Line 6 XPS-AB Schematic

[gaztech]

Oh, and Bill... before I contact them I will almost certainly need the serial number of the unit!

PM me with it if you don't wish to post it here. Thanks.

[Billguitarvin]

Hi Bill,
I took a look at your pictures. Yes... the board you have is a bit different! This won't help the process at all.

I'm going to appeal to Line 6 today to see if they will release a Version 2 drawing to me. Note that if I do get it I might not be able to share it. I'm very rigid on this. If a manufacturer tells me specifically NOT to share it, I won't. It's important to respect their wishes in this regard. If you don't they totally clam up which doesn't help anyone.

I'm expecting them to say no and refuse to give it to me but we'll wait and see. We might get lucky.

I really, really appreciate your offering to call up Line 6 to see if you can get a schematic for the version I have. That is so kind of you and truly way beyond what I would ever expect someone in this forum to do. If you are lucky enough to convince them I totally understand about not being able to share it. I just sent you a pm with what I could find as far as the serial number goes. THANKS AGAIN!!!!

[Billguitarvin]

Oh, and Bill... before I contact them I will almost certainly need the serial number of the unit!

PM me with it if you don't wish to post it here. Thanks.

Just sent another pm with a serial number I found in the owners manual. Don’t know if this is for the guitar only or what. Hope it helps!

[Billguitarvin]

Well the good news is D10 has made it through unscathed. I have removed U1, U2, U3 and Q9. I removed what was left of L2 and to my untrained eye it looks like the solder pad on the right side has detached from the pcb. I posted a couple of pictures in my albums folder under my profile. I tried bending the solder pad back into place, but I’m not sure if it will conduct in its present state. As a work around, could I possibly bypass the right solder pad of L2 and solder a new L2 from the bigger solder pad that is right below and in between L2 and C6 and connect the other end of L2 to the original L2 solder pad on the left? I think the bigger solder pad is coming from the tip of the AC adaptor. If not, should I try to redo the right solder pad of L2, or any other options? I should have a replacement for L2 sometime Monday so hopefully I can get it installed and start checking some voltages now that I have removed U1, U2, U3 and Q9. BIG THANKS!!!

[Billguitarvin]

Hi Bill,

We're way off base with this.. You keep referring to a TL431 - this isn't an inductor.

The TL431 provides the 2.495 reference voltage - which is component U8 - not L2.

If you really did blow out L2 (which sits right at the supply input) then you shorted something directly to ground. This could be really bad news.

For the moment, you can replace the inductor with an 1/8W 10 Ohm resistor. You will have to replace the inductor at some point but this component will make it work at least for testing. If anything else nasty happens it will blow out the resistor.

I'd be concerned now about Diode D10 - you might have taken that out as well. You really MUST be careful when taking measurements. These small components are very unforgiving. If you make a mistake then you can kill stuff very easily. When stuff blows out, it can "knock on" to other components that were previously ok. God only knows what has blown out now.

You still need to have the +7V working AND the -5V and the +5V. Without these, nothing will work at all. You will now need to go back to the beginning and start again.

Do you know how to test a diode? Do you have a diode test on your meter. If you do, you will need to make sure this done is ok before turning the unit back on. You "can" make a rudimentary test with a resistance mesurement but it's best to remove the component. If you remove it, Note the direction it was installed. There will be a stripe on one end. Note this. It's important. When out, test the diode. On a resistance only test yuo should see it conduct one way but not the other. If you have a proper diode test on your meter then it will not conduct one way and show about .6V the other way. (I'm trying hard to keep this as simple as I can but it's not easy...).

If it checks out ok, put it back into circuit.

Take out Q9. Take out U1, U2, U3. They could all now be damaged. Once you have removed all these components, plug it back in (not the guitar! - but with a jack in the input.)

Ok, now being VERY careful with your probes....

Check voltage across C9 - should be about +9V.
Now check voltage across C12 (negative probe to + on the cap). You should have -5V
Check voltage across C11 (negative probe on to - of cap). You should have +5V.
You should also have around 2.5V on two of the pins of the TL431 (U8) - I think... You might not. If you don't don't worry about this for the moment.

If any of these voltages are missing, do not try putting any components back. You need these voltages right first. Take these measurements and let me know what you find.

Hi gaztech! Finally got around to replacing L2 and took voltages for C9, C11 and C12. These were taken with Q9, U1, U2 and U3 removed from the board. I also inserted a TRS cord into the “TRS IN” jack. I can’t find a U8 UL431 on my board, but there is a Q8 UL431. Is that the part you were referring to? If so, I checked out the voltage on Q8 as well. Thanks again for all the help!!!


