# Vintage PH meter



## MarcoP (Dec 23, 2014)

Luckily today I've got a PH meter for free, it comes from a clinic and the owner (different one since the clinic originally opened) doesn't know much about it.
It turns on but I guess the electrode is gone, in fact put it in a glass of water and it didn't move at all.

Could someone give me some keywords so I could search for a replacement, and what type?
Or would it be possible to use a different socket at the back of the unit or modify one to use a BNC electrode (today easily available).



 

 

 


*Click on thumbnail for hi resolution image.

Got it for free, if I can make it work (even if it's a huge unit) great, otherwise nothing lost. For once I've got something for free I just hope in good news :lol: 

Thanks in advance


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## necromancer (Dec 23, 2014)

follow the "type" and "number" sticker / plates on the front

good luck, good score


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## necromancer (Dec 23, 2014)

i found this.

http://www.radiometer-analytical.com/pdf/meterlab/Electrode_Guide_en.pdf

or the home page if you want to contact them to ask any questions http://www.radiometer-analytical.com/


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## MarcoP (Dec 23, 2014)

Searching for the model number didn't gave me any valuable result but your PDF made me immediately aware of the connector used, a type 7. At least I know how to name it. Will search on those new details and will try to guess which type of electrode best fits my usage based on the PDF, I will also contact them in any case.

A little hint and I'm back in the road, thank you!


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## necromancer (Dec 23, 2014)

very welcome !!


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## Smack (Dec 23, 2014)

Looks like it dried out....don't know how accurate it would be after drying out, hope it's still good though.


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## MarcoP (Dec 23, 2014)

Smack said:


> Looks like it dried out....don't know how accurate it would be after drying out, hope it's still good though.


I put it inside a glass of water and the needle didn't move at all, later tried with acid and caustic and still dead. It wasn't used for a decade, so I bet the electrode is dead.

I registered and contact them and asked for availability and a quote for the electrode. I also asked them if they could still found an instruction manual, on the mean time I'm also searching for one, just to understand what I have I'm my hands (all new to me)


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## 4metals (Dec 24, 2014)

Hard to tell from the picture but it looks like a calomel electrode. They are filled with a saturated solution of potassium chloride and there is usually a small hole in the glass electrode near the plastic collar where the solution can be refilled. The hole is usually covered with a slip over rubber cover. 

Often you can refill the electrode with fresh saturated potassium chloride solution and it will work. Maybe it has gone too long but for the price of a few milliliters of saturated KCl it's worth a shot.


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## MarcoP (Dec 24, 2014)

Sir, your experience is surely invaluable. It has a small hole that was carefully covered by some electrical tape. After your insight I was able to notice the hole and a drop of solution still inside the electrode.

I'm already looking for some KCl, not much luck today but it is cheap enough and easily available online. As soon I'll get some in I'll try and let you know. What's also important to me is how to name it, calomel electrode with type 7 connector, this will surely help me looking for one.

Thank you!


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## MarcoP (Jan 8, 2015)

No go!

I've ordered pure KCl and made a saturated solution using distilled water, reaction was endothermic so I applied some heat, when cooled down I sucked the solution with a syringe living the crystals at the bottom, filled the electrode with the solution and sealed the hole.
Placed the electrode inside a cup of water, turned on the unit but the needle didn't move a millimeter so it must have died because left dry for over 10 years.

I think this is a combined? calomel electrode but the price for a new one is well over $100, too good to be true moreover they have never replied to me 

To have a better chance to get the unit working, what type of electrode could I use from the PDF that necromancer has posted? Or does anyone have a different opinion?

I'm having hard time with litmus paper. When I use some in very acidic solution it wont turn blue anymore, probably because it was too cheap when I bought it?
If I can't measure the pH, I can't get rid of waste solutions (unless I keep using new litmus paper every test and it's pretty annoying).


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## goldsilverpro (Jan 8, 2015)

MarcoP said:


> No go!
> 
> I've ordered pure KCl and made a saturated solution using distilled water, reaction was endothermic so I applied some heat, when cooled down I sucked the solution with a syringe living the crystals at the bottom, filled the electrode with the solution and sealed the hole.
> Placed the electrode inside a cup of water, turned on the unit but the needle didn't move a millimeter so it must have died because left dry for over 10 years.
> ...


Do you mean litmus paper or pH paper? In any case, neither are reusable as far as I know.


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## necromancer (Jan 8, 2015)

have you contacted the manufacture ?

have you opened it to see if it's not "burnt out" smelling it sometime works & looking to see if their are any blown caps.

not sure if you have ever tested electronic parts before.


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## necromancer (Jan 8, 2015)

litmus paper and/or pH paper are one time use only. just like stannous chloride.


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## MarcoP (Jan 8, 2015)

necromancer said:


> have you contacted the manufacture ?
> 
> have you opened it to see if it's not "burnt out" smelling it sometime works & looking to see if their are any blown caps.
> 
> not sure if you have ever tested electronic parts before.


