Teardown of an ISG Talisman Thermal Camera by Mike

[Fraser]

I have just seen that Mike did a teardown of an ISG Talisman thermal imaging camera.



The camera is a Pyro-electric Vidicon based unit that predates the later BST and Microbolometer technologies.

It is still a useful camera and, when set up correctly, produces a decent image.

Mikes camera needs the voltages on the tube setting along with the electronic focus, so it is blurry on his video. Pyro Vidicon's are capable of  better images than shown here.

I own some ISG Talisman Pyro vidicon based units and later ISG Talisman Wasp's that use a BST detector. The Wasp produces a superior image, has a X2 image magnification mode and temperature measurement. My Talisman cameras are in need of some repair or 'calibration' so I will upload pictures of their internals here, as and when I get to them on my to-do list.   

[mikeselectricstuff]

Tesla500 also looked at a similar unit a while ago

[TopLoser]

I bought a couple of those Talisman cameras a few weeks ago, £50 each in non-working condition. They looked exactly like the ones in the video but had a solid state sensor instead of the videcon - looking at the video output from the camera it looks like the sensor resolution is 320x240.

The faults were easy enough to fix, the spinning shutter wasn't working on either of them. Bought new motors and they both came back to life.

[Fraser]

Hi Toploser,

The Original Talisman was a Pyro-Vidicon unit but the model progressed to 320x240 BST detector and used the same case. Obvious differences are that the BST units have a sharper edged PTFE lens shroud and a multi pin configuration socket adjacent to the handle. The next generation of Talisman was the 'WASP'. It is a 320x240 BST detector unit and is basically a slightly different case with RF transmitter and 2X Electronic Zoom function. BST based TICs are very good quality so you should be getting a decent image from them.

I am interested to hear that yours had failed rotary shutter motors. I understand the shutter was the weak point in most systems that needed them. Are you able to share identity and your source for the new motors ? I currently own one Pyro-Vidicon Talisman and three BST WASP's.

Regards

Fraser

[TopLoser]

One of mine had the configuration connector, the other didn't. One had a black lens shroud, the other was white. I guess they just used whatever bits they had lying around during the transition from one model to the next!

The image quality is excellent. I wish the focus wasn't fixed, but £50 for a 320x240 resolution TIC I can't complain too much can I?

I got the motors from FAULHABER, DC-Micromotor 1516T012S

http://www.faulhaber.com/servlet/com.itmr.waw.servlet.Anzeige?fremdaufruf=ja&kdid=40929&sprachid=1&htdigurl=/n167866/i86089.html

Hope that helps,
Ian

[Fraser]

Thank you for the info. Much appreciated.

For close up electronics work just place a ZnSe lens in front of the fixed lens. (no mods needed) I acts like a jewellers Loupe for the TIC !

A 20mm diameter ZnSe lens with 100mm focus distance is approx. $30 delivered via e*ay

[TopLoser]

100mm focal length lens on its way to me 

Next mod is to junk the smelly yellow case and internal CRT, replace with nice new housing and LCD 

I've owned lots of Fluke TIC's before this one but I must admit I'm loving the resolution of this Talsiman.

[Fraser]

I intend to build one of my BST based Talismans into a new case as well. These units take a beating in their normal role !

You will need to mount the ZnSe lens into some form of rigid holder. I have purchased metal camera lens holders that date back to the 1970's. These come up on e*ay often and make a perfect building block for an auxiliary lens mount.

Be warned, ZnSe is a relatively soft material so can be scratched easily, so treat the lens like plastic lens specticles when cleaning.

Let me know how you get on.

[Henning]

Hi guys,

I have also two of the ISG (here in Germany sold by Draeger) Talisman thermal imagers.

They work with another type of sensor, not the vidicon tube.
This one also has a shutter wheel, and is cooled by a peltier element with a fan attached.



It has a 2.4GHz video transmitter, and a video camera, but no magnification or temperature reading.

You can see the whole thing open here:

http://bit.ly/1SAE0Gb

[Fraser]

@Henning,

Thanks for the pictures of your ISG Talisman.

The unit you have is the successor to the Talisman classic that used the Pyro-vidicon tube. It contains a BST detector array that uses a spinning shutter wheel to refresh the detector elements at IIRC 30fps. The BST detector 'sees' change rather than static temperature and needs the wheel to create such synchronised change.

