851

LA502 Optical Compressor / Re: Meter LEDs -12, -16, -20 are not lightning

« on: February 10, 2022, 06:20:34 PM »

All good.
Check that you didn't reverse one of the LED's. You can do this with the DMM in diode position, it will light up the LED when connected in the right direction.
Check that there is continuity between U8 pins 5, 7, 9 and U9 pins 5, 7, 9.

852

MP573 Microphone preamplifier / Re: Problems setting up the MP573 - General power check

« on: February 10, 2022, 04:12:10 PM »

Are you taking the 0V reference on the test pin at the back of the PCB?
There must be a short somewhere in the circuit. Look for a solder bridge somewhere. Is there an other component that gets hot (out transformer disconnected).

853

LA502 Optical Compressor / Re: Meter LEDs -12, -16, -20 are not lightning

« on: February 10, 2022, 03:39:44 PM »

What are the DC voltages you get on both sides of R37, against 0V.

854

LA502 Optical Compressor / Re: Behavior of the GR-LEDs has changed

« on: February 10, 2022, 03:36:38 PM »

Check value, direction and solder joints on U7, U8, U9, R36, R37.
What are the DC voltages you get on the 2 sides of R36, against 0V.
What is the revision number of your PCB?

855

MP512 Microphone preamplifier / Re: connector missing

« on: February 10, 2022, 12:20:29 PM »

Correct.
The jumper JMP1 forces the XLR input. It is only to be used during initial testing without the DI board installed.

856

LA502 Optical Compressor / Re: Meter LEDs -12, -16, -20 are not lightning

« on: February 09, 2022, 11:24:51 AM »

Check value and solder joints of R36, R37, U7, P7, P8, P9, U9.

857

MP573 Microphone preamplifier / Re: Problems setting up the MP573 - General power check

« on: February 09, 2022, 11:17:08 AM »

The current limiter U1 sees too much current 
Can you measure the ohmic resistance
- between the case of U2 and 0V,
- between the case of U2 and V+ ?


Do you also get TP2 near 0V when the output transformer is disconnected?

858

MP573 Microphone preamplifier / Re: Problems setting up the MP573 - General power check

« on: February 08, 2022, 09:41:50 AM »

Is U1 getting quickly very hot after powering?
Same question for U2.
Can you measure the ohmic resistance
- between TP2 and 0V,
- between TP2 and V+ ?

859

MP573 Microphone preamplifier / Re: Problems setting up the MP573 - General power check

« on: February 07, 2022, 11:16:31 AM »

but my voltage is 0V at TP2
Verify you don't have a short circuit between TP2 and 0V.
Check the voltage (against 0V)
on the anode of D4 (should be -15V),
on the case of U1 (should be -15V),
on the case of U2 (should be -15V).

The jumper on CN1 is on the wrong pin.

860

MP573 Microphone preamplifier / Re: Problems setting up the MP573 - General power check

« on: February 07, 2022, 09:15:41 AM »

TP2 is NOT connected to 0V.
Make sure it is the case with an ohmeter.
The 0V is the ground of the lunchbox. In the MP573, the local ground (TP2) is shifted down by -9V by U2. This is how we get 24V between TP2 and V+ (15+9 = 24V).

861

CP4500 Stereo Bus Compressor / Re: Actuator Button

« on: February 02, 2022, 11:22:42 AM »

Mouser 611-PVWH
Digi-Key 401-1151-ND
Not sold by RS.

862

MP573 Microphone preamplifier / Re: Tantale capacitor C20 plus lead position ? Doc number / board revision link ?

« on: February 02, 2022, 11:16:05 AM »

We have removed the sentence "plus lead always on the right" because we since have found capacitors that didn't follow this rule.
The correct and universal rule is: the + lead is the longest and it is marked with a + on the cap.

You should stick to the DOCS-19 if that it what is written on the kit box.

863

LA502 Optical Compressor / Re: C5 or not c5

« on: January 31, 2022, 07:57:21 AM »

Yes solder C5.
It is an error in parts list.

864

MP566 Tube microphone preamplifier / Re: Faulty MP566 - video and audio files

« on: January 31, 2022, 07:49:41 AM »

Can you check if the voltages (225V on TP2, +16V, -16V and TP8 ) are steady during the blinking?

865

MP566 Tube microphone preamplifier / Re: Faulty MP566 - video and audio files

« on: January 28, 2022, 04:38:22 PM »

Can you describe the problem in words, it is no very clear from the audio files?
The LED is blinking. Does it means that the lunchbox PSU is switching on and off? Or is it only the MP566?
Does it pass any audio or none at all?

866

EQP501 Passive Equalizer / Re: alternative opamps

« on: January 28, 2022, 04:30:32 PM »

It must be the connections between the pot and the mainboard:
Check solder joints of:
- the pot,
- CN2A & CN2B the lower 2 pins, near the spacer.

You can check the continuity between the center pin of P5 and TP3 and C12 top pin.

867

MP566 Tube microphone preamplifier / Re: Faulty MP566 - video and audio files

« on: January 27, 2022, 03:32:08 PM »

First thing to do is to test the voltages.

868

EQP501 Passive Equalizer / Re: alternative opamps

« on: January 26, 2022, 05:33:38 PM »

Can you check the P5 pot by measuring the resistance between the 2 extreme pins. It should vary from 0 to 100k.
If it doesn't you will need to replace the pot: Contact me by mail here.

869

501 Single Host / Re: Strange noise

« on: January 26, 2022, 11:04:00 AM »

Difficult to say from a distance.
Maybe you can send us the switcher for a diagnosis?

870

501 Single Host / Re: Strange noise

« on: January 25, 2022, 04:58:18 PM »

Try to see what the pressing may have moved?
Probably a solder joint somewhere.

871

EQP501 Passive Equalizer / Re: alternative opamps

« on: January 24, 2022, 09:30:03 AM »

With all the gains at 0, does the low frequency attenuation changes when changing the low frequency CPS?
In sucha case it would suggest an issue with the low freq attenuation potentiometer.

872

501 Single Host / Re: Strange noise

« on: January 23, 2022, 09:06:24 AM »

So the switcher works, good point!
Check that the case of U1 (LM317T) is not touching any pad or track on the PCB.
Look for a solder bridge on the main PCB.