Roland E-70, one speaker down

[matopotato]

Hi first post. And come to think of it first synth
I got a Roland E-70 from a friend today, who got it from a church where it had been "sitting" for 1.5 yrs.
It seems that the right speaker does crackle slightly but no sound. Left is as I think it should be. Same with phones. I was planning on opening up and try to fix, but would be happy of any help or tips before doing so.
Thanks

 

[happyrat1]

Take LOTS of photos when you're taking it apart to get the cables and screws back in their right places when you reassemble.

Probably a bum capacitor or op amp in the audio chain.

Check youtube to see if anyone has done a similar repair to help guide you.

Gary

 

[delaware dave]

Yep, check the op amp. $5 part.

 

[matopotato]

Thanks. YT did not yield as clear hits as I hoped for. Will open up and try to find the opamp and measure pins I guess.

 

[matopotato]

I find a dual opamp M5218P and an opamp NJM4565M-TE3 (flat) in the service manual. Any thoughts on which one is the more likely culprit?

 

[happyrat1]

If you think you can fix it by randomly eyeballing and swapping parts then you'll probably create more damage than you'll fix.

My advice is to take it to a tech for repair.

This is not something you can fix with a clawhammer and a prybar.

Gary

 

[happyrat1]

Since it's stereo, the dual opamp is more likely, but the problem could just as easily be a capacitor.

 

[happyrat1]

Read this first...

How to Diagnose and Fix Everything Electronic, Second Edition eBook : Geier, Michael : Amazon.ca: Kindle Store

How to Diagnose and Fix Everything Electronic, Second Edition eBook : Geier, Michael : Amazon.ca: Kindle Store

www.amazon.ca

 

[matopotato]

If you think you can fix it by randomly eyeballing and swapping parts then you'll probably create more damage than you'll fix.

My advice is to take it to a tech for repair.

This is not something you can fix with a clawhammer and a prybar.

Gary

Thanks, I was more thinking along the lines of a soldering iron, solder pump and solder...
Edit: unless it is socketed of course.
Might be useful with a DMM as well...

 

[matopotato]

If you think you can fix it by randomly eyeballing and swapping parts then you'll probably create more damage than you'll fix.

My advice is to take it to a tech for repair.

This is not something you can fix with a clawhammer and a prybar.

Gary

Thanks Gary, your words of caution are of course correct. And I would not dig very deep if it turns out to be complicated. I got it for free and I have yet to learn piano/kbd yet. I habe guitar and some bass in my background. So I was not planning on putting money on repairing if cost will run away, but to try first. I thought it might be a loose connection to the speaker, but considering phono jack is half as well, I suppose opamp or cap sounds more reasonable. I think I can source one of the opamps but the other seems a bit more elusive, thus my question.
Plan was to get speakers going, some clean up and see if I like it.

 

[happyrat1]

If you replace the op amp, install the new one with a socket for future possibilities.

 

[RedEyeC]

If all else fails, some synths with built in speakers will shut off if used with an external amplifier. Or, there could be a way to turn off (mute) all speakers in this E70?

 

[happyrat1]

This is not a settings issue.

It only affects one out of two stereo channels.

Unless there's a Global Pan setting that's acting up somehow.

Gary

 

[RedEyeC]

This is not a settings issue.

It only affects one out of two stereo channels.

Unless there's a Global Pan setting that's acting up somehow.

Gary

What I mean is - it would bother me to have one speaker working well, and one buzzing. But I guess this can't be solved without a repair. There are keyboards that have a speaker off function, though I am unfamiliar with the Roland E70.

 

[matopotato]

Much to my surprise I managed to solve it
I unscrewed the bottom/top. Looked it over and realized this is beyond me to troubleshoot. I could have done some connectivity tests on the Op-Amps or measured what voltage they get, but it was not for now at least. I noticed when it was separated that each speaker had like a copper foil fastened by one screw and then running across some "holders" (?) for the speakers. On the good side it was stretched out and sort of glued in place, but the bad side had it freely "flapping in the wind" sort of. I doubted it had anything to do with anything, but attached it back as well as I could. Cleaned the keys, vacuumed some dust away and reassembled it back.
Lo and behold, it now played through both speakers, and both headphones too. I did not check the subwoofer because it was on a table and I forgot. Will look for a stand and try it out more in earnest.
I also tried to connect Output/Mono to my guitar amp, but there was only noise, so that combination might not be suitable. (Or I misunderstood something)
Really cool! Thanks for the tips and ideas.

Is there some way to change the title of this thread to :

SOLVED: Roland E-70, one speaker down ?​

Cheers