BST was a very good technology but, like so many other products, the microbolometer won out on simplicity and greater investment by the US military.

I own one original Pyro-Vidicon Talisman and five of the much later BST cored WASP models which appear very similar to your unit but with a later case design.

I contacted ISG regarding the Talisman schematics and they tried to help. Sadly the classic Talisman is so old that the schematics have been lost over the years. The later BST based cameras are covered by the ITAR regulations due to the performance of the detector assembly.

Via my helpful contact in the industry I can advise that the ISG products are similar electronic design to that produced by EEV. The two were past partners  The BST detector core is a Raytheon product (hence ITAR regulations) and is a complete operational thermal camera in itself, with analogue video output. The control lines from this self contained Raytheon camera are married to a third party microprocessor board to provide the functionality that the OEM desires.  Even if the third party microprocessor board fails, the Raytheon camera is still usable on its own

The schematics for the BST equipped Talismans are not available to the public and I do not have access to them. They are protected under ITAR so ISG cannot supply any internal technical information.

IMHO, the Talisman is not the greatest build quality with its very DIY appearance inside. The EEV ARGUS 1 (Pyro Vidicon) and ARGUS 2 (BST)  of the same period are far superior in terms of build. I own several ARGUS 1 and 2 units as well. The Talisman saw service throughout the world and appears to have performed well in its role.

Aurora

[Fraser]

@Henning,

I forgot to ask..... what was the cause of the strange dash pattern that is visible on your cameras CRT screen ?

Kind Regards

Aurora

[helius]

Is the battery level indicator processed as a video overlay, or is it scanned by the CRT during vertical refresh to achieve higher brightness? It looks like the latter by the way that it appears broken up scattered over the display. It appears that the circuit to control its vertical deflection is integrating incorrectly.

[Henning]

Hi,

sorry for the late answer, I don't check here very often.

Yes, the strange pattern is the battery status overlay. Somehow it goes all the way over the screen... Maybe some timing issue, Idk...

[Alexander R]

Hello everyone!
As you can see I just logged in for the first time here and searched for some answers. A few are found, one is not:

I just got some Dräger/Drager/Draeger Talisman C series thermal imagers. One is ok so far, but the screens of two of them are flickering. As I am not an electronics guy myself (just can go to my brothers' company and get some help there), I don't want to search for the failure just by myself- I could do too many things wrong.
Basically I understood that most of the internals could be left out if I wanted to re-embed the important parts in another (smaller) case. The cameras so have an external, analog video out, so another screen will be used.
But, if I wanted to keep the whole setup, is there a well known failure that makes the backside screen flickering (0,5Hz to 1Hz approx.)?

Any help would be appreciated. I am German, so I could talk to someone here, too. Of course overseas as well... :-)

Alex

[Fraser]

The chopper wheel that rotates in front of the BST sensor needs to be checked for damage and correct synchronisation. ISG Talisman chopper wheel motors do fail. The symptom being stiffness when turning the shaft. New motors are available, but expensive. Refurbishing the motor bearings is a possibility, but not a simple task.

Without schematics, fault finding on these cameras is not simple.

The power supply circuits are always a good place to start a fault investigation. Ensure or power supply rails are healthy before blaming any other area of the camera electronics for a fault. The video monitor section is just a simple composite video monitor so the composite video signal feeding it may be fed to another monitor to see if the flickering is present. If not, the cameras internal monitor has a fault. If the flickering persists with an external monitor, there is a problem in the in the signalrocessing stages but that is more complex to work on.

These cameras use a Raytheon Core kit that has an ISG video overlay and control system added to it. The core is capable of producing a video signal without the ISG boards. You may with to go looking for the video signal output on the Raytheon core board connector with an oscilloscope and see what the signal looks like at that point on a monitor. If the flickering is present, there is a problem in the Raytheon core section or its power supplies. If no flickering is present, the fault lies in the ISG video processing circuitry.

Fraser

[Spirit532]

New motors are available, but expensive. Refurbishing the motor bearings is a possibility, but not a simple task.

There are no bearings in those motors, they're oil-infused bronze bushings.
However, you don't need to buy that exact motor, since it's a closed loop system. Just find a motor that fits and is capable of producing speeds equal to or higher than the failed one at the same voltage.
A good place to look is old DVD drives - the tray ejection motor is almost certainly going to fit the Raytheon cores.

