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Crest Century VX - Refurb project
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johnylondon
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#1
3rd February 2012
Old 3rd February 2012
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Crest Century VX - Refurb project

Hi, new to this forum, just picked up a Crest Century VX 52 channel.
I took a bit of a punt on this one as it's without its power supply, but the price was too good to miss.

So, I will be posting a few snaps as I go along. The first thing was getting it up the stairs to my flat - took the channel strips out as they need servicing anyway, wow what a great thing this desk is.

So, on to the tech stuff...
Firstly, I'd appreciate any help getting hold of a pdf of the circuit diagrams - especially the PSU as I may end up building one.
Secondly... if anyone has a spare PSU going please let me know! (I'm in London by the way!).

What do you guys think about this desk? I'm pretty ok cleaning pots and soldering stuff, my main concern is if the vca groups are down, might be beyond my abilities.

But first I need to power it up and see what I have - I was thinking a bunch of switch mode supplies would be ok but have been told they could prove too noisy - any views?
Well, most likely I'll be searching ebay for something suitable.

Pictures to come soon!

John
#2
4th February 2012
Old 4th February 2012
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never used one, but I checked them out at trade shows and spoke to one of the principles. It was very affordable, and appeared to be well-thought out. Good luck.
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5th February 2012
Old 5th February 2012
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Hey Johnny,

Got your message. Here's where you can download the schematics:

http://www.groupdiy.com/index.php

You'll need to create an account and look in "The Lab" in the "Technical Library" section. Third page under Crest.

No PSU schemo's though I don't think. Maybe ask over there and maybe somebody can come up with them.

I wouldn't worry about the VCA's. They where robust as was the desk as a whole. You know if you picked it up Mine has been doing 25+ shows a month in the venue I'm the production manager for since I refurbed it. Since I finished going though it and found/fixed/replaced every little problem the only trouble it's given me are some dirty switches that I've cleaned, three bad LED's, and every once in six months a dirty high pass filter pot will oscillate and make noise until it's exercised then it goes away. The pots are sealed and I haven't had many problems with them. Dirty insert return jacks not normalizing correctly and worn out switches where the biggest amount of work. I did replace a few channel cards and one group card I just didn't feel like working on anymore. And even those worked well enough to use. Just that the meters where out and stuff like that. I'm just not into living with funky channels. I don't have enough time or patience to deal with that when I've got 3 band on a sold out night.

When I get the time and feel tweaky I'll get around to modding it

I really love the desk though. I really like the pre's and all the EQ. Sure there's better for recording but this desk is no slouch. And I can't mix without VCA's anymore.

Now the same guy I got it from wants to sell me his 40 channel Allen and Heath GL4. Man life is hard.
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johnylondon
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9th February 2012
Old 9th February 2012
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Hey thanks Funk-O-Meter, I'll check that link out though I really wanted the psu diagram... maybe I'll get lucky and find a working supply on ebay but anyway - as promised a few pics...

Here is the desk as I got it - the guys I collected it from loaded it into my van with a forklift...

(First thumbnail)

I had to take the channel strips out to make it light enough for a neighbour and I to carry up a flight of stairs and into my flat, but at least it fitted in pretty well into my existing studio/study...

(Second thumbnail)

A bunch of the channel strips...

(Third thumbnail)

And a couple more after I reloaded it - the strips are not plugged/screwed in yet...

(Fourth & fifth thumbnails)

All I have done so far is to clean off some stickers/tape etc, and re organise the control knobs - there are 4 odd channels that have the later (?) grey scheme P&G type knobs, and a few channels had odd gain knobs etc. I managed to put all the later knobs on the subgroup/master sections, and use the ones off for the channels. Everything looks perfect now, save for two or three odd channels at the far end and one or two knob caps the wrong colour in the middle.

Condition wise the desk is good - I have only found one switch that doesn't lock, there are two fader knobs and one switch cap missing, one channel has a sticky fader.

