Greg-Electrical Tech Journal

581
Neotek Elite Channels Channel ?Intermittent switches in the signal path cutting out, or distorting the signal in various modes. I previously hit the suspect switches with an alcohol cleanse, exercise, then stabilant routine (via syringe). This had mixed results, probably due to the fact that the dirt can't escape, so it took it to the next level. I pulled the channel and took apart the switches. This way, I was able to scrub the parts individually with q-tips and apply the conductive lube in a clean way. I lost 3 of the 36 contact tension springs in the process (about 1 x 3mm in size), but had some spares to steal from. It's a little tricky to get them in there. A slight misjudgment sends the spring 15 feet off into oblivion (as far as my eyesight is concerned). I found my rhythm using a tiny flathead screwdriver (flathead wedged between the last turns of the spring, pressed the other end into the back of the wiper piece, compress and twist into place, drawing out the screwdriver with my finger holding the spring in place). This all took more time that I hoped. The faceplate had to come off and there were some stubborn nuts to remove. This problem is becoming more frequent. It would certainly be quicker to replace the switches. I'll wait to see if this channel gives us any more grief.Installed in Channel 2 position now.Channel 2-Pad and Phantom power switches intermittent.Pulled. It's worth noting that the microphone signal goes through the phantom power switch (as opposed to the switch just handling the 48 volts). It's just as important for it to be perfectly working as the pad switch. Replaced the switches with a pair of new gold contact versions. This took 5 minutes to do, mainly because they can be removed without taking the faceplate off.
Greg Norman FG

Greg-Electrical Tech Journal

582
thecr4ne wrote:Hey Greg, RE: altec 525A1:When replacing the selenium rectifier, did you just put in 4 diodes in a bridge configuration? I have one of these that just has 2 diodes soldered onto the old rectifier, wondering if this is sufficient.Just replace the selenium rectifier with two diodes (as it appears in the schematic). It's not meant to be a bridge. The old rectifier should be completely out of the circuit if you do. It sounds like yours might have two new diodes in parallel with the old?We have converted a few supplies to use a regulator circuit for the filament. In that case, a bridge rectifier is good for getting the most out of that transformer winding. 2:Do you also put a new diode in place of Rect.2? should this be left half wave or bridged?It should be left half wave as it is in the schematic.
Greg Norman FG

Greg-Electrical Tech Journal

583
Awesome, Thanks Greg. Yes, mine has the diodes paralleled to the old rectifier, just soldered to it's terminals. I have 5 of these I'm trying to recap and standardize, figured I'd update the rectifiers along the way. I finally got a 29B capsule, but it looks like its' got some crud in the screen around the base. I've seen some posts indicating you've cleaned these before, and even taken some apart. Do you have any advise for taking care of this?Thanks again. I really appreciate the help.

Greg-Electrical Tech Journal

585
RCA 74 Jr Velocity-No output, ribbon in good condition.Primary measuring a short (roughly .2Ω)Altec 436c-No audio getting through... Hi voltage secondary is on the power transformer is dead, as is the selinium rectifier.Replaced the original power supply caps, and power cable. Cleaning up some other wiring.Ordered new transformer.
Greg Norman FG

Greg-Electrical Tech Journal

587
I've read about the potential for oxidized leads to make a semiconducting junction with connector contacts, like a cat's whisker or a diode, do you think that's what happens inside the solder joint or the solder joint breaks and becomes intermittent?
steve albini
Electrical Audio
sa at electrical dot com
Quicumque quattuor feles possidet insanus est.

Greg-Electrical Tech Journal

588
I've read about the potential for oxidized leads to make a semiconducting junction with connector contacts, like a cat's whisker or a diode, do you think that's what happens inside the solder joint or the solder joint breaks and becomes intermittent?
steve albini
Electrical Audio
sa at electrical dot com
Quicumque quattuor feles possidet insanus est.

Greg-Electrical Tech Journal

589
Hey Greg! I love all the tech talk and information that is shared here. Inspiring and generous. I m brand new to the forum and glad to be here. We are having troubles with our Furman HD6 system at our studio. Do you by chance have the PDF drawn up for your modifications? You had mentioned it in your post (from many years ago) If that is handy, I might try my hand at that for our team Also, did you have any other non belden 10core cables that you may have considered? That cable is only available in 1000ft rolls Cheers and thanks! Eric

Greg-Electrical Tech Journal

590
Hey Eric,You referring to this?viewtopic.php?p=1401195#p1401195After years of experience with our past and current setup, I've concluded that you're better off dedicating several stands for the furman mixers and wiring as-is, then zip tying the cables to the stands to strain relieve the connections. This worked in my studio, and is a lot less of a pain than refitting the old boxes. Our new wiring is nice, but it cost quite a bit in parts and labor. We still have more issues than I'd like, because of the density in the small connectors and abuse. A bag of heavy duty zip ties, and broken cymbal stands is much more efficient. I'd twist the grey and blue wires together as a pair, so it's tidy too. dearatanha wrote:Hey Greg! I love all the tech talk and information that is shared here. Inspiring and generous. I m brand new to the forum and glad to be here. We are having troubles with our Furman HD6 system at our studio. Do you by chance have the PDF drawn up for your modifications? You had mentioned it in your post (from many years ago) If that is handy, I might try my hand at that for our team Also, did you have any other non belden 10core cables that you may have considered? That cable is only available in 1000ft rolls Cheers and thanks! Eric
Greg Norman FG

Who is online

Users browsing this forum: No registered users and 0 guests