[Alexander R]

Thank you, guys! Since I am on holidays now (picked the Dräger's up on the way to our island...) I do have only very limited possibilities to check the cameras.
But the two flickering ones have slightly different frequencies when flickering (whoa, what a sentence). So a little lower and differently turning chopper wheel could be a good point... I would try ro make the motors run smooth again. I do have a bunch of Faulhaber, fan motors (brushed and bl) and many other motors availabe.
Someone have the motor size and (min) rpm of the motors needed for this cam?
So the chopper wheels are not synchronized with whatever? Sou said the just have to have high rpm? That should be easy.
Yes, I was planning to connect an external screen as well. Can do that at home. That would be the easiest way so solve the problem, because the cameras will be stripped anyway. Only the analog out is needed (security cams around the house).

[Spirit532]

Someone have the motor size and (min) rpm of the motors needed for this cam?

They're a standard size, but I don't remember the exact dimensions. It's the same size used in cheap toys and CD/DVD drives.
I believe the speed should be around 3000 RPM @ 3V, but it's not a really big issue, see below.

So the chopper wheels are not synchronized with whatever? Sou said the just have to have high rpm? That should be easy.

They are. The wheel itself has a reflective piece(or could be an interrupter slit on your version) that forms a closed speed control loop. The wheel will always run at one speed, which is synchronised with the sensor's readout(it needs to be "reset" by the wheel every frame, because BST sensors only see changes in temperature).

[Fraser]

It should be noted that the chopper wheel motor used in the various Raytheon BST core kits varies depending upon application and the generation of kit.

Two types of motor are common. The Faulhaber compact coreless type and the 'pancake' type commonly found in CD drives to spin the disk. Apparently the Faulhaber motor suffers from angular inertia induced speed variances. The CD drive type motors are better in this respect.

Oilite bearings in the motors can be restored with some effort. I have just copleted such a task on an expensive motor. I used a combination of Acetone, a vacuum chamber, an ultrasonic bath and some W30 weight motor oil. It was not actually very difficult to do. More info if needed.

I do not have a motor to hand but on the similar ARGUS 2 camera it has the motor type marked on it. I shall take a look for details in my data archive and spares boxes.

Fraser

Fraser

[Fraser]

Some information I quickly scraped together on the two motor types used in teh Raytheon core kit.

The Faulhaber coreless motor is a far superior unit that contains precious metal contacts, hence its high cost ! It is fitted with ball bearing races for long life. The CD type motor is a much cheaper affair that uses a cored motor and Oilite bearings.

The Faulhaber motor in the Argus 2 Raytheon core is type 1516T. I forget the voltage marked on it.

The CD type motor is type Mabuchi / Kysan RF-300PA 11400 and rated at 5.9V. It measures 24.35mm x 13.2mm with a 2mm diameter shaft.

Fraser

[Alexander R]

Thanks again to both of you. As soon as I am back fro holidays (don't want to think abount that too much) I will look inside of one of those Dräger's.
Like I said: I am not an eletronics man, but all the mechanical stuff isn't really a problem. I do have a pretty complete workshop with a bunch of CNC machines and to relatively often do interesting jobs in CNCing things for people...
Once I'll get the new 3D printer (TFT/resin type), I can print in 350x250mm... Could be imteresting for new housings of these cams and so on.
Fraser, you don't have to look it up now. I'll try to find out. Let you know in a couple of days, when Itook one of those apart. Aaahh, just seen that you wrote another reply. Thanks!
I know that I have a bunch of Faulhaber motors at home. All geard. But the gearbox can be removed. As long as they only have to spin (in roughly the right rpm) they could do it...

[Fraser]

I just dug out one of my dismantled units to check the motor model and supply some pictures. The unit in these pictures has a failed motor that is quite hard to turn. Gummed up or corroded ball race I suspect.

The motor used in your Talisman is a Faulhaber 1516T012S so it is the 12V version.

Some pictures for you .....


Fraser

[Fraser]

While I had the chassis on the table, I thought some pictures of the main PCB's might be of interest.