Of course - no psu so who knows what I will find come power up!
Attached Thumbnails
Crest Century VX - Refurb project-dsc00897.jpg   Crest Century VX - Refurb project-dsc00899.jpg   Crest Century VX - Refurb project-dsc00900.jpg   Crest Century VX - Refurb project-dsc00904.jpg   Crest Century VX - Refurb project-dsc00902.jpg  


Last edited by johnylondon; 9th February 2012 at 08:02 PM.. Reason: pics too big
johnylondon
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22nd February 2012
Old 22nd February 2012
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Hey I just found the schematic for the 4a/6a psu... it was on the Crest website all along.
They have Century GT and GTX but not vx - any ideas? Is one similar to the Vx?
Getting there...
#6
22nd February 2012
Old 22nd February 2012
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You can whip up a good linear power supply using Power One supplies. Just follow the designs grounding and voltage requirements and put them into a box. You may need to source the power connector to the console.
johnylondon
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22nd February 2012
Old 22nd February 2012
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Quote:
Originally Posted by Jim Williams View Post
You can whip up a good linear power supply using Power One supplies. Just follow the designs grounding and voltage requirements and put them into a box. You may need to source the power connector to the console.
Yes, thanks for that - it was the sort of rout I fancied going really, until the proper thing one day turns up on ebay. As a start I have sourced a power one 24v supply - it's only the 4.8amp version but I can always run with a few channel strips unplugged. Still searching for suitable 20 volters.
I think I would need to ad an output fuse and clamp diode circuit though - wouldn't want to risk going over voltage and zapping all the ic's. (I see that power one do over voltage protection boards as ad ons for their psu's which could be handy)

Looking forward to getting the beast fired up

Last edited by johnylondon; 22nd February 2012 at 09:37 PM.. Reason: more info
#8
23rd February 2012
Old 23rd February 2012
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Any of the Power One 24 volt supply can be trimmed down. Contact the apps dept. for specifics. It's as easy as adding a resistor across the voltage sense resistor to expand the adjustment range.
#9
18th March 2012
Old 18th March 2012
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crest century

hi i can help you i have all the circuit diagrams and can provide info on power supply options.
#10
30th March 2012
Old 30th March 2012
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Love that Century Vx Console!

I had the pleasure of using a Century Vx from 2002 to 2005 and it was the best ever for live sound. Very reliable, quiet and predictable. I loved the aux's with the push-on, push off feature. The VCAs were awesome.
I never did any maintenance in it but it seemed well designed.
Best of luck getting it running. Somebody might put a power suppluy on ebay. Set an alert just in case.
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#11
15th April 2012
Old 15th April 2012
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Well I have been making a bit of progress with the desk - I used a couple of Vero eurocard smps for the +/-20v. When I got them I had expected to have to make up regulator circuits to drop them down from 24v, but surprisingly they adjusted down JUST far enough (20.5 and 20.6v), which saved a bit of effort and means I'm benefitting fully from their o/v protection etc. I had been advised against going the smps rout - for the sake of any noise they might introduce - but these quote very low ripple for this type of supply (40mv p-p) not quite as low as a linear but still not bad. Anyway - amp up full with no signal and all I got was a little analogue hiss so I'm pretty happy with them. The power one is doing the 24v. No 48v as yet though.
Anyway - no real problems appart from the tiny square switches that often need switch cleaner and a good bit of working to clear - the led lights stay on until you get them right.
Found a handfull of duff switches (not locking) but only a few so far. I've got a couple of subgroups that rarely work (that is, their o/p isn't making it to the l/r bus) but should be traceable.
It's a nice desk - a smooth and warm sound, quite clear but not cold.
Will have to do quite a bit of new cabling thanks to the way the inserts are wired but what the heck.
By the way - I might just be being stupid but I can't get anything out of the oscillator/pink noise generator? It's probably bust unless there's some trick to it.
Happy days
#12
16th April 2012
Old 16th April 2012
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Quote:
Originally Posted by johnylondon View Post
Well I have been making a bit of progress with the desk - I used a couple of Vero eurocard smps for the +/-20v. When I got them I had expected to have to make up regulator circuits to drop them down from 24v, but surprisingly they adjusted down JUST far enough (20.5 and 20.6v), which saved a bit of effort and means I'm benefitting fully from their o/v protection etc. I had been advised against going the smps rout - for the sake of any noise they might introduce - but these quote very low ripple for this type of supply (40mv p-p) not quite as low as a linear but still not bad. Anyway - amp up full with no signal and all I got was a little analogue hiss so I'm pretty happy with them. The power one is doing the 24v. No 48v as yet though.
Anyway - no real problems appart from the tiny square switches that often need switch cleaner and a good bit of working to clear - the led lights stay on until you get them right.
Found a handfull of duff switches (not locking) but only a few so far. I've got a couple of subgroups that rarely work (that is, their o/p isn't making it to the l/r bus) but should be traceable.
It's a nice desk - a smooth and warm sound, quite clear but not cold.
Will have to do quite a bit of new cabling thanks to the way the inserts are wired but what the heck.
By the way - I might just be being stupid but I can't get anything out of the oscillator/pink noise generator? It's probably bust unless there's some trick to it.
Happy days
May be this will be suitable.
Attached Files
File Type: pdf X Series Consoles Power Supply.pdf (847.3 KB, 293 views)
johnylondon
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#13
18th April 2012
Old 18th April 2012
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Thanks for that! It's quite different to the psu diagrams I got from the Crest website for lmx20 4 and 6 amp psu - I assumed they would all be similar.
I have built a supply from Vero switched modes and a power one now - seems to be working well.
Next stop a few replacement switches!
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#14
2nd May 2012
Old 2nd May 2012
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A quick update - All working ok now, minus the last dozen channels which I have left out due to psu limitations (the set I have do 5 amp each per rail so I'm an amp short everywhere, but have aquired 2 more linear modules, just waiting for a third to come along then I can build the mk2 all linear supply... and put the rest of the strips in!).

