Calrec S Series service manual/schematics?

[David Aurora]

I know this is going to be a long shot, but yeah, I don't suppose there's some maintenance info floating around for these by any chance?

I've been handed some bad modules (not just bad, but also butchered by other techs bad) and I think I'm going to have a long enough road ahead of me fixing things without also having to trace a lot of stuff out. Also, the console they came out of is all over the place in terms of level/metering/etc and is going to need a tune up, would be good to have some proper info on the adjustment procedures to get this thing back to the way it should be.

I've emailed Calrec but got nothing back, and I've been told the tech before me basically got nowhere on that front too.

Thanks!

 

[gyraf]

Your best bet is probably the guys that butchered it in the first place - to go parts hunting like that, they probably have access to a real manual..

/Jakob E.

 

[David Aurora]

How do I word this diplomatically...

Hmm...

The guys that butchered it DEFINITELY have a real manual, if you get my drift  :'(

 

[Gareth Connor]

Hello David,

You will come up against various brick walls with Calrec.
1. As a Company, they are ultra-protective of their IP..... even for out of support products. Do not expect a quick or initially favourable response.
2. You may be able to purchase a service manual or a number of specific drawings, but these will come at a high price and may well have NDAs attached as a condition of sale.
3. Supporting broadcasters who have paid $ /£ hundreds of thousands to purchase consoles is a higher priority than an out-of-production / out-of-support analogue product that is now (likely to be) in private ownership.

Any manuals / schematics that you get hold of will not have alignment procedures detailed. Trim pot and trim cap purposes and functions are often stated on the schematics, but not how to trim and what the test parameters are.

That said, here is some guidance on the S-Series:

An ESR meter is your best friend. Many of the problems with level and/or frequency response "being all over the place" is due to failed electrolytic caps.

Your next best friends are good-quality surface-mount rework tools.

The low-value (1uF and 2.2uF) caps in the pan circuit strangle the performance when they fail.
The 100uF & 220uF caps that form the majority of the inter-stage coupling go high-ish in ESR... a couple of dozen ohms does not sound like a lot, but when this is added stage-on-stage through a complex module, the performance tends to droop-off quite quickly.

Dried-out electrolytics are easy enough to deal with, the worst-case scenario is if the caps have leaked and the modules continued to be powered with electrolyte on the board surface. This is BAD NEWS..... VERY BAD NEWS. The board surface takes on an oily appearance under reflected light, with the oily areas being centred on leaky caps. Components may be damaged or even failed due to the conductive nature of the electrolyte. Corroded traces and component terminals as well as burned components are the signs of serious damage to look for.

The worst leakers are the 1uF, 100uF & 220uF.

22uF & 47uF power decouplers just tend to dry-out.

After you get the electrolytic capacitors sorted, electronic faults are then mainly down to failed op-amps or other silicon. Look for DC on op-amp output pins. No DC is good news. DC suggests a sick IC, or a failure in the surrounding circuitry. If the mic stage transistors have died, then you will need to find substitutes because the type of transistor used is no longer available.... anywhere.... I know 'cos I have searched!

Take a close look at the SMD plastic caps in the EQ and filter stages. These are easily damaged by heat and if the "module butchers" have been gung-ho with their soldering iron, it is easy to accidentally damage these delicate components.

Best,
Gareth.

Edited for spelling - no tech changes made.

 

[David Aurora]

Thanks mate!

Yep, caps are definitely a problem in the modules I've taken a meter to, they're long gone. I'm betting most of the console is pretty close to being in the same condition, so you're likely right than most faults are coming from bad caps.

Some modules HAVE been recapped, by a place that definitely, definitely had the service info (), and the work is atrocious. Someone reeeeally didn't know how to work with SMD, or just didn't care.

Obviously I can recap, then use the best modules as references for the bad channels and see where we are then, but geez... would it really hurt companies to just support the maintenance of their products? How do they not see that it's actually good marketing to be known for solid support?

 

[dunk91]

Hi David, I'm in the same process with a cm102s mixer, you can find my thread a few threads lower in the lab section.

As you, I've contacted Calrec for schematic/service manual/calibration routine, but they tend to not share anything beside pinout and block diagram, nothing that can disclose their technical choices.

The best way is do a straight recap of all electrolytics on the boards, I've found a few gone leaky, then check for faulty section and if everything works as it should pass to the calibration routine (wich without service manual you will have to discover by yourself).

I have good luck with a stock channel against the ones to be calibrated, a spectrum analyser and a meter. I've measured all the trimmers resistance before moving them, so if I screw up something I always can go back to initial conditions, then starting adjusting a trimmer at the time and monitor what the change in terms of level, maybe center freq ecc, after a solid afternoon of work I've traced down what each trimmers do and a way to set them up (in my case a few trimmers are correlated so you have to adjust them in a specific order).
Now repeat you discovery for each channel and you will be more or less good  ;D

 

[Gareth Connor]

If you find leaky caps, be very careful to clean off ALL of the leaked electrolyte. If you leave even just the smallest amount it will continue to degrade the PCB & nearby components. IPA alcohol and similar cleaners are quite effective. Cleaning the board twice or three times usually shifts the electrolyte.

A simple check for leaked electrolyte is a vile smell when soldering / desoldering components. In bad cases it stings the eyes, reams the nose and has a rank stench of skanky, minging, rotting fish! .... and that's in a workshop WITH fume extraction!  "Unforgettable" is a mild description of the pong!

