BBC Maida Vale studio 3 4040E

[StarF666]

Just a little update as it seems a little quiet around the forum. Hope you're all busy with exciting projects.
Cleaning of the channels goes on. Ultrasonic cleaning on the switches brings out some dirt. The E channels look very nice after cleaning. Anybody knows where to get the colored caps on the pots for a reasonable price? Meanwhile I started work on the patchbay. We got all the tooling for the EDAC connectors and have just started rearranging the connections for our new studio wiring. Still trying to get EDAC plugs, Jim might help but is very busy atm.
Also bought a soldering/desoldering station which is great. Might bring back the fun to soldering and I might fix my Tweed Twin finally.
Still trying to find more information on the 82E148 cards and what they are good for.
If only the new power supply would finally arrive. Just can't wait to fire it up but would rather do that with all the protection candy of the Atomic.

Edit: Sorry, I forgot to resize the images, they are quite big. I'll do better next time.

[xmax]

The Atomic is ready to go, Ian will contact you today. Thanks! N

[StarF666]

Great news. Thank you.

[xmax]

Those per-bucket solo defeat mods are wired to the bucket backplane pcb,
they cut the traces near the S3E ribbon and put them there. And yes the
atomic will go down to 18.5 with the center section and 1 module. Cheers
it will ship today! N

[xmax]

I take it you are now up and testing with the Atomic?

[StarF666]

Almost. I wanted to fire up the center section on Tuesday but we had enough man power to work on the patchbay. I will probably test it tomorrow. The colors of the wires on the 19-way power Bicc differ a little from the service manual. I have to carefully sort this out. I don't have a white cable for example but 4 red ones. So I have to double check, where all the wires go. And then I pledge for mercy and the genius of your protection circiut.

[xmax]

What do you need to sort out? Are you having to build power cables?

[StarF666]

No, I have the power cables. But the bucket with the panel where the power connector is mounted, was removed and therefore all internal wiring. I have to connect the wires from the internal power loom back to the 19-way Bicc connector on the panel. So I know 3 red wires to B,C,D, but I have 4 of them. I guess one of them should be white and inserted to E. I also have no yellow wires but all green ones for 0V. I'm just worried because of the different current ratings on the white +20V. I guess the one with the lower (5A) current rating goes through the bargraph motherboard. I'll check where all the wires go and am pretty sure, I can figure it out. I will post once we got something running. The S1 and the power brick look great.

[xmax]

Oh no! Fun, we have rewired some of those, I would double check everything on the other side, like at
the bucket edge connectors, also the the + audio and + logic get connected together at the breakers.
Another note, they have the +265 on one connector and the -265 in the other (M and N) I presume
to make it harder to kill yourself. May the force be with you. N

[xmax]

And they reference the 265 off the Logic - for some god awful reason, it made the Atomic a
a nightmare in the beginning.

[StarF666]

Well, they were in there and it worked. I just have to figure out, where everything belongs. There are some wires labeled B and I'm pretty sure these are the ones going to the bargraph board. I will sort out the rest tomorrow. Does anybody exactly know what the E pin on the B2 connector is for?

[sintech]

The 'White Wire' is not well documented, apart from Jim's power wiring scheme, available in the 'Technical Manuals & Documentation' section...

But from memory white is the +18v console end feed back to the power supply to act as the +6v ground to make the logic

[xmax]

Yup, that's where that connection is made, in the early stages of the Atomic development
our logic voltage meter did not kick on until connected to the desk, but that did not
end up working because of the protection circuit, I get a lot of questions regarding
what the hell that voltage actually is because they call it 6, 7, 11 and 13 in the manual.
So we made our meter just read the actual logic psu because that is the number they
use in the manual to calibrate. It confused the hell out of me about 15 years ago.
I would like to know why they did it that way to begin with and the fact that the 250
is also tied to the logic is bizarre to me. N

[sintech]

Yeah, the power supply maths is done at the console end, guess from a service point of view it's easier to have individual rails.

[StarF666]

It's been a while since the last update. We were busy with work and had not too much time for the SSL. Nonetheless we made some progress. The patchbay is almost finished. We prepared everything for our eight extra channels in the producer bucket, which got its bus cards and wiring installed. We also received our Atomic S1 and it was great to bring power to the desk for the first time (only with center section and two channels). It took me a day to figure out the wiring and grounding scheme and though the Atomic has great protection circuits I triple checked everything.
After everything was up (and I fixed a fault with the logic voltage wiring) I had to troubleshoot some things. The oscillator wasn't working (missing +18V from the status lock switch) and I had to repair the MD talk back switch. The logic board seems fine and status switching works. The master fader didn't work and I was very embarrassed to find out, I had forgotten to bypass the computer. Unfortunately none of the monitor outs is working.
This is what I'm going to investigate next. By then, the rest of the team will have finished the patch bay. After that we will take care of the plasma mainboard and install channels, faders and plasmas to see, what's working and what's left to fix. Meanwhile I'm trying to get some EDACs (no DLs for us) for the studio connections from Jim but he's pretty busy atm. I'll attach a pic of the current test setup.
If anybody is interested: The SSL power supply is for sale. I've got the changeover, one working unit and one with the transistors removed and the large capacitors marked "faulty". We will most probably sell the computer as well but I will try to make it work first.
Feel free to chime in. Any ideas on the non working monitor outputs are welcome.

Martin