Vintage Microphones PCB D-47 build issue with Really.
« on: June 27, 2018, 05:58:40 AM »
Hi, I've got a mic that I've been having problems with for awhile now. the relay won't switch to Omni mode.
At first I thought the capsule was faulty so I exchanged it. Still I got no sound from the back of the mic in Omni mode. Then I tried replacing the relay which also did not help.  I've checked for continuity an all seems well. Only the relay is not switching. I'm not sure what I can measure or check anymore. Any tips would be greatly appreciated :) !


Re: Vintage Microphones PCB D-47 build issue with Really.
« Reply #1 on: June 27, 2018, 05:59:56 AM »
I've just realized that spellcheck corrected the word "relay" to "really"..... I meant RELAY.

TLRT

Re: Vintage Microphones PCB D-47 build issue with Really.
« Reply #2 on: June 27, 2018, 07:19:11 AM »
PSU is working well? It is terminal slot 6, +48V DC should come out when you put the pattern switch to omni position. Actually the 48V is just opening the relay thru a diode,so then the back membrane is connected to the front.

Re: Vintage Microphones PCB D-47 build issue with Really.
« Reply #3 on: June 27, 2018, 10:19:16 AM »
PSU is working well? It is terminal slot 6, +48V DC should come out when you put the pattern switch to omni position. Actually the 48V is just opening the relay thru a diode,so then the back membrane is connected to the front.

Yes, I realize through the schematic that this relay is just connecting the front to the back plate. But it's not switching. I've bridged the front and back for a test and it works like this. And I am getting +48V DC at terminal 1 POLRtRN but only when switched to Cardioid mode.  Also, in this mode, I am getting +48V at terminal 2 POLV. When I switch to Omni I get 0V.

Re: Vintage Microphones PCB D-47 build issue with Really.
« Reply #4 on: June 28, 2018, 08:40:49 PM »
Small checklist:

– is flyback diode the right way round?
– measuring at relay itself, is 48V arriving at +ve side of coil?
– is -ve side of coil connected to ground?

You'll want to measure at pins 1 & 3 on relay (see pic)

Re: Vintage Microphones PCB D-47 build issue with Really.
« Reply #5 on: July 13, 2018, 08:01:48 AM »
Small checklist:

– is flyback diode the right way round?
– measuring at relay itself, is 48V arriving at +ve side of coil?
– is -ve side of coil connected to ground?

You'll want to measure at pins 1 & 3 on relay (see pic)

Hi, sorry for the late reply - I was away for a couple weeks.
Anyway, the diode direction is right and the -ve side is connected to ground.
I'll measure the relay now.



 

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