Avalon U5 need power LED

[arsmusic]

Avalon is not making products right now. Then said apr 2022. But who knows. Maybe they are going out of business. Anyways, I needed another U5 and had to buy one used. got it from Reverb. But the power led is out. It is reading 3.7v so it is getting power. Just needs a new bulb. I have contacted Avalon and no reply yet. They have a service center in Burbank but that place has not got back to me with the part number yet. Anyone know what it is? The solder in LED mine is LED6 written on the PCB.

PS it is the blue LED. I have the black Anniversary Edition all blue led one.

 

[Khron]

5mm diameter blue LED?

https://www.mouser.fi/Optoelectroni...P=1z0yt3kZ1y82myx&Ns=ManufacturerPartNumber|0
Enjoy.

 

[pucho812]

Avalon is stuck like just about every audio electronics manufacture at the moment with supply problems due to covid. Hard to make equipment when you can't get the parts you need to make the equipment. They are not going anywhere to my knowledge.
Is the unit working other wise? I would confirm you are getting the correct voltages at the PSU. It's rare that the power LED goes out in those things, if it is out it's usually an indication of a problem elsewhere. I am not saying it doesn't happen but if it's out, it's usually because of something else and not because the LED has burned out. the PSU outputs +/-31VDC and +/-15VDC. the bipolar 31VDC is for the discrete and the bipolar 15 is for the d.c. servo's.
Measure DC voltage in reference to ground at the top of R9 which is the point closer to the black power transformer and next to ZD2 for around +31VDC
Then Measure the bottom of R15 which is near sw3 and sw4 and next to ZD4. You should have around -31VDC. From there you can measure the IC's for the bipolar 15VDC to run the servo's. If you are not getting those voltages, we can check further upstream and see if we are getting the correct output of the PSU transformer. The units are built like tanks and very few things go wrong on them.

 

[Whoops]

Desolder the LED and solder a new LED in place to try out

 

[arsmusic]

Thanks guys. I got a little impatient waiting for the correct part number earlier today. So I just popped in a green LED I had around the house. It is working fine now. I was going to order the blue one and make it stock but the green one looks sort of cool. So I will keep it.

 

[pucho812]

how unusual but nice fix.

 

[tgs]

Thanks guys. I got a little impatient waiting for the correct part number earlier today. So I just popped in a green LED I had around the house. It is working fine now. I was going to order the blue one and make it stock but the green one looks sort of cool. So I will keep it.

An improvement if you ask me, don't know what's up with all these blue LEDs that everyone insists on using. To me it only makes things look cheap.

 

[scott2000]

If it looks good it is good...
oh wait...lol

 

[pucho812]

An improvement if you ask me, don't know what's up with all these blue LEDs that everyone insists on using. To me it only makes things look cheap.

there was a a period where Avalon used all green LED's, it was in the later half of the 1990's

 

[BroMarduk]

Avalon is stuck like just about every audio electronics manufacture at the moment with supply problems due to covid. Hard to make equipment when you can't get the parts you need to make the equipment. They are not going anywhere to my knowledge.
Is the unit working other wise? I would confirm you are getting the correct voltages at the PSU. It's rare that the power LED goes out in those things, if it is out it's usually an indication of a problem elsewhere. I am not saying it doesn't happen but if it's out, it's usually because of something else and not because the LED has burned out. the PSU outputs +/-31VDC and +/-15VDC. the bipolar 31VDC is for the discrete and the bipolar 15 is for the d.c. servo's.
Measure DC voltage in reference to ground at the top of R9 which is the point closer to the black power transformer and next to ZD2 for around +31VDC
Then Measure the bottom of R15 which is near sw3 and sw4 and next to ZD4. You should have around -31VDC. From there you can measure the IC's for the bipolar 15VDC to run the servo's. If you are not getting those voltages, we can check further upstream and see if we are getting the correct output of the PSU transformer. The units are built like tanks and very few things go wrong on them.

I'm also having a fun time tracking down the lack of power LED and some other issues with a U5.

If I'm getting 21VDC at the top of R9 and -8VDC at the bottom of R15 is there anything else I can check?

 

[JohnRoberts]

An improvement if you ask me, don't know what's up with all these blue LEDs that everyone insists on using. To me it only makes things look cheap.

Blue LEDs were developed decades later than the other colors so relatively expensive and rare when they first came out. They were adopted to look different, but now they are so common they are getting boring (my dishwasher has blue LEDs).

