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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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LED lamp help needed
I apologize because have very little info on the lamp but am still
seeking guidance. My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Besides various diodes, capacitors, inductors, and resistors each board has an 8 pin device and a power transistor. There are no other semiconductor devices. Only one of the LED modules works properly. All the others flash for a bit, then stay but don't come up to full brightness, and then shut off after several seconds. Then the sequence repeats. My son figured the LEDs were probably driven with a PWM voltage and so he measured the frequency of the power to the LEDs. The one good LED module is being driven at 150 Hz. The failing modules are being driven at various lower frequencies, depending on which module he tested. My son replaced all the electrolytic caps and this had no effect. The 8 pin device on each board has some sort of opaque coating on it that completely obscures and numbers or letters that may be printed on it. I think the problem with the boards is probably the power transistor. I think the 8 pin device is either a microcontroller or a LED driver IC that is designed to drive a power transistor. The meter my son used to measure the frequency of the pulsed DC powering the LEDs is undoubtably some cheap meter so I don't know how trustworthy it is. From what my son says the lamp is supposed to be some kind of "smart" lamp so that it is more efficient etc. and this is why I think the 8 pin device is a microcontroller or a LED driver. I think the various frequency measurements he is seeing are the result of the power transistors failing. I told him he should order some new ones and try them out, especially since, according to my son, they do have legible numbers on them. Since I'm really busy right now and don't know much about how these things work anyway I'm asking for some advice and opinions. So, is the 8 pin device probably a microcontroller? And are failing power transistors probably the problem? What can my son do to determine what the 8 pin device is? Thanks, Eric |
#3
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LED lamp help needed
On Sat, 29 Jul 2017 13:22:30 -0700, Jeff Liebermann
wrote: On Sat, 29 Jul 2017 12:10:34 -0700, wrote: My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Is the lamp one of these? The numbers are similar, but there are additional suffix letters that you did not provide: http://www.larsonelectronics.com/p-70368-class-1-division-1-explosion-proof-150-watt-high-bay-led-light-fixture-paint-spray-booth-approved.aspx http://www.larsonelectronics.com/p-144814-ceiling-mount-explosion-proof-150w-high-bay-led-light-fixture-17500-lumens-140-beam-spread.aspx Only $2,200 each: https://www.grainger.com/product/LARSON-ELECTRONICS-LLC-Explosion-Proof-Lighting-20LN23 I don't see six LED modules, although with 12 LED's, I can how 6 modules might work and fit: https://www.google.com/search?q=Larson+Electronics+epl-hb-150led&tbm=isch No disassembly photos. Bummer. Could you double check the model number? If you only have one out of 6 modules currently functional, my guess(tm) is that you're doing something wrong in the operation of the light. It might be getting too hot, insufficient ventilation, or too much applied AC voltage. Difficult to tell from here. If you repair one or more modules by replacing blown parts with identical parts, I would give it 5 chances out of 6 of blowing up again. What I do in situations like this is first make a schematic. Identify as many parts as possible. For parts obscured with epoxy, use some type of epoxy softener to ID the part: https://www.dynaloy.com/products/epoxy With the one remaining working module, use an oscilloscope to measure waveforms and voltages. Be sure to isolate the light with an AC line isolation transformer to prevent the oscilloscope case from being at AC line potential. Or, use a dual trace scope in differential input mode. After you repair a module, compare voltages and waveforms. Thanks for the reply Jeff. I forwarded your message a few minutes ago to me son and I'll let you know what success or lack of same he has. I'm gonna get some epoxy softener. I didn't even know the stuff was made. I should have too because I use epoxy for lots of fixes. Eric |
#4
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LED lamp help needed
On Saturday, July 29, 2017 at 3:04:09 PM UTC-4, wrote:
