400w Ballast Capacitor technical question

[JohnnyToke]

Im trying to repair a Sunlight Supply 400w switchable ballast that has a weak/bad HPS capacitor. The coil inside is a Universal and says it should have a 55mfd capacitor for the HPS side and a 26mfd capacitor on the MH side.

The installed MH capacitor is correct however I found a 29mfd on the HPS side instead of a 55mfd. Amazingly, it has been working fine until recently. now it only burns the HPS bulb at about 50% brightness thus the need to replace it.

Am I correct to think I should slap a 55mfd capacitor in there since the coil calls for that? The warranty seals on it were not broken either so I am assuming it came from the factory with the wrong capacitor in it. weird.

Any help would be appreciated.

Regards,
JT

 

[00420]

DO NOT PUT A 55MFD when you replace

26mfd + 29mfd = 55mfd theres a one way diode so when you switch to HPS it use's both caps, also make sure that the diode is not removed when your taking out the old cap have you used it as a MH dose that bulb work fine? it could be either one of them caps that are bad only way to find out is by running the MH and seeing if it works....or a volt meter.

if one went out more then likely the other will soon, you might want to replace both and keep the one thats good around for a spare

 

[JohnnyToke]

00420, thanks for that info. It makes perfect sense now...duh me...lol

sometimes i'm a little slow when it comes to electronics.

I havent used the MH side nor do I have a bulb on hand to check it. The ballast was built in 2002 so I will go ahead and replace both caps. I found the diode you are talking about under the 26mf rubber cap cover.

now the challenge of finding these caps online.

regards,
JT

 

[hoosierdaddy]

http://www.atlaslightingsupply.com/cap_ignitor.html

 

[JohnnyToke]

http://www.atlaslightingsupply.com/cap_ignitor.html

thanks for the link. I have searched this link along with Google search and have been unable to find the 29uf capacitor. The 26uf are readily available.

I may have to go back to go back to Sunlight Supply and have them fix it.

any suggestions where I can find a 29uf oil filled high voltage capacitor?

thanks,
JT