MH ballast dying?

FreedR · 12/12/2009, 10:02 AM

I inherited a metal halide ballast that drives two 175w bulbs. I just replaced the bulbs, and the one on the left fired for a day or two, but then stopped. Now, it just makes sparks, but does not come on all the way. I turned the ballast off, waited 15 minutes, switched the bulbs, and the one on the left still just makes sparks. So, it's not the bulb. Am I looking at a new ballast, or is there something I'm missing here?

DOTZ · 12/12/2009, 10:09 AM

The ballast makes sparks or the bulb? Could be a bad wire, ballast or cap. If the ballast sparks I would unplug it, take the case off and check for any loose, burned, or broken wires.

Is that ballast electronic or magnetic?

Sisterlimonpot · 12/12/2009, 10:14 AM

What kind of ballast is it?

FreedR · 12/12/2009, 10:43 AM

The bulb makes sparks - inside the glass chamber which is inside the glass of the MH bulb.

The ballast is an Energy Savers Unlimited AF175WD. (I'm guessing it's magnetic, but not sure.) Looks something like this one, except a double rather than a single (two switches, two pairs of wire to drive two bulbs):

Quote:

Originally Posted by DOTZ

The ballast makes sparks or the bulb? Could be a bad wire, ballast or cap. If the ballast sparks I would unplug it, take the case off and check for any loose, burned, or broken wires.

Is that ballast electronic or magnetic?

DOTZ · 12/12/2009, 03:28 PM

Sounds like the ignitor or capacitor. I believe you can check them by the micofarads. It will look like a uf on a multimeter. The cap should have a micro farad number on the side with a +-%. If it's + or - the percetage ay 10% of the number you're within specs if it's out of range replace it. You can get a new one from hellolight.com.

Example say the cap says 7.5 +- 10% then if you read anywhere from 6.75 to 8.25 micro farads you're okay. If it's above or below then replace. Also if there is a bulge on the sides or top replace it right away. Some have a round spot on top that will bump up to to relieve pressure on the unit.

When my cap went out the bulb would flicker and try to come on then go off. Every now and then it would come on.

DOTZ · 12/12/2009, 03:33 PM

BTW that case is no easy task to get into. I believe they're tap welded shut and will take some work to open. You may do some cosmetic damage to do it.

jherrin215 · 12/13/2009, 09:27 AM

Yeah definitely sounds like the cap to me. I've got a double 175 watt unit with magnectic ballasts also and have already had to replace 2 caps. 1 that was original and I replaced with a junk cap and then it blew so I had to replace it later. They were cheap but finding them was the hard part. I lucked up and found someone selling a box of 17 of them on ebay and I get them for like 12 bucks shipped!! Exact matches!!

insane · 12/13/2009, 09:47 AM

Be careful if you open up the ballast box and move wires as the insulation on the wires can be very dry and brittle due to the amount of heat mag ballasts put off. If they are dry and brittle the insulation will crack and make it possible for electricity to arc.

I have an antique Hamilton dual 400watt mag ballast (10 years old) that initially blew the common neutral wire apart knocking out power to both ballasts. I carefully fixed the wire, used the unit for a month then ended up having the wiring catch on fire inside the ballast box. Luckily I was home and in the room when it happened.

If your mag ballast is very old you might want to just consider it time to do an upgrade to either a new dual mag ballast or electronic ballasts if replacing it is in the budget.

jherrin215 · 12/13/2009, 11:03 AM

I would suggest not opening the metal box with power on it for sure!! The power coming out of transformer will be more than the power coming into the box, so I promise it won't feel good!! If I were you, if you have any electrical experience or are very handy is first take the box apart. Then unhook the capacitors and swap them between the transformers. If the problem follows the cap then it's the issue. Replace the capacitor with an identical one and then redo the wiring as insane is very correct, the wiring will probably be very brittle and the insulation will probably crack when you start moving wires. Good luck and be sure to ask if you have any more questions!!

DOTZ · 12/13/2009, 06:50 PM

Hellolights.com sells them in the DIY metal halide section.

FreedR · 12/19/2009, 06:51 PM

After drilling out the rivets holding the case shut (unplugged of course!), I tested both capacitors, and both of them were well lower than the acceptable range. Ordered a new pair from McMaster-Carr for about $20 for the pair, S&H included. Installed them, and we're now back in business.

The insulation on the wiring in there was a bit dry, but still intact and flexible.

Although an upgrade is on the wish list, I think this ballast still has some life in it yet.

Thanks for the help, DOTZ in particular!

DOTZ · 12/19/2009, 06:58 PM

No problem. Glad it worked out for you.

I have never seen that site. I had to pay 20.00 plus shipping for just one cap for my 175 watt, so that's a great price for two. Thanks for the great resource.

FreedR · 12/19/2009, 07:01 PM

McMaster is our go-to for all sorts of parts. I've found great prices on ball valves, gate valves, and other hardware goodies. They have everything, and they ship almost instantaneously.

12/12/2009, 10:02 AM	#1
FreedR Registered Member Join Date: Jun 2007 Location: Milton, MA Posts: 34	MH ballast dying? I inherited a metal halide ballast that drives two 175w bulbs. I just replaced the bulbs, and the one on the left fired for a day or two, but then stopped. Now, it just makes sparks, but does not come on all the way. I turned the ballast off, waited 15 minutes, switched the bulbs, and the one on the left still just makes sparks. So, it's not the bulb. Am I looking at a new ballast, or is there something I'm missing here?

