LED Circuit Aluminum Base

[davg]

Re: LED Circuit Aluminum Base

Tks Retro but none of the LED's light up except as I said in post 3 probing the center of the burnt LED will cause that board to light up?

[davg]

Re: LED Circuit Aluminum Base

Here is the label on the driver

[budm]

Re: LED Circuit Aluminum Base

It is constant current (CC) power supply: 0.350A as printed.
if all 3 boards has perfectly matched then each board will have .350 A/3 = 0.117 A (116.667mA)

[Retro-Hipster]

Re: LED Circuit Aluminum Base

Tks Retro but none of the LED's light up except as I said in post 3 probing the center of the burnt LED will cause that board to light up?

Hmmm.... well.. What do you guys think? lol I mean, it sounds like there is some sort of damage to the other 2 panels. ^^; This is definitely the type of thing that would be made a bit easier with the ability to test each of the 3 panels in turn..

Something you could do to check if the LEDs on each panel are good is to test each LED in turn, seeing if it lights up. There are 12 LED packages a panel and the output voltage should be 80v max based on the label.. So I'm betting you will be able to get a single LED package to light with 6v. Maybe take 4AA's or 2 lithium button cells (like a CR2032) in series and then slap a few wires to the pack. (Lithium button cells would be good since they have a limited current. You would probably want to throw a 10ohm resistor on there if you used the AA's..) I would start with 3v though, just to make sure that there isn't wierdness and the packages are actually 3v led packages. ^^; I don't think so based on the label, but I'd hate to be the cause of you killing more LED's. haha Then you could probe the positive/negative of each LED package with your battery pack to make sure that each of the LED's will light on their own. If the LED's can light on their own individually for a full panel, then I don't know why that panel wouldn't light. No matter how I look at this, those two panels should be lighting unless they are damaged. That, or the driver is unable to put out the voltage it needs. From what I remember though, it was putting out a mixture between 80 and 100v, so yes.. lol That really sounds like open circuit voltage.

Based on that, I would be you probably have a failed LED on each of the panels, caused by the one LED failing. :/ With all three being off I would probably recommend doing the individual LED check and marking any dead LED's. After that, you would want to replace the failed LED's if you feel ok with the surface mount stuff. :/ The last thing I figure I should check would be this.. is it showing voltage on each of the panels where the wires are soldered on? I figure you've checked that already, but you know.. just wanting to be thorough. ^^;

[davg]

Re: LED Circuit Aluminum Base

Hmmm.... well.. What do you guys think? lol I mean, it sounds like there is some sort of damage to the other 2 panels. ^^; This is definitely the type of thing that would be made a bit easier with the ability to test each of the 3 panels in turn..

Something you could do to check if the LEDs on each panel are good is to test each LED in turn, seeing if it lights up. There are 12 LED packages a panel and the output voltage should be 80v max based on the label.. So I'm betting you will be able to get a single LED package to light with 6v. Maybe take 4AA's or 2 lithium button cells (like a CR2032) in series and then slap a few wires to the pack. (Lithium button cells would be good since they have a limited current. You would probably want to throw a 10ohm resistor on there if you used the AA's..) I would start with 3v though, just to make sure that there isn't wierdness and the packages are actually 3v led packages. ^^; I don't think so based on the label, but I'd hate to be the cause of you killing more LED's. haha Then you could probe the positive/negative of each LED package with your battery pack to make sure that each of the LED's will light on their own. If the LED's can light on their own individually for a full panel, then I don't know why that panel wouldn't light. No matter how I look at this, those two panels should be lighting unless they are damaged. That, or the driver is unable to put out the voltage it needs. From what I remember though, it was putting out a mixture between 80 and 100v, so yes.. lol That really sounds like open circuit voltage.

Based on that, I would be you probably have a failed LED on each of the panels, caused by the one LED failing. :/ With all three being off I would probably recommend doing the individual LED check and marking any dead LED's. After that, you would want to replace the failed LED's if you feel ok with the surface mount stuff. :/ The last thing I figure I should check would be this.. is it showing voltage on each of the panels where the wires are soldered on? I figure you've checked that already, but you know.. just wanting to be thorough. ^^;

The voltage on the three panels where the wires are soldered is fluctuating from 90v and climbs to around 150v than back down to around 90v and will continually do that? the panel with the burnt LED is trying to light and it do glow all LED except the burnt one nothing on the other ones. I will try your method with the 6v battery pack. Would a 6 volt AC/DC adaptor do the same as the battery? Will I need to de-solder the panels?

