Fix a Biyang Tri Reverb- waste of time?

[Govmnt_Lacky]

Does this mean IC6 is the clock?

I think that the 3201 chip is set up like the Spin Semi FV-1. Does not need an external clock. The clock and LFO are internal.

Hope that helps. 

P.S. Of course, I could be totally wrong about this but, that is how the datasheet read to me 

[Ice-9]

IC9 is a digital reverb engine chip BD3201-14a
http://www.bdnc.com/datasheet/bd3201-14A_spec_V1.6.pdf

IC6 is a CS4340 is a D/A converter   
http://pdf1.alldatasheet.com/datasheet-pdf/view/58109/CIRRUS/CS4340.html

IC7 ia a CS5340 A/D converter
http://pdf1.alldatasheet.com/datasheet-pdf/view/115334/CIRRUS/CS5340-CZZ.html

The other 3 chips are ST microelectronic EF797 dual op amps.

There is no clock chip , the main processor takes care of all that.

[Paul Marossy]

IC9 is a digital reverb engine chip BD3201-14a
http://www.bdnc.com/datasheet/bd3201-14A_spec_V1.6.pdf

IC6 is a CS4340 is a D/A converter   
http://pdf1.alldatasheet.com/datasheet-pdf/view/58109/CIRRUS/CS4340.html

IC7 ia a CS5340 A/D converter
http://pdf1.alldatasheet.com/datasheet-pdf/view/115334/CIRRUS/CS5340-CZZ.html

The other 3 chips are ST microelectronic EF797 dual op amps.

There is no clock chip , the main processor takes care of all that.

Sounds like that's the essence of the pedal. So why won't it switch to effect on mode?! What is the most likely culprit with it apparently being a conventional 3PDT switch based true bypass pedal?

[anchovie]

What is the most likely culprit with it apparently being a conventional 3PDT switch based true bypass pedal?

Any of the above!

An audio probe will give an easy check of opamps in the audio path and the output of the D/A converter. I guess you'd need a scope to see if the A/D and 3201 outputs are working.

[Govmnt_Lacky]

I would start by making sure that the 3.3V regulator is functioning as this is what the processor, D/A, and A/D are powered by.

If it is anything like the FV-1, it REALLY, REALLY needs that voltage to be AT LEAST 3.3V to work well.

[Paul Marossy]

I would start by making sure that the 3.3V regulator is functioning as this is what the processor, D/A, and A/D are powered by.

If it is anything like the FV-1, it REALLY, REALLY needs that voltage to be AT LEAST 3.3V to work well.

+1. Sounds like a good place to start. Easy to verify with a DMM.

[seedlings]

Dirty dog!

I went to check some voltages at lunch and the thing came on!  While it was on I tapped around with the chopstick to see if it would glitch, but no! 


CHAD

[Paul Marossy]

Doh! This is one of those weird intermittent problems that can drive you nutz! 

[Quackzed]

you got gremlins...

[Paul Marossy]

Is that what an electron gremlin looks like?

[seedlings]

I didn't feed it after midnight, and I hummed that cool song it likes 

Re-boxed and it still works.  Like I said, it's done this before, just not for this long.  I did notice one thing that may or may not make any difference.  The stereo input jack is wired so that a cord has to be inserted for it to power up on batteries and via DC adapter.  When the pedal is powered, and then the input cord is inserted, it takes about one second for the LED and effect to come on.  Is this suspicious at all to you?

CHAD

[Mark Hammer]

Not at all.

Typical wiring is that the input jack makes a ground connection for the power supply when a plug is inserted, and does not discriminate which sort of power supply it may be.

It may be the case that the delay for powering up is a reflection of a) a big power supply cap that takes a moment to charge up, or b) some routines that the digital side of things has to go through before signal can be passed.

[jubal81]

I had the same problem and after about an hour of poking around I got it fixed. The transistor in the red square was toast. I replaced it with a BS170 and the pedal came back to life.
I was sure I was just gonna have to chuck it. Whew!

[eagleaudio]

I'm trying to fix this effect. The picture above is blocked by antivirus program and reported as dangerous. Can anyone tell me what type is the Q6 transistor (I suspect it has failed)? I cannot see the symbol.

[hazboss]

I'm trying to fix this effect. The picture above is blocked by antivirus program and reported as dangerous. Can anyone tell me what type is the Q6 transistor (I suspect it has failed)? I cannot see the symbol.

I think it's an S8550.
I was having the same problem as OP - I replaced mine with an MPS8599... it was the closest thing I had with the same pinout. Works fine now. Nice reverb!

[[Gringo]]

Same issue here, pedal wouldn't turn on. Changed the usual suspect S8550 and now it turns on and passes signal, but only clean, no effect and controls make no perceptible changes.

Any ideas/pointers where to check next? Not sure it's worth the effort as it's awfully tight with all the smd, but hey, fixing stuff is fun, right?