BBC Maida Vale studio 3 4040E

[marcmozart]

That is of course 100% correct. Luckily, my own console had completely new G+ cards in the centre section when I bought it.

[waltzingbear]

I would categorize that as yet one more instance of reality rearing its head...... in a good way!
:-)

Cheers
Alan

[StarF666]

Should I recap even though the caps show their full value on my DMM? The channel input cards are the only ones that have the orange caps on and are missing up to 30% of their printed value and the extreme cases. I'll get to play around with some analyzer software this week and see what the bass response looks like. The desk sounds very good nonetheless.

[Artur D'Assumpção]

Hi,

As a rule I would recap the center section completely no matter what. (an exception to the rule is if you know it was definitely fully recapped in the previous 5 years)

Regarding your channels, I would plan for a full recap also (check my exception). What I would do in your place, if you have doubts, just do a full frequency sweep analysis in one channel strip. Fully recap that only one and measure again. Check if there was a big improvement in frequency response.

Of course if you're having erratic channel strip problems with the electronics overall you should do this no matter what. Remember that caps are not only for the audio chain, but also for the overall electronics behavior. Sometimes off-spec capacitors can trigger a myriad of random problems not easy to troubleshoot. 

Do you know if your console what fully recapped in the recent years? Sometimes techs put a small stamp on the electronics with the  year.

Cheers,

Artur

[StarF666]

I also had the plan of recapping one channel and measure the result. I'll go this way. The desk is running now and besides some small problems (faulty switches and two EQ cards) everything is working fine and I have no hurry with the recap as there are a still some other little things to fix. I doubt the console has been recapped in the very last years but it wasn't really used in these years. And it sounds good. I think recapping one channel completely and comparing it is the way to go. If this makes a significant difference it's a no brainer. I already have new caps for this ready. Just have to find the time. Recapping the center section is also on our todo list. But for now we are really happy for what we got for our money.

[Artur D'Assumpção]

Just my 2 cents, recapping the center section should be top priority before channels. Specially if you're not certain when a last recap was done, if it ever was. This will save you lots of problems, specially if you now start using it regularly, problems will appear with usage and heat.

In the other side of the coin, center section is much easier to recap it being so modular.

Good luck!

[StarF666]

Any hint is appreciated. Thank you all. I'll keep you updated, of course.

[StarF666]

Time for an update. Desk is running and sounding gorgeous. We're trying to fix all the small things on our list step by step. While calibrating the VCA boards I did frequency response measurements on all channels and they are all very good. If these are the original caps they didn't see much action since 95 or they just hold up very good. I will do this with the center section as well but the important cards look recapped and it's just sounding so good. We got a few replacement VCA (13) cards from CML and they are as good as the originals.
I finally got the monitor section running. T2 on the 24 card was faulty and kept the whole monitor section in mono. And a 5534 on the 22 card had to be replaced to get the quad monitor outs running.
At this point a short detent: I already had a replacement 24 card ready. It came from ebay, seems to be a very early on whith tantal caps. I checked it, put it in and it shorted immediately with some nice fireworks of course. Anyway it provided T2 for the original card.
The main outs we're off about 1,5dB, we switched the 26 cards until LF and RF had the same levels and will look into the other two cards sometime soon. Any ideas how to correct this?
I got myself an early christmas present and ordered a new oscilloscope (Hameg/R&S HMO1002) which should be with me anytime soon. It should help following/measuring signals throughout the circuit. Only two things in the center section not working now: Listen mic and the meters. Meters are out because we accidently cut the cables (going through distribution amps in the producers desk, we removed everything from there for our channel extension early in the process and now focus the consequences ).
And we got ourselfes a better ultrasonic cleaner. The desk did not look really dirty but we had some trouble with wire bridges corroding/shorting through to the traces. Maybe the desk was in some not so dry environment for some time where it collected moisture and dust on the cards. Anyway the ultrasonic bath really helps cleaning it and we are very happy with the results. Cards going through it look like new.

That's it for now. Still looking for channels to bring it up to 48.

Greetings,
Martin

[Matt Sartori]

...
That's it for now. Still looking for channels to bring it up to 48.

Greetings,
Martin

have you tried the usual suspects like Funky Junk London or recycle audio or AES pro audio?

Mattia.

[StarF666]

Yep but nobody has anything in stock right now. Might have to wait a little.

[DigitalMetal]

Hi,

Sorry looks like ive missed a lot and got a lot of reading to do to catch up, i thought my topic subscription would email me when there were replies in this thread but thats obviously not working!
I had a quick look at your pictures of the custom BBC panels, in case you were wondering:
RM means Ringmain which is an internal broadcast distribution system within the BBC of all BBC station outputs so for example you are working in a Radio1 studio and you want to check you are making it on air etc, or if you are in one studio and going to contribute to another studio's program you can listen before you go live.

EMX is an internal emergency direct telephone system to BBC master control rooms if you need to contact them if you are experiencing a problem and need them to do something about it.

The meters are standard BBC spec PPM peak meters whcih were a requirement on all BBC gear until last year.

The varispeed and transport are remote tape machine controls.

Feel free to ask any questions if you havent already and i'll reply and read through all the other posts asap.

Neil

[xmax]

You have been busy...