BOSS CE1 PROJECT: MN3002 or TDA1022P: DOC UPLOADED

[Ricotjuh]

A note was placed in the building description for the 11V zener: "* OMIT-Only needed if using the MP211 DC Converter"
So this is not necessary for the Recom DC / DC module.

[Scruffie]

I can't find an MP211, there's an MD212D though, which... also doesn't need it, but not really important as to the current issue.

The MD212D datasheet does give a tiny bit more information, it recommends an L/C input filter and a 1uF ceramic (tantalum would do as that's a large value for ceramics) and 10uF electro on its output when testing output ripple so that's probably a good starting point for values for our purposes.

But again, no power filtering and a potentially poor layout (I haven't seen it to comment) will be just as big a concerns as getting the brick running optimally.

[madbean]

It's not shown in the datasheet linked earlier in this thread but if you look at the REM2 one on the RECOM site their dual output circuit shows a 470pF 6kV cap between COM and V+IN (plus an inductor at the PS).

https://recom-power.com/pdf/Medline_DC-DC/REM2.pdf

What's bugging me about this is the RECOM brick gives you ground isolation but you don't need it in this application - you only need the two power rails it makes. And, given your noise sounds like a ground hum, well...

Maybe I'm confused here but what I am taking away from the datasheet is "single" output is +/- out and "dual" output is the same plus ground isolation.

[Scruffie]

Maybe I'm confused here but what I am taking away from the datasheet is "single" output is +/- out and "dual" output is the same plus ground isolation.

Some of the bricks only offer a single supply voltage rather than split rail so I think that's where that's coming in to play, the - output is the isolated ground in that situation.

[Ricotjuh]

Still the same problem with two 9V batteries. So the problem does not seem to come from the power supply. Now continue to measure where it can come from.
Someone tips? I have a scoop at my disposal.

[RDL68]

That's bad luck, but you did the right thing eliminating the power supply as your issue, even though it remains an issue with this circuit, so be sure to keep using batteries for now while you sort out what's wrong with it. Unfortunately it's a drama having to troubleshoot from here though.

There's a fellow on ebay selling ce1 clones. In his listing he says "MUST BE POWERED BY A HIGH QUALITY ISOLATED Linear TRANSFORMER BASED POWER SUPPLY!
INFERIOR AND SWITCHMODE SUPPLY MAY CAUSE NOISE!"
(his capital letters, not mine)

As for the hum in your clip, sounds too intense & constant to me for something nearby to be causing it. It was exactly like what I was getting until I solved the power issue.
At least you only have 1 of your 2 issues left.
Most likely it's a short or wrong/dead part or orientation, dry joint, something grounding or not grounding when it should be, anything along those lines. Sometimes a bit of hookup wire can be problematic like this too depending on the batch. I went through hell with a bad batch of wire once, it was testing ok for continuity, re-soldering didn't sort it out, yet it was the cause of the issues I had (maybe too many broken strands in places, even though it wasn't bent).
It's disappointing to hear it wasn't just the power issue, lot of work still to go then.

[Ricotjuh]

Thanks for your comment. I have done some measurements around TDA 1022. I have my doubts about the measurement on pin 8 and pin 12. I initially test a 12V DC supply. And from 0.20 sec I do the measurement again but with a 9V battery.
0.00 sec -> Pin 1
0.04 sec -> Pin 4
0.07 sec -> Pin 8
0.12 sec -> Pin 12

0.20 sec -> Pin 1
0.24 sec -> Pin 4
0.27 sec -> Pin 8
0.31 sec -> Pin 12



There is no signal input. Is it correct that I do measure something on the 2 outputs of the BBD?

[Ricotjuh]

If I look carefully, I should not measure anything on the outputs when there is no input. The clock signals present should control the MOS transistors. But as long as there is no input, can't a signal be transmitted? In my opinion this is not correct ..

[RDL68]

Before diving that far in, I'd suggest checking all the caps/soldering in that infamous power section & then using a voltmeter to see if it's putting out the correct voltage before it hits the rest of the circuit. You're now using an isolated PSU with the batteries, first problem solved (unfortunately there was also another) so once you verify the rest of that power section it'll make it easier for everyone to help you narrow it down from there with the rest of the circuit.

[RDL68]

Ricotjuh, I just read back a couple of pages of this thread. First thing I noticed was the PCB layout you posted a few days ago. Paying it more attention, it's clearly different to the v1 version, basically it has the chorus depth mod & possibly other changes, otherwise the rest is likely the same.

Going back a bit further you said you did your own PCB. I have to ask, is that v2 PCB layout you posted what you've done or is it what drog_trog has done? Or is your PCB completely different?

I tried unsuccessfully to find a revised v2 build doc, also couldn't find any trace of drog_trog anywhere, even his ebay account is gone. It'd be helpful if you could post a link to the v2 doc (the file might be too big to post here).

As for mods, I abandoned all of them because even as simple as they are, I had major issues getting them working with this circuit, possibly due to the multiple GND points of weirdness, split rails, different voltages etc. I just boxed it up stock & working to be done with it. Actually, the only thing I did was I added an extra LED, so there's a blue one on for chorus mode & a different one for vibrato mode, they flash in time to the rate, but due to GND issues (again with something that should be so simple) I ended up having to replace a 3pdt with a 4pdt instead to do that, when otherwise it shouldn't have been necessary.

Anyway, if you've taken drog_trog's original schematic & added mods, that could be a big problem, especially if you've gone it alone with your own PCB layout. Whatever power hum noise a switch mode PSU introduces, it could also be introduced another way & feeding back into GND or something, it sure sounds like it in that clip you did.
 

[Ricotjuh]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F362736262293

Above the link to the V2 version. I have copied the layout of the V1 version. All tracks and components correspond to the layout of the original.

[RDL68]

Thanks.

That'd be drog_trog, it's just a different ebay account to what he had before & he's listing them as retrosonic clone, not king of chorus anymore.
He's updated the schematic too with the CH depth mod, which is done differently to the 2 failed ways I tried it from stuff I'd found online.

With yours, the clock seems working, possibly the whole thing is, it just has the same power hum as using a switch mode PSU, so it shouldn't be too hard to track down where it's happening. My gut feeling for now is that something is shorting to GND or not connected to GND, which itself could also throw all the IC readings out.

[nmbb]

Only got here today and missed avilable boards... still have on or two TDA1022 and no use for them at moment...

[kaeisy]

You can find the designer of the boards as dfx_parts on ebay uk. At the moment he only has the MN3002 board for sale, but you could drop him a message and ask for the TDA1022 version.

[nmbb]

You can find the designer of the boards as dfx_parts on ebay uk. At the moment he only has the MN3002 board for sale, but you could drop him a message and ask for the TDA1022 version.

Hi. Already see the seller, will send message soon. Thanks for the info.

Nuno