Microsun light repair

[bodger]

I'm a fan of bright, high-quality light for reading and crafts, so I figured I'd try the fancy Microsun lamps. These are 68W metal halide lamps, and provide 5300-6000 lumens with a CRI of 72-90, depending on who you believe. The lamps are expensive, but nicely made. I bought two of 'em, a floor lamp (for crafts) and a table lamp (for reading). They work well, and several people admired the quality of light they produce. However, after two years of fairly light use, the reading lamp started to flicker and then died. I tried swapping bulbs, but the problem remained with the lamp.

People who know me will not be surprised by my next move. The ballast (called a "gear pack" by the seller) is clearly marked "DO NOT OPEN. NO USER SERVICEABLE PARTS INSIDE." maugorn and others might remember me reciting the litany "Do not open, no user serviceable parts inside, pilot lamps soldered in place, danger high voltage, warranty void if opened, etc." as I tore into things.

Well, I found out some things. The manufacturer claims that you can't just make your own lamp by buying a gear pack, because the gear pack doesn't include "the transformer". I had initially believed there was a transformer tucked into the base of the lamp, as the lamp was sufficiently large and heavy. But there isn't one. The AC leads go straight to the gear pack. You could easily retrofit any ordinary threaded-tube lamp by buying a $60 gear pack and screwing it on top.

The ballast is patented. This means I can download the schematic. It's not quite the same as the one used in the lamp, but it's pretty close. It's just a current-regulated DC power supply with a transformer-coupled starting pulse network, run off a voltage doubler. Armed with that info, and the failure mode, I deduced that it isn't the starting circuitry (the lamp failed when it was already started), and it probably isn't the current regulator (those generally work right or not at all). That leaves the voltage doubler. Not much to it, an inrush current limiter, a pair of diodes, and two big electrolytic capacitors. And electrolytic capacitors are famous for drying out and failing. So I read the specs off 'em, measured the relevant dimensions, and found equivalent units on Digikey. The inrush limiter was a house-numbered part, but a little research convinced me that it was a 10Ω, 1.7A unit or thereabouts, and such things aren't critical (it's just there to make sure that the discharged capacitors don't pull too much current when first turned on). I chose a similar unit that would physically fit and ordered it too.

While I waited for the parts to show up in the mail, I considered my other options. These days, low-wattage metal halide bulbs aren't too hard to find, and ballasts can be had from Fulham (a manufacturer whose products I like) and cheaper manufacturers. If it dies again, I can always re-use the lamp body and nice, high-temperature ceramic socket with a 70W (or more!) metal halide bulb and ballast.

Comments

RE: Microsun Light Repair

[microsunengineer]

Greetings All,

I recently found this post, and wanted to chime in. I am Microsun’s engineer. Just to be clear, I am a mechanical engineer, and I work primarily on designing and building the lamps from a mechanical fashion. The Gearpack is an established technology that I personally had no part in designing. However, I do have a rudimentary understanding of electronics from my time in college as well as personal endeavours, and I am familiar with the functionality of the Gearpack.

Bodger, I wanted to take a moment to applaud your ingenuity in repairing your lamp. I have to assume that since you originally posted in 2010, and then have replied as recently as 2015 that your lamp is once again working. I am very glad to hear that you are still able to enjoy your lamp and its light.

There were a few things that I would like to clear up though:

I am unsure why you were told that a transformer was present in the lamp body. My understanding is that was true at one time. Before the Gearpack was introduced, all of the electronics for the ballast were present within the lamp. However, the Gearpack was introduced to consolidate all of those parts, and allow us more flexibility in the design of the lamps. All lamps that we presently sell use the Gearpack, and do not have any electronics within the lamp body itself.

With regards to the question about utilizing a different bulb or ballast with the lamp, I would not recommend that. Someone, especially someone with your technical knowledge, Bodger, could create a lamp with an off-the-shelf ballast and bulb fairly easily, but it would likely not produce optimum results. Metal halide bulbs work much better when paired with specific ballasts that fit the specific bulb. In addition, there are many lesser quality ballasts and bulbs out there that would be best avoided. Finally, our Microsun bulb is specifically tuned not only to provide high lumens, but it also provides a particular color spectrum that is friendlier to aging eyes.

We no longer ship our lamps with the “DO NOT OPEN” labels, you are more than welcome to repair your Gearpack if you have the knowledge and expertise required. However, we do not recommend it, as most people do not possess this knowledge. Though, we are not responsible for any problems that you run into if you decide to go that route.

We are still selling lamps and expanding our business. We recently introduced a Build Your Own Microsun kit that may be of interest to some of the readers here. The kit includes everything that you would need to retrofit most lamps with our lighting technology. Not all lamps can be retrofitted, but many can. The kit can be found at our website: https://microsunlamps.com/shop/build-microsun-lamp/ If you have any questions please feel free to let me know here, email me directly at Matt.Buschur@Microsunlamps.com, or give us a call at (888) 328-8701.