Tokai CH-1 Chorus not chorusing

BDuguay · May 05, 2011, 11:41:12 AM

I've done my homework and have read this is very similar to the Boss CE-2. I'm trying to get this one fixed but it's giving me fits!
Everything works but it doesn't produce a chorus effect. I've checked all IC's but the BA728 and they're all fine. I also swapped out a few transistors but they check out too.
I need help please. Anyone up for it?
Thanks,
B

anchovie · May 05, 2011, 11:45:56 AM

Time for the audio probe! DC voltages on the chips might look OK, but do you know for sure that there is sound in/out of the BBD?

Govmnt_Lacky · May 05, 2011, 11:49:34 AM

Quote from: BDuguay on May 05, 2011, 11:41:12 AM
I need help please. Anyone up for it?

SURE! Could you post some of the information that you collected? Voltages, link to schematic/layout, etc.

Also, some pics of the board and wiring would help

BDuguay · May 05, 2011, 12:38:04 PM

I audio probed it to some degree. There are 2 4558's and I'm signal in and out of both but only 1 half of each. That doesn't make sense to me but I'm a hack.
G.L. I couldn't find a schematic for this beast but did read that it's essentially a CE-2. I'll try and link it.
B.

BDuguay · May 05, 2011, 12:42:45 PM

Did that work?
B.

Govmnt_Lacky · May 05, 2011, 12:49:03 PM

It did work!

The problem is... the CH-1 that you have has a dual output option (Stereo?) and the Boss CE-2 does not. This could possibly be a factor in what is causing your problems.

Also, does the CH-1 use MN3007/MN3101 or MN3207/MN3102 for the BBD and Clocking? That is a big difference as well.

There may be too many factors involved to effectively TS this. No schematic. Different parts???

EDIT: A picture of the circuit may help.

Mark Hammer · May 05, 2011, 01:04:59 PM

Sometimes, when there are stereo outs, the effect is determined by a switching action performed by plugging into the 2nd output jack.

Govmnt_Lacky · May 05, 2011, 01:10:21 PM

Quote from: Mark Hammer on May 05, 2011, 01:04:59 PM
Sometimes, when there are stereo outs, the effect is determined by a switching action performed by plugging into the 2nd output jack.

I see where you are going with this Mark

In this case, I believe the CH-1 has an actual mechanical switch located on the top of the pedal to choose your output options. As seen here:

http://www.effectsdatabase.com/model/tokai/1/tch1

Also, for reference, it is numbered as the TCH-1.

BDuguay · May 05, 2011, 02:32:32 PM

3101 for sure and I believe 3207. And yes, like Mark said and provided in picture form, there is a rotary switch on the top of the pedal to select between separate and rev.
Incidentally, activating this switch with the pedal engaged results in a slight different tone.

Mark Hammer · May 05, 2011, 03:10:19 PM

As I understand it, the one switch setting has dry out one jack and wet out the other, and the other switch setting routes dry and wet to both jacks, but inverts the wet for one of them. When the first setting is used (i.e., one kind of chorus sound) implies that if only one output jack is used, the dry and wet are routed out the the same jack. If that jack-switching doesn't occur properly, then the wet may never make it to that jack. This is why I suggested examining the jacks themselves. They have to do a lot of signal-routing work which is NOT done by the switch. If you only tested the beast in mono, you may not have been able to detect the problem.

BDuguay · May 05, 2011, 03:42:52 PM

I see what you're saying. I shall give the 2 outputs a close look tonight. I've thought all along that it's probably something really simple and thought I had covered off all the simple things. This pedal is in really good condition and very clean so it doesn't look like the problem was a result of hard use or abuse.
Thanks again all and if anyone else has some insight, please share.
B.

Govmnt_Lacky · May 05, 2011, 03:47:40 PM

Like I always say.... A picture is worth a thousand words.

If the problem does not bite ya (is simple), then I would recommend posting some pictures of the circuit and wiring.

Good Luck

BDuguay · May 05, 2011, 07:28:50 PM

Correction: 3102/3207 combo.
B.

BDuguay · May 06, 2011, 10:04:21 AM

Okay Mark, I had acloser look at the 2 outputs and they are standard non-switched jacks. Of course I didn't think to trace the wires back to the board and investigate that end of things.
B.

BDuguay · May 18, 2011, 07:38:07 AM

Fixed!
Bad BA728 was the culprit. It seems that chip handled the LFO duties and that's what was missing.
Thanks to all and now onto the Yamaha Chorus fix!
B.

saucer4 · September 19, 2011, 11:22:54 AM

Hi all (my first post)

I am going to learn to fix these things, but atm all I am good for with a soldering iron is fixing speaker cables and the like

One of the first things will be a Tokai Chorus. I have three of them (two TCH-1s and a TCH-2) and NONE of them make a chorus noise

I have noted that in place of my TCH-1s' BA728, my TCH-2 has a IR94558 (766D Sharp)

are these interchangeable, and interchangeable with other 4558s (for LFO purposes?)

Jeremy

Apocalypto · February 10, 2015, 10:23:03 PM

Hey guys, just to add another experience here...

I just had exactly the same "no chorusing" problem with a Tokai TCH-1 and I replaced the BA728 and it now choruses perfectly!

Thanks BDuguay for all the help.

News:

Tokai CH-1 Chorus not chorusing