In this set of pictures, the upper board is the ISG designed control PCB and the lower board id the Raytheon designed core PCB that is provided in the core kit. The PCB's are held in place by aluminium end plates and RTV to provide further security for the connectors.

At the rear of the chassis there is the power board and the PCB 'backplane' sits at the other end.

Fraser

[Fraser]

PCB detail.....

ISG PCB first.....

Lots of unpopulated pads on this PCB. The board is populated as required for different camera models and capabilities.

Fraser

[Fraser]

Now the Raytheon PCB .......

[Fraser]

Power and Backplane PCB's......

[Alexander R]

Ooookay; Well, all that stuff seems to need a lot of space. So my plans to fit all that is really needed get harder realize.
The motor itself should not be a problem. As long as I can unscrew everything more or less easy I can replace that one for sure.
I was wondering if the main board was smaller... But looking at the pictures, I am in doubt that all the new housing can get small enough for me. And it's called main board for a reason, I bet. So I cannot "just" leave it out, hm...? ;-)
I was outside a while ago. Took the Dräger that is ok and was stunned of the still very good quality of it. Could recognice and identify my dog Elvis from, well, very far away (About 40cm shoulder hight he has).

[Fraser]

The Raytheon kit produces a perfectly usable camera on its own. The kit comprises the following parts that you can extract from the Talisman.

From the front.....

1. Lens block
2. Chopper wheel and motor
3. BST sensor PCB
4. Backplane PCB
5. Raytheon Core PCB
6. Power supply PCB (not required to be the one from the Talisman but that would be the simplest way)

The output from the Raytheon Control PCB is composite video.

Miniaturisation of the BST core is most limited by the large sensor array and its Chopper wheel.
Building a camera using the Raytheon Core kit does require a decent knowledge of electronics.

Fraser

[Alexander R]

That sounds to me as if I have to keep the whole stack, maybe just can fit it in a little smaller housing, but that's it.
If there was a small pcb that would connect to the sensor array and that would have a video out... That would be nice. But I think in that case I could try to get a used FLIR Tau or Vue instead. Ok, still very costly.

[Spirit532]

For professional firefighting cameras, they still look like a horrible hobbyist bodge all around.

[Fraser]

Spirit532,

There is a lot of interesting history behind ISG and it's camera designs. The man behind ISG was Ex EEV ARGUS. Basically It appears he took his EEV ARGUS TIC knowledge and started a new company.

The Talisman is basically a 'cottage industry' thermal camera that is built around the Raytheon BST Core kit that the ARGUS 2 used. It should be stated at this point that the EEV ARGUS products are a far more professional piece of hardware that incorporates sound engineering and excellent electronic design.

When I first saw inside a Talisman I thought it was a dodgy DIY build. There was a very basic bent aluminium plate chassis and masses of RTV spread around the unit. The whole unit looked home made and very amateur when compared to the ARGUS 2 that I know so well. The RTV was intended to stop parts and connectors moving if handled roughly.

The Talisman case is also a very crude affair and could never be described as good looking or of impressive design. I personally dislike the Talisman cameras but have a few for projects that may, or may not happen 

In the world of bespoke, limited production run equipment, it is not that unusual to see the build style and questionable build quality found in the Talisman. Some such units are iterally built in a shed with basic tooling and limited budget. Such equipment often looks very home made, but it performs the desired task. A 'It ain't pretty but it works' kind of situation. The Talisman prototype might be excused such build style and quality, but this was a professional fire fighting tool. It should have been better.

The good news is that the chopper wheel is relatively resilient and the Raytheon Core kit is easily extracted in order to use it in a different format case. Take a look at the EEV ARGUS 3 for an alternative camera format that uses the same style of Raytheon BST core kit. It is EEV's attempt at moving from the 'gun' or camcorder style ergonomics to the upright camera format that is now common in mobile phones. The E2V Mi-Tic (microbolometer sensor) that I own continues with this format and I must say I love the Mi-Tic 

Fraser

[Bill W]

The ISG story is a little different to that Fraser has given, the split happened a lot earlier back in the EEV-P4428 / Pevicon era and both companies essentially developed in parallel when cores became available from Raytheon. Quite a few EEV folks headed down the road.  ISG had a slightly greater interest in solid state cores as they did not make Pevicon tubes - EEV did and had the financial benefit (and technical drag) of their own sensor supply.
Rumour has it that the Talisman case was originally moulded on a Morris Minor inner wing.

