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Tidying Up An Analoy 1401 Alloy Analyser

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My recent resurrection of the Induction Furnace has encouraged me to dig out a pair of Alloy Analysers that I've had for ages - indeed in the Furnace thread there are examples of their use.

This has brought to my attention what a dreadful state they have got into - mainly due to the original case foam having degraded and bits crumbling all over the place. This isn't just cosmetic, it makes the instrument unpleasant to use and pack away, and physically difficult to get bits in and out.

So the plan is to entirely remove the instruments from their cases, give them a good clean up and replace the original lining with a modern neoprene closed cell foam - a square metre of which arrived by post this morning  :thumbup: There are also the usual age related frayed cables and general wear and tear to redress.

The green perspex 'arc shield' on one has broken - I remember supergluing it a few years back. Superglue scraped back to perspex and cover clamped together and gluing as I type, this time using a perspex glue - the same stuff that successfully repaired the lube oil reservoir on the little Mirac CNC Lathe.

Now I didn't think that I had much in the way of technical information on these instruments so have been in touch with the manufacturers - Arun Technology, where their Finance Director is very kindly trying to find out what he can. It seems my instruments date from the late 1980's and Arun have moved twice since then and their archive isn't digital. However he is putting me in touch with one of their long standing Service Engineers when he returns from holiday.

When I opened up the second instrument, not only did I find that I have an operating manual, but partial circuit diagrams and a spare EPROM !

So before I start pulling them apart have a few pictures:

So the first thing to do is remove the contents of the case and clean off the original heavily degraded foam lining and it's adhesive.

The lid has a complicated bit of metalwork in it retained by four screws that makes various compartments to store accessories. - it must have been an expensive bit of metalwork to make - nowadays it would probably be a plastic injection moulding.

The foam is held on by double sided tape - I have yet to find a solvent that removes it satisfactorily without removing the underlying paint work. Zippo lighter fluid (refined petroleum) removes the remains of the foam but doesn't touch the tape. IPA doesn't touch either, I daren't use acetone which happily removes the adhesive as it's equally happily removing the paint  :bugeye: In the end I used Toluene, which softens the adhesive to a sticky mess that can then be scraped off, but it's not a very satisfactory process.

So the result of an afternoons work  is the case of instrument #1 cleaned off internally with the lid inner frame also cleaned, but there is one cavity in the electronics unit that is the storage for the probe that remains covered in the old foam. I had hoped to be able to dismantle the framing such that the foam covered bits could be removed to be cleaned but it turns out that the cheeks of the cavity are fundamental parts of the structure. The foam will have to be cleaned off mechanically as I don't want solvents and sticky gunge all over the electronics. But that's a job for tomorrow - I have a head full of Toluene vapour so time to finish.

As I thought, the electronics is built round an 8085 microprocessor and is all rather nicely made with 1989 dated test labels everywhere.

I will treat the probe head as a separate unit as indeed it is, as it just plugs in.

Yes, that is a product "of its time"! 1985 date codes on some of those old ICs, multicoloured ribbon cables, WIMA(?) film caps, TO-3 power transistors. Those were the days. As you say, seems to be from the late 80s judging by the date code on the micro.

I wonder how the sensor head works? Pretty sure you said it analysed the light spectrum but can't see any mention of it in the furnace thread now that I look - years of self abuse have clearly taken their toll on my eyesight.

I think that the clever scanning bit is in the probe which Iíve never opened up, but I will be !

Andrew, you are a lucky man to own that level of equipment.  :beer:


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