VHO Fluorescent Ballast: IceCap 660 Teardown / Repair

[theatrus]

My venerable IceCap 660 VHO ballast (which I use with T5 lamps) on my aquarium started flickering and would not restart. After smelling the sickly smell of pop electrolytics, I decided to test the "Repairable" moniker.

First step not pictured: drilling out 4 rivets





Yup, thats popped. And sprayed everywhere.



The logic section. The connector on the bottom is for a dimming control signal.

IR2110 - driver IC
http://www.irf.com/product-info/datasheets/data/ir2110.pdf

TL594 PWM controller: http://www.ti.com/lit/ds/symlink/tl594.pdf

LM339 Comparator: http://www.ti.com/lit/ds/symlink/lm339.pdf

555 Timer  (time the ignition cycle?)

LM393 precision comparator
http://www.ti.com.cn/cn/lit/ds/symlink/lm393-n.pdf




The ballast transformers.



The input section (with the caps removed)



A current sense transformer (likely?) hiding under the big transformers. There is a row of passives under each of the two transformers.



IGBT: http://www.irf.com/product-info/datasheets/data/irg4pc40ud.pdf


I don't have caps which will fit in the height footprint of the case, but those are on order.

[Evil Lurker]

Wow that looks to be like a fairly high quality build. There are tantalum capacitors on the control side and even a silver mica capacitor in there!

If it were me I would consider doing a total recap job + replacing the MOV's. Might as well get all of them while you are in there.

[theatrus]

I figured it was of some interest as these types of ballasts are usually potted affairs - this is one of the few I've run into which was not.

Good catch on the silver mica - didn't even see it.

[amyk]

That case style on D3/D4 is pretty rare too. I remember seeing those in military hardware.

[theatrus]

MR756 Silicon 6A diodes: http://www.onsemi.com/PowerSolutions/product.do?id=MR756

ON has discontinued them, but they do appear to be available from other sources.

[thm_w]

Nice macro shots.