Author Topic: Side LEDs are too dim (Read 1448 times)

redtiger · « **on:** September 15, 2009, 04:32:11 AM »

Lately my bass has arrived, but one problem.
Plugged in to DS-5R, but thought LEDs were not turned on. Then I took a close look carefully, and recognized that they were on but extremely too dim to notice.
How shall I adjust them? Any idea or technical advice would be greatly appreciated.

Shoji

grateful · « **Reply #1 on:** September 15, 2009, 04:56:40 AM »

Shoji; non-series instruments LEDs are powered by four 9v batteries. Are you sure a series bass's LEDs are powered by the DS-5R? I noticed from looking at your Factory to Customer thread you have what appears to be a LED battery compartment in the upper bout. I suggest you have a look in there to see if there's batteries in there.

Gorgeous bass BTW, Mark

georgie_boy · « **Reply #2 on:** September 15, 2009, 05:04:32 AM »

Mark
I think you'll find that that is where the PF6B circuit board goes on Series instruments, unless, like the old ones, which were mounted on the control cover.

George

(Message edited by georgie_boy on September 15, 2009)

grateful · « **Reply #3 on:** September 15, 2009, 05:06:27 AM »

You're right George, I'll get me coat!

(Message edited by grateful on September 15, 2009)

georgie_boy · « **Reply #4 on:** September 15, 2009, 05:10:07 AM »

The battery backplate houses 2, 9 volt batteries which are used if one uses the 1/4 jack.
The cover is at the rear end of the neck lams --not to be confused with the larger circuit board cover on the top half.

George

redtiger · « **Reply #5 on:** September 15, 2009, 06:54:03 AM »

Mark & George,

Thanks for the comments.
I checked with another series I bass Red Tiger, and made sure that LEDs are powered by the DS-5R as they work even without two 9 volts batteries.
Any possible reasons or technical advice welcome.

Shoji

georgie_boy · « **Reply #6 on:** September 15, 2009, 06:59:33 AM »

Nice reply Mike LOL!
Shoji........I'm not sure what could be up with your new bass......I thought Mica would have contacted you by now.
Try to send the E-Mail to Technical support.
it may just be a loose connection due to shipping.

George

georgie_boy · « **Reply #7 on:** September 15, 2009, 07:04:50 AM »

oops!!!.........meant to say Mark!!
This keyboard can't spell Jack S.

G

JimmyJ · « **Reply #8 on:** September 15, 2009, 08:33:48 AM »

Shoji,

I am wondering if your DS-5R was set to operate at 117v instead of 100v? This might account for a slightly lower voltage output. (I don't know if the current version of the power supply has a selectable input voltage or is omni-voltage...)

If you have two series basses and one is bright and the other dim, then it's not the PSU. There is a large resistor in the controls compartment of the bass which is in charge of dropping the voltage for the LED strip. You will need more advice from Alembic as to what the value and voltages should be.

Good luck!
Jimmy J

mica · « **Reply #9 on:** September 15, 2009, 12:00:14 PM »

I can't recall, but look inside your bass and see if there is a dimmer control inside. It will look just like the volume pot, only backwards with the shaft pointing towards to the backplate. If you have the dimmer, then it may be adjusted to low. if you don't have the dimmer, then it may be a difference in the selection of the resistor as Jimmy suggested.

If you can post a picture of the electronics cavity, I can confirm for you.

redtiger · « **Reply #10 on:** September 16, 2009, 05:53:51 AM »

Mica, Here are the requested pics;

Thanks for your support. Shoji

rjw · « **Reply #11 on:** September 17, 2009, 07:52:33 PM »

hi Shoji,

as Jimmy said, since the power supply works properly on one instrument, that confirms it's operating normally.

a switch failure is very unlikely, but easy to eliminate. disonnect the plugs from both sides of the switch and connect them directly to each other...which would make the LEDs on constantly when the instrument is connected to the power supply. if the LEDs return to full brightness then the switch is the problem.

if you have a volt meter, it would be good to know the voltage between the red and blue wires at the LED connector, expecting a reading of 36 to 44 volts.

if that is good, then we would measure the voltage accross the LED string itself. we would stick a steel pin into the insulation (shrink tubing) where the red wire connects to the resistor, and measure to the black wire, which a probe can access at the connector. the expected voltage is around 24 volts depending on the characteristics of the individual LED devices, usually in the range of 22 to 26 volts.

a lamp failure is indicated when the measured voltage is nearly the same at both points above.

-ron

redtiger · « **Reply #12 on:** October 15, 2009, 10:20:08 AM »

Hi Ron,

Lately I've got a volt meter, and checked as you suggested.

Here is the result as follows;
The switch is good.
The voltage between the red and blue wires:36 volts.
The voltage across the LED string itself:36 volts.
That seems the resistor doesn't work, does it?

Further suggestions would be deeply appreciated.

Shoji

mica · « **Reply #13 on:** October 16, 2009, 10:48:58 AM »

While it's extremely rare, the only conclusion is that one of the LED components has failed in a manner that the resistance is greatly increased.

Actually, this is the first possible LED component failure I've encountered since I started working here over 20 years ago. My dad tells me they were slightly more common early on, but the components were not as reliable.

So what to do? The only way to repair is to send the bass back here. Because of the great distance involved, and since you just received the bass, I have placed a note in the instrument file describing the problem and stating that your LED repair will be free of charge at any time you see fit. We're very sorry that your bass' LEDs are not functioning properly and require this service.

redtiger · « **Reply #14 on:** October 20, 2009, 07:40:27 AM »

Mica,

Thanks for your diagnosis.
Before we go any further, let me make sure one thing.
If LED component failure is the reason, I guess it is a factory defect (NOT MY FAULT), and should be covered NOT BY WARRANTY, but by ALEMBIC itself.
And all of the costs including round trip shipping charges should be compensated for by ALEMBIC regardless the warranty.
Request your comments.

Shoji