I apologize because have very little info on the lamp but am still seeking guidance. My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Besides various diodes, capacitors, inductors, and resistors each board has an 8 pin device and a power transistor. There are no other semiconductor devices. Only one of the LED modules works properly. All the others flash for a bit, then stay but don't come up to full brightness, and then shut off after several seconds. Then the sequence repeats. My son figured the LEDs were probably driven with a PWM voltage and so he measured the frequency of the power to the LEDs. The one good LED module is being driven at 150 Hz. The failing modules are being driven at various lower frequencies, depending on which module he tested. My son replaced all the electrolytic caps and this had no effect. The 8 pin device on each board has some sort of opaque coating on it that completely obscures and numbers or letters that may be printed on it. I think the problem with the boards is probably the power transistor. I think the 8 pin device is either a microcontroller or a LED driver IC that is designed to drive a power transistor. The meter my son used to measure the frequency of the pulsed DC powering the LEDs is undoubtably some cheap meter so I don't know how trustworthy it is. From what my son says the lamp is supposed to be some kind of "smart" lamp so that it is more efficient etc. and this is why I think the 8 pin device is a microcontroller or a LED driver. I think the various frequency measurements he is seeing are the result of the power transistors failing. I told him he should order some new ones and try them out, especially since, according to my son, they do have legible numbers on them. Since I'm really busy right now and don't know much about how these things work anyway I'm asking for some advice and opinions. So, is the 8 pin device probably a microcontroller? And are failing power transistors probably the problem? What can my son do to determine what the 8 pin device is? Thanks, Eric Have you been able to separate in the driver modules from the LED array? The picture shows what looks like 12 "bulbs". Are each of these single large die LEDs or are they made up of many small LED dies in an array? If you can swap the electronics from the working module to one of the misbehaving LEDs, you can see if it's an LED problem or driver board. From what I've seen over the years, it's more likely the LEDs are crapping out than the driver boards unless the boards are particularly poorly made or designed. I don't have a lot of faith in high wattage LEDs. Have you contacted the manufacturer? |
#5
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LED lamp help needed
On Tue, 01 Aug 2017 08:47:25 -0700, wrote:
I forwarded your message a few minutes ago to me son and I'll let you know what success or lack of same he has. I'm gonna get some epoxy softener. I didn't even know the stuff was made. I should have too because I use epoxy for lots of fixes. Eric You can also soften some epoxy mixes using acetone and heat or freezing with cooling spray: http://www.wikihow.com/Remove-Epoxy See the list of references at the bottom of the page. The paint section of a hardware store will have some kind of paint stripper that will also work with epoxy. The main active ingredient is methylene chloride. For example: https://www.lowes.com/pd/Jasco-1-Quart-Semi-Paste-Multi-Surface-Paint-Remover/3586546 -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#6
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LED lamp help needed
Jeff Liebermann wrote:
The paint section of a hardware store will have some kind of paint stripper that will also work with epoxy. The main active ingredient is methylene chloride. Depending where you live ... methylene chloride strippers are banned here apart from for professional use, as a result you might as well use porridge for paint stripper now. |
#7
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LED lamp help needed
On Wed, 2 Aug 2017 03:22:32 +0100, Andy Burns
wrote: Jeff Liebermann wrote: The paint section of a hardware store will have some kind of paint stripper that will also work with epoxy. The main active ingredient is methylene chloride. Depending where you live ... methylene chloride strippers are banned here apart from for professional use, as a result you might as well use porridge for paint stripper now. Thanks. I forgot to mumble something about the VOC ban. Here's a list for various states: https://www.issa.com/data/moxiestorage/regulatory_education/voc_limits_summary_12-6-16.pdf In California: http://www.dtsc.ca.gov/SCP/Paint_Stripper.cfm http://media.mofo.com/files/uploads/Images/140313-Profile-Paint-Stripper.pdf There seems to be a proposed law banning methylene chloride, but it seem to have NOT been enacted quite yet. I seem to recall that I can still buy the stuff at the local hardware store. I'll check tomorrow. The EPA and the Trump administration seem to favor not banning it: https://www.dcreport.org/2017/06/13/epa-may-kill-ban-of-deadly-paint-removing-chemical/ -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#8
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LED lamp help needed
Jeff Liebermann wrote:
Andy Burns wrote: Depending where you live ... methylene chloride strippers are banned here apart from for professional use Thanks. I forgot to mumble something about the VOC ban. EU wide ban for household use of DCM http://www.paintsquare.com/news/?fuseaction=view&id=7328 I've never tried to obtain the real stuff in the UK since the ban, but it seems to exist on ebay/amazon so presumably some suppliers are less strict than others about who qualifies as "professional" |
#9
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LED lamp help needed
