]

Very nice, I'm looking forward to seeing what voltage reference they used inside.

I like that multidot display for the "V" symbol, reminds me of their arch enemy Advantest. Mine's hopelessly dim. =P

[enut11]

Hi deadlylover!! I will be cleaning the 7552 and having a look inside in the next few days.
I like the look of the Advantest. Certainly more modern than the 7552 which looks rather antique.
If that is a green LED display on your Advantest, I wonder why it is so dim? May be fixable?
Lou

[deadlylover]

If that is a green LED display on your Advantest, I wonder why it is so dim? May be fixable?

I think they just get dimmer over time, this unit was made in 1990. Which reminds me....I better get around to changing the backup battery.

[nowlan]

The 2 meters on ebay have 110v only =(

[crispy_tofu]

Shame they don't have voltage selection switches, these look like quality meters... 

[helius]

From the Card Interface pdf, the specs match a CardBus interface for Compact Flash cards. It states 66.6 MB/s peak, which is the throughput of CardBus word DMA.

[deadlylover]

Shame they don't have voltage selection switches, these look like quality meters... 

Hmmm I might be confusing the models, but some of them have another hidden set of switches behind the sticker showing the selection of 230v/200v like on enut11's unit.

Maybe he can have a feel around and see if there's anything behind that sticker just to confirm. I guess we'll know for sure when he lifts up the skirt.

[Muttley Snickers]

Here are the model codes from the 7561/7562 series manual which are most likely similar codes used on enut11's 7552 unit, the 7561 looks like it does not have AC measurement going by the codes.

[enut11]

Welcome back Muttley. Yes, my 7552 is similar to the 7562 in that it has a serial interface. It also has an additional current range to 20A but no rear terminal inputs. The large slot at the bottom left which was a source of amusement in an earlier posting is for a removable CF memory card. It was used to store additional measurements or to boot up the meter into a specific configuration. However, needs a special adapter to hold the card.
Below are first pix of the inside. I was not able to identify the voltage reference chip so if someone could have a bit of a look in case I missed it.

[enut11]

Hi All. I checked out the low DC volts on the 7552. I have a handy home built DMM checker built 5 years ago from a Silicon Chip (Aust) kit. It is based on an AD588 reference chip with a nominal output of 10.000V. I also added a voltage divider based on 0.1% resistors to check the 2V and 200mV ranges.

Nominal 10.000V reads 10.0003V on the 7552
Nominal 1.962V reads 1.96202V on the 7552
Nominal 186.5mV reads 186.49mV on the 7552

I don't really know how accurate the AD588 is but the figures look encouraging nonetheless.

I ordered a DMM checker from the states which is calibrated so looking forward to that. It will check spot values for DCV, ACV, DCA, ACA and R.
http://www.ebay.com.au/itm/271791808061?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

[Muttley Snickers]

Thanks very much enut11, it looks like you scored a keeper.. ..and the pictures showing the inside of the unit indicate a very nice and clean meter, not to mention bug free..

I've only had a brief look over the 7562 manual and did notice that it indicates that each mode can be independently adjusted which is very nice as opposed to running through an entire calibration sequence, which some of us are either not geared up for or confident enough to do, yours so far looks like it is spot on.

Was that 7562 manual suitable or are we still keeping an eye out for the dedicated manual ?.

Many thanks and well done...

Muttley

[enut11]

Thanks Muttley. I had a long look for the 7552 manual without luck. So far the 7562 manual has been extremely useful. Based on my experience so far I can recommend the 7552 DMM. It has a useful range of features, promises good accuracy and has a good clear display. I could not find any evidence of leaking caps on any of the boards despite its age (>20yrs?). Because it is not well known It can be bought for a discount compared to a HP, Fluke or Keithley. Someone asked if there was a way to switch a 110AC unit to 240AC internally. I will have a look at this next time I open the case.
BTW, thanks for starting this post as I found it while looking for a manual. Eevblog has been a great source of info for lots of electronic stuff that I am interested in.

[enut11]

Shame they don't have voltage selection switches, these look like quality meters... 

Hmmm I might be confusing the models, but some of them have another hidden set of switches behind the sticker showing the selection of 230v/200v like on enut11's unit.

Maybe he can have a feel around and see if there's anything behind that sticker just to confirm. I guess we'll know for sure when he lifts up the skirt.

Hi nowlan, crispy-tofu and deadlylover. Had a look inside my 7552 and there is a switch behind the 230VAC/200VAC label which most likely selects 100VAC/115VAC operation. Also, the 7562 manual describes the process - see pic below.

[crispy_tofu]

Ah okay, I stand corrected.  Thanks!

[enut11]

Very nice, I'm looking forward to seeing what voltage reference they used inside.

I like that multidot display for the "V" symbol, reminds me of their arch enemy Advantest. Mine's hopelessly dim. =P

Hi deadlylover. Had a good look inside the 7552 at the chips trying to identify the voltage reference chip.

Main PCB chips
SL161525 (8 pin metal can)
LM339
6N137
9136?
TC4001
TC4049
TC4052
TC4053
74LS04N
74HC00
CA4558
OP27
LT055
AD707
A2004C uP?

Sub PCB
LM339
LF351
LF353
LT012
LT1055
AD707
4200?
C311C
NE5532

I suspect the the SL161525 may be the voltage reference chip but I cannot find any info on it. Equivalent to an LM369???

Anyone up to speed on reference chips?