Hi -

Found this ballast on eBay:

   GE 8G6012W - also branded Valmont or PowerLighting, apparently.

Looks like still one available, if you want to follow along at home:

   https://www.ebay.com/itm/293131923913

I wired it to a Lutron NF-10 fluorescent dimmer, which lists the Valmont 8G5007W ballast as compatible. And that model is also on the equivalence charts matching the GE 8G6012W & GE 8G5007W models.

So I wired it using the GE ballast diagram (attached). But when I turn it on at full power, I just get a glow from the electrodes on one side of the lamps, and It doesn't attempt to ignite with new or old lamps.

Then I compared the Lutron switch wiring for magnetic 2-lamp ballasts (also attached), and noticed it includes a connection from neutral directly to the disconnect lampholder pin on each lamp, in addition to the white ballast wire. I (foolishly) tried that, and one lamp lit brightly, along with a high-pitched whine and puff of smoke from the ballast (always a bad sign!).

It's all properly grounded with grounded metal reflector in place etc. And I even used actual disconnect lampholders for this setup.

Any ideas or experience to share that I can (safely!) try? I was really looking forward to that romantic lighting above my GE appliances in the basement!

Thanks!

   - Russell

I'm not sure why it wouldn't have worked if you had it wired as per the ballast diagram.
One thing I found with the Universal 2xF40 dimmable ballasts I have is that sometimes I had to run my hand across the lamps to make them start, especially with modern low-mercury lamps. (but that was also running un-grounded). And I also found putting a small incandescent load on the dimming wire for some reason helps too.
(Note Universal has a different wiring, I think its more like what your dimmer instructions shows.)

If these are anything like the Universal I have, you can simply skip the dimmerswicth & connect both the black and orange to hot.

Sadly because of "puff of smoke from the ballast" something in your ballast is now fried. Probably not much you can do with that.


Oh and circuit interrupting lampholders suck. If it were me wiring that up, I woulda just used normal ones. .lol.
So many times I've had those fail to make proper contact that I will not use them at all.

Yeah - Pretty bummed to fry this old monster!

I'll give it one more shot with the orange and black - maybe it can still manage the simple On/Off trick.

Thanks for the sympathy.

   - Russell

If these are anything like the Universal I have, you can simply skip the dimmerswicth & connect both the black and orange to hot.

Sadly because of "puff of smoke from the ballast" something in your ballast is now fried. Probably not much you can do with that.

No luck with the black & orange dimmer bypass.

Guess that "puff of smoke" really was the last breath of the dead parrot!

Yeah probably so
Do you have a meter where you can do any tests to see if you're getting anything at all out of it?
Like voltage output to any of the filament heating circuits? (any pair of same-color wires)
Or across the lamp circuits? (reds-yellows or blues-yellows)

Be curious to know just what part got fried, if it was the low-voltage/filament heating section (that would be my guess if I had to pick), or the actual ballast section.

It'd also be interesting to figure out if this is actually what it looks like: just 2 1xF40 ballasts attached together, or if they are truly integrated in some way...

Like voltage output to any of the filament heating circuits? (any pair of same-color wires)
Or across the lamp circuits? (reds-yellows or blues-yellows)

Here are the voltage pairs with the full "bright" dimmer setting -
Filament heating:
red to red+red/white = 5v
brown to brown = 4.8v
blue to blue+blue/white = 5v
yellow to yellow = 4.8v

Lamp circuits:
brown to blue+blue/white = 32v
brown to blue = 47v
yellow to red = 51v
yellow to red+red/white = 47v

On another F40T12 fixture (nondimming ballast), the voltage when lit between red & yellow is around 100v, which would give around 40w at the 430 mA rating for T12 lamps. 

Here's something I found on the Lutron site about 3-wire dimming:

"3-wire control is an analog control method that is primarily used to control Lutron fluorescent ballasts. It allows dimmers to set the intensity of ballasts by providing a line voltage phase-control signal from the dimmer to the ballast on a dimmed hot wire. The dimmer separately switches the power to the ballast over a dimmed hot wire."