On Tue, 01 Aug 2017 20:16:14 -0700, Jeff Liebermann
wrote: In California: http://www.dtsc.ca.gov/SCP/Paint_Stripper.cfm http://media.mofo.com/files/uploads/Images/140313-Profile-Paint-Stripper.pdf There seems to be a proposed law banning methylene chloride, but it seem to have NOT been enacted quite yet. I seem to recall that I can still buy the stuff at the local hardware store. I'll check tomorrow. I went to the local hardware store and methylene chloride furniture stripper is still available: http://www.learnbydestroying.com/jeffl/crud/Furniture%20Stripper.jpg Just about everything from the center of the photo to the right would disappears if the methylene chloride was banned. I bought some of the Jasco epoxy stripper and plan to check if it will soften epoxy glue. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#10
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LED lamp help needed
On Tuesday, August 1, 2017 at 11:41:50 AM UTC-4, wrote:
On Sat, 29 Jul 2017 13:22:30 -0700, Jeff Liebermann wrote: On Sat, 29 Jul 2017 12:10:34 -0700, wrote: My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Is the lamp one of these? The numbers are similar, but there are additional suffix letters that you did not provide: http://www.larsonelectronics.com/p-70368-class-1-division-1-explosion-proof-150-watt-high-bay-led-light-fixture-paint-spray-booth-approved.aspx http://www.larsonelectronics.com/p-144814-ceiling-mount-explosion-proof-150w-high-bay-led-light-fixture-17500-lumens-140-beam-spread.aspx Only $2,200 each: https://www.grainger.com/product/LARSON-ELECTRONICS-LLC-Explosion-Proof-Lighting-20LN23 I don't see six LED modules, although with 12 LED's, I can how 6 modules might work and fit: https://www.google.com/search?q=Larson+Electronics+epl-hb-150led&tbm=isch No disassembly photos. Bummer. Could you double check the model number? If you only have one out of 6 modules currently functional, my guess(tm) is that you're doing something wrong in the operation of the light. It might be getting too hot, insufficient ventilation, or too much applied AC voltage. Difficult to tell from here. If you repair one or more modules by replacing blown parts with identical parts, I would give it 5 chances out of 6 of blowing up again. What I do in situations like this is first make a schematic. Identify as many parts as possible. For parts obscured with epoxy, use some type of epoxy softener to ID the part: https://www.dynaloy.com/products/epoxy With the one remaining working module, use an oscilloscope to measure waveforms and voltages. Be sure to isolate the light with an AC line isolation transformer to prevent the oscilloscope case from being at AC line potential. Or, use a dual trace scope in differential input mode. After you repair a module, compare voltages and waveforms. Thanks for the reply Jeff. I forwarded your message a few minutes ago to me son and I'll let you know what success or lack of same he has. I'm gonna get some epoxy softener. I didn't even know the stuff was made. I should have too because I use epoxy for lots of fixes. Eric Wow Eric, if those things are ~$1k+ each I would contact Larson and talk to some tech guy there. Often when something blows it will take out several parts... you probably know that. George H. |
#11
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LED lamp help needed
Jeff Liebermann wrote on 8/2/2017 11:51 PM:
On Tue, 01 Aug 2017 20:16:14 -0700, Jeff Liebermann wrote: In California: http://www.dtsc.ca.gov/SCP/Paint_Stripper.cfm http://media.mofo.com/files/uploads/Images/140313-Profile-Paint-Stripper.pdf There seems to be a proposed law banning methylene chloride, but it seem to have NOT been enacted quite yet. I seem to recall that I can still buy the stuff at the local hardware store. I'll check tomorrow. I went to the local hardware store and methylene chloride furniture stripper is still available: http://www.learnbydestroying.com/jeffl/crud/Furniture%20Stripper.jpg Just about everything from the center of the photo to the right would disappears if the methylene chloride was banned. I bought some of the Jasco epoxy stripper and plan to check if it will soften epoxy glue. Methylene Chloride was used to glue plexiglass together. You place the parts in position and use a capillary tube to administer enough to wet the joint. Since the plexiglass is clear you can see it wet the joint. It dissolves the plastic and when it evaporates you have a welded joint. -- Rick C |
#12
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LED lamp help needed
On Fri, 4 Aug 2017 20:43:37 -0400, rickman wrote:
