# Powering up a VSS-3A, what's inside the controlbox?



## Walterk (Mar 12, 2011)

For those who don't know this lights: It’s a 1000W short arc xenon light with 50 million candela reaching miles and miles.
Usually mounted on M60 tanks and other vehcicles, from the Vietnam Era up till unaided night vision equipment became widespread. 

What I like best is the extremely narrow beam, being 1 degree up to 7 degree. (Search CPFF for VSS, some beamshots there.)
A bunch of CPF-ers have/had them, so hope they jump in with some info.

I had the luck of stumbling over a VSS-3. Naturally I couldn't resist. Now I've got a bare light unit, without cables or controlbox.Sorry, no beamshots yet.

For Europe I think it's especially a rare find. Don't expect to find me a controlbox here, so placed an ad for that on CPF Marketplace. 
Thrilled as I am, I am fully aware it might take a long time to make this work. (After all, what's the use of a having a light that can not be fired up, and it could be a non-runner anyway.)
Hope to get some answers to make this powerlight shine!

*Main question: *What's inside the control-box?
And thus, is there a work-around using different parts, or can it be duplicated/reverse-engineered?
(Power, wiring and connectors is not the problem. It’s the igniting of the lamp I think.)
*Other questions:*
 -Who owns a VSS-3? Is it working?
- Anyone managed to, or heard of powering up a VSS-3 without a controlbox?
- What is the arc-length of the bulb?
- Just-in-case: does anyone know what bulb can be used for replacement?


Thanks to googlebooks I got some manuals, for the VSS-3A: (Housing has rounded corners.)
TM 5855-217-12-1 (1970) Operator manual VSS-3A (NSN 5855-00-177-3529 and NSN 5855-00-405-0404)
Besides that there are some diagrams to be found, from 5 different models (electrical-wise): 
TM 11-5855-217-35 Maintenance manual VSS-3 (NSN 5855-00-058-1293)
They are difficult to read and don't know yet how to make up what model mine is.

For the VSS-3: (Housing has partly chamfered corners.)
To some extent the build and operating of the VSS-3 and VSS-3A are much alike I think.
TM 11-5855-217-35 (1971) Maintenance manual VSS 3 (NSN 5855-00-058-1293)
TM 11-5855-217-12 (1970) Operator manual VSS 3 (NSN 5855-00-058-1293)


Especially this Maintenance manual is elaborate about its inner workings. Couldn't find any for the VSS-3A. *Does there exist one?*

*I am looking for* one of the following control-boxes:
They should have the following numbers on them:
C-7905B/VSS-3 FSN 5855-00-189-6065 or 
C-7905A/VSS-3 FSN 5855-00-177-3525. 


Although the label of my light says VSS-3, it is a VSS-3A, this can be concluded from the federal stocknumber.
The controlbox for the VSS-3 (7905 FSN 5855-135-0154) does not work and damages the VSS-3A.
The VSS-3A works and accepts both types of controlboxes designed for the VSS-3A.
( Apparently there where made 5 sub models of the VSS-3A, they al work on any of the two above mentioned controlboxes. ) These lights have a controlbox, and a remote controlbox with fewer controls and without plugs on the front and without the testswitch. I do not need the smaller remote control, it just doubles some switches on the main controlbox. 
(I do not plan to buy new connectors, as I don't even know if the lamp nor bulb is working. )

It could look like this: 








Type-plate of my light: 








Searchlight, Infrared MX-8272B/VSS-3
FSN 5855-189-6066
80063-SC-D-647252
Ser.No. 0186
CONTR 73-C-0147
CEI
MFR 50054


I can not date my light, is it from 1973 ?


So, any information welcomed !


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## ma_sha1 (Mar 12, 2011)

How did you get so lucky? 

Congrats on getting the VSS-3A, dead or alive. I haven't been able to find one yet.


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## Walterk (Mar 12, 2011)

Found it on the local virtual marketplace for not too expensive. I guess someone sometime imported it or it originates from one of the US bases in Germany, e.g. Grafenwohr, where they have been in use on M551. Found this pic.





Thanks for the congrats, but feel ambigious and holding my cheer out with my luck. Had time to ponder while CPF was troubled. Don't know yet what to do with it. When possible; buy a set, not parts . 

Wouldn't like to wreck it for placing another light-engine inside. Its a very decent parabolic reflector with 900cm2 surface though.


