Old e22 prototype-
Noises when mic cable is bumped.XLR barrel that holds the connector was loose. Tightened the fasteners.
-This isn't a possible failure mode for the production model since the body of the mic is one milled part.
Greg-Electrical Tech Journal
502Manley/Langevin VTL CR3a-
Noisy when HPF is engaged.
One or Both mylar capacitors that make up the filter circuit were the source of the noise. I tried rewetting the solder joints, and the caps themselves measured ok. Replaced both with a single film capacitor equalling the composite value of the old ones. All quiet.
Dyanmite
Regulator heatsink broke free when it was shipped for a session. It was held in place by a nylon screw which became brittle over a long life of heat and stress.
New screw. No shorts. All together again and working.
RCA BK11 and 77DX mics off for reribboning.
Noisy when HPF is engaged.
One or Both mylar capacitors that make up the filter circuit were the source of the noise. I tried rewetting the solder joints, and the caps themselves measured ok. Replaced both with a single film capacitor equalling the composite value of the old ones. All quiet.
Dyanmite
Regulator heatsink broke free when it was shipped for a session. It was held in place by a nylon screw which became brittle over a long life of heat and stress.
New screw. No shorts. All together again and working.
RCA BK11 and 77DX mics off for reribboning.
Greg Norman FG
Greg-Electrical Tech Journal
503Pretty much the same thing happened this week sans Shea. Going to see if I can do something without shipping anything.greg wrote:Flying Faders- Channels 16, 32, and 48 are linking in complicated ways, on their own. For instance, if I solo chan 16 in momentary solo mode, no problem. If I solo chan 16 in latching solo mode, chan 32 solos on the down stroke (16 mutes with the rest of the board). As I lift my finger, 16 joins 32 in being soloed. A whole bunch of other anomalies occur between the three channels, all relating to Group, Solo, Link and Rec functions. It is strange that the problem channels are 16 spaces from each other. This might point to a buss driver issue.We've tried all of the resetting variants. Today, I tried calibrating the fiber optic signal. The rough square wave, which is never square, should have roughly a duty cycle of 50nS on the top excursion. I am unable to change the waveform going from the SEFA (FF card cage) to the computer. There might be something wrong with the transceivers, or even the cable. I will check monday, and get advice from Martinsound. I am not totally convinced that this hasn't been going on since installing the new computer last year.
2/10/10
Got some help for Shea Ako (local smartypants tech/friend). We observed, through the diagnostic switch check window that when any button was pressed on channel 16, a command signal was also read on the same button for channel 32. e.g. when I press and hold down the Solo button, command line is
"16 Solo True"
when I release the solo button, two command lines appear
"16 Solo False"
"32 Solo True"
Only the first should be there.The same type of interaction occurred between channel 32 and 48, and 48 and 64. Which is significant since we don't have a 64th fader. We do have channels 1-61 for automated faders, which means that we have the electronics for 64 (the fader control boards (FSA boards) control 8 channels a piece, and we have 8 ). We removed all but the first two 8-channel FSA boards, and performed the switch test with the same results. Even though channel 32 was dead, and disconnected from the system, the computer was still seeing commands from it when I actuated channel 16's switches.
We confirmed that the fiber optic signal strength couldn't be changed going from SEFA to the computer. We swapped the fiber optic cable to eliminate that as a possibility. Martinsound says that the signal we are observing should be sufficient, and the problem we are seeing seems more complex than just poor fiber optic communication. He recommends sending in the computer and SECA board for testing. So we are.
2/21/10 Problem located in the computer. Everything is back, and I already had a successful, glitch-free mixing session. More details later...
After some dicking around, the power supply to the computer failed. It was measuring slightly low on all the power rails before failing, and sounded like it was struggling (switcher frequency audible and loud, modulating). Taylor found a replacement power supply and installed it. All the glitches appear to be clear now, hopefully for good...
Greg Norman FG
Greg-Electrical Tech Journal
504FMR Audio RNC returned repaired.
FF issues.