12/12/2009, 10:14 AM	#3
Sisterlimonpot R.C. Fraternity President Join Date: Dec 2008 Location: Litchfeild Park AZ Posts: 11,490 Blog Entries: 2	What kind of ballast is it? __________________ Jimmy MASVC President Dishes are done man! Current Tank Info: 300 in progress

12/19/2009, 06:51 PM	#11
FreedR Registered Member Join Date: Jun 2007 Location: Milton, MA Posts: 34	capacitors replaced; problem solved. Thanks! After drilling out the rivets holding the case shut (unplugged of course!), I tested both capacitors, and both of them were well lower than the acceptable range. Ordered a new pair from McMaster-Carr for about $20 for the pair, S&H included. Installed them, and we're now back in business. The insulation on the wiring in there was a bit dry, but still intact and flexible. Although an upgrade is on the wish list, I think this ballast still has some life in it yet. Thanks for the help, DOTZ in particular!

12/12/2009, 10:09 AM	#2
DOTZ Registered Member Join Date: Nov 2007 Location: Benton, Il Posts: 1,764	The ballast makes sparks or the bulb? Could be a bad wire, ballast or cap. If the ballast sparks I would unplug it, take the case off and check for any loose, burned, or broken wires. Is that ballast electronic or magnetic?

12/12/2009, 03:28 PM	#5
DOTZ Registered Member Join Date: Nov 2007 Location: Benton, Il Posts: 1,764	Sounds like the ignitor or capacitor. I believe you can check them by the micofarads. It will look like a uf on a multimeter. The cap should have a micro farad number on the side with a +-%. If it's + or - the percetage ay 10% of the number you're within specs if it's out of range replace it. You can get a new one from hellolight.com. Example say the cap says 7.5 +- 10% then if you read anywhere from 6.75 to 8.25 micro farads you're okay. If it's above or below then replace. Also if there is a bulge on the sides or top replace it right away. Some have a round spot on top that will bump up to to relieve pressure on the unit. When my cap went out the bulb would flicker and try to come on then go off. Every now and then it would come on.

12/12/2009, 03:33 PM	#6
DOTZ Registered Member Join Date: Nov 2007 Location: Benton, Il Posts: 1,764	BTW that case is no easy task to get into. I believe they're tap welded shut and will take some work to open. You may do some cosmetic damage to do it.

12/13/2009, 09:27 AM	#7
jherrin215 GO COLTS!! Join Date: Jun 2008 Location: Kentucky Posts: 854	Yeah definitely sounds like the cap to me. I've got a double 175 watt unit with magnectic ballasts also and have already had to replace 2 caps. 1 that was original and I replaced with a junk cap and then it blew so I had to replace it later. They were cheap but finding them was the hard part. I lucked up and found someone selling a box of 17 of them on ebay and I get them for like 12 bucks shipped!! Exact matches!!

12/13/2009, 09:47 AM	#8
insane Moved On Join Date: Jul 2009 Location: under your bed Posts: 771 Blog Entries: 7	Be careful if you open up the ballast box and move wires as the insulation on the wires can be very dry and brittle due to the amount of heat mag ballasts put off. If they are dry and brittle the insulation will crack and make it possible for electricity to arc. I have an antique Hamilton dual 400watt mag ballast (10 years old) that initially blew the common neutral wire apart knocking out power to both ballasts. I carefully fixed the wire, used the unit for a month then ended up having the wiring catch on fire inside the ballast box. Luckily I was home and in the room when it happened. If your mag ballast is very old you might want to just consider it time to do an upgrade to either a new dual mag ballast or electronic ballasts if replacing it is in the budget.

12/13/2009, 11:03 AM	#9
jherrin215 GO COLTS!! Join Date: Jun 2008 Location: Kentucky Posts: 854	I would suggest not opening the metal box with power on it for sure!! The power coming out of transformer will be more than the power coming into the box, so I promise it won't feel good!! If I were you, if you have any electrical experience or are very handy is first take the box apart. Then unhook the capacitors and swap them between the transformers. If the problem follows the cap then it's the issue. Replace the capacitor with an identical one and then redo the wiring as insane is very correct, the wiring will probably be very brittle and the insulation will probably crack when you start moving wires. Good luck and be sure to ask if you have any more questions!!

12/13/2009, 06:50 PM	#10
DOTZ Registered Member Join Date: Nov 2007 Location: Benton, Il Posts: 1,764	Hellolights.com sells them in the DIY metal halide section.

12/19/2009, 06:58 PM	#12
DOTZ Registered Member Join Date: Nov 2007 Location: Benton, Il Posts: 1,764	No problem. Glad it worked out for you. I have never seen that site. I had to pay 20.00 plus shipping for just one cap for my 175 watt, so that's a great price for two. Thanks for the great resource.

12/19/2009, 07:01 PM	#13
FreedR Registered Member Join Date: Jun 2007 Location: Milton, MA Posts: 34	McMaster is our go-to for all sorts of parts. I've found great prices on ball valves, gate valves, and other hardware goodies. They have everything, and they ship almost instantaneously.