SSlmixed.com Forum
Tech discussion => 4K,6K,8K Series => Topic started by: marcmozart on August 09, 2013, 06:56:09 PM
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Hey guys,
since yesterday I'm getting some strange behavior from my centre section.
I've been running my console from 1 power supply for a few weeks, powering not more than 32 or 40 buckets.
For the last few days I powered only the centre section as all I needed was to listen to some external 2 track.
At one point the centre section started following behavior:
- no sound at all on Monitor
- Mono LED comes on when pressing DIM
- DIM button mutes external to studio source completely
Thats with a maximum of two buckets of channels powered.
As soon as I switch on 3 or 4 buckets of channel, there is no sound coming out of the monitors.
My first thought was "aligning power supply"...
Any ideas?
Really appreciate your input...
Best,
Marc
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Sounds like you have problems with the 24 card in your centre section.
Most likely a logic IC, will have a look at the drawings now.
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Thank you so much Andy!
More observations:
Tried both powersupplies, seperately and together. Behavior is always the same.
Centre Section works fine as long as no channel buckets are powered. Becomes erratic once I switch on one bucket and more problems when I power more than 3 buckets. (sound cutting off from external to monitor).
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The following switches are definitely affected and involved in the error:
FILM
STEREO (or QUAD on some consoles)
MONO
(LED for STEREO doesn't go off if I switch in film mode)
DIM
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My tech Gil Martini send me a quick e-mail (from Brasil...)
He thinks it could be a bad switch for the Centre Section under the patch.
Here's what he wrote "If you have a bad connection thru the small power switches under patch, that means voltage is ok untill you drift
Current to drive status lines to console buckets.
Usely itīs on logic +11v rail that problem appears, no other way than measure on center pcb"
So I guess I have to buy a voltage-meter, measure the voltage on the PCB and try to swap the switch...
Thoughts?
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I still feel this is a card fault in 651, rather than a switch.. but you never know. Really you would need to buzz through the 11v rail to each bucket to find that for sure.
Maybe leaving the buckets dark and the 651 on has loaded down the 11v rail and caused some damage to the Cmos IC's
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I still feel this is a card fault in 651, rather than a switch.. but you never know. Really you would need to buzz through the 11v rail to each bucket to find that for sure.
Maybe leaving the buckets dark and the 651 on has loaded down the 11v rail and caused some damage to the Cmos IC's
Sounds right - I looked at the switch but it looks and feels solid.
So do you think I should replace some ICs on the 024 card?
EDIT: I take if I find the following types of CMOS ICs I can swap them:
4042
4011
4069
4013
4071
I found them online, they seem very common - any thing I need to specifically look at when ordering these?
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Hi, It's all standard stuff, as long as it has the block of four numbers it'll work (don't worry about odd letters after)
As you know eBay is really good for Cmos IC's :-)
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I don't know anything ;-)
Cool, your help is legendary as always!
Hi, It's all standard stuff, as long as it has the block of four numbers it'll work (don't worry about odd letters after)
As you know eBay is really good for Cmos IC's :-)
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While I'm running out to buy a Multimeter...
can you guys point me to where to measure the voltage at the centre section PCB?
Thanks!
Marc
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Voltage rails are clearly marked on 651 morherboards backside. Just remember to measure logic voltage between +11V and +18V rails.
-Paavo
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Thanks Paavo,
indeed too easy... the voltages all look great except between +48 and 0 which is only about 40V
between +11V and +18V rails
reads -7.5V (centre + 2 buckets run from 1 power supply)
reads -6.42V (centre + 6 buckets run from 1 power supply)
reads -7.18V (centre + 2 buckets run from 2 power supplies)
reads -6.51 (centre + 6 buckets run from 2 power supplies)
all others (+18, -18, +11 against 0V) are always within +-0.6V)
I take this as a sign that the voltages are NOT the problem and I should indeed proceed with replacing MOS ICs on the 024 card?
Voltage rails are clearly marked on 651 morherboards backside. Just remember to measure logic voltage between +11V and +18V rails.
-Paavo
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My tech says (via e-mail):
"Only signal running fron 274 card (film version of 24 card) is the stereo/ film format bus to switch the staus on each channel
May be have a look on voltage resistors on 274 card or possibly one channel is drifting too much current from the transistor sending the status over all bays"
Of course that doesn't tell me too much. Where are the Voltage Resistors and how do I replace them?
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Posting pictures of my 024 centre section card...
the backside looks pretty modified - is that due to the film panning?
I'm lost - should have done a mix today. :-\
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Patching the mix-bus directly into speakers (using master-fade as monitor level).
Mix-Bus is fine, only problem is that console is stuck in film-mode which is a big problem (means that everything panned to center comes out the Center Channel). Unfortunately no solution.
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Here's pics of the standard 24 card for reference for the mods to Marc's board.
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OK now I found something...
I just checked the voltages on the inputs of the Logic Controller IC T1 (pin 55, 56, 57 on the back of the center PCB)
They all show about 8V (against 0V rail) with 2 buckets of channels on.
With all buckets on these values increase to 13V (against 0V rail).