CR3A mic fixed (above)
Sent two Beyerdynamic M130s out for repair. Both needed re-ribboning, one has a part broken loose inside the ribbon assembly. Ugh.
FF issues.
CR3A mic fixed (above)
Sent two Beyerdynamic M130s out for repair. Both needed re-ribboning, one has a part broken loose inside the ribbon assembly. Ugh.
Greg Norman FG
Greg-Electrical Tech Journal
505Traynor Monoblock B-
Smoking in the front by the power switch, lamp.
Power switch was making partial contact in the on position. Replaced, tested...
Replaced the foam in the two remaining Beyer M380s.
Smoking in the front by the power switch, lamp.
Power switch was making partial contact in the on position. Replaced, tested...
Replaced the foam in the two remaining Beyer M380s.
Greg Norman FG
Greg-Electrical Tech Journal
507Beyerdynamic. It's the same as the TGX50 foam.Jared Paolini wrote:Speaking of the 380, where do you get the foam from?
Greg Norman FG
Greg-Electrical Tech Journal
508Bryston power amp-
Left channel intermittent.RCA connector broke loose through twisting action, ripping the pcb trace off the board.
I refastened the connector, and spliced the signal to the remaining circuit board trace.
RCA 74 Jr. Velocity-
No Output
The cable strain relief broke loose inside. The free cable yanked down on a transformer winding which had a bare spot. The winding came in contact with the frame, grounding the signal from the ribbon.
Fake Marshal JTM45 -
Blowing mains fuses Power transformer's filament windings shorted (together).
Ordered and received a replacement.
Fixing the individual problems on this amp over the years has become a prolonged game of whack-a-mole. There are enough deviations from the schematic and layout that I'm putting this on the strip down/rebuild pile.
-Elsewhere-
EMI TG12345 MKII/III 24 channel, 8 bus boardInstalled and completely tested in a new control room, noted few issues which will be dealt with later. It's crazy how well this 50 year old console has held up. Great quality parts, switches, few pots, few elecrolytics, and a low stress power supply distribution I think are keys to that. Great to play around on.
I did a complete control room instal in NY with a Neotek SII board, 24-track, pro tools, 2-track, and hoards of outboard gear. There wasn't any legend for the console punchblock, so some time was spent figuring that out...
Left channel intermittent.RCA connector broke loose through twisting action, ripping the pcb trace off the board.
I refastened the connector, and spliced the signal to the remaining circuit board trace.
RCA 74 Jr. Velocity-
No Output
The cable strain relief broke loose inside. The free cable yanked down on a transformer winding which had a bare spot. The winding came in contact with the frame, grounding the signal from the ribbon.
Fake Marshal JTM45 -
Blowing mains fuses Power transformer's filament windings shorted (together).
Ordered and received a replacement.
Fixing the individual problems on this amp over the years has become a prolonged game of whack-a-mole. There are enough deviations from the schematic and layout that I'm putting this on the strip down/rebuild pile.
-Elsewhere-
EMI TG12345 MKII/III 24 channel, 8 bus boardInstalled and completely tested in a new control room, noted few issues which will be dealt with later. It's crazy how well this 50 year old console has held up. Great quality parts, switches, few pots, few elecrolytics, and a low stress power supply distribution I think are keys to that. Great to play around on.
I did a complete control room instal in NY with a Neotek SII board, 24-track, pro tools, 2-track, and hoards of outboard gear. There wasn't any legend for the console punchblock, so some time was spent figuring that out...
Greg Norman FG
Greg-Electrical Tech Journal
510Definitely. I've come to realize that with a few modifications, this would be the perfect board. Too bad it's worth more than a nice house.scott evans wrote:EMI TG12345 MKII/III 24 channel, 8 bus boardWhoa.
Klark Teknik DN780 Studio A-
Crackling along with the audio, pre effects engine.
Exercised the many board to board internal connections, and made sure all the supply rails were healthy. Tested on the bench for 2 days. The only time I could reproduce the noise was by messing with the input level pot which eventually cleaned itself.We'll see.
Greg Norman FG