Accidentally bought a second HP 2802A thermometer a few weeks ago from CDL for £20 + p&p, bit surprized no-one else bid, maybe the lack of probe with it put others off.
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif)
Anyway it came very well packed as usual.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183242)
After opening I had to decontaminate it of this BS sticker.
![Bullshit Detector :bullshit:](https://www.eevblog.com/forum/Smileys/default/BullshitDetector.gif)
Straight in the bin where it belongs.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183246)
This is a bit older than the other one I have, serial number is 140 (ref A board), very few differences inside apart from they forgot to put a trace for the +5V to the connector on this one and minor component layout changes, later one has some extra test points (rev C board).
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183250)
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1118274)
As expected it clearly had problems (checked with probe from the other meter) , it was cold a few weeks ago when I took this picture but not that cold, also the switches were very intermittent and kept getting stuck.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183254)
It was put to one side while I was identifying what probe & connector to buy, the connector turned out to be a standard locking DIN type and the probes are industry standard PRT 100, a four wire type is needed.
The probe & connector from Farnell cost slightly more than the meter did.
Those arrived this week and got wired up & tested with the working meter, after confirming it worked I tried the faulty meter again, still broken.
Someone forget to order a second connector for the performance tests with a decade resistor box
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/facepalm.gif)
, a bit of searching found a non-locking DIN, soon had that wired up, but still not working properly.
Before going into the fault finding procedure I thought it would be best to try cleaning those switches, they were a bit fiddly to take apart but cleaning the contacts & re-greasing the latching mechanism made a hell of a difference.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183258)
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183266)
A bit later after adjusting the zero & 2408 cal settings, pictured with the newer meter (which has a noticeably dimmer display) all good now.
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/cheesy.gif)
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183270)
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1183274)
They both probably need a cal check with an ice/water bath at some point, as per the the calibration procedure. Despite the extra resolution mode the accuracy is apparently only +/- 0.5°C.
David