2 more trouble spots I should fix before the next gig

[Kats]

There are two more things I need to fix during my recording break and I appreciate the friendly help (I hope to reciprocate).

1. Listen back mic. It stopped working, are there any "check this first" areas (excluding mics and connection

2. I have plasma meters and it seems that the spectral cable is not connected. From where can I trace the source of the ribbon from the master section?

Again, thanks in advance!

[jimlfixit]

To clarify what you mean before anyone else answers this and can offer you better technical advise:

1    Are you referring to the 651 RTB (Return Talk Back) mic and not the two studio Listen Mics? If it is the 651 mic, they sometimes had dry joints but be careful if you resolder it as they don't like much heat. I recall that the larger soldered area was the ground which was also shorted via tinned copper wire (TCW) to the shell of the mic which also caused some problems at SSL. I have a schematic of that 1.5v "Eagle" mic here somewhere and will post on the forum when I find it.

2    The Bargraphs are fed in bunches of 8 or so (I think) from the main 82E75 card (or could be the 73 or 74) via 40 way coloured ribbons. Is this the cable that is missing?

[Kats]

No problem to clarify.

1. I meant the studio listen mics (I only have one connected)
2. The spectra cable is one ribbon cable ( I believe) that allows the EQ spectrum of the program material to be shown visually on the plasma meters.

[sintech]

Regarding the listen back mic, I'd reseat the 33 cards in the 651. Then I would swap the two cards over.

The 33 card that's at the top (after the oscillator/34 card) does Talkback, the next card does the 2 listen mics



I'd rechip the 5 Op-amps for maybe a quick fix. It's largely passive/apart from the caps after that.

Failing that it's extender time.

Regarding Spectra, with a 24, I guess you'll get one side.. personally it's a bit crappy as a tool. 

[Kats]

HA! Who said excluding connection...

2 pins on the DL had the wire pulled out...

I put a new cable on Listen Back 2 and all works. Although, now listen back comes up on the 'Mini' speaker not main. Is that the difference between 1 and 2 or is something up?

[sintech]

The 2 listen mics are summed to the mono talkback limiter, the correct operation: this is fed to the Mini's whilst dimming the Mains.