trouble shooting a large format console oddity...

o.k.  this one is a puzzler and I am thinking aloud in the hopes maybe someone has a suggestion.  let me see if I can explain the issue well enough.  The console is quasi-custom a 48 channel frame, the channels are removable.  They are a trident a-range copy as is the desk but it does have some changes, mix amps, bus amps, etc are a different design, utilizing 990's. that doesn't effect what is going on in this case as I can use direct out from the channels at the patchbay.  I have two slots on the frame where any  channel modules do not work.  This is regardless of what modules I plug into them. If I take the same modules and put them elsewhere in the frame they work.  The modules connect to the Frame via those red 32 pin mcmurdo connectors.

So far here is what I have found.
1. any channel in that Frame slot does not work but will work elsewhere
2. the female mcmurdo connector on the frame for those channels visibly do not have any damage
3. any module fits the connector and is visibly  the same as any other of the mcmurdo connectors in any other position on the frame
4. I can measure continuity and almost 0Ω from the female connector where a module plugs in to it's respective connections on the patchbay.  The frame is all individually wired. I also do not measure any shorts  from the female connector to the patchbay
5. with modules connected I do not get mic or line inputs, but I can get insert returns.

While I have not ruled out the female 32 pin mcmurdo on the frame I fid it odd that its two of them randomly across the desk.  About the only thing I can think of is the pins are not making contact from the male to the female end.  not sure what else to really check...

Sounds like a failure to deliver power to those dead slots...

Can you measure voltage probing at the connector with no module in place ?

JR

Insert sends not normalised to the returns in those two channels.

JohnRoberts said:

Sounds like a failure to deliver power to those dead slots...

Can you measure voltage probing at the connector with no module in place ?

JR

Click to expand...

Yes and we get correct voltage so it's not a power issue.

[silent:arts] said:

Insert sends not normalised to the returns in those two channels.

Click to expand...

I wish it was that simple but alas it is not. The normals are normalizing as intended on the patchbay and in the connector

on the upside the other non-working modules have been failed transistors causing issues  or cap replacement so at least  other things have been getting fixed.  but yeah stumped on this.

Can you wire up an extender so you can probe the channel out of the console? Sounds like a connector issue...and if imagine that would be really hard to troubleshoot in the console!

A few times I've had to trace oddball probs on a large desk without any available extender.  What I did was "tack solder" a wire to various points for testing so I could bring out that wire to the top of the desk with an adjacent module removed for access.

Not elegant, but it worked.

Bri

pucho812 said:

Yes and we get correct voltage so it's not a power issue.

Click to expand...

I have seen dry/bad solder connections that measured good with no load.

An extender card may be necessary if you can't probe in place. If a bunch of modules in a row don't work, or not, can you remove a bunch nearby to make room to probe around?

Working elsewhere, but not working there really suggests the wiring harness/buses are faulty.

JR

I wish it was that simple but alas it is not. The normals are normalizing as intended on the patchbay and in the connector

Click to expand...

iampoor1 said:

Can you wire up an extender so you can probe the channel out of the console? Sounds like a connector issue...and if imagine that would be really hard to troubleshoot in the console!

Click to expand...

yes I can wire up an extender, I have a male and female end of the mcmurdo's that I need to complete. It would just be a pin to pin pass through cable.

Brian Roth said:

A few times I've had to trace oddball probs on a large desk without any available extender.  What I did was "tack solder" a wire to various points for testing so I could bring out that wire to the top of the desk with an adjacent module removed for access.

Not elegant, but it worked.

Bri

Click to expand...

Indeed. I have done something similar but not in a desk.

JohnRoberts said:

I have seen dry/bad solder connections that measured good with no load.

An extender card may be necessary if you can't probe in place. If a bunch of modules in a row don't work, or not, can you remove a bunch nearby to make room to probe around?

Working elsewhere, but not working there really suggests the wiring harness/buses are faulty.

JR

Click to expand...

Interesting,  more testing needs to be had for sure. the good news, is the frame is open at the bottom  meaning it is literally two pieces of square metal stock running the length of the desk and spaced connectors  for each channel, with a lot of wiring looms in-between.  so I can probe any pinout from the bottom and from the top with ease.

anything look like this?        (wow, this sure got big...sorry about blowin up yer screens)

sorry was away all week. yes it does but only at the summing for stereo bus, multi track bus and auxes

Sometimes certain slots on larger consoles have to be used with certain modules , for instance in my AmekBC3 the talkback , aux send  and master module need to go into the correct slots otherwise it wont work properly , there are certain jumper wires on those channel slots which are prewired at the factory , you said its random the locations that dont work so maybe thats not your issue ,just thought it was worth a mention all the same .

Can you take a modules panel off, assuming that's what restricts how deep the module sinks into connector. Then you can 'waggle' it around to check if it's mating properly?
[Apologies for technical language]

We had trouble with a few modules mating in our desk when we moved it, think we bent the frame a touch, or the floor isnt quite level.

mrclunk said:

Can you take a modules panel off, assuming that's what restricts how deep the module sinks into connector. Then you can 'waggle' it around to check if it's mating properly?
[Apologies for technical language]

We had trouble with a few modules mating in our desk when we moved it, think we bent the frame a touch, or the floor isnt quite level.

Click to expand...

that is next trip out