[budm]

Re: LED Circuit Aluminum Base

The Voltage will go up higher than the spec (80V 350mA) when it sees no load, that is how CC power supply function, it adjusts its output Voltage to maintain current through the load, and if the power supply is well built the it will go into OV shutdown.

[sam_sam_sam]

Re: LED Circuit Aluminum Base

Some pic of the front and back of the board. The # on the IC is LD7832GR 1434FC

Here is the data sheet for this IC chip this device is hard to find the data sheet for it

http://www.alldatasheet.com/datashee.../LD7832GR.html

I read this data sheet for this device but I do not completely understand just how this device works can someone who understands how this device works please explain it to me in more
layman terms for figure number 1 where it shows the typical circuit diagram I do not understand how the feedback part of the circuit works in this chip

The Voltage will go up higher than the spec (80V 350mA) when it sees no load, that is how CC power supply function, it adjusts its output Voltage to maintain current through the load, and if the power supply is well built the it will go into OV shutdown.

I see your post and this somewhat explains how this works

[Retro-Hipster]

Re: LED Circuit Aluminum Base

Here is the data sheet for this IC chip this device is hard to find the data sheet for it

http://www.alldatasheet.com/datashee.../LD7832GR.html

I read this data sheet for this device but I do not completely understand just how this device works can someone who understands how this device works please explain it to me in more
layman terms for figure number 1 where it shows the typical circuit diagram I do not understand how the feedback part of the circuit works in this chip



I see your post and this somewhat explains how this works

Nice Job sir! I tried to find it for a while and failed miserably. lol

They definitely don't pull punches on the acronyms on this description. haha

I just quickly glanced at this, but I'd like to just point out that this is a buck converter type circuit and that it drives the led's using rectified mains. So just be careful not to get electrocuted poking around on those LED panels sir! ^.^ Anyways, it has some interesting features for sure.. I didn't know that there was a point in a High Voltage startup with LED's. (If someone knows the point of this, I'd love a message on the info.)

It sounds like this chip has a lot of interesting protections. It looks like it has under current, over current, under voltage and over voltage protections. It also looks like it's feedback might make it essentially ramp up to a voltage until things conduct, then try to drive it with a specified current. Essentially, it looks like it is made to be very "all inclusive." It might be that the reason why you can get one panel to light is that it is ramping up the voltage until something conducts, then tries to push the current through it. That might be the whole reason why those other panels aren't lighting. I know that you mentioned that the panel with the LED will glow, but they probably aren't passing enough current in that state to move past the undercurrent protections. When you bypass the led and the rest of the panel lights up well, that is probably clamping the voltage down which keeps the voltage too low to start up the other panels.. At least, that is my guess. lol

So basically, the easiest test/plan might just be to desolder that bad LED, then solder on a new LED. ^^; Or, if you don't have that style of SMD LED, solder two normal white LED's in series (to make the up 6v) and then tack them across the bad led and see if all the panels light. I suppose that buying the right LED's for the panel might be a good idea anyways since it does seem like this is pretty fixable. (You need to replace that bad LED anyways.)

[budm]

Re: LED Circuit Aluminum Base

More info about LD7832 Off-Line PFC Buck Technology.
The start up is for getting the IC to start running when power is first applied and disabled after the IC is running, similar topoloy to many SMPS IC.
The Blue through hole resistor on the board is the Rs resistor, the formula is Rs = 0.2V/ILED, since we know the current of this board is set 0.350A, so that blue resistor should be about 0.57 Ohms.
There is also U2 and some other small Transistors on the board which I cannot trace out the board to see what they are for yet.
Btw, there are only L and N wires feeding the lamp assembly, correct?

[davg]

Re: LED Circuit Aluminum Base

Tks Bud and yes two wires feeding the lamp assembly LEDP and LEDN

[davg]

Re: LED Circuit Aluminum Base

Nice Job sir! I tried to find it for a while and failed miserably. lol

They definitely don't pull punches on the acronyms on this description. haha

I just quickly glanced at this, but I'd like to just point out that this is a buck converter type circuit and that it drives the led's using rectified mains. So just be careful not to get electrocuted poking around on those LED panels sir! ^.^ Anyways, it has some interesting features for sure.. I didn't know that there was a point in a High Voltage startup with LED's. (If someone knows the point of this, I'd love a message on the info.)

