Products > Thermal Imaging
Argus 3 (BST) teardown and repairs
Bill W:
The Argus 3 was a fire fighting camera made by Marconi and e2v mainly between 2002 and 2006, hence the name change. The version covered here is the most common 'yellow' version which used the Raytheon BST core and was 320x240 pixels. The other versions were 'blue' with a Raytheon ASi (160x120) and 'orange' with a Lockheed VOx (also 320x240).
As I have repaired a couple of these recently, I took some photos along the way to give a 'teardown' and provide a repair story. I will post slowly so there is a chance to reply roughly in the time line. The teardown / tour also appears on www.fire-tics.co.uk/project2
So the camera here was reported as 'not working' which can cover a whole load of actual conditions from totally dead, through black, white or grey screens to 'noisy but grey' screens. To most users these are all 'not working' although you can probably guess what each is due to.
So it arrived, and although not from a fire service it still needed a good clean before even holding it. The casing and box mainly stayed in the shed ! Initially I powered it from croc clips on the battery terminals from a PSU. A lot can be learnt from the current draw, and in this case all was well (10V, 3A current limit, took 850mA initially and then settled to 450mA). The picture though was a rolling mess.
On these cameras the screen runs off the external video so not surprisingly the external feed was the same. It was however thermally sensitive, a soldering iron could be seen flying up and down the screen. On the scope the video was clearly out of sync and variable field times.
So I am thinking something to do with the TV line standard switching. As that is easier for me to fix internally (and it was still smelly) I took it apart. In the end I could have corrected it from outside with the customer software, but would not have been able to fix the rest.
So after giving it a bath, on with the pictures....
Bill W:
The first set are just getting into the case and a few pointers to what is accessible on the sealed case. The screws are all hex head, 2mm or 2.5mm.
First image - shows how to remove front panel to access BNC video and alsos ee if there is a transmitter
Second image - Connectors and functions around the lens window. That RS232 (Fischer) connector had a dust cap but everyone loses them and they can just fill up with crud.
Third image - shows how to remove the handles. The cameras also came with side straps in which case there's two big screws each side as well.
Fourth image - these screws only let you remove the bezel and window, so OK to clean it but no use for disassembly.
I have also added the battery and base contact pinout.
The base power contacts are useful as they bypass the on/off switch circuit, apply power and the camera will start.
The charge contacts need some care, as the charger control is in the camera but the power supply was external, so the supply here is 1A constant current, up to 8V.
Bill
Bill W:
Now the fun starts for proper. There are 14 screws holding the case together (arrowed in the second photo). The camera chassis is attached to the front part of the case, so it is best to remove the back.
Bill W:
The split case. The LCD and buttons cable is marked with the green arrow, the chassis is held in with the 6 fixings arrowed in purple. The coin cell is for the clock IC and also memory backup, so a camera that has lost its' time (reset to 1 Jan 2000) or that will not store pictures can be repaired with a new battery. Given most cameras were built around 2005, the coin cells will now (2021) be getting near end of life.
Second image is running the chassis & front on the bench, with the pins for the buttons shown to 'hot wire' the camera. Just short the end two pins shown to pretend to be the 'on' switch.
These fixing varied over time, from rubber mounts (which let the chassis bounce around too much) to pillars (fiddly) and eventually spacer posts fixed into the chassis plate. Electrically there is an FFC connection and a power connection from the front case to the chassis to remove (third image) while lifting the chassis out.
Fiinal image, the removed chassis. This image has the power input connector shown as well as the 6 way 'export test' connector that I will come back to later.
The 6 way is marked up for the wire colours from the front case:
White 1 Unswitched power in +ve from base pin Red 2 Battery +ve - to on/off switchingBlack 3 0V / case / groundYellow 4 Charger +ve from base pinPurple 5 Battery ThermistorBlue 6 Battery 3rd pin - for AA pack detection
Bill W:
As for the repair, I got connection for RS232 and could read out the camera settings. This function is available on the 'public' software that came on the Argus 3 CD, a copy of which is available here http://www.fire-tics.co.uk/Argus3_CD/index.htm
Among all the usual settings, of note was it reported as 625 line but was not enabled to switch between 525/625. It thought it was January 2000, which means flat backup/clock battery.
Once inside I could look at the core video which was fine, and 625 line standard. Having persuaded the core to be 525, all was well. So it was running a mix of 625 on the core and 525 on the rest of the camera.
So how did it get like that?
Maybe after switching over the battery went flat as a lot of things only get saved during the turn off, or the user panicked, so the core changed but the camera did not. Given the flat coin cell more likely seems that on starting sometime the settings storage for the camera might have been lost and so reverted to defaults (525 & no switching).
So changed the coin cell and did the full factory setup & tests. After this I could switch back and forth as expected.
A couple of other things had also became apparent. The spot temperature was reading low (37°C for 54°C) and the lens iris was stuck (as this is common I had checked before putting it all back together).
So onwards.....
Bill
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