Previous Thread
Next Thread
New Reply
Print Thread
Rate Thread
Electrical Experts... #269139 Sep 7, 5:30pm Sep 7, 5:30pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Electrical Experts...
Ok, I think I soldered in my LED's in backwards, and before I go in and reverse the polarity, answer me this question...

In the picture below, is a crude drawing of the "T" symbol on the back of a surface mount light emitting diode. I'm having some trouble intreperting it.

1870217179-ssss.jpg

Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269140 Sep 7, 5:56pm Sep 7, 5:56pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Bastards...


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269141 Sep 7, 5:58pm Sep 7, 5:58pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Sons a bitches...


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269142 Sep 7, 6:31pm Sep 7, 6:31pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
frown


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269143 Sep 8, 6:57am Sep 8, 6:57am
Joined: Jul 2004
Posts: 23
Florida
2003 White Toyota Celica
brianhaman
Member
2003 Toyota Celica
brianhaman
2003 White Toyota Celica
Member
2003 Toyota Celica

Joined: Jul 2004
Posts: 23
Florida
If you have access to a volt meter you can use the diode checker function to test the LED for polarity.

Re: Electrical Experts... [Re: brianhaman] #269144 Sep 8, 7:13am Sep 8, 7:13am
Joined: Sep 2004
Posts: 126
Louisville, KY
2000 Silver Toyota Celica
Teknikal
Member
2000 Toyota Celica
Teknikal
2000 Silver Toyota Celica
Member
2000 Toyota Celica

Joined: Sep 2004
Posts: 126
Louisville, KY
Well generally your Anode is your "longer" terminal of your LED also the positive.

Also from your drawing I would assume that it is anode->cathode because a typical diode symbol is --|>|--

Re: Electrical Experts... [Re: Teknikal] #269145 Sep 8, 10:03am Sep 8, 10:03am
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Originally Posted by Teknikal
Well generally your Anode is your "longer" terminal of your LED also the positive.

Also from your drawing I would assume that it is anode->cathode because a typical diode symbol is --|>|--
It's a surface mount LED meaning that it doesn't have prongs as terminals.


And yeah, I did do a test with a voltmeter, and found out that I did have them on backwards.

But I still have a problem...


I changed a few around to the correct way that they should be mounted, and went back and tested it in my car expecting to see only those few light up.

Wrong. None of them are lighting up still.


I wonder if it's because they are all along the same circuit, and they have to all have the same polarity, or perhaps it's because at the bottom of the board, I'm missing two LED's due to the fact that on the board on one side, one of the mounting pads is missing, so I just left out the LED on that side, along with the LED on the other side so it would look like it's supposed to be that way.


Anyone know if this is perhaps why none of them are lighting up? Because two LEDs are missing?


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269146 Sep 8, 1:22pm Sep 8, 1:22pm
Joined: Jun 2004
Posts: 22
CO, USA
2000 White Toyota Celica GT
s71ck
Member
2000 Toyota Celica GT
s71ck
2000 White Toyota Celica GT
Member
2000 Toyota Celica GT

Joined: Jun 2004
Posts: 22
CO, USA
Yes the LED's are connected in series of 2 or 3 so if one is reverse polarized the other 2 or 3 on that circuit wont work. So what i did to test this was only unsolder 1 LED and replace it with 1 new blue LED, if it didnt work i had it in backwards. I just found this out last night because i was doing the same thing. What i found to be the easiest is to look at the front of the surface mount LED and make sure the little square in the clear part, called the die, is pointing to the bottom of the gauge circuit board. This is of course if you are using blue LEDs, if they are red however the die should be at the top.


PS: This is what part of the alphabet would look like if Q and R were eliminated.
Re: Electrical Experts... [Re: s71ck] #269147 Sep 8, 1:58pm Sep 8, 1:58pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Originally Posted by s71ck
Yes the LED's are connected in series of 2 or 3 so if one is reverse polarized the other 2 or 3 on that circuit wont work. So what i did to test this was only unsolder 1 LED and replace it with 1 new blue LED, if it didnt work i had it in backwards. I just found this out last night because i was doing the same thing. What i found to be the easiest is to look at the front of the surface mount LED and make sure the little square in the clear part, called the die, is pointing to the bottom of the gauge circuit board. This is of course if you are using blue LEDs, if they are red however the die should be at the top.
Gotcha, thanks.