Anyway, intermitent subgroup and master channels turned out to be the ribbon cable connectors - I'd already crimped them up a bit more before refitting things, but gave the offending plugs another nip with a vice and a good spray of switch cleaner and that seems to have sorted them. Just a few switches to replace now... and one led on a strip that stays on (vca overload).

I made all the trs cables etc so my whole set up is nearly running again.

Funk-O-Meter - I saw you found switches, can you offer any advice? I need 5x 12pin grey, 2x 6pin grey, 2x 18pin grey. Just had a look on ebay and I'm going to order these...

http://www.ebay.co.uk/itm/PS909L-62-...80039520716073

and these...

http://www.ebay.co.uk/itm/PS909L-42-...92267830864861

They look exactly right, pity theres no 6 pin (2pdt) ones.

Also I need a couple of faders (100kb) Anyone know what the faders are... P&G? Maybe ebay will have the answer...

Can't wait to make some music with this thing

Last edited by johnylondon; 2nd May 2012 at 05:54 PM.. Reason: Found some switches on ebay!
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23rd May 2012
Old 23rd May 2012
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Well, all the new switches are in and working - was mildly concerned that the contacts appear to be silver rather than gold but I guess they will last long enough... especially if used regularly. What a pain getting the old ones out though - it was a destructive process.
There's just one vca light that stays lit (red=overload) on a channel, otherwise everything is perfect now, and I'll have a look at that when I get a chance - been too busy laying down some tracks

I noticed that things are a little out of cal though - saw a couple of presets on the circuit boards namely DC Trim and Dis (channel strips) don't sound like they are the right thing for gain adjustment but really its only a db or two here and there (according to the meters anyway!) I can live with that.

Oh one other thing - I've been busy making up desk sheets for this - so if anyone would like me to send them the word document of it just pm me!
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25th May 2012
Old 25th May 2012
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DC Trim is DC offset adjustment, check with a multimeter before adjusting, it may not need adjustment at all. Dis, i have no idea what that stands for.
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9th June 2012
Old 9th June 2012
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Hows the refurb going?

I just had to send out a PSU cause a thermister went and shut it down. It had gotten real dusty in there after only a year of being in the venue and that might have done it. Good thing I sourced an extra


I've also been buying up used cards as I find them. Most I've bought have needed switches which seems to be the reason they're yanked from their home to begin with. Got a L/R master bus card coming as one side of my desk appears to be dim at times compared to the other. I know one of the cards is a replacement from some times in it's sorted past and is a revised design with a few components different or all together not there. Either that is causing it or the master section needs a recap but I think that problem would manifest differently no?