I am not sure quite how easily the Raytheon core can be extracted from the Talisman electronics set, but it should be no worse than from the Argus 2 or 3 cameras.  Much depends on exactly how much is intercepted by the ISG backplane and control PCB.
There were only two PCB in the Raytheon kit, a detector PCB and a processing 'SECCA' PCB, and both EEV and ISG made their own detector PCB containing the Raytheon circuit to get control of the shape.

The 'Backplane' PCB Fraser shows is an ISG design to connect to the SECCA. With the Raytheon detector board (and also the EEV Argus 2 version) the SECCA 80 way connector fitted directly to it.  ISG have inserted a cabled connection to the sensor and included iris and fan control.  I never worked out what the fan was for - it only made things worse.

I have plenty of the chopper wheel motors if required by anyone, either variety.  Just drop me a mail.



regards
Bill

[Bill W]

Here is an image of the minimal Raytheon BST camera core built from an Argus 2, the lens and chopper wheel are omitted.

With suitable test connections this can be a 'Power-in Video out' system, and runs without the EEV/Marconi control board and display.  I am not sure if the ISG implementation would allow a similar extraction although the cabling would give some flexibility in mounting.

The same can be done with parts from an Argus 3, which by its' nature is a thinner form factor.

regards
Bill

[Fraser]

Thanks Bill 

Excellent information, as always, from you 

I am thinking that the Mechanical IRIS found on these fire cameras may not be essential at more limited temperature ranges, so that would further simplify a system 'slimming' process. Of course the EEV and ISG camera control boards would likely complain about no IRIS detected, but without those boards the core looks like it would behave like the IRISless Thermal Eye 300A camera.

Fraser

[Bill W]

Hi Fraser,

The core shown above does not have any iris functionality, so you'd just ignore or remove the iris mechanics and go.  What it does have added is a couple of links / pots to take control of the image away from the Control PCB and give it back to the Raytheon core which is probably how the 300D and Cadillac cameras are set up to work anyway.  This could be set to allow some AGC functionality in the core in place of the iris although ultimately the Raytheon BST sensor had a relatively limited dynamic range.

I do not know how the ISG camera is set up to work, but if anyone fancies probing a couple of pins on the 80 way connector I can tell you.

As you note, an EEV/Marconi/e2v Control PCB would put up the warning triangle on its' video output and therefore on the screen.  The core's own analogue output would not be affected.

regards
Bill

[Alexander R]

Hello guys, some short info from the non-electronics side.
Just came back from holidays. Pulled everything out of the housing (which seems to be made relatively... simple; looks in the inside like my first attempts of making GRP parts for model airplanes when I was 12 or so...).
Once the whole stack was without the housing, it worked just fine. No flickering of the image visible. I can not test the Video out as I have vo BNC-cinch converter here. But I will do.
There was a lot of silicone on the threads of the front caps of the two lenses (making them "water tight"...?). I removed most of it, put everything together again and it works just great.
The other camera was almost the same, but the motor for the shutter wheel seems to be weak. Most of the time it is working good. Holding the camera face down or up an then shaking a little bit (axial direction) lets the image flicker, then stabilizing again. So either the bearing of the motor are the reason or something else. But it's mechanical.

Bill, what information would you need to look for aproper motor and: Would you sell me one?

Or I might be thinking getting rid of two of those cameras, if someone would be interested. I still have one, looking for another one and just lost my job (extra tip: don't become a pilot in Germany...). So clearing up would be a good idea, too. :-)

[Fraser]

Alexander R,

Sorry to hear about your job loss 

The motor used for the chopper wheel is a relatively low torque coreless design that does suffer issues when the camera is panned quickly. The more powerful CD drive motor overcame this issue. The motor would not normally become 'weak' but the bearings can become an issue if they become tight. It would be worth comparing the voltage across the motor on the two cameras and the current passing through them. There could be a motor driver issue effecting the motor that appears 'weak'

I have provided pictures of the motor so Bill will recognise it as the same that is used in the ARGUS 2 cameras that he kindly supports.

