IWS questions

[Kev G]

Is it possible to upgrade an L1A1 IWS to L1A7? with the brightness controller on the rear of the battery cover ?
If so has anyone got the parts or know where I might get them ?

What date was the L1A7 version introduced ?

Any help much appreciate,Kevin

Information

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[blurrededge]

Yep, you can retrofit the variable controler. Best bet is to keep an eye out on that well known online auction site for one or you could try ringing round some of the militaria dealers that occasionally have these sort of items in.

[Peter Laidler]

Be warned though......... It's not just a case of swopping the battery cover over and putting the ABC type cover on. You also have to replace the original static inverter with a dummy inverter in the little compartment ahead of the battery housing. That's because the........... anyway..........

[Kev G]

OK thanks to you both.
Any date as to when the later ABC type cover was introduced ?

Cheers Kevin

[Peter Laidler]

Difficult because it wasn't introduced across the board but as a modification as and when certain IWS's went in for overhaul or other repairs. Some weren't modified because their use didn't require the ABC, such as the IWS used on certain weaponry whereas others did need it for other weapons (like the L42) and when used for night vision purposes (as opposed to a night sight). First use of the then 'new' ABC IIW's fo far as I remember seeing them was in the late 70's/early 80's.

[Elphiel]

Hm... can you please give the reason why it wont work with the regular inverter unit? I rebuild my civilian SS20 IWS from scrap to running order over the years. First i used a self made proprietary battery cap that had no brightness control and it worked fine. Recently acquired one of these regulated ones from a guy from said online auction platform and it worked well too. All with using the same inverter piece. But i can't tell what kind of inverter it is because i acquired the IWS from some greek guy who doesn't know anything about it or even what it was in the first place.

[Peter Laidler]

Before I start a long spiel about the electro-mechanicals of the circuit and the relationship of the inverter on the electronic tube with voltage variations, do you - and all the others out there with one of these Rank Precision/RP-SS20/L1AX IIW's - have a copy of the a) user handbook and b) the instructions for use? If not, van I suggest that you speak to Brian at BDL Ltd and get one of each.

Without them you're not going to understand what's going on inside now or what's coming next.........

Batteries are also available from a forum member too.........

[Kev G]

Yes have copies here.