Power from the Matrix?

54f37a1928a96a1c

Also a Matrix question???
The online circuit diagrams for Seqv4 suggest that it might be possible to power the Seq via the BLM socket’s extra pins (assuming a fully wired BLM cable).
Could you advise me on this as the Midiphy PCB designs may or may not already have this ability. I don’t see any references to this idea so that suggests not.
This idea obviously also relies on the Matrix supplying said power so could you also advise on that aspect?
My Matrix PSU runs cold so I can’t see why it wouldn’t cope with the extra half-amp or so, mods to both Matrix and Seq wouldn’t be a problem, even if it means fitting a sneaky switch to select USB or BLM power in the Seq somewhere.

0fc5608d995b44ff

@Mechie the optional POWER header available on the MIDI8 PCBs was originally used to power the existing first-version BLM 16×16+X through the SEQ - this hardware was the predecessor to MatriX and it was designed and released in 2015 by @latigid on .

This explains why the optional MIDI8 power socket (needs some jumpers to be active as such!) is only a power-out from SEQ v4+ - it is not a power input for SEQ v4+.

This port could be used to power the very first iteration of the BLM, so that it does not require a power adapter.

Depending on the brightness, the newer MatriX with the new RGB LEDs can be a lot more power-hungry and definitely needs its own PSU.

While it might be possible to find other ways to power the SEQ v4+, i’d suggest to power it over USB - it’s an easy and convenient method - you can even run the SEQ v4+ off a USB powerbank for many hours and use it in a mobile environment.

Best regards,
Peter

17703227d9536da1

It was not the intention to power SEQ v4+ from MatriX, but if you really wanted to try it, it could work. If you try it is at your own risk!

On SEQ v4+ MIDI8: +5V is connected to pin 8 of the DIN8 plug (this is the single pin on its own row in the middle). This +5V would only be connected into the SEQ v4+ +5V domain if the wire jumper is bridged, then the power would flow back through the IDC J1. Instead, it would make more sense to populate the Molex 3-pin header and use thicker gauge wire. Pin 1 (closer to the 220R resistor) carries +5V and the middle pin is 0V. This could then be connected to other Molex headers, e.g. on the USB board or even directly to e.g. lemec_R J7. Note that lemec J1 also uses the same footprint (with smaller solder pads) and rather is for connecting a pair of LEDs.

On MatriX: the DIN pin 8 is not connected, but it could be bodged e.g. from the J5 header or the switching regulator itself. Please make sure not to connect +12V here!

The older BLM 16×16+X didn’t work that well when powered over the DIN header. There was significant voltage drop/droop in the cable so much that I found it best to install a boost regulator to get proper +5V in the case. Thus although more cables are needed, I recommend to use separate power supplies for each device. Your mileage may vary!

Best,
Andy

54f37a1928a96a1c

Well, I finally got back to this idea.
A 5v regulator in the MatriX now gives an independent supply to the Seq v4 via the 8-pin BLM lead and it works like a dream 😁
For anyone else interested in trying it (still at YOUR OWN RISK)
The MatriX Core PCB needs a little mod (don’t belive the silkscreen ref to a 5v plane - it’s 12v!)

Note I added a diode (any scruffy old 1A job should do - I used a 1N4001 equivalent, it’s just reverse-voltage protection.
A Traco TSR-2-2450 5v reg (as per the one in the MatriX) is just tacked in place atop the original.
I have linked the two BLM sockets’ pin 8 so either will power my Seq.

For the Seq, I found a simple lead could be made and fitted to existing headers, from USB/SD board to MIDI8 board (white is 0v, orange is +5v)

Now a BLM 8-pin lead has to be made, I wired all 8 pins - pin 8 (centre carries +5v) and you are done 😀
The MatriX PSU is a 60W unit as per the original BOM, the Seq is ‘phantom powered’ from the Matrix.

17703227d9536da1

Cool! And sorry about the wrongly labelled plane. Will fix it in the next revision!