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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Default 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
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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.


--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default 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
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Default 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?



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Default 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.
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Default 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
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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"
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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
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Default 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.


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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
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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
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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
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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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