Broken Boss GE-7 Equalizer Needs Help

[Roger Martin]

Hello guys,
I'm just trying to help a fellow member, Mr. Zakarum, by bringing up his topic here.
His Boss GE-7 Equalizer pedal was deadly broken a few days ago.
Perhaps anyone who owns one or has built it can help this issue.
Let me quote what he said in other room, here's the link :
http://www.diystompboxes.com/smfforum/index.php?topic=92474.0;topicseen

zakarum
Posts: 2


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   Re: BOSS GE-7 NEW
« Reply #2 on: August 24, 2013, 11:41:35 AM »
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Hi,
I'm searchin for it too.

Some days ago my GE-7 has stopped to work but I don't know why. I tried with another PSU and a new battery but nothing. Usually I use Voodo Labs Pedal Power 2 Plus and a Dunlop DC Brick but it doesn't run with no ones. Being in a daisy chain he interrupt the sound passage through the other pedal FX so I remove it from my pedalboard, but I need GE-7 to control and balance the sound of the OD-2.
I'm newbie to electronics, so I don't know how to fix. Anyway I can take this time to attempt a mod.

Here some shot of the PCB (https://docs.google.com/drawings/d/1ZpJ3Nz7ojtd2b9HHTWYxIxX_mOLWBElsRU8f-LPQZns/pub?w=2595&h=1608) . Hope you can help me to find a way to run it again.

Have a nice day. Many thanks ^^.

zakarum
Posts: 2


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   Re: BOSS GE-7 NEW
« Reply #4 on: Today at 02:50:53 PM »
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First of all, thanks for your reply.

Well, I scanned the PCB schematics but I'm unable to scan/make a photo of the front. Anyway I found some diagram that seems to be about BOSS GE-7 (hope them are of the new GE-7... mine is around 2006).
I wish you can help me.
Thanks a lot... again ^^

https://docs.google.com/drawings/d/1Sv7TOU1TDYT3zowdzd9lBRHGcu93vDn6Ok2KckPfSgA/pub?w=960&h=720
If the previous image is lowres try this www.takusama.com/media/boss_ge7_scan.jpg
   

Well, for me, i'm interested in building it myself first so that to be able to tell him what's wrong with that pedal later on.
As i don't own one, so i can't offer much help now. But i can't let him wait that long.
So perhaps some good guys here would be so generous to help him, please ?
And in the meanwhile maybe you guys are willing to discuss how to DIY this pedal.  

Ok, here is the schematic drawn by Jon Halverson in April 2000.
If you need to email him, his email is jhalvers@enteract.com
He modified it with lower noise modification.
Boss GE-7 Schematic Drawn By Jon Halverson
http://img600.imageshack.us/img600/5871/1qnd.jpg

Here are the gut shots...
But these pics are not from the same pedal.
I think the upper pcb silk screen pic (vangelismetheny's pedal pic) is from a different version from the underneath 2006 Boss GE-7 pcb layout (zakarum's pedal pic).

vangelismetheny's upper pcb silk screen pic :
http://i1023.photobucket.com/albums/af355/vangelismetheny/GE7_New.jpg


zakarum's 2006 Boss GE-7 underneath pcb layout pic :
http://www.takusama.com/media/boss_ge7_scan.jpg


Please someone helps us.
Thank you in advance, i really appreciate it.

[R.G.]

Please someone helps us.
Thank you in advance, i really appreciate it.

See the thread "Debugging: what to do when it doesn't work".

Sudden death has many causes. Almost all of these show up quickly in the measurements requested in the debugging thread. It's going to take someone being able to use a voltmeter on the insides of the GE-7 and posting that info here. It may well be a broken wire, or something else. But the measurements usually tell the tale.

[kingswayguitar]

it appears from my internet search that the 4037s are op amps. what are the sip ics?

[R.G.]

it appears from my internet search that the 4037s are op amps. what are the sip ics?

Probably dual opamps in 8-pin SIP packages.

[Roger Martin]

Please someone helps us.
Thank you in advance, i really appreciate it.

See the thread "Debugging: what to do when it doesn't work".

Sudden death has many causes. Almost all of these show up quickly in the measurements requested in the debugging thread. It's going to take someone being able to use a voltmeter on the insides of the GE-7 and posting that info here. It may well be a broken wire, or something else. But the measurements usually tell the tale.

Yes, R.G. it may be broken wire. I hope zakarum can do the debugging volt measurements and post it here.

Looking at Jon Halverson's schematic drawing
U1,2,3 are TL 072
U4 is JRC 2068
U5 is OP A 134 (DIP->SIP)

Ok, here is the schematic drawn by Jon Halverson in April 2000.
If you need to email him, his email is jhalvers@enteract.com
He modified it with lower noise modification.
Boss GE-7 Schematic Drawn By Jon Halverson
http://img600.imageshack.us/img600/5871/1qnd.jpg

[zakarum]

Hi to all. Thanks for your replies and interest and sorry for my delay.
The fact is very... weird and stupid for me. Today I checked with voltmeter and saw that signal passed, so I retry to power again the pedal then I try to plug another cable and .... well, I know it's kinda funny, but all works well... so the problem was on my previous cable instead of the pedal... I never checked it before today.

I'm really sorry, but anyway I hope in you support if tomorrow my pedal stops to work.

Thanks to all for your cares.

[R.G.]

No problem. I'm glad your pedal is working - and that you found your bad cable.

As I tell people here, Mother Nature requires that everything, no matter how small, be working right all at the same time. This makes it difficult to find small, simple things sometimes.

[Paul Marossy]

As I tell people here, Mother Nature requires that everything, no matter how small, be working right all at the same time. This makes it difficult to find small, simple things sometimes.

Yeah, and then she makes you feel really dumb when you find the simple reason why it ain't working, after pulling out your hair for four hours. Ask me how I know.