 

[dunk91]

Long gone fish smell is a pretty accurate description, especially when you pass on leaked liquid with an hot iron... Fresh air!!  :-\

If you find leaky caps, be very careful to clean off ALL of the leaked electrolyte. If you leave even just the smallest amount it will continue to degrade the PCB & nearby components. IPA alcohol and similar cleaners are quite effective. Cleaning the board twice or three times usually shifts the electrolyte.

A simple check for leaked electrolyte is a vile smell when soldering / desoldering components. In bad cases it stings the eyes, reams the nose and has a rank stench of skanky, minging, rotting fish! .... and that's in a workshop WITH fume extraction!  "Unforgettable" is a mild description of the pong!

 

[David Aurora]

Thanks champions, looks like we're all on the same page with the best approach. I was hoping to be able to minimise labour for the customer by having the right info on hand rather than having to do things the long way, but I'll chat to him about how to proceed and maybe spread out as a longer term restoration it won't be quite as bad as a massive overhaul in one hit. Studios here spent most of last year closed due to COVID, I doubt anybody has a lot of cash to burn right now

 

[abbey road d enfer]

You will come up against various brick walls with Calrec.

Looks like a horror story...
I never had access to a Calrec mixer, but my understanding was they were über-qualitat in the same league as a Studer, but it seems like they are not even in par with a Soundcraft, in terms of durability.
I know they had very stringent design rules, particularly regarding EMI/RFI, so I thought the build quality would be on par.
Was R&D let down by shop managers or bean counters?

 

[gyraf]

I genuinely think that lifetime expectancy and repair-ability were simply not parameters considered. The sound and functionality was, as you mention, on par with Studer and the great ones. But.

Our UA8000 (named so because of its 8000 knobs(!)) was designed to run at an internal temperature of ca. +80 degrees C. Kills 85degrees electrolytics in a year or so. Shove through some aircon, and the fader VCA's are all out of whack - their deasign REQUIRE well-controlled, high, ambient temp.

And for servicability, calrecs are some of the worst I've encountered. Like always using component pins for vias, sandwiching switches in large linked groups between several pcb's, using ribbon cables that break the third time you open the module (yes, we kept logs for this purpose)

So in all, I think whoever commissioned the build of those large-scale desks were simply not prioritizing those aspects, and thus didn't get

/Jakob E.

 

[Gareth Connor]

@ Abbey.

To maintain context:

The horror story is to be focussed on a reluctance to pro-actively support non-broadcast, small-time, private or personal studio operators who are NOT in the league of spending mega-bucks on a new console..... in the corporate world these small guys are not able to provide a profitable revenue stream - that is the problem.

Technically, there are no issues.
Here is my take on that statement, with a particular focus on S-Series:

The last of the analogue consoles were put through production several years ago - everything is now digital and focussed on digital.
On personal experience of a working relationship with Calrec that spans decades, I can say from first-hand, the quality of the analogue consoles is top-notch both in terms of build and design - up there with Studer is about right. There is nothing wrong with the durability; it is the way the consoles are maintained by their owners (or not maintained) that is the problem. *Since 1993 the focus has been to design with SMD. This required a whole new set of skills in terms of design and manufacture; out in the field, there is also a whole new set of skills required for maintenace and repair. Some console owners have the maintenace skills available, some don't, some contract-in the skills, some drop into butcher mode through ignorance or tight-wallets.
* The start of my first R&D contract in 1993 co-incided, within a month, with the arrival of Calrec's SMD assembly equipment. It was a fantastic experience to be in at the beginning of that new era.

The fact that Davis Aurora's customer's previous tech has been described as a butcher cannot be laid at the door of the manufacturer.

As tech-savvy people we all know that electrolytic caps dry-out, go high ESR and audio suffers. The answer is to replace the caps. In my business we have been doing this on Neve VRs and Calrec M, S and Q series consoles for years. The Neve VRs and Calrec M's require standard through-hole tools and equipment, the Calrec S and later Q SMD products require specialist SMD tools - in my business we have invested in these and as a result, unless the boards are already damaged, we do no damage in our repair & service processes..... in the technical services industry you get what you pay for.

In regards to the leaking capacitors, it is unfortunate that a particular cap type/manufacturer was chosen. I am not privy to the decision making process surrounding the choice of cap/supplier/manufacturer, so will not speculate. Calrec is not the only manufacturer to have had problems with eletrolytics: theirs is the SMD equivalent of the 1990's Neve VR cap replacement project.
Components have improved greatly in a quarter century.
IIRC the Neve 55 had a similar SMD cap issue with regard to leaking.
Hindsight is a wonderful thing.


@ Gyraf.

The only UA8000 I have worked on was the one in Studio 3 at Abbey Road in 1989, and even then my involvement was minimal. I cannot really comment on the UA8000 due to the lack of detailed personal experience. There certainly was a heck of a lot of electronics in a very small space. To achieve the component packing density with a through-hole design was impressive at the time - it still is impressive today.

I know the inflexible break-because-they-can ribbons that you note. A thoroughly nasty interconnect component! Unfortunately, there were very few choices back then.

The UA8000 is a product design that was likely a decade or two ahead of its time in terms of facilities and was ideally suited to the packing densities of SMD and the tight component tolerances that today are simply taken for granted - I'm thinking of the modern That Corp VCAs, 0.1% resistors, 1% capacitors, temperature compensating components, multilayer PCBs, flat-flexi ribbons and other 21st century PCB interconnect technology.

The sandwiching of switches, as you describe, is frankly unforgivable  and on some M-Series has caused me more than one sense of humour failure accompanied by excessive swearing.... and that's before starting on the delicate dis-assembly procedure to get to the failed switch latch!