Tokai TCH-1

[Apocalypto]

Hi guys.  I just bought an old Tokai  TCH-1 and it doesn't work.

When you hit the switch the LED lights up and there's a slight tonal change, but the knobs and switch don't alter the sound.

I opened it up and poked around but I'm not even sure where to start figuring out which part(s) might be causing the "lack of effect".

Is it cool to post some photos here in this sub-forum and see if anyone can help me with ideas?

Here are some photos.  It seems like it would be a cool pedal.  Hopefully it will be something simple causing the inert sonics.

http://i.imgur.com/GmwTsmH.jpg
http://i.imgur.com/udboFn6.jpg
http://i.imgur.com/wAPrH0X.jpg
http://i.imgur.com/I3eGMlu.jpg
http://i.imgur.com/A561RPQ.jpg

This is a stitched photo to see the whole board a little closer.
http://i.imgur.com/A561RPQ.jpg

http://i.imgur.com/pbA7Jbg.jpg

[Apocalypto]

I did more searching tonight and I may have found the answer!

This fellow had the same problem as me and it turned out to be a bad BA728 opamp.

Title: Tokai CH-1 Chorus not chorusing
http://www.diystompboxes.com/smfforum/index.php?action=printpage;topic=91441.0

I'll replace that and see if mine has the same problem.   

[chromesphere]

Could be the MN chips as well if the problem is pedals not chorusing.  That's going to be a tough one to fix, maybe take some voltages and make sure everything is roughly where it should be?

[Scruffie]

Could be the MN chips as well if the problem is pedals not chorusing.

Not to scold you... but try to avoid saying that, people always assume the BBD is what's dead as it's the most expensive/rare part when most of the time it's not the case.

Post voltages first of all as chromesphere suggests, it could well be the BA728, but it could just as easily be 300 other things (guessing that's about as many solder points as there are in that thing).

[chromesphere]

I was going to say they were fakes Scruffie? lol Definitely agree. Dead MN's was just throwing one possibility to the wind

I wouldn't ordered anything until I'd sussed out the board with voltages.  Going to be a tough one to fix.

[Apocalypto]

Okay guys.  Thanks for the help.  I will take voltages first.

Kind of a tough one for my first broken pedal.  I guess I've given myself a big challenge.   

[Apocalypto]

Well so far I'm getting nothing but zeros.  (Tested all the ICs)  Wow.  I'm surprised.  But I know almost nothing about this so maybe this is common on a problem pedal?

chromesphere, I followed your great video on how to take digital readings.  For now I left everything in the enclosure but I suppose it's time to disassemble it and take a closer look.

[chromesphere]

Some of the more experienced dudes around here might chime in but if I had to have a stab could be no power getting ot the board or bridge from 9v rail to ground somewhere.  Stab in the dark.

[Apocalypto]

Thanks.  I tested the power solder joint on the board itself and I got a solid 9v reading.  After that I'm lost.

[Scruffie]

So you have 9V on the board, why isn't it getting to any OpAmps, you need to trace with your meter where that 9V goes and where it's getting lost.

[Apocalypto]

I got it going!  I went to the store and got a BA728 and followed in BDuguay's footsteps.  It was the same issue.
http://www.diystompboxes.com/smfforum/index.php?action=printpage;topic=91441.0

This is so cool man.  Very interesting sound.  Kind of subtle yet wacky.  I like it!

Thanks everyone for the help.  Learning something new every day in this awesome hobby.

Now I'm going to get a Pork Barrel and put that together.