Jeff Liebermann wrote on 8/2/2017 11:51 PM: On Tue, 01 Aug 2017 20:16:14 -0700, Jeff Liebermann wrote: In California: http://www.dtsc.ca.gov/SCP/Paint_Stripper.cfm http://media.mofo.com/files/uploads/Images/140313-Profile-Paint-Stripper.pdf There seems to be a proposed law banning methylene chloride, but it seem to have NOT been enacted quite yet. I seem to recall that I can still buy the stuff at the local hardware store. I'll check tomorrow. I went to the local hardware store and methylene chloride furniture stripper is still available: http://www.learnbydestroying.com/jeffl/crud/Furniture%20Stripper.jpg Just about everything from the center of the photo to the right would disappears if the methylene chloride was banned. I bought some of the Jasco epoxy stripper and plan to check if it will soften epoxy glue. Methylene Chloride was used to glue plexiglass together. You place the parts in position and use a capillary tube to administer enough to wet the joint. Since the plexiglass is clear you can see it wet the joint. It dissolves the plastic and when it evaporates you have a welded joint. Yep, that works as long as it's the clear liquid form of methylene chloride and not the gelled furniture stripper I usually find at the hardware store. For plexiglass, also known as PMMA, poly methyl methacrylate, acrylite, lucite, and perspex, I prefer to use acetone instead: http://ourpastimes.com/use-acetone-solvent-weld-plexiglass-7847777.html Various other banned chlorinated hydrocarbon VOC solvents will also work. My favorite mistake is getting some acetone into the pores on my fingers, and dissolving my fingerprint into the plexiglass. This video is very similar to your method: https://www.youtube.com/watch?v=qKHbKlq7aPg Notice the use of a syringe to apply the solvent. Try to find a syringe where the plastic and rubber parts will not be attacked by the acetone. I use an all glass syringe with no plastic or rubber parts. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#13
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LED lamp help needed
On Wednesday, 2 August 2017 03:22:34 UTC+1, Andy Burns wrote:
Jeff Liebermann wrote: The paint section of a hardware store will have some kind of paint stripper that will also work with epoxy. The main active ingredient is methylene chloride. Depending where you live ... methylene chloride strippers are banned here apart from for professional use, as a result you might as well use porridge for paint stripper now. It isn't, it's just not allowed to be marketed as paint stripper. NT |
#14
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LED lamp help needed
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#15
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LED lamp help needed
On Fri, 4 Aug 2017 16:10:58 -0700 (PDT), wrote:
On Tuesday, August 1, 2017 at 11:41:50 AM UTC-4, wrote: On Sat, 29 Jul 2017 13:22:30 -0700, Jeff Liebermann wrote: On Sat, 29 Jul 2017 12:10:34 -0700, wrote: My son has this lamp: Larson Electronics epl-hb-150led. It is a 150 watt high bay type lamp. It has six LED modules and each module is driven by its own driver board. Is the lamp one of these? The numbers are similar, but there are additional suffix letters that you did not provide: http://www.larsonelectronics.com/p-70368-class-1-division-1-explosion-proof-150-watt-high-bay-led-light-fixture-paint-spray-booth-approved.aspx http://www.larsonelectronics.com/p-144814-ceiling-mount-explosion-proof-150w-high-bay-led-light-fixture-17500-lumens-140-beam-spread.aspx Only $2,200 each: https://www.grainger.com/product/LARSON-ELECTRONICS-LLC-Explosion-Proof-Lighting-20LN23 I don't see six LED modules, although with 12 LED's, I can how 6 modules might work and fit: https://www.google.com/search?q=Larson+Electronics+epl-hb-150led&tbm=isch No disassembly photos. Bummer. Could you double check the model number? If you only have one out of 6 modules currently functional, my guess(tm) is that you're doing something wrong in the operation of the light. It might be getting too hot, insufficient ventilation, or too much applied AC voltage. Difficult to tell from here. If you repair one or more modules by replacing blown parts with identical parts, I would give it 5 chances out of 6 of blowing up again. What I do in situations like this is first make a schematic. Identify as many parts as possible. For parts obscured with epoxy, use some type of epoxy softener to ID the part: https://www.dynaloy.com/products/epoxy With the one remaining working module, use an oscilloscope to measure waveforms and voltages. Be sure to isolate the light with an AC line isolation transformer to prevent the oscilloscope case from being at AC line potential. Or, use a dual trace scope in differential input mode. After you repair a module, compare voltages and waveforms. Thanks for the reply Jeff. I forwarded your message a few minutes ago to me son and I'll let you know what success or lack of same he has. I'm gonna get some epoxy softener. I didn't even know the stuff was made. I should have too because I use epoxy for lots of fixes. Eric Wow Eric, if those things are ~$1k+ each I would contact Larson and talk to some tech guy there. Often when something blows it will take out several parts... you probably know that. George H. This is my son's lamp and he has been busy getting his girlfriend's mothers's house ready to sell. He finally finished on Saturday last and can now look again at the lamp. He did contact the maker and they will only sell him new LED drivers. No advice on troubleshooting the existing drivers. Maybe this is because they have updated the drivers. So my son can buy the new style but will try first to fix what he has. Eric |
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