Issue with Eurorack modules.

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For J5 the positions are Vreg, USB and DB. If I am using 5v from my eurorack PSU I should use Vreg?

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pat_00 Well, the RS DB25 lead spec looks fine and is only 1.8m long so I imagine that can be eliminated.
I drew this during my experiments with interconnections but it shows my understanding of the J5 positions, Eurorack 12v via Eureciever regulator, Eurorack 5v direct or USB. For info, I have used all three whilst playing but my final build uses Eurorack 5v supply as I too have hefty PSUs - hope this helps.
PS. Also check the Line Tx module is healthy - could it be the problem???

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What PCB version of Euroceiver are you using? As you said “DB”, I presume v1.5 or earlier? If so, the jumper setting to use the +5V buss is to leave J5 empty and close solder bridge SJ5. Measure the voltage on either side of D1 to see if there is power applied. It would make sense to try with the Vreg setting.

To see if you get power, measure voltage across any +5V capacitor.

Do you have the line transmit board installed in the SEQ case? Are all cables connected there with proper polarity, also check the cables for faults.

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latigid on I must have been typing whilst you replied 😅 Sorry if I am causing confusion with terminology but I use the term DB25 for the connector, as per the RS description :-

The Roline 1.8m RS-232 connection cable has male DB25 to male DB25 connectors

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latigid on Thanks a lot for the suggestions! I appreciate it.

It is version 1.3. Just realised I built the modules with 10 pin eurorack headers, so i will need to fix that to take advantage of my 5v PSU line. But the module should still work with the onboard reg, so for now am leaving the header selecting Vreg.

I have probed D1 and get 12v one side and a bit less on the other side. Getting 5v on Vreg the jumper pin. So I’m guessing that means the onboard 5v reg is all good?

Ribbon cables look fine, correct polarity. Will probe them later to make sure. As far as the line transmit module, I remember installing it as I was looking forward to using the CV expansion. But the D1-D3 outputs shouldn’t be lighting up when the D25 cable is not connected? That is what is happening.

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Mechie No problem at all, your answers are always full of wisdom and much appreciated! DB-25 is what I would call it too. Connections of longer than 1.5m are possible. I think I have either a 3m or a 5m cable installed.

Earlier Euroceiver boards had the option to use the +5V from the SEQ, but the voltage drop is too great over that cable so it was removed for later revisions. Thus the solder jumper to use the Euroack +5V buss was connected to the free position on THT jumper J5.
There was also at some point a J0 jumper to dis-/connect 0V across the two domains (check both line driver and euroceiver). Here it should be closed even though a differential signal is used as the voltage levels might drift apart.
If there is only a 10-pin header installed, understandably the Euro +5V won’t be connected. It is more of an “expert” option as the on-board regulator works well, but of course we want to support other usecases if they make sense.
Check that the J19/J89 cables go to the correct sockets inside the SEQ and that they are built the right way around.

And mechie is totally right about undefined 595 register outputs showing whatever electronic state they happened to be in on startup. MIOS will clear the registers as part of an ini routine when all is connected properly.

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pat_00 But the D1-D3 outputs shouldn’t be lighting up when the D25 cable is not connected?

Don’t panic on this - there is no new data being clocked into the shift registers so they contain whatever garbage was left there at power-up or when the cable was unplugged (which can cause random data).

Getting 5v on Vreg the jumper pin.

Not sure where you are referring to here, 5v is available over the DB25 lead, but not enough to run the boards (tried it!) so just for clarity, where are you referring to?

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OK, so maybe I am worried about nothing regarding the random LEDs.

I have opened up my SEQV4+ and the line driver is installed and all looks fine. Only J19 is connected as per Hawkeye’s video. Some of the docs on ucapps show J2 connected, do I need to do that? Also is the jumper J2-SI supposed to be left open?

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J2 will send out the SRIO data required for the D1-3 modules. Sorry if I mixed up naming here.
J2-SI doesn’t need to be jumpered because you are not receiving any data from the chain.

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Hmm… J2 on the Line Transmit module? Where does it go to? I have rewatched the SEQ build video and only the J19 is connected, which is what I have done.

It still seems there is no communication between the modules and SEQ. I tried to change CV calibration to see if the A1 responded but nothing. And the D1/⅔ LEDS are all still on.

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J2 should be connected to the last JA/lemec module in the chain.
The HWCFG also needs to be adapted to match the register chain of the modules.

If you can power up (even with a USB cable on Euroceiver instead of Eurorack power, check J5 of course), you can connect the D1/⅔ directly and rule out issues with the line drivers.

Have a look at mechie’s drawing above for a great interconnection diagram. The modules show a view from the rear, just check the silkscreen labels that it isn’t backwards.

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latigid on Brilliant! that never occurred to me, link direct from (on the Seq4+ RH) JA Board J89A to Eurorack D1J8/9 to eliminate Tx and Rx modules from fault finding

Or (on Seq4+ LH), LeMEC Right-hand board J89A.

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Ah OK, so J2 on Line Transmit needs to be connected to J89A (SRIO Out) on my RH LE-MEC board? It’s currently not connected to anything.

Sorry for all the questions. I find this stuff a bit confusing as the connection diagrams on Ucapps are not for the SEQV4+

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@Mechie - thanks for the great diagram - this makes it a lot easier!

pat_00 - sorry, if was not clear in the video tutorial - here’s the relevant section from the video tutorial (connect JA to LineTX):

But it was indeed only a very short verbal note - having a diagram as made by Mechie definitely helps a lot!

Best regards and enjoy!
Peter

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Right, the Line_TX extends the SRIO chain and it keeps going in the modular rack.

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Thanks everybody for your help.

Well it seems to work now, I’ve installed the cable and the buffers have cleared. I’m getting clocks on D2. Haven’t tried gates or triggers yet.

However I have hit another obstacle.

I’m trying to calibrate A1 and have watched the calibration video 5 times now. I cannot seem to change the CV output. It is stuck at approx 5v on all channels. I have AOUT selected on the right of the CV config screen. Scrolling through the CV outputs and changing the calibration parameter seems to do nothing to the voltage coming out of the A1’s outputs.

Perhaps I am missing a step somewhere?

At least I am making progress.

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Hello,

Great that you got the D modules going.

All outputs at -5V (also red LEDs) would mean that nothing is getting into the op amp stage.

A photo of your work might help here to see if it’s something obvious with soldering? Any trouble with the DAC chips? Cables all tested and working and plugged in the right way/correct sockets?
Again, you can wire directly from J19 on the wCore to the superDAC board, but you do need +/-12V power for this.
You can also swap the ribbons on line transmit (and on Euroceiver) to check if the drivers do their jobs. As you know that the D modules already work, this can rule out an issue with the driver.

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Found the problem. A little surprise from sloppy 2019 Pat.

All works as expected now, except for A1 output 4, which is stuck at 5v. I will do some more inspection of the module, probably a dry solder joint somewhere.

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Happens to the best of us!

Channel 4 on SuperDAC should come out of pin 4 of J3, if not it must be on pins 18/19 of IC1.
Relevant parts on transmute8 are prefixed with 4Rxx, plus R5, R13, VR4, C17, R21, R53, C25 and the “southern” end of IC2.

Best regards,
Andy

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It sounded familiar… analogue channel 4…
See Me
The fault finding done in the above thread may be useful to you?

edit…
And Me!