It sounds like this chip has a lot of interesting protections. It looks like it has under current, over current, under voltage and over voltage protections. It also looks like it's feedback might make it essentially ramp up to a voltage until things conduct, then try to drive it with a specified current. Essentially, it looks like it is made to be very "all inclusive." It might be that the reason why you can get one panel to light is that it is ramping up the voltage until something conducts, then tries to push the current through it. That might be the whole reason why those other panels aren't lighting. I know that you mentioned that the panel with the LED will glow, but they probably aren't passing enough current in that state to move past the undercurrent protections. When you bypass the led and the rest of the panel lights up well, that is probably clamping the voltage down which keeps the voltage too low to start up the other panels.. At least, that is my guess. lol

So basically, the easiest test/plan might just be to desolder that bad LED, then solder on a new LED. ^^; Or, if you don't have that style of SMD LED, solder two normal white LED's in series (to make the up 6v) and then tack them across the bad led and see if all the panels light. I suppose that buying the right LED's for the panel might be a good idea anyways since it does seem like this is pretty fixable. (You need to replace that bad LED anyways.)

I have no problem trying to de-solder the bad LED but how do I find a replacement? Not at all familiar with how to identify these SMD LED. A quick measurement is 3.03 x 3.16??
Tried your method with 6v battery nothing lighting up.

[Retro-Hipster]

Re: LED Circuit Aluminum Base

Like, you tried on either side of a single LED package and none of them lit up? That's interesting.. I figured that there were two led's in series.. maybe there are 3? But 80v / 12LED's is 6.7v and that sounds right. (3.2v per LED) Are you able to light up one of the LED's that you know was working? (like the ones on the panel with the bad LED's..)

[budm]

Re: LED Circuit Aluminum Base

Tks Bud and yes two wires feeding the lamp assembly LEDP and LEDN

I am asking about the AC wires to unit. There is no other control wires to the unit, correct? Just the AC power cord, right?
Something is not right if you cannot even light up the LED with 6V battery, my be you are not getting good contact.
Did you remove the bad LED to see what kind of footprint it has?

[sam_sam_sam]

Re: LED Circuit Aluminum Base

https://www.badcaps.net/forum/attach...8&d=1557258055


I found this it is not the same part number but it explains ( “ QUASI-RESONANT CONTROLLER “ )

Which is something that I did not understand what it does and how it works

I have to read this a few more times before I might able to more less understand how this works

https://cdn.badcaps-static.com/pdfs/...af065a1733.pdf

[budm]

Re: LED Circuit Aluminum Base

Skipped, please ignore this post.

[davg]

Re: LED Circuit Aluminum Base

I am asking about the AC wires to unit. There is no other control wires to the unit, correct? Just the AC power cord, right?
Something is not right if you cannot even light up the LED with 6V battery, my be you are not getting good contact.
Did you remove the bad LED to see what kind of footprint it has?

Sorry Bud misunderstood 120v AC only going to the unit but there is a Photo cell in the circuit which I have covered, that's it. Tried the battery again Tks Retro, and you were right I was not getting good contact. It now appears one board has several LED not working and the board with the burnt LED and the third has one not working. I have not attempted to remove any LED from the board as yet not much point till I can locate a replacement?? As suggested by someone earlier I will need to replace all the LED with a known brand? Any suggestions. I was hoping I might be able to buy the 3 module complete?
BTY these LED are very bright when testing almost need welding goggles??

[davg]

Re: LED Circuit Aluminum Base

Would this be a good replacement for these SM LED https://www.digikey.ca/product-detai...1CT-ND/3074387

[budm]

Re: LED Circuit Aluminum Base

You should remove the LED to find out what kind of footprint it has first, the rating of the one form Digikey is 3V, not 6v.

[Retro-Hipster]

Re: LED Circuit Aluminum Base

Sorry Bud misunderstood 120v AC only going to the unit but there is a Photo cell in the circuit which I have covered, that's it. Tried the battery again Tks Retro, and you were right I was not getting good contact. It now appears one board has several LED not working and the board with the burnt LED and the third has one not working. I have not attempted to remove any LED from the board as yet not much point till I can locate a replacement?? As suggested by someone earlier I will need to replace all the LED with a known brand? Any suggestions. I was hoping I might be able to buy the 3 module complete?
BTY these LED are very bright when testing almost need welding goggles??

Ah, nice! As for the brightness issue there, that is likely to happen if you don't have any current limiting in series with your power supply. LED's will essentially grab all the current they can once they start conducting.

If you have a 100ohm resistor, try sticking that in circuit with that 6v power supply and that should make it much less bright.

[davg]

Re: LED Circuit Aluminum Base

You should remove the LED to find out what kind of footprint it has first, the rating of the one form Digikey is 3V, not 6v.

Here is a pc of the LED Footprint the large pad being negative