Circuit Diagram for TEM-1555B

[bernardgreen]

I have just bought a TEM-1555B insulation tester from a yard sale on the off chance that it might be ( or become ) functional as it would be a lot smaller than my home constructed tester.

Does anyone know where I might be able to obtain a circuit diagram to save me the time and effort of reverse engineering it ?

Regards

 

[securespark]

Can only find this by Googling:
http://www.ebay.co.uk/itm/ws/eBayIS...vc9b317sIb6OncJoyvS3k%3D&orig_cvip=true&rt=nc

and the auction is over.

Can't find any paperwork associated with it. Sorry.

 

[bernardgreen]

That is the device, I wish the case I have was that good condition.

There are two wire wound resistors that look a bit over cooked so some work is needed.

 

[securespark]

Can you still decipher the colour code or are they well roasted?

Sorry, you said wire-wound....

 

[bernardgreen]

After cleaning the board I realised they were not "cooked" while on the board as there is no dis-colouration of the board. They are apparently a type that has a "cooked" appearance from new.

 

[ban-all-sheds]

http://www.ebay.co.uk/itm/ws/eBayIS...vc9b317sIb6OncJoyvS3k%3D&orig_cvip=true&rt=nc

Nice box.

 

[bernardgreen]

Update

I have finally got round to renovating the 1555B. I have reversed engineered to create a circuit diagram. Nice bit of good innoventive design.

The good news is it works and is remarkable accurate given it was dumped in a pile of junk for many years before I bought it as scrap.

The meter movement needed cleaning and the push buttons may need to be replaced. After cleaning they work but how reliable they will be is in doubt.

The 500 volt DC was 515 volt. Resistance readings are accurate to better than 5 %

Sadly tbe wooden carrying case is a write off and will have to be replicated.

The 1555B is going to make the final and documented tests ( for building control ) much easier and faster. Best £ 2 investment.

 

[JohnW2]

Update I have finally got round to renovating the 1555B. The 1555B is going to make the final and documented tests ( for building control ) much easier and faster. Best £ 2 investment.

Good to hear that you got it working. Will BC not want to see that it has been formally 'calibrated'? If so, how are you going to achieve that?

Kind Regards, John

 

[bernardgreen]

It will be calibrated against an AVO 8 and standard ( 1% ) resistors at full and mid scale values. Which is effectively the method used by the calibration services.

 

[JohnW2]

It will be calibrated against an AVO 8 and standard ( 1% ) resistors at full and mid scale values. Which is effectively the method used by the calibration services.

That would be enough to satisfy you and I, so I hope it also satisfies any of those who may be obsessed with the need for a 'calibration certificate'

Kind Regards, John

 

[ban-all-sheds]

It will be calibrated against an AVO 8 and standard ( 1% ) resistors at full and mid scale values. Which is effectively the method used by the calibration services.

No it isn't, because behind that is an auditable chain of certifications of calibration testers, of the calibration of the equipment which calibrates the calibration testers and so on.

Your method has none of that.

 

[bernardgreen]

The resistors can be sourced together with a certificate that they are within 1 % of the stated value. Of course the accuracy is dependent on the temperature but graphs are available from the manufacturers to show the variation in resistance with temperature.

The voltage calibration is a bit more involved if one is looking for better than 1% but far from impossible as a DIY process.

 

[JohnW2]

The resistors can be sourced together with a certificate that they are within 1 % of the stated value. Of course the accuracy is dependent on the temperature but graphs are available from the manufacturers to show the variation in resistance with temperature. The voltage calibration is a bit more involved if one is looking for better than 1% but far from impossible as a DIY process.

I have to say that, as I implied in earlier posts, I fear that BAS may be right. However, the whole thing is totally daft since, in practical terms, an accuracy of ±100% or worse would usually be more than adequate for an IR tester!

Kind Regards, John