Conclusions?
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You maybe witnessing the loading from having dark buckets, I did some loading tests last year.. and the logic rail dropped as I populated dark unpowered buckets.
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Update: I've just ordered a bunch of these CMOS ICs for the 024 Logic-Card.
Looking at the specs of these they can be run from 3 - 15 V so the voltages I've measured should all be fine.
I've compared my 024 card with sintech's 024 and recognized that T1 is a 4042 CMOS IC ("quad latch") whereas my 024 card has a Motorola MC14013BCP (a 4013-type "dual type D flip flop") installed. I could not find any evidence of these being compatible but will just order one of each and see what happens replacing them.
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Hi, this would explain all the cut traces and mod work at a the back of your 24 card, it's all in the T1 area. Stick to the 4013
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Hi, this would explain all the cut traces and mod work at a the back of your 24 card, it's all in the T1 area. Stick to the 4013
Who and why would do something so cruel to my 024 card ???
Will report back once I replaced the MOS ICs...
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Probably SSL
Alan
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Update: I just replaced all the CMOS ICs - unfortunately it didn't solve the problem.
Any other ideas? I really appreciate your input.
Thanks,
Marc
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Recal one supply to about at center section with ALL channels pulled (fun I know) then
add channels one at a time until shit freaks out (recalibrate p.s. after each bucket) I did not have time
to read the whole post but it sounds like the center section works fine alone, or try pulling the ribbons
on one side of each center section, first right side then left side.
it sounds like you have a bad bucket or module freaking it out.
are you solos's working properley? good luck. N
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I would highly recommend pull 3 modules on each side of the center section and pulling The top 3 ribbons, then calibrate the p.s. to exactly+/- 18 and of course 6.5 between 18 and 13, I have never seen a logic chip fail in the center section, and with over 20 years on this crap I have maybe seen 3-4 chips fail at all! (unless there is a ps problem that kills them) what I have seen fail on these desks are logic related diodes and fets. they usually short out, and one channel or bucket or ribbon can often freak out the whole desk! on any of the mini monitor switches you should see a logic swing from -18 to +18. N
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Pulled the top 3 ribbons on each side of the center section, however nothing changes.
I would highly recommend pull 3 modules on each side of the center section and pulling The top 3 ribbons, then calibrate the p.s. to exactly+/- 18 and of course 6.5 between 18 and 13, I have never seen a logic chip fail in the center section, and with over 20 years on this crap I have maybe seen 3-4 chips fail at all! (unless there is a ps problem that kills them) what I have seen fail on these desks are logic related diodes and fets. they usually short out, and one channel or bucket or ribbon can often freak out the whole desk! on any of the mini monitor switches you should see a logic swing from -18 to +18. N
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Here's a detailled report
(with a video clip)
- when I switch the desk on, the bulbs for MONO and QUAD switches on the MONITOR MATRIX are burning
- the channels are always stuck in Film-Mode, and the Monitor Matrix can not be switched from FILM to QUAD / STEREO. The MONO light is always on
- I can get a signal from EXTERNAL TO MONITOR, when I press the DIM button, the signal gets cut and the MONO button bulb goes out. Same when I press the CUT button.
- Whenever I switch on more than 3 buckets, all signals from both EXTERNAL and the QUAD BUSS get cut. I've already tried to remove the top 3 ribbons on the left and right side of the Master Section to rule out that it is not one particular Channels that makes the Logic Board go mad.
- The entire STATUS-section works fine.
I have uploaded a movie to this link:
https://app.box.com/s/v3g8ulhjmurp0vtd98h7
I think I remember that when the problem first occured, I smelled like burned electronic parts for a moment. Could be wrong though. What part could potentially be blown? As I mentioned, I replaced all the CMOS ICs on the 024 card already.
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Crazy, as all these operations relate to the 24 card.
Could the bucket's going on be a bad diode? letting voltage travel the wrong way into the 24 card.
You could look for a diode gone short circuit on the 24 with your multimeter.
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Thanks! How would I test for a diode gone short?
Crazy, as all these operations relate to the 24 card.
Could the bucket's going on be a bad diode? letting voltage travel the wrong way into the 24 card.
You could look for a diode gone short circuit on the 24 with your multimeter.
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You can put it diode test/continuity (if it's short it will beep)
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Had a similair problem in the status section, turned out it was a broken button which in turn burned a couple of components in the center section
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TR 1 and TR 2 on the 024 card clearly look blown, which leads me to the next question:
1. Are these transistors socketed or do I need to solder?
2. Are these all the same types of transistors? Which type? Can I replace them with another one from another spare card?
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Got some good results from removing the burned-looking TR 1 and TR 2 (those are related to the FILM and STEREO lamp) and also removed ALL bulbs from the switches that caused problems (Quad Meters, Monitor Matrix, Monitors).
Diodes measured all fine.
Any body got some ideas how to get all my channels to switch from FILM to STEREO mode? Because thats the only thing that holds me back from doing a mix again.
All my channels are stuck in FILM mode meaning when panned in the middle they send to the CENTER bus.