ld300 pro troubles

[hardboiled_egg]

Hi!! I've been playing for my school and I tested all the amps we have when I got the chance since I'm our first bass player in a probably a decade. I found a nice looking Line6 LD300 Pro but the only issue with it is a lot of constant scratching sounds (like the sound you get when you yank out your cable on accident or sometimes with dirty pots) and nothing else coming through the speaker. There was some humming when I first tried it that sounded very high voltage like and the scratching only after a couple seconds of it sitting with it getting worse with any knobs being turned, but that hasnt continued. Sometimes the lights would flash weirdly on it, but that didnt really continue either. I tried it turning it on without a bass plugged in at all, with at least 3 different good cables, different ports, once with headphones plugged in, and even took a couple months of waiting between some of these tries with absolutely no positive change. The sound even vibrated my headphones on 0 volume once!

I couldn't really find anything like this online and I'm more curious about what the issue(s) could possibly be rather than trying to fix it on my own, but I also don't currently have access to a place that would probably even consider taking it for repairs. I'm also curious about how finding the root cause of these issues can work, so I thought it wouldn't be a bad idea to ask about it. Thank you to anyone who might see this and reply!

 

[agedhorse]

It can be hundreds of possible things, impossible to say what without thorough diagnostics which includes understanding how the circuit is supposed to work and then identifying where it's not working correctly according to the design.

Online information is generally more often wrong than right, it can be dangerous too.

 

[B-string]

Hopefully no one abused the amp before it went out of service (no one to play it). Let me first link the manual and presets for you.
https://line6.com/data/6/0a060b316a...LowDown Pilot’s Guide - English ( Rev F ).pdf
https://line6.com/data/6/0a060b316a.../LowDown Preset Chart - English ( Rev A ).pdf
I don't see an "Effects Loop" for an external effects unit so that leaves the most common cause out. This could be internal "ribbon style" interconnect cables that corroded when sitting that could benefit from unplug, DeOxit treatment and plug back in. I can't in good conscious make suggestions of unplugging and opening up the amp case. Maybe there is a repair shop local to you that would be willing to be of service and maybe even mentor you in MI equipment repair. This is a "hands on" type of thing for your safety and the life of the amp. It is WAY too easy to turn amps into paper weights with simple miss-steps.
Good luck and I hope you can find that path to the future.

 

[hardboiled_egg]

Yeah, unfortunately I was hoping there would maybe be some direction I could be pointed in even if I'm not really interested in trying to fix it or mess with the electronics on my own, as well as making sure it's likely not only something obvious. I'm more curious about things that could be wrong rather than a solution, but I understand that electronics are strange and can be super difficult to diagnose sometimes. Thank you anyways! I usually try to be pretty careful about online advice, especially with most electronics, but I'll take things with an extra grain of salt

 

[B-string]

Yeah, unfortunately I was hoping there would maybe be some direction I could be pointed in even if I'm not really interested in trying to fix it or mess with the electronics on my own, as well as making sure it's likely not only something obvious. I'm more curious about things that could be wrong rather than a solution, but I understand that electronics are strange and can be super difficult to diagnose sometimes. Thank you anyways! I usually try to be pretty careful about online advice, especially with most electronics, but I'll take things with an extra grain of salt

Other than give all the controls a good workout with the power off and unplugged. Give a look into the repair shops and let them know it is school owned stuff. Most of us that repair this stuff would like to teach the next repair force. Hey they can either get a tax break or maybe the floors swept and benches cleaned as payment for your education into amp repair?

 

[hardboiled_egg]

Hopefully no one abused the amp before it went out of service (no one to play it). Let me first link the manual and presets for you.
https://line6.com/data/6/0a060b316ac34f05934b940f8/application/pdf/LowDown Pilot’s Guide - English ( Rev F ).pdf
https://line6.com/data/6/0a060b316ac34f05934c9a8a1/application/pdf/LowDown Preset Chart - English ( Rev A ).pdf
I don't see an "Effects Loop" for an external effects unit so that leaves the most common cause out. This could be internal "ribbon style" interconnect cables that corroded when sitting that could benefit from unplug, DeOxit treatment and plug back in. I can't in good conscious make suggestions of unplugging and opening up the amp case. Maybe there is a repair shop local to you that would be willing to be of service and maybe even mentor you in MI equipment repair. This is a "hands on" type of thing for your safety and the life of the amp. It is WAY too easy to turn amps into paper weights with simple miss-steps.
Good luck and I hope you can find that path to the future.

Thank you! I appreciate the information you left here, especially the warning to not open it lol. I've certainly been tempted, but I've luckily been in spaces that firmly state to not dig into anything that sensitive or that deals with high voltage without knowing exactly whats happening + having proper training. I'll have to spend some time looking at places around to see if anywhere nearby might take it. Theres like one instrument shop around that offers amp repairs but they have a pretty hefty fee for unknown electrical issues I'm likely going to be in there soon though so I'll definitely ask about training and the possibility of a repair! I appreciate your reply!

 

[agedhorse]

Why not contact Line 6 and see which of their authorized service centers might be experienced with and capable of handling the repair?

 

[hardboiled_egg]

Why not contact Line 6 and see which of their authorized service centers might be experienced with and capable of handling the repair?

That might honestly not be a bad idea even if some other threads have said their support line wont be of much help. Only issue is I'm a minor that cant drive and I live in a pretty rural area so I doubt theres going to be any in the range my parents would be willing to take me for it. Even then, theres a site checker on their website and nothing shows up in any range from where I live (seems like a website issue though. nothing in 1000 miles seems impossible.) so I'm still going to talk to the closest instrument place when I can stop there and maybe even a teacher of mine that knows most of the repair places around and what they do to see if there might be somewhere I could go. It might not be possible for a while but hopefully this works out soon!!

 

[agedhorse]

This amp is better serviced by somebody experienced with Line 6 products. They are tricky to work on, most average techs do not have the chops to do the work. I would hate to see you waste your money on a tech that isn't going to be successful.

Give Line 6 customer service a call and ask them.

 

[dbsfgyd1]

Other than give all the controls a good workout with the power off and unplugged. Give a look into the repair shops and let them know it is school owned stuff. Most of us that repair this stuff would like to teach the next repair force. Hey they can either get a tax break or maybe the floors swept and benches cleaned as payment for your education into amp repair?

Next gen qualified repair techs:

I sold my tube amps for this very reason, concerns over finding one that isn't over 65.

 

[Alivefor5]

Line 6 repaired a VTBass 500 amp for me in February this year. They had a short turn around, reasonable price and were very willing to work on their discontinued equipment.