Unable to switch global status

[MartyAckerman]

Upon first powering up my new (to me) 6048, the global status buttons worked as expected.  Now, two days later, I'm unabale to change them.

The console is currently using computer bypass cables.  It starts up in Record+Mix with VCA's to Monitor engaged. Status lock is off, but does illuminate and activate the AFL light when turned on. Master Ch Input Flip does not work. Mix to cues works as normal.

I pulled the 82e21 card, but didn't notice anything obvious.  I don't have the proper extender to pull that card while powered up. Can someone point me to it if there's one available somewhere? Any ideas on probable causes for this situation?

[horizonsound]

Hi Marty,

It is a very basic circuit, and will be an issue within the card (possibly edge connector), or a connection from the switches. Assuming the status lock is not affecting it.

I would check that you are seeing +18v returned to the E21 edge connector when the switches are pressed. Look at pins 10,12, 13 (rec, mix, replay). Potentially the looping +18v supply to those switches is broken. Are any of the status switches lighting up? Does omni light up if pressed, with status lock on?

Who was the broker you bought this off?

Anthony.

[MartyAckerman]

Hi horizonsound,

I was hoping you'd answer, actually.  Getting some fresh, new cards in the center section is starting to feel like a good option at this point.  I have another post queued up about intermittent monitor out problems and found a modified monitor output card in here as well.

As for the status switches:
Record, Mix, and VCA's to Monitor are permanently lit.
I measure 12.68v from 0v rail to pins 10, 12, and 13. i measured from the trace side of the raised center section since I have no extender. No change as any of the switches are pressed.

Omni never lights when pressed, regardless of status lock being lit or not.

My broker was Sphere Recording Consoles.

[horizonsound]

Hey Marty,

I would suspect then that there is an +18v supply wire broken to the status switches (and status lock). Without diving in there myself, the +18v should be looped between all these switches. When pressed it will send a logic 'high" to the E21 card. +12v (relative to ground) is your logic low.

As the Omni is doing nothing, that means +18v is not getting to the Status Lock switch either. They are all chained together like xmas lights on the =18v rail.

Unfortunately you will need to trace the +18v on the switches and find out where it is broken. Be very careful as the wiring is fragile.
Best to take the whole centre section out and lay it PCB down on the console, to give good access.

Anthony.

[horizonsound]

Just to clarify, did you check for a change in voltage at the moment you pressed the switch? Hold it down, and check the voltage at that point.
It will only send +18v when the status switches are pressed.
The momentary high signal triggers a flip-flop on the E21.

Anthony.

[MartyAckerman]

I did check for a change in voltage while pressing the buttons and repeated that test this morning just in case.  Getting rock solid 12.7v today on all 3 pins while pressing the buttons. Looks like I'll be taking the center section out today. A little scary as I have a band coming in on Friday. Thanks so much for your help!

[horizonsound]

Looking a bit deeper in to the problem from what you have described, I would be checking that you have +18v coming in to the Status Lock switch.
It is at this point, that the Status Lock switch supllies +18v to you Rec, Rep, Mix, Input Flip, VCAs/Mon, Auto Cue, Omni switches.
When Status Lock is engaged, it cuts the +18v on the rail to those switches, inhibiting them.

Or the Status Lock switch is not functioning and passing the +18v

You should be able to sort this all out by Friday.

Anthony.

[MartyAckerman]

I truly appreciate the time and thought you're giving to this, it is extremely helpful. I was getting concerned about finding the the earliest point I could with the +18v, since I don't know the path it takes to get to those switches.

I wouldn't call it sorted out, but it is working again. I pulled the center section completely and started searching. It seems there is a loose wire or cold joint somewhere, because I did nothing and the switches started working again once it was laid out on top of the console. I took the opportunity to look at the joints and make some measurements. It seems there is permanently +18v on pin 1 of the global status switches, and permanently +12v on pin 3. When the switch is depressed, it momentarily puts +18v on pin 3. I found continuity between all of the status switches on pin 3 and was able to follow those reddish brownish wires to the omni button, which also appears to work again.

I reassembled the board for now and it continues to work, but I don't feel great knowing that the potential issue is still looming.

[horizonsound]

That’s no issue, you got me at a good time, as I’m currently refurbishing a 651.

Anthony.