Tekronix DMM914 Calibration

[mhennessy]

Hello all,

Just on the off-chance, would anyone have the calibration instructions for a Tek DMM914?

This was made in the mid-1990s, so almost 20 years old, and still works well. But it is out of calibration on some functions. Inside are a number of pre-set resistors (and a capacitor), but I'm not about to try random twiddling.

I wasn't really aware that Tek made a range of hand-held DMMs, so this is quite an interesting find. It's pretty nicely made - almost Fluke quality

Many thanks in advance,

Mark

[Radio Wrangler]

I don't think they did make it. Quite a few firms were buying in hand-held instruments with a few twiddles to appearance and their own logo on the front. THe quality wasn't bad at all.

David

[mhennessy]

Yes, you're probably right. Here is a "teardown" of the next model down in the range: http://mrmodemhead.com/blog/tektronix-dmm912-teardown/ - and in the comments there is a suggestion that it might be made by Brymen.

Whether that helps or not it another question - if I were able to find calibration instructions for a similar-looking model from someone else, I'd need to be pretty sure they were the same before I start tweaking

OT, but there is some interesting history between Tex and Fluke, who are now owned by the same parent company, of course. http://www.eevblog.com/forum/reviews...meters-oh-wow/

Cheers,

Mark

[mhennessy]

Just to update this, I'd actually forgotten about it, but was reminded by a video posted on the eevblog website, so I asked the question on the forum there. The answer came back:

Calibration info inside this big document

https://www.lcsr.jhu.edu/main/images...254_Manual.pdf

All the info for these DMMs starts on page 232 of the PDF.

Hope this helps,

Mark

[retiredcaps]

Originally Posted by mhennessy

Yes, you're probably right. Here is a "teardown" of the next model down in the range: http://mrmodemhead.com/blog/tektronix-dmm912-teardown/ - and in the comments there is a suggestion that it might be made by Brymen.

I actually made that suggestion about Brymen, but after more investigation, I think it is made by APPA tech.

Both companies are based in Taiwan.

[retiredcaps]

Originally Posted by mhennessy

The answer came back:
All the info for these DMMs starts on page 232 of the PDF.

It took me a long time to find that document originally, but it was for modemhead's DMM912 blog entry in case calibration was required.

Originally, modemhead purchased it as "non working", but all it needed was a 9V battery. Of course, we didn't know that in advance, so I went looking for the service manual/schematics and thus found the above document.

Originally Posted by mhennessy

I wasn't really aware that Tek made a range of hand-held DMMs, so this is quite an interesting find.

Many of the other Tektronix handheld multimeter are obviously made by APPA. Take a look at APPA's 60 and 90 series and you will spot the equivalent Tektronix 150 models.

http://www.appatech.com/appa_product...81003113623241

Another example is the Tektronix DMM252 = APPA 105.

http://s.ecrater.com/stores/132368/4...7c_132368b.jpg

http://www.eevblog.com/forum/testgea...a)-idm105-dmm/

[mhennessy]

Hi Retiredcaps, and welcome to the forum

And please allow me to thank you here for providing the calibration information, and for the additional insights in this thread.

All the best,

Mark