I'm also having a fun time tracking down the lack of power LED and some other issues with a U5.

If I'm getting 21VDC at the top of R9 and -8VDC at the bottom of R15 is there anything else I can check?

LEDs are pretty straightforward to troubleshoot. In operation they will exhibit a couple volts of drop across them, and are routinely fed through a resistor from a DC voltage rail. Once you identify the resistor feeding the LED you can use ohms law to calculate the current flow. I=E/R so current will equal the voltage across the resistor divided by the resistor's value. Old school LEDs could need tens of mA, modern high efficiency LEDs 10mA or less.

JR

 

[BroMarduk]

Thanks @JohnRoberts. Agree with you on the blue LEDs.

As for my issue, I should state the Power LED is not coming on, but the LED itself is fine. I think it's not coming on due to the voltage being out of range on the device, but without schematics and known test point data I'm trying to figure it out a bit blindly so looking for any known information. I'm OK with repairs like these, but not an expert by any means.

According to @pucho812 from an earlier post, the voltage should be +/-31VDC coming in and +/-15VDC at the ICs, but I'm not close to those number so trying to track down where the voltage differences might be coming from.

 

[Khron]

Internal photos?

 

[pucho812]

Thanks @JohnRoberts. Agree with you on the blue LEDs.

As for my issue, I should state the Power LED is not coming on, but the LED itself is fine. I think it's not coming on due to the voltage being out of range on the device, but without schematics and known test point data I'm trying to figure it out a bit blindly so looking for any known information. I'm OK with repairs like these, but not an expert by any means.

According to @pucho812 from an earlier post, the voltage should be +/-31VDC coming in and +/-15VDC at the ICs, but I'm not close to those number so trying to track down where the voltage differences might be coming from.

Those are correct. The most common issues related to power are transformer weight can crack traces and cause connection issues from the secondaries into the psu and recaps. When I get in tonight. I’ll share some photos and test points etc. what voltages are you measuring?

 

[noizetoys]

First: The LED used is a standard KingBright 3mm LED. 20mA, 3.3 - 4v
Second: The most common power issue seems to be related to C9 (100uF, 50V). Problem is, if one goes, it could take out others and there are (17) other 100/50 caps that might be suspect.

Also check out C1-4 (2200uF/50 or 63v). I've had one give up the ghost and lower the voltage.

EDITED: changed '230' to '20'...Damn fingers

 

[pucho812]

First: The LED used is a standard KingBright 3mm LED. 230mA, 3.3 - 4v
Second: The most common power issue seems to be related to C9 (100uF, 50V). Problem is, if one goes, it could take out others and there are (17) other 100/50 caps that might be suspect.

Also check out C1-4 (2200uF/50 or 63v). I've had one give up the ghost and lower the voltage.

power led is not king brite brand to my parts list but it will do I also may have an older parts list. if one of the 100uF goes, there is no relation to others going out as well, but when people don't see the schematics, the shotgun approach often happens.
the 2200uF/63V usually do not give up the ghost regularly, again part of the shotgun approach. I did however work on a u% recently where a failed 2200UF wasn't filtering properly which gave a higher then expected noise floor.

 

[noizetoys]

I'm only passing along what Avalon's tech (a friend of mine) told me earlier today.

 

[BroMarduk]

@noizetoys 230ma seems high for an LED (3mm), but I'll check Kingbright's site.

Here is an internal photo and some voltage measurements of the board. If there are any other places I can check, let me know.

Nichicon 2200uF caps measure between 1999uF and 2220uF (in circuit).

 

[Khron]

I'll venture a guess and say the "3" got typed by mistake, within that "230mA"; 20mA is indeed a pretty standard rating for 3-5mm LEDs.

I'm still borderline shocked that the power indicator LED, of all things, is apparently this prone to failure in these units.

Depending how they're connected, those capacitance figures may or may not be ok.

 

[tgs]

Blue LEDs were developed decades later than the other colors so relatively expensive and rare when they first came out. They were adopted to look different, but now they are so common they are getting boring (my dishwasher has blue LEDs).

Indeed. First one I ever saw was on a PS2 around -99 or so. Then I thought it looked kind of neat but then they were everywhere, and god were they just brighter and brighter...

One problem I always have with blue LEDs is that I just can't focus my eyes on anything around them. I have plenty (too many) in my side rack and I need to cover them or use a flashlight to see what it is I'm doing.