Also just did a few more switches as they seem to go with some regularity after 10+ years of age. A few I've replaced looked to have been done before at least once as well!

Anyway she sounds great and it a full frame of 46 mono and 6 stereo now. Pretty huge. I've yet to fill it up at any show yet though I've been close a few times. I kinda went ahead and loaded all the cards up just to have more of something then the big fancy ass mega club across town that my good friend is PM at so I could rib him about it.

At some point I should send the wrist rest and meter bridge cover out for a repaint. I did them with a heavy duty enamel but they're chipping already with so much console tape coming and going. I need to have them powder coated probably. I sometimes think about emptying out the frame and sending it off to get media blasted and repainted as well as it has a tad bit of rust here and there. If I ever do I'm gonna have the arms and what not painted some custom hot rod color or something one of a kind Maybe candy apple red? Hummm

Oh and BTW Johnny, I didn't catch it before when you discussing finding PSU schematics but the 4a and 6a are the PSU's for the VX desks. The 4a does up to the 32 frame I think and the 6a is required for 40+ frames. Keep asking I bought a few from an audio company that where doing a rebate program for new Crests. They had to provide proof they destroyed the desk but could sell the PSU :/ How sad.
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14th July 2012
Old 14th July 2012
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Quote:
Originally Posted by Funk-O-Meter View Post
Hows the refurb going?

I just had to send out a PSU cause a thermister went and shut it down. It had gotten real dusty in there after only a year of being in the venue and that might have done it. Good thing I sourced an extra


I've also been buying up used cards as I find them. Most I've bought have needed switches which seems to be the reason they're yanked from their home to begin with. Got a L/R master bus card coming as one side of my desk appears to be dim at times compared to the other. I know one of the cards is a replacement from some times in it's sorted past and is a revised design with a few components different or all together not there. Either that is causing it or the master section needs a recap but I think that problem would manifest differently no?

Also just did a few more switches as they seem to go with some regularity after 10+ years of age. A few I've replaced looked to have been done before at least once as well!

Anyway she sounds great and it a full frame of 46 mono and 6 stereo now. Pretty huge. I've yet to fill it up at any show yet though I've been close a few times. I kinda went ahead and loaded all the cards up just to have more of something then the big fancy ass mega club across town that my good friend is PM at so I could rib him about it.

At some point I should send the wrist rest and meter bridge cover out for a repaint. I did them with a heavy duty enamel but they're chipping already with so much console tape coming and going. I need to have them powder coated probably. I sometimes think about emptying out the frame and sending it off to get media blasted and repainted as well as it has a tad bit of rust here and there. If I ever do I'm gonna have the arms and what not painted some custom hot rod color or something one of a kind Maybe candy apple red? Hummm

Oh and BTW Johnny, I didn't catch it before when you discussing finding PSU schematics but the 4a and 6a are the PSU's for the VX desks. The 4a does up to the 32 frame I think and the 6a is required for 40+ frames. Keep asking I bought a few from an audio company that where doing a rebate program for new Crests. They had to provide proof they destroyed the desk but could sell the PSU :/ How sad.
Hi Funk-o-meter,

I just bought three 12A linear PSU's from ebay, so that's me sorted! They are ex military for radios and stuff, adjustable up to 33v, but they have o/v control which can be set - so little risk of accidentally going over the 20v or 24v. I'm looking forward to inserting my last ten channel strips... could do with them!

You said one side was dim? I had a similar problem early on with one side dropping out until I crancked the signal - turned out that a squirt of switch cleaner into the ribbon connector sockets sorted it out... worth a try?

The only fault I have is that the oscillator/noise gen doesn't do anything - but I tried out the tape ins for the first time the other day which are two jack sockets on the same strip, and they didn't work either so I guess there's a fault there stopping most audio. Not really a prob for me though, I'll maybe look into it one day.

My switches are all bearing up well though (occasional squirt of switch cleaner excepted!). I don't think my desk has seen too bad a life, I know it was on a cruise ship for a time.
I've got the thing fired up as we speak - just getting dark here, and the lights look cool

My wrist wrest was really good... till I chipped it a bit getting it into the flat :( I think you need a good primer on that metal if you are doing it yourself.

Hard to imagine anyone could "scrap" one of these beauties :(

John
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