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Philips L4135 CWA Ballast for 180W SOX

Posted: Mon Apr 27, 2026 12:44 pm
by Alex
Hello,
Last meet i was given a CWA Ballast for SOX 180W by Kev of the type L4135. I got the ballast safely home and when i tried to run it, i noticed that the capacitor was mechanically brocken. I replaced it, and then tried to light my only 180W SOX lamp. It is a newer philips but is alredy used but "should" still work... Well the lamp didn't ignite, however I noticed something: The open circuit voltage is only 290V... With the lamp having an operating lamp voltage at 245V im pretty sure something is wrong...
Does anybody know the supposed open circuit voltage of that ballast?

Last week I got a Philips SRP251 180W SOX streetlight that had a proper leak transformer in it as areplacement ballast. Thatone has an open circuit voltage of around 700V which is more to my liking for these lamps. If i find the time, i plan to see if my SOX lamps works on that gear at least or if i need to hunt down a new bulb...

Re: Philips L4135 CWA Ballast for 180W SOX

Posted: Mon Apr 27, 2026 6:08 pm
by Nick217
Ive a few I think. These a grey coloured ballast?

Re: Philips L4135 CWA Ballast for 180W SOX

Posted: Mon Apr 27, 2026 7:14 pm
by Alex
yes

Re: Philips L4135 CWA Ballast for 180W SOX

Posted: Wed Apr 29, 2026 12:39 pm
by AngryHorse
Was your replacement capacitor rated at 440 volts?

Re: Philips L4135 CWA Ballast for 180W SOX

Posted: Tue May 05, 2026 10:54 am
by Alex
Hello,
thank you for the replies. I took the ballast out of my test bench and replaced it with the May and Christe leak transformer that can be seen in my gallery. I checked, and my SOX 180W lamps indeed works and the open circuit voltage of the may and christe is 740V. I then had againa proper look at the philips unit.
@AngryHorse, i checked and indeed ma capacitor was only rated for 380VAC so a bit short. Im am aware that this is not ideal, however it should work at least for testing--and indeed the capacitor was not the problem. The problem was a corded lead in wire into the ballast from the terminal block. I cleaned that up and retried the ballast, without lamp however and was pleased to find an open circuit voltage of 690V.

Re: Philips L4135 CWA Ballast for 180W SOX

Posted: Sat May 09, 2026 7:42 am
by Nick217
Drop me a private message. I have over 30 of these gear sets under my stairs so can bring a few to Cornwall for you.