| Author |
 Topic  |
|
|
leclipse
Copper Member
Japan
2 Posts |
 Posted - 12/06/2009 : 13:59:54
|
Hello, I am a new member here, and I am also a beginner at electronics. I searched the forum as best as I could, but I didn't find this topic. I apologize if something similar has already been posted.
I have a Boss GE-7B Bass Equalizer pedal. The LED has stopped lighting up when the pedal is engaged. The pedal still performs its function as an equalizer, but since the LED indicator isn't working, it's kind of annoying not be able to see whether it's on or not at a glance.
So, I tried switching out the LED. I tested the old LED in an LED tester, and actually the LED itself still works fine.
I had read (in the Boss Area forum) about the DM-2 (http://www.bossarea.com/forum/topic.asp?TOPIC_ID=2131) that the zener diode could be the cause of the problem. I tested the zener diode (RD5.6EB-3 / D4 on the schematic), but it seems to be okay (I think).
When I removed the LED and tested the two contact points with a continuity tester, there was no connection. Is that correct? I apologize if that's an obvious or stupid mistake.
If anyone has any suggestions or advice of something I should check, or what could be going wrong, I would really appreciate it.
Thank you very much for reading this.
-Dan |
|
|
Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 12/06/2009 : 14:26:07
|
Hi leclipse
Welcome to the forum from Australia.
You have some interesting music on your MySapce page.
What settings on your multimeter were you testing the diode with?
Did you put the New LED in the correct way around?
- as you are aware LEDs are polarity conscious.
Check for broken wires to & from the PCB & LED.
The Zener (on diode test) should read like a normal diode in one of the directions. (about 0.6V or 0.7V).
What happened to your pedal before the LED stopped working?
Perhaps you can upload some internal pics.
Regards Dr. Bob 
|
 |
|
|
ssanyee
Silver Member
Hungary
288 Posts |
Posted - 12/06/2009 : 15:04:24
|
Hi leclipse,
Welcome to the forum!
I also would advise to you that at first check the wire continuities of the parts are serial with LED (zener, resistor, transistor...).
I would not suggest any parts breaking at first, so some soldering crack or open wire connection can be the issue. If all connections are ok, then should step forward to check the parts one by one!
Feedback about any results!
cheers |
Edited by - ssanyee on 12/06/2009 15:05:35 |
|
|
|
Dirk
Platinum Member
Netherlands
1309 Posts |
Posted - 12/06/2009 : 17:03:44
|
The LED on my GE-7b also stopped working due to a cracked soldertrack.
I bypassed the faulty track with a piece of wire. |
|
|
|
leclipse
Copper Member
Japan
2 Posts |
Posted - 12/07/2009 : 02:45:16
|
Thank you for all of your helpful responses.
Dr. Bob:
>What settings on your multimeter were you testing the diode with?
I tried the continuity test mode (the one in which it makes a beeping sound if there's a connection), and I used the diode test mode.
>Did you put the New LED in the correct way around?
I think so. But then again, even the original one wasn't working when it was attached to the circuit. (The original LED did work in a separate LED tester, after I rather unwisely unsoldered it).
>Check for broken wires to & from the PCB & LED.
That's something I'm having some difficulty with. It's a bit difficult to follow the paths leading to the LED visually (at least, it's difficult for me). The path on the circuit board seems to lead from the LED to a white wire ribbon, which is connecting to various things on the larger circuit board.
>What happened to your pedal before the LED stopped working?
That's a very good question. I don't recall anything noteworthy having happened to the pedal. It's a mystery to me as to why the LED stopped working.
>Perhaps you can upload some internal pics.
I will try to do so in the next few days. For the next couple of days I'll be away from home.
Dirk: I wonder if it's the same problem. Do you happen to recall where the faulty track was?
Ssanyee:
I will definitely try that. As I said to Dr. Bob, however, I'm having some trouble figuring out what is wired to what. I will poke around some more though.
Thanks to everyone for your advice. I will update you in a few days when I am back home and can give the pedal another look.
Thanks again!
-Dan
|
|
|
|
Dirk
Platinum Member
Netherlands
1309 Posts |
Posted - 12/07/2009 : 16:43:30
|
quote:
Originally posted by leclipse
Dirk: I wonder if it's the same problem. Do you happen to recall where the faulty track was?
Yes, if you open the pedal it was on the small board where the LED is soldered to the board, I just jumpered a wire from there to the 2nd right wire of the multiwire on the big board.
That is, facing the solderside of the board with the AC jack pointing away from you. |
|
|
| |
Topic |
|
GE-7B LED fix (need help/advice)