Sadly I cannot offer a home to your cameras as I already own five of them  I will likely sell mine at some point in the future as well. They are a very affordable basis for a DIY thermal camera project and do perform well when correctly set up.The sad truth is people seem to be put off by the relatively ugly casing on these cameras. The Raytheon Core that resides within is very nice quality though. The lens block alone cost a great deal of money when these were built as they are high quality Germanium lens elements of decent size. Some people on ebay recognise this fact and strip out the lens elements to sell separately for more than they can achieve on the whole camera ! Its a weird world we live in.

Fraser

[Bill W]

Hi Alexander,

No problem sorting you out a motor. Drop a PM/email.

There's a lot of silicone in those early ISG products and it was a bit 'DIY' back then for them.  Rumour has it that the Talisman GRP case was moulded on a Morris Minor inner wing.  It is in fact a fairly well accepted technique for fire helmets. 

Using it for a camera case - and those glued on bushes inside - is not so clever.  They did not survive drops very well.

regards
Bill

[Bill W]

A couple of pictures of the Raytheon core 'minimal camera' from an Argus 3.

The partly cut off connector allows power-in video-out.
Some minor fiddling is needed to bypass the Argus 3 control drive via the MAX510 - for a later thread of its' own.

Bill

[Fraser]

Thanks Bill,

The first pictures of the ARGUS 3 internal chassis I have seen on the WWW. 

It is a nice chassis suitable for incorporation into DIY projects 

Fraser

[Bill W]

You mean you have not done a teardown on any of yours yet........... tut tut 

regards
Bill

[Fraser]

 

I know Bill, I am ashamed of myself 

I have too many partially completed camera projects so did not want to open anything else up until I have the situation under better control  I was hoping to find a better condition Argus 3 case into which to transfer the electronics package, and would then have combined the opening of my working ARGUS 3 with the transplant operation. Otherwise, I end up with boxes of disassembled cameras awaiting action  I have decided that I would like to restore my Argus 3 as the slimmer model that does not have the side handles. Sadly I missed out on the last sensibly priced good cosmetic condition faulty Argus 3 on ebay and I am no longer looking for thermal cameras, as per my New Years Resolution 

I shall have to get onto that restoration soon, but I am about to start my major sale of other equipment via ebay so I must get that sorted first.

Fraser

[Finderbinder]

How can I know sensor type from ISG K-90 Talisman (or it's version) external look? All black, no symbols can be seen on housing, 3 sensors at front vertically. Also is there any sense for such old thermal cam although cheep.

[Fraser]

Displayed image circular = Pevicon tube version

Displayed image standard 4:3 rectangle = BST version

[Finderbinder]

Displayed image circular = Pevicon tube version

Displayed image standard 4:3 rectangle = BST version

I think I see a circle in that display rectangle ant then rectangle even deeper in circle (do you mean this, or should it be turned on to be sure?):

[Bill W]

Needs to be on.
All of them used the same miniature CRT and magnifying lens arrangement.

Equally cameras with either sensor could come with the spot temperature / video overlay, although they would be more likely on a BST core.



Bill

[Bill W]

How can I know sensor type from ISG K-90 Talisman (or it's version) external look? All black, no symbols can be seen on housing, 3 sensors at front vertically. Also is there any sense for such old thermal cam although cheep.

Worthwhile with the BST core IMO. 
End camera sensitivity has not changed much over time and it is a 320x240 30Hz

If you were so minded, it is a bit trickier extracting the core for reuse from an ISG compared to the Argus2 Argus3.

Bill

[Finderbinder]

If you were so minded, it is a bit trickier extracting the core for reuse from an ISG compared to the Argus2 Argus3.

Bill

I mind to use it outside as a surveilance camera with some wireless video transmitter So maybe better not to dismantle.

[Finderbinder]

Here it is. Painted all over in black 
Appears it is a Wasp version.
Does a pinout exist for that multipin connector?

p.s.: the last picture is of poor quality because it is difficult to photograph a small CRT.

[dalittle]

Gain/Offset was preset at the factory for Talisman Wasp. That said, we could adjust gain/offset using a device (not provided to customers) that we connected to that Hirose connector.  The connector may have also given access to other functions (black hot etc.) but we didn’t really care and never used those functions. 

Additionally, I’m sure you already know the BNC on the other side is NTSC out.

That teardown was years ago. Just goes to show you that it is possible to be resurrected from the dead. That’s quite inspiring, actually.