I do have some basilar understanding in electronics, It does turn on and a couple of hours ago I open it but I didn't see anything wrong, no leaks, no swallowed condensers... when I have a couple of hours I'll try to use a tester and see how it goes.



necromancer said:


> litmus paper and/or pH paper are one time use only. just like stannous chloride.


Oh ok, good to know. I've read in different places that people just drop a piece of litmus paper in a solution and observe the paper changing color when the pH does. In that case I'll try to get this unit up and running, if not I'll get in more litmus papers.

Thank you!


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## MarcoP (Jan 8, 2015)

... and yes, I contacted them but no reply :shock: I might have to try again.


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## necromancer (Jan 8, 2015)

MarcoP said:


> ... and yes, I contacted them but no reply :shock: I might have to try again.



that's good !!

dropping a piece of litmus paper in a solution may not let you see the true colour of the litmus paper, (for example) if the solution is yellow or green. 

dipping & removing the litmus paper or putting drops on it will give you the best results.


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## justinhcase (Jan 8, 2015)

necromancer said:


> litmus paper and/or pH paper are one time use only. just like stannous chloride.


And you can put what little value is in the paper in with your filter bag for latter recovery.With an electronic P.H. meter you have to keep rinsing after use.
And you may contaminate the next solution you test so I proffer to use a good cheep as chips multi PH indicator paper.
Electronic probes are very useful for one use monitoring of an individual reservoir as long as it is not to hot and about neutral.
The contacts and components do not stand up very well under the harsh corrosives that you find in a P.M. processing aria.


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## necromancer (Jan 8, 2015)

this guy is in Canada
http://stores.ebay.ca/TheUnderCutter
you can buy from China with no shipping charges


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## dannlee (Jan 8, 2015)

With the pH paper strips - cut into squares or little oblong rectangles, hold one piece with tweezers, dip a glass rod into solution to bring up a clinging drip to meet with the paper away from fumes & heat.


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## MarcoP (Jan 8, 2015)

@justinhcase
I do already put the papers with filter for later recovery if they were used with PMs in solutions, however good point on the corrosion.

@necromancer
I'm not following you, the ebay page have only unrelated stuffs...

@dannlee
Great tip, I normally dip the paper with tweezers and pull it out but I have to try to keep the paper away from fumes and heat using a glass steering rod as suggested.

I'll wait for their reply on my quote request, if no go I might try to sell the unit on ebay and if it doesn't sell I'll scrap it, it does have some transistors with gold plated legs, the first I ever had in hands and I just can't resist to use pliers on it lol

It was a good unit because it could measure mV, so I presume it could have also been of help in a silver and a sulfuric cell?


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## necromancer (Jan 8, 2015)

he sells cheap ph paper strips.

http://www.ebay.ca/itm/80-pH-Test-S...ll-Range-1-14-pH-Meter-Canadian-/151302211405


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## goldsilverpro (Jan 8, 2015)

I haven't used litmus paper since I was about 10 with my 1st chemistry set. It only gives a go-no go test for acidity or alkalinity and is worthless for actual pH. Red or blue. pH paper, on the other hand, gives an indication of the pH, which is much more informative. The pHydrion brand comes in a roll like scotch tape and you only tear off what you need.


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## MarcoP (Jan 9, 2015)

GSP, from your post I gather that litmus papers are different then multi pH papers.

If that is the case, my bad! I'm using multi pH papers in 5 meters roll and erroneously kept calling them as litmus.


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## rickbb (Jan 9, 2015)

Wasn't Litmus the guy who developed the testing method? And the reason the name?
Not trying to sidetrack the discussion though.


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## MarcoP (Jan 9, 2015)

From memory it's the name of the algae it come from or something like this. Google search? Just testing my memory, however I'll search as soon I submit...


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## necromancer (Jan 9, 2015)

some info:
http://en.wikipedia.org/wiki/Litmus


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## MarcoP (Jan 9, 2015)

> Litmus is a water-soluble mixture of different dyes extracted from lichens





> A lichen is a composite organism that emerges from algae or cyanobacteria (or both) living among filaments of a fungus in a mutually beneficial (symbiotic) relationship.


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## solar_plasma (Jan 11, 2015)

The cheap electrodes I know contain a silver wire, AgCl and KCl. If the wire is still shiny and the solution is renewed, the only problem could be the membrane. I believe, that after drying out, the membrane got clogged. One possiblity I can see is to try to leach out the dryed or decomposed salts from the membrane or to use something else as a membrane or, if this whole thing is made of glass and/or ceramic to treat it with some hundred degrees celsius heat, though far below melting point. 

I have no clue if this would work. Easier to buy a cheap electrode for 10-20€ and evt. change the connector yourself.


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