Soundcraft Spirit Live 4 Repair

[GBird]

Hi all,

 

Disclaimer: First time trying to fix a board, not my forte but more than willing to learn hence posting for advice :)!

 

I've got a couple of issues with a Soundcraft Spirit Live 4 that I picked up for peanuts and thought would be a fun little project to start with. I started with stripping the desk and giving every nook and cranny a good clean which resolved a number of issues but there's a few leftover that I'm looking for your assistance to solve / advice on.

 

The first issue is that one of the IDC ribbon connectors between the modules requires replacement as the securing brackets have worn and snapped. The connector is marked ELCO 8284, has 18 pins and is the female side that's damaged but after a fair amount of googling, I cannot find a replacement. Can anyone help find one / have one spare that I can purchase?

 

Second issue is where I'm starting to get out of my comfort zone. On one of the mono channels, there is no output to group 4 on the desk. I've tested for continuity across the PCB from the switch and everything looks ok (in my naive wisdom going from component to component) which lead me to try it on a different connection to the IDC cable. The module still doesn't work when connected to a different connector which has left me a bit stumped. Any ideas on how to test, identify and resolve the issue please? I've looked at the diagram from the manual which has offered up no clues.

 

Final issue is that I'm struggling to find one of the 100mm 10k Alps faders that requires replacement. The part number is RSA0N111900Q but to buy one from mouser, I would have to pay £12 delivery which seems quite excessive. I can't seem to find them anywhere else to buy more locally. Can anyone point me in the right direction for something more locally sourced and thus not £20 for 1 fader?!

 

Thanks in advance!

[kgallen]

On the mono/group channel ideally you need a schematic. Other option is to compare like for like on another of the same. The nice thing about analogue mixers is you have many of the same circuit repeated and possibly with the same PCB layout you can compare 1:1. For any transistors, with the power off, use your DVM in diode mode across the pins each way round and compare like for like across channels.

 

On the fader, see if you can find a Bournes equivalent. I’ve needed to do that before when the Alps part was discontinued or not readily available in the UK.

 

Good luck! Bringing back to life good quality older kit is very rewarding!

 

Kevin

[bruce]

So a few mins google tells me that the Elco 8284 range is a 2.54mm pitch (ie 1/10 inch) single row IDC connectior

 

Searching (eg) Farnell for 2.54mm 18 way single row IDC female connectors gives:

 

https://uk.farnell.com/w/c/connectors/idc-connectors?contact-gender=female&pitch-spacing=2.54mm&no-of-rows=1-row&no-of-contacts=18contacts

 

Or from RS:

 

https://uk.rs-online.com/web/c/connectors/pcb-connectors/idc-connectors/?searchTerm=idc%20connector&applied-dimensions=4294870441,4294884869,4294876964,4294881961

 

 

 

Re the output to group 4. I’d really need to see a circuit diagram or service manual rather than the user manual you link to - or see the board - but according to the schematic, the section which controls the switching to the LR bus and the 4 groups is just passive switches - there are no “per channel” op amps or anything like that - so I’d be suspecting a mechanical problem with the switches or connector. Time to get a meter out....

Of course, there might be components that have been omitted from the schematic...

 

Update:

 

Here’s a circuit diagram for the mono input channel.

https://forum.cxem.net/index.php?/topic/197376-soundcraft-spirit-live-4-2-1-4-ауксы-на-пост/

 

The section at the top right is the output bus selection, it’s just switches and 22k resistors.

 

So if the output to bus 2 works OK, but 4 is faulty, and it’s the same when you plug into a different ribbon cable socket, then the problem must lie with either the switch, the resistor, the ribbon connector on the PCB, or something in that area.

 

Meter out the switch, and check the resistor.

[GBird]

On the mono/group channel ideally you need a schematic. Other option is to compare like for like on another of the same. The nice thing about analogue mixers is you have many of the same circuit repeated and possibly with the same PCB layout you can compare 1:1. For any transistors, with the power off, use your DVM in diode mode across the pins each way round and compare like for like across channels.

 

On the fader, see if you can find a Bournes equivalent. I've needed to do that before when the Alps part was discontinued or not readily available in the UK.

 

Good luck! Bringing back to life good quality older kit is very rewarding!

 

Kevin

 

Thanks Kevin. I think I've managed to find a suitable replacement for the fader here from RS so I'll order a couple in case another is needed later on.

 

With regards to the mono channel, I can't believe I never thought of comparing side by side! I'll take out another channel from the desk and will work through to see if there are any differences. The schematic is available in the manual on page 33. (Now superfluous given Bruce's post!)

 

Thanks again for your help!

Edited May 24, 2020 by GBird

[bruce]

And re your fader - here’s one on Ebay - £7.82, plus 59p postage.

https://www.ebay.co.uk/itm/RSA0N111900Q-Potentiometer-slide-10k-250mW-THT-20-logarithmic-ALPS-/192928661351

[GBird]

So a few mins google tells me that the Elco 8284 range is a 2.54mm pitch (ie 1/10 inch) single row IDC connectior

 

Searching (eg) Farnell for 2.54mm 18 way single row IDC female connectors gives:

 

https://uk.farnell.c...acts=18contacts

 

Or from RS:

 

https://uk.rs-online...6964,4294881961

 

Thanks for this, I wasn't sure how to identify what I was looking for and you've answered that!

 

Re the output to group 4. I'd really need to see a circuit diagram or service manual rather than the user manual you link to - or see the board - but according to the schematic, the section which controls the switching to the LR bus and the 4 groups is just passive switches - there are no "per channel" op amps or anything like that - so I'd be suspecting a mechanical problem with the switches or connector. Time to get a meter out....

Of course, there might be components that have been omitted from the schematic...

 

Update:

 

Here's a circuit diagram for the mono input channel.

https://forum.cxem.n...ст/

 

The section at the top right is the output bus selection, it's just switches and 22k resistors.

 

So if the output to bus 2 works OK, but 4 is faulty, and it's the same when you plug into a different ribbon cable socket, then the problem must lie with either the switch, the resistor, the ribbon connector on the PCB, or something in that area.

 

Meter out the switch, and check the resistor.

 

Again, thanks for finding this! I've gone through step by step and it all looks ok so I'll revisit the ribbon cable / IDC connector. Only strange thing is that all the mono channels in this board have 15k resistors after the switches, not 22k as per the schematic you linked to :S

Edited May 24, 2020 by GBird