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

[zenlizard]

"Do not attempt to open Spam. No user-servicable part inside this person."

Note to self

[bodger]

Here are the components in question, in case I (or someone else) wants to duplicate this repair. Capacitors were two 338-1492-ND, Cornell-Dubilier SLP331M200C1P3, 330µf 200V snap-in aluminum electrolytic, 10mm lead spacing, 25mm dia x 25mm height. Current limiter was 490-3957-ND (no longer stocked), muRata NTPAA100LDNB0 NTPA Series Inrush Current Limiter, 10Ω, 1.7A, 70s, 13.5mW/ºC, 12mm dia x 5mm thick with 7.5mm lead spacing.

[roadstir]

Bodger,

Bodger,

A couple of questions on your Microsun.

Can I run more than a 70w bulb in the desklamp?
Any bulb numbers that you can recommend? I know it has to be protected, but there are so many 70w bulbs out there... And does it have to be frosted?

Many thanks

[bodger]

You're pretty much stuck with 68 or 70 watts, unless you replace the ballast with something else. Most ordinary 70W bulbs wouldn't work well, as the Microsun operates the lamp on DC, whereas most metal halide bulbs are designed for AC operation. Again, if you replace the ballast, you can go for more common bulbs and higher wattage. If you're curious, the Microsun bulb is a Venture Lighting product, part number 69000.

[roadstir]

Many thanks for the advice and quick reply, Bodger!

From: bodger - DW Comment [mailto:dw_null@dreamwidth.org] Sent: Wednesday, May 6, 2015 11:10 PM To: dlydiard@verizon.net Subject: Reply to your comment. [ bodger - 11977 ]

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bodger http://bodger.dreamwidth.org/profile replied to a comment you left in a Dreamwidth entry http://bodger.dreamwidth.org/11977.html "Microsun light repair". The comment they replied to was:

Bodger,

Bodger,

A couple of questions on your Microsun.

Can I run more than a 70w bulb in the desklamp? Any bulb numbers that you can recommend? I know it has to be protected, but there are so many 70w bulbs out there... And does it have to be frosted?

Many thanks

The reply was:

You're pretty much stuck with 68 or 70 watts, unless you replace the ballast with something else. Most ordinary 70W bulbs wouldn't work well, as the Microsun operates the lamp on DC, whereas most metal halide bulbs are designed for AC operation. Again, if you replace the ballast, you can go for more common bulbs and higher wattage. If you're curious, the Microsun bulb is a Venture Lighting product, part number 69000.

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Micro sun lamp repair

[vectrageek]

Hi Bodger! I was really impressed with your micro sun lamp repair! Although I'm a chemical engineer, my electrical skills certainly aren't as keen as yours. I was wondering if you would mind walking me through repair of my micro sun lamp (which just died).

Needless to say, any help would be greatly appreciated!

Thx! Vectrageek

Re: Micro sun lamp repair

[bodger]

If yours failed the same way mine did, there are only three parts to replace, but they will require soldering. Fortunately, they're all large, easy to see parts, not the tiny things that are most electronics these days. Removing the gear pack (the white plastic assembly that the bulbs screw into) isn't difficult, it simply screws onto the lamp. Unplug the lamp, remove the bulbs, unscrew it, and then carefully pull it away from the lamp while pushing the cord into the lamp from the other end. If I remember correctly, the gear pack is just screwed together with four screws. Remove those, and the housing should pull apart easily. The parts that usually fail are the two largish black cylindrical items (the capacitors) and the inrush current limiter (shaped like a thick coin with two wires, black or grey in colour).

Re: Micro sun lamp repair

[vectrageek]

Thx for the reply! I Haven't done much soldering (if any) although I'm such a nerd, I'd be happy to take it on. Just curious, could I just id the lamp & order a new gear pack & replace that without having to replace capacitors & limiters,etc. iI inherited the lamp from my parents & it's essentially an heirloom.

In lieu of that, i live in the Denver area. I know the chances are slim, but if you lived around here, I'd pay you to fix it. I could even probably ship it to you if you wouldn't be adverse to working on another Microsun lamp. I would really like to save this if I could. 😊

Thx! Vectranerd

Re: Micro sun lamp repair

[bodger]

Yes, the Microsun recommended procedure is to just replace the gear pack. They even give the instructions with pictures: https://microsunlamps.com/wp-content/uploads/2015/05/Gear-Pack-Assembly-Instructions.pdf

I live in Virginia, so I'm not local. I wouldn't be adverse to working on it, but it may be easier for you to just get a fresh unit from Microsun with all-new parts.

Re: Micro sun lamp repair

[vectrageek]

Thanks for the information Bodger! I have a call in to Microsun re a gear pack so I will keep my fingers crossed, hoping they'll have a replacement gear pack for this lamp since I suspect it's probably more than 25 years old. I guess if nothing else, I could convert it to a regular lamp but even so, I highly prefer the enhanced light spectrum it provides. I recently repaired my dishwasher with an electrical part that had failed but luckily, I just wired it into place rather than having to solder it.

So thanks again for all the help. If I can't find a suitable new gear pack, I may E you back re soldering the capacitor, limiters, etc since I'm determined to somehow salvage this lamp. Just curious, does Microsun have any instructions regarding fixing components in the gear pack itself? I would guess not because of liability issues since I couldn't even find anything about a replacement gear pack online until you forwarded the url to me.

In the meantime, have a great weekend and thanks so much for all the help!

Vectranerd

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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.

Followup.. just replacing caps worked for me

[dr_innovation]

Our 20+ year old microsun died. Bought a new bulb, no help. I found this article, which was great, thanks!!. Ordered the capacitors listed ($12/delivered from Digikey since we are under stay at home) but could not find a suitable inrush limiter. Since those, a less problematic part, I figured I'd try just the caps first. Parts arrived and Opened the unit and yep the capacitors were bulging big time. Replaced them easily (large solder joints are easy). Turned unit on-off about 8 times to check inrush seems to not be a problem. So far and been running for hours. Wife happy, and we now have a spare bulb ;-)

Figured I'd report that just cap replacement worked for me, since those parts are easier to get.