Even when I reversed the direction on some of the LEDs, they still won't light up. Could it be the fact that I'm missing two LED's on the very bottom of the board?

I believe those two light up the hole in the tape deck.


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269148 Sep 8, 3:38pm Sep 8, 3:38pm
Joined: Jun 2004
Posts: 22
CO, USA
2000 White Toyota Celica GT
s71ck
Member
2000 Toyota Celica GT
s71ck
2000 White Toyota Celica GT
Member
2000 Toyota Celica GT

Joined: Jun 2004
Posts: 22
CO, USA
If the LED's weren't there from the factory, dont add extra ones, but if you de-soldered some and didn't re-solder in a new LED it would be the same as having one reverse polarized, the rest of the LED's in that series wont turn on.


PS: This is what part of the alphabet would look like if Q and R were eliminated.
Re: Electrical Experts... [Re: s71ck] #269149 Sep 8, 5:25pm Sep 8, 5:25pm
Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
slidr OP
Specialist
2000 Toyota Celica
slidr OP
Specialist
2000 Toyota Celica

Joined: Sep 2003
Posts: 3,077
Saint Louis, MO
Originally Posted by s71ck
If the LED's weren't there from the factory, dont add extra ones, but if you de-soldered some and didn't re-solder in a new LED it would be the same as having one reverse polarized, the rest of the LED's in that series wont turn on.
There were two LEDs there from the factory. The reason I didn't put them in is because I damaged one of the mounting pads, and I left the other one out because it was coupled with the other one.


And none of the LEDs light up, so I guess this is near the source of the power, and I broke up the circuit?


Aqua Teen Hunger Force...number one in the hood, G
Re: Electrical Experts... [Re: slidr] #269150 Sep 8, 10:13pm Sep 8, 10:13pm
Joined: Jun 2004
Posts: 1,003
San Diego, CA
Sancho
SD Syndicate
2004 Toyota Celica GT
Sancho
SD Syndicate
2004 Toyota Celica GT

Joined: Jun 2004
Posts: 1,003
San Diego, CA
Like I said in another post, theres many pathways in the circuit they could go. I'll assume that all the LEDs are on the same pathway.

Simple circuits, rule of thumb is if you have an open cicuit, nothing will happen. If there were LEDs in the two open ones, you should replace those or replace them with equally impendent resistors (keep the current the same). Make sure they are all polarized and check you solder connections. It took me a long time to realize that I needed flux with the solder I purchased.

If anything else, you could have burned one of the LEDs out. They're strong buggers, but it happens sometimes. idunnoGood luck and keep us informed.


[Linked Image]
2004 Toyota Celica GT
***Blue Batmobile sponsored vehicle***

Join the conversation - Register Now or Log In to add your comment


Moderated by  isaac 

Member Spotlight
xXMaGNuSXx
xXMaGNuSXx
2000 Toyota Celica GT
Smog City LA

Posts: 975
Joined: October 2003
Show All Member Profiles 
Recent Topics
Resurrecting a 2000 GT automatic.
by cosmo64. 10/19/2017 1:19 PM
APR strut bar brace for 2000 GTS
by TweakMaster. 10/15/2017 8:02 PM
Help with vacuum hose
by Chaos. 10/15/2017 6:07 PM
My 2000 GTS
by TweakMaster. 10/14/2017 6:29 PM
Replaced bad MAF. Now getting p0300/p1300 CEL codes. HELP!
by Bblee1989. 10/14/2017 4:34 PM
What kind of rim is this?
by mariahjordan. 10/10/2017 8:05 PM
Changed Headlight but so Dimm
by smsih. 10/10/2017 2:55 PM
Anyone know this remote unlock key? trying to ID it!
by kieronboz. 10/04/2017 2:36 AM
Customize Your Toyota Celica Privacy Policy · About · Contact
Privacy Policy · About · Contact
CelicaHobby.com is an independent Toyota Celica enthusiast website. CelicaHobby.com is not sponsored by or affiliated with Toyota Motor Sales, USA, Inc. in any way. The Toyota and Celica names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.
© CelicaHobby.com, 2001-2017
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Snapshot build 20171020)