>>It seems to me that a flourescent ballast is probably just a transformer
>>and
>>a high-voltage electrolytic cap.  And when it "goes out" it's probably
>>because the cap failed.  If these are true, could I just replace the cap
>>and
>>make it work again?  Assuming (hate that word) of course that I could get
>>the ballast open.  What thinks the group?  Please offer whatever laughing
>>criticism or encouragement you feel is appropriate.  I do not need a fire
>>hazard in the kitchen...

>  There are several different kinds of fluorescent ballasts.

> 1.  Simple choke - has 2 leads, usually used with a starter (occaisionally
>  a "push-to-start" switch).  There is normally no capacitor.

>  When they fail, there is generally no repair other than rewinding
> (extremely unlikely to be worth the time and effort), and sometimes the
> core is welded together.

> 2.  High leakage reactance autotransformer - has 3 leads, and is
> effexctively a choke combined with a step-up transformer.  Same story as
> 1.

>  A variant is the 1-lamp trigger start ballast, which has filament
> widnings added.  It is still essentially non-user-serviceable.

> 3.  The USA-usual "traditional" dual-4-footer - high leakage
> autotransformer with a capacitor in series with the secondary.  Also has
> filament windings and a small capacitor (in the ballast case along with
> all other parts) to leak a small amount of current around one lamp to help
> start the other when both are not conducting but voltage is applied.  The
> 2 lamps are in series with each other.

>  If the lamp-series capacitor (which is not electrolytic) shorts, lamp
> current will be somewhat high and ballast input current will be very high.

>  There are similar "trigger start" ballasts for 2 2-footers.

>  The case is usually packed with tar.  This one is also essentially
> non-user-serviceable.

> 4.  Electronic ballasts - more repairable than the others, but only by
> those who know how to troubleshoot and repair them *safely*.  Capacitors
> may store charge, and improper repairs may add a fire risk.
>  It may be difficult to verify that replacement parts are of
> suitable grades (temperature rating, life expectancy at given temperature,
> voltage and frequency, also failing less catastrophically, any flame
> retardance/resistance) and with suitable characteristics (such as losses
> sufficiently low to prevent overheating - and capacitors have 2 main
> losses).
>  Also, one is unlikely to repair a ballast for less (including value of
> time) than to replace it.

>  Bottom line:  Fluorescent lamp ballasts are generally unrepairable.

> - Don Klipstein (d...@misty.com)