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## BVH (Mar 12, 2011)

I thin you've seen this before but here's a post by TVODRD showing the inside components.

http://www.candlepowerforums.com/vb/showthread.php?169564-Looking-for-AN-VSS-3&highlight=tank+light

I have a couple working light heads, 1 control box, cables and a custom alum stand made by TVODRD that are not currently in my possession that I wouldn't mind getting back and possibly selling as a package.


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## Walterk (Mar 12, 2011)

Thx BVH, 

I knew I've seen it before, the picture. And it are the same diagrams that Ive found.





But whats the printboard on the side doing, I think its called Timer P.W. board. 
Is it to do with the igniter, or just the trigger for the igniter ?
Or is it a timer to have the beam go back to narrow ?
Something else ?


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## Walterk (Mar 19, 2011)

The more I've read, the more feasible it seems to get this light powered up. 
IMO, for model 5, its mainly pin M and the capacitor bank to power up.

Its kind of Russian roulette to just try, untill I know what diagram is best to follow for this light.

Some typenumbers and age/model dating could be most helpful. How to recognize and date a model?

 If an VSS-3 searchlight is attached to a VSS-3A controlbox, the booster-starter module will burn out.
 If an VSS-3A searchlight is attached to a VSS-3 controlbox, the searchlight will not operate but nothing will be damaged.

 I have no indication the bulb is different, so I assume the igniting electronics are different.
For the VSS-3 the controlbox sends 3kV to the igniter, and for the VSS-3A it is 6kV. Maybe for easier hot-strike or faster full output?


 In essence the same design principles in wiring and hardware are used.


For example the capacitor-bank in the controlbox:
VSS-3 Model .. --- 6x capacitor 360uF
VSS-3A Model 1--- 8x capacitor 
VSS-3A Model 2--- 3x capacitor 
VSS-3A Model 3--- 3x capacitor
VSS-3A Model 4--- 3x capacitor 360uF/350V
VSS-3A Model 5--- 3x capacitor
(From the model 3+4 diagrams show the capacitorboard inside the lamp has 5 capacitors.) 

The electronics inside the controlbox are:
A delay-timer for the igniter-booster module.
It makes sure the igniter repeats the starting pulse for maximum 7 seconds, and 4 seconds after the arc has been established. 
Capacitators, for giving a pulse to start the igniter-booster module.
 A relay (and maybe a timer) to make sure the fan is running after the light is shut down.
A main power relay. 

Hope that one of the (at least in the history of CPF) 9 owners of VSS-3 on CPF could jump in!


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## Walterk (Mar 20, 2011)

For the time being;
For model 5, from deduction on this diagram (link), I made this diagram (link) that I think would help me out. 
But I need checking with people that could know better yet. Electronics is not my brightest side.....so suggestions appreciated. Feel free to think it over for a while. 


(And still can't tell what model I have and what the differences are between model 1-5.)


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## Walterk (Mar 22, 2011)

Some pics here.


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## BVH (Jun 21, 2012)

Did you ever get your light going?


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## Walterk (Jun 22, 2012)

No, I sold the light, it required to much time and investments to my idea, for a light thats awesome but would hardly be used. If I had more spare storage space I would have kept it for 'some time later'.


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## ma_sha1 (Jun 22, 2012)

I believe Ra bought that, but haven't seen any actions...


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## dizzytats (Nov 20, 2015)

I came across a few of these lights. 10 i beleive. A couple are new "shells" and others look like what you have posted above. Is there a market for these things?


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## NoNotAgain (Nov 21, 2015)

dizzytats said:


> I came across a few of these lights. 10 i beleive. A couple are new "shells" and others look like what you have posted above. Is there a market for these things?


 There's a market, if the price is right and there are cables and control boxes to be found.

Seems that the west coast has to most surplus available.

I've also seen a few in Israel, but shipping is a deal breaker. 

The AN/VSS3 light requires 60 plus amps supplied at 28 volts. Unless you have a military truck with a 200 amp alternator or a surplus genset, most people don't want to mess with them.

Depending on price, I might be interested in one unit.


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## dizzytats (Nov 21, 2015)

I've read here on some prices. From what I've seen, 250-300 seems to be the price people were jumping all over. I have 12. I'd like to sell them all, but I'll ship one at a time. Below is a link to my craigslist ad. Please, shoot me a message. I'd like to know more about what I've got here.
http://dallas.craigslist.org/ftw/bfs/5325415423.html


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