BOSS CE-1 Stuck in EFFECT mode

[looselectron]

First of all, thanks to everyone who posted about modding the CE-1 elsewhere. I'm currently restoring one I picked up as "junk." However, I can't even get mine to switch to "normal" mode to see how badly it sucks tone!

I tried replacing S3 with the old switch from my pre-true bypass vox wah . Nothing. Then I tried making direct connections between the yellow (7) and cream wires (24), and then purple (9) and yellow wires. Again, no change in the sound except for some crumbly distortion on the decay.

I don't know if this makes any difference, but there is a second resistor soldered onto R86(?) that I didn't notice before. According to the schematic, this connects directly to the yellow wire (24).

Does anyone have any idea what could be wrong and how I can fix it?

[looselectron]

Addendum

Further to my previous, I removed the extra resistor. The only effect it seemed to have was to reduce the output and induce some very nasty distortion peaks.

More importantly, I put the original switch back and noticed that it DOES have an effect on the LED (solid-flashing), but no change on the sound.

Any ideas, anyone?

[cjlectronics]

You might try replacing Q13, the 2SK30A. I've seen these JFETs go bad in this pedal.

[looselectron]

2SK30A

Hey, thanks!
I found Q13 on the schematic, but finding it on the board is proving challenging. There is a transistor that says "30A" on it. Is this the right one?

[Mark Hammer]

Yes, that would be it. Japanese transistors are essentially printed with their "nicknames". So the full number would be 2SK30A, but what you'll see is K30A.

[looselectron]

Cheers, Mark.

[looselectron]

2SK30A

I tried replacing Q13 with a K30A, but there was no change at all.

Any other possibilities?

[cjlectronics]

At this point I would recommend that you start taking voltage measurements. The schematic has voltage values at printed key points. Focus on the power supply and output circuit. Then maybe we can get a better idea of whats going on.

[Patzwald]

my ce-1 has got the same problem.

stuck in the effect mode and chorus / vibrato is always on.

is there any news about the repair?

where does the voltage for the s3 comes from to switch the f-fet for effect/normal mode?

thanks for your post

[looselectron]

No news. I checked all the components - nothing is burnt out. The only odd thing is some traces on the board around Q13 might be severed.

Today I rechecked it using a step-up transformer since the sockets in Japan put out 100V and this unit is rated for 117V. There was no change in sound or operation at either voltage. However, I did notice something new:

I plugged my headphones into the the R output, and noticed a change in sound when I hit the Normal/Effect switch. The sound goes from a rich, swirling chorus to just detuned. So something is happening.

I consulted Analog Man about doing a true-bypass mod. He said it should work, but the chorus doesn't function the same in stereo with this mod.

[martinez_90]

Hi guys, I've got similar thing with my MT-2 but quite opposite- my pedal stuck in NORMAL mode and it's constantly bypassed. I've noticed that sth must be broken in switching mini-circuit because before I had a period when it was always in EFFECT mode like in yours pedals. Stupid BOSS pedals, always problems with'em :/

[Patzwald]

hi,

fixed my ce-1 chorus ensemble.

the q13 was damaged. chnaged it to an new one and now everythings works perfect. cost about 5 minutes and 0,13 euro cent.

[loz7]

Had the same problem,Replaced Q13 and now it switches fine-thanks cjlectronics

[cjlectronics]

Awesome, glad you got it going!

CJ

[Mark Hammer]

Hi CJ,

Switching FETs have come up as issues many times over the years, which gets me to thinking about why that might be the case. I don't know if there is simply a limited lifespan on that sort of device, whether they are more subject to electrical damage in this particular application or what. Consider just how may 2SK30A trannies are out there in the legions of 4 and 6-stage phasers, both for switching purposes and for voltage-controlled resistor purposes, and you never hear about people saying "My phaser switches on and off but it sound weaker than before".

So what is it that makes K30As crumble in this application? I'm mystified.