C9 +14.5 VDC


C12 -4.99 VDC


C11 +3.7 VDC


Q8 (TL431)
Pins 1&2 +2.49
2&3 +2.49 VDC
1&3 0VDC

[gaztech]

Hi Bill,

Sorry about the wait... been busy!

Looks like all are ok except the measurement across C11. Make sure that there is +5V across the 5V regulator. The cap should be C11 but I notice that your board is a bit different to the earlier version so it's posisble it might be a different component reference. The +5V supply MUST be there. If it's not we'll have some issues. I also notice that there are some other chips on the board that we have not removed yet. These ones should be removed too as the issue could lie there. what we're aiming for is a scenario where we remove a part and the 5V comes back.

Since all the other readings seem about right, we need to find out which component is making the +5V take a dive. It looks like you're only going to be able to do that by taking some stuff our to find out what could be taking all the juice! It's of course possible that the +5V regulator is bad too. You'll only really find that out with substitution though...

Have a poke around to see if you can get the +5v back and then we'll look at it again.

[Billguitarvin]

Hi Bill,

Sorry about the wait... been busy!

Looks like all are ok except the measurement across C11. Make sure that there is +5V across the 5V regulator. The cap should be C11 but I notice that your board is a bit different to the earlier version so it's posisble it might be a different component reference. The +5V supply MUST be there. If it's not we'll have some issues. I also notice that there are some other chips on the board that we have not removed yet. These ones should be removed too as the issue could lie there. what we're aiming for is a scenario where we remove a part and the 5V comes back.

Since all the other readings seem about right, we need to find out which component is making the +5V take a dive. It looks like you're only going to be able to do that by taking some stuff our to find out what could be taking all the juice! It's of course possible that the +5V regulator is bad too. You'll only really find that out with substitution though...

Have a poke around to see if you can get the +5v back and then we'll look at it again.

Thanks gaztech for your response and no problem about the delay. Just glad you haven’t given up on me. I think the only chips I have left are U6 and U7, so I’ll remove those. Anything else I should remove?

I’ll check on C11 and see if that is the capacitor that goes from the output of U4 to ground. One thing weird to me is the voltage after L2 is +10.8 VAC but the voltage at D10 Cathode is +5.1 VDC. Does that seem strange to you, or is it just indicative something downstream is causing the voltage drop? I’m wondering, because if I’m reading the schematic correctly, the VBUSS after D10 feeds to U4 which I think is the + voltage regulator? Would 5.1V going into U4 be enough voltage to produce a +5V output?

[gaztech]

Are you saying that you DO have 5V output on the regulator output now?

I do agree with you that 5.1V into the regulator would be an issue for proper operation but you'll still have to pull the remaining chips out. We must start from a point where the regulator outputs and the supplies are correct. Once we get to that point, then is the time to move forward.

[Billguitarvin]

Sorry for the confusion. No, I’m still not getting +5v at the regulator output. I’ll take out the remaining chips and check the voltage output on the positive voltage regulator. Hopefully get around to doing that in the next couple of days. Thanks!

[Billguitarvin]

Greetings gaztech! Took out U6 and U7 and all voltages I checked are still the same (C11 still reading around 3.7V, should be 5V). It looks like to me U4 is going to C11 on the traces. Any thoughts of what to check next? Thanks again!

[gaztech]

Hi Bill. Still here - just been busy with other stuff.

I managed to get in touch with the right person at Line 6 (I think). Looks like I might be able to get hold of the correct manual for this unit - which will make an enormous difference!

The issue is that there are a load of different variants on this one. Can you tell me which model of guitar you have and give me some pictures of the outside of the guitar and the XPS box too. We need to absolutely identify it so that I can get the correct info. I believe you have my personal email address so please forward what you can to there and I'll see what I can do.

Credit to Line 6 is due for taking the time to respond - properly. They took all my comments onboard and looks like they will be helpful. Unusual in this day and age.

I'll wait to hear from you.

[Billguitarvin]

Thanks gaztech!!! I just emailed you pictures of the outside of the guitar front and back as well as several of the AB box. Line 6 has been great the few times I have called them. Very helpful and very nice as well. Take care and stay healthy!

[gaztech]

Hey Bill... Not got these yet. Not sure where you sent them....

[Billguitarvin]

Sorry you didn’t get them. I just resent the email to the email address you PMed me on April 9. I also just sent you 3 separate emails breaking up the pictures in case the files were too big. Hope you get them and let me know if there are still problems. Thank you!!

[gaztech]

Sorry you didn’t get them. I just resent the email to the email address you PMed me on April 9. I also just sent you 3 separate emails breaking up the pictures in case the files were too big. Hope you get them and let me know if there are still problems. Thank you!!

Hi Bill, I got the pics ok. I'm now waiting on Line 6 to give us the correct schematic for this. Will be in touch.