Yes, what I have is M940 model. I will check them out for sure. Thank you so much for letting me knowAs far as I know Telefunkenn USA power supplies are not very reliable, if it's an M940 check out a few capacitors in the red box.View attachment 134964
looks like old school zener /BJT based regulated, RC filtered thing. There is plenty of room for RF chokes an/or ferrite beads on signal- and power lines.Yes
Yes, what I have is M940 model. I will check them out for sure. Thank you so much for letting me know
Are there some cases that those capacitors have problems?
Thanks for your information, but I really don’t know about the technical things. Even though you explain with the map detailedly, I can’t understand deeply. Sorry for that. I’m not gonna repair it by myself, but just wanna know somethin’looks like old school zener /BJT based regulated, RC filtered thing. There is plenty of room for RF chokes an/or ferrite beads on signal- and power lines.
I'd make a copy of the PSU in a new box, and design it for RFI, with power line filters, RF chokes, and a better regulated HF design.
Adjust R20/R19 to desired output voltage. The SIM has bad input supply (20V p-p) to measure the the regulation effectiveness.
View attachment 134969
The vanilla Mike Maida 1980's circuit has less regulation:
View attachment 134973
Do you mean it can be occured due to heat?Could be heater - cathode leakage in the tube, or a sometime oscillation in the LV PS.
Since the problem is intermittent, it may simply be that one of the filter caps has a dry solder joint on one of it’s pins.
The most common of any fault, and fits the symptoms perfectly. I’d start by looking at the solder pads on the bottom of the board.
90% of problems in new electronics can be found by visual inspection, if you know what you are looking for.I will check it out too! thank you![]()
I disassembled the PSU again and took a picture of the back side of the board.90% of problems in new electronics can be found by visual inspection, if you know what you are looking for.
Solder joints should have concave fillets and be shiny (except for lead free alloys that always look suspect).
This could be the PCB or the connectors.
Intermittent noise can be from cellphone transmitting. Test your setup with active call sending voice or data, noise would be in pulses. Keep close to mike, cables, power supply, mixers etc.
The weaker the cell tower the stronger the phone uplink signal.
The tube in the mic. The tube is an amplifier for the capsule voltage and gives it enough power to drive the output so you can plug it into your console.Do you mean it can be occured due to heat?
the tube that you mentioned is brown one, right? What is the function of those tube? Regulation of low and high noise?
No, it's not bad if the solder joints are good. It's hand soldered for sure. And the board was not intended for wave soldering. Odds are that this was done this way because it is "Vintage gear" so no one would bitch about it being modernized, despite being brand new. And it is unlikely the cause of the problem.I disassembled the PSU again and took a picture of the back side of the board.
I think it looks terrible. Even tho I have literally no knowledge about it, I can feel it.. lol Plz look into it.
View attachment 134986
Is it bad??
How could the PSU of 10000 dollars microphone be soldered like this?
How could the PSU of 10000 dollars microphone be soldered like this?
Well, is very easy to identify the filters electrolytics, but I can not advice you to repair it yourself: is a new mike, Telefunken must take care of the problem! The fact the issue is randomly appearing is probably due to a temperature related faulty condenser, also the new ones can develop this kind of problems... to be honest, I trust more a 30 years old Siemens cap than a brand new Chinese one (and yes, Telefunken is NOT the original German brand anymore, they use very common off-the-shelf components... sorry!).Yes, you are right. Following the method you told me, it’s gone after turning off the power supply while the mic is still working for 2-3 seconds.
As I posted before, someone said the problem is electrolytic capacitor on the similar case(124hz hum noise)
https://repforums.prosoundweb.com/index.php?topic=23670.0
I’m still waiting for a reply from Telefunken, and I’m gonna visit an audio repair shop next week, but If I show you the inside of the power supply, can you recognize what the filter capacitors are?
Actually I bought a brand new mic, and I’ve been using with great care. I totally don’t why this kinda thing happen.
I also wanna know why it works perfectly fine now, but sometimes that hum noise occurs again.
to be honest, I trust more a 30 years old Siemens cap than a brand new Chinese one
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