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View Full Version : DC SSR Problems, RGB LED 5050 and Renard 64xc



PYoung
12-10-2012, 09:50 PM
I have RGB LED smd 5050 strings driving by Wlcventure DC SSR and Renard 64. I had 8 DCSSR at the start of the show 3 of them have failed one right out the gate one a week later and the next a week after that If they keep failing at this rate I wonít have any working by the end of the show I need to figure out Why their failing and how to fix them.

I Followed a DCSSR trouble thread. But the thread didnít seem to finish solving the problem. But like the other thread Iím getting less voltage after the MOSFET Then the supply Voltage.

It Not the Renard 64xc or the firmware, Other DCSSR work just fine on the same port, cables and power supply.

I donít thanks it the MOSFET as I was only using 3 of the 4 to drive the LED and all four donít work.

I Thought it was the OPTOA Jumpering pin 16 to pin to 15,13,11,9 seemed to light the string. So I ordered replacement they still didnít work. I didnít know what to use as a common while using the jumper until I found and printed a similar DCSSR Schematic. And realized the Vreg uses the supply voltage and reduced it to the 5v need. I thought the renard 64xc supplied the 5v.

I Thank it is the Vreg MC78M05BT. It not producing 5V to center pin GND.

The Question is The DCSSR was made for 24V supply Volts. Am I blowing the Vreg because Iím using 12V? Do I need a different Vreg for 12.

I will admit to a miss calculation or lack of any at all. I started the Show with a WAY to small power supply. Since the first two went and I realized how much current was needed I have added a large PC power Supply for the LED. So I was under power them at first.

LabRat
12-10-2012, 10:21 PM
The VREG is only used to for power to the OPTO. As you have a volt meter handy, you can check the input and output voltage of the 7805 regulator. That would tell you right away if that is the problem (which seems to fit your description). I believe that the part you described, the center pin is GND, you should have your input voltage on one side, and 5v on the other.

The reason the input voltage is used, is because these are opto isolators. You power the transmit side of the isolation circuit from the REN64, and the receives side from the lights input voltage. It all happens inside the plastic, but the transmitters emit light, that causes the receive side to trigger (turn on). There is no common electrical connection between the two. (that's it's job.. to isolate the two circuits from each other)

budude
12-10-2012, 10:32 PM
Without the 5v from the regulator the entire opto would not work which means all 4 outputs would not work. Since they were working, the assumption is that you didn't install them backwards or anything like that. You might want to try the full size 7805 (TO-220 package) regulator in place of the smaller 78L05 (TO-92 package) as it apears they might be overheating or something for some reason. I think you can get these at RadioShack (http://www.radioshack.com/product/index.jsp?productId=2062599) if you don't have a larger electronics store around.

PYoung
12-11-2012, 08:26 PM
It was the Vreg. The ones from RadioShack are in and running. Since the boards have the second set of holes it made this an easy fix.

Thanks for the help

Here is the shadow box tree that is now back up and running.16960

FIRECOP252
12-11-2012, 09:09 PM
Thanks for the info guys....I just had one go down last night and havent had time to perform side street surgery on it but I will check that as per mine did the same thing as yours so that might be the issue with mine.

Pyoung what did you do just remove the small one and replace it in the other holes with the larger one?

LabRat
12-11-2012, 09:28 PM
I'm really surprised that you could trash the VREG like this.
It might be prudent to check two things on the working device.

a. The resistors to the Opto are correct
b. Is the larger part getting hot/warm?

(Consider it a preemptive investigation)

ps. Love the tree.


It was the Vreg. The ones from RadioShack are in and running. Since the boards have the second set of holes it made this an easy fix.

Thanks for the help

Here is the shadow box tree that is now back up and running.16960

PYoung
12-12-2012, 12:26 AM
As sugested I have double checked the resistors they match the screen on the board and the Schematic 470 Y,V,B and 10K O,Bk,Br
16975
Once I figure out where to meter the common for the +5 I was only getting 1.7 V on two boards and only .7 on the other.

All three have the same problem so I am concerned I will lose the other 5 at some point. Id like to know what is causing them to fail. I spent hours reading and testing to find out what was wrong so Iím glad to have found it. Even if the cause of the failure is yet another problem.

My best guess is that when I was using the small 4A power supply to drive the led, the Volts where dropping out as I turned too many on. I assume this might have stressed the Vreg.
Im still using the 4A but only on one display If it is the next to go I will stop using it. The other are power by a new PC duel 12V rail 28A PS. I would assume it to be a cleaner power source.

I will take any suggestion to check something that might have caused this.

Should I get Het sink for the new Vreg?

Firecop252: My unsoldering skills are poor so I just cut off the old and install the new in the other set of holes.

budude
12-12-2012, 12:53 AM
The current draw should be fairly low - really the smaller one should be fine. You may want to do the finger test on a running DCSSR regulator and see if it's getting warm/hot. You should not need a heat sink but that will tell you.

THurrle
12-12-2012, 08:51 AM
I have not had a ny problems with mine yet but I did order a bunch of the vregs from Tayda and have them here just in case.

P. Short
12-12-2012, 01:59 PM
As sugested I have double checked the resistors they match the screen on the board and the Schematic 470 Y,V,B and 10K O,Bk,Br
16975
Once I figure out where to meter the common for the +5 I was only getting 1.7 V on two boards and only .7 on the other.

All three have the same problem so I am concerned I will lose the other 5 at some point. Id like to know what is causing them to fail. I spent hours reading and testing to find out what was wrong so I’m glad to have found it. Even if the cause of the failure is yet another problem.

My best guess is that when I was using the small 4A power supply to drive the led, the Volts where dropping out as I turned too many on. I assume this might have stressed the Vreg.
Im still using the 4A but only on one display If it is the next to go I will stop using it. The other are power by a new PC duel 12V rail 28A PS. I would assume it to be a cleaner power source.

I will take any suggestion to check something that might have caused this.

Should I get Het sink for the new Vreg?

Firecop252: My unsoldering skills are poor so I just cut off the old and install the new in the other set of holes.

Are you sure about the 10K resistors? The color bands should be Br, Bl, O (and not the other way around).

There should not be any need to mount a heatsink on the regulator. With the proper parts installed, the output current of the 78L05 regulator should be around 2mA, and total current through the part is 8mA (including the quiescent current). With a 24V supply the power dissipation should be around 200 mW, which translates to a junction temperature rise of about 30įC (a very comfortable number). If the regulator is dying due to overheating, there is something else wrong that is killing it (over-voltage, reversed voltage, applying AC, etc). The one thing that I've noticed about the design is that the input capacitor (C2) is only 0.1μF, where the recommended value is 0.33μF (or larger), although I don't really think that is your problem.

LabRat
12-12-2012, 02:14 PM
Hmm.. I'm seeing Brown (nearest top of image), Black, Orange, Gold band.

Perhaps it was just a batch of faulty 7805's ?

PYoung
01-11-2013, 07:24 PM
I just wonted to say thanks to all for the info and help
And that the rest worked fine the rest of the show.