So does that signal get passed through as higher or lower voltage to the blue/white & red/white output wires? I'm pretty clueless about how this stuff works, and I didn't try checking voltage at the dimmed settings.

Meanwhile, I found a picture of the exact Valmont model no. (8G5007W) that's listed in the NF-10 dimmer switch instructions as compatible, and the wiring on that ballast is just like the wiring for Advance/Universal/Valmont included in those instructions. So now wondering if my GE 8G6012W ballast really is compatible with the switch.

It'd also be interesting to figure out if this is actually what it looks like: just 2 1xF40 ballasts attached together, or if they are truly integrated in some way...

Yeah - I'm guessing you could just switch the 2 browns for the 2 yellows, and then each side of the conjoined twins would control a different lamp. (Would just need longer wires to reach all the way across this monster!) I can send this off to anyone interested in doing the autopsy report.

So looks like the filament heating is actually still working just as it should. Those voltages *should* remain the same no matter what the dimming level is set to(or even if the orange/dimming wire is completely disconnected)

Interesting that you're still getting something out of the lamp circuits, so it isn't completely dead. Maybe a blown capacitor or something then?? Yeah, should be more something like what you saw on the good ballast. This voltage should vary as you change the dimmer setting.
I wonder if it would still light a F15 or F20?

I looked to see what I had dimmer-wize from when I was trying out the Universal ballasts, they're Lutron NF-20 (which is same thing as the NF-10, but able to handle more power).
 
My understanding on how the old magnetic dimmable ballasts worked is they are very simple, and basically 2 independent circuits inside, so there's 2 hot wires:
The black, which goes to the filament heating circuit.
The orange (brown in my case), which goes to the ballast circuit.
..The dimmer simply dims the ballast wire, filament heating remains on & constant unless you turn the switch completely off.

I found some YouTubes showing you can check continuity from neutral for each color wire to test the ballast. The red wires are shorting to white. Guess I should have tested before installing it, might have saved some annoyance. Also the orange, red/white, and blue/white are beeping  - but that’s I think just part of the “hot neutral” 3-wire dimming.

Interestingly, I also tested the old Advance ballast which  was in that light, and the blue wires on that one are shorting also. It sorta worked anyway. From early 60s looks like, with postal zone listed on the address, see attached photo.

EDIT: 1975 actually. See date code pic from back.

Yep, some wires should test as short to neutral. (or black, depending on the ballast)
with others, you should see resistance on some of them.

OK! I finally got the Valmont 8G5007W dimming ballast on eBay, and now my basement appliances look Marvelous!

After my ill-conceived experiments with the bad GE dimming ballast, I ended up frying both my GE CW lamps.  Which were fair game, with the dying old GE product taking back its own. Mars eating his children, etc. But now I only have brand new tubes. So I cranked them up full power for 4 days (& 4 hours) to properly “season” before trying the dimmer.

Apparently, they won’t dim well without this burn-in, because “all new lamps contain a small amount of impunities.” (No explanation about where the impurities go within their sealed tubes. But where physics falters, metaphysics will prevail, or so one assumes.)

Meanwhile I also added a dimmer to my 4 ft bathroom fluorescents. This also required a couple of attempts, but no smoke, as I discovered the lamps we’ve been using for the last 12 years are T5s, not matching the T10 ballast I ordered (rookie mistake). And now the replacement ballast (Mark 10) is working great, with its deliberate glow at both ends from the programmed start, and smooth dimming down to 5%.

Full disclosure - though the bathroom light is properly installed, the basement light is still on the the bench (like a patient etherized upon a table), until I get motivated to hoist that monster back up on the ceiling for the 3rd time & stuff the switch guts into its box.

I think my next frankenlight will be retrofitting some 98 CRI T8 tubes into a LifeLite from the 90s. Maybe should of kept that T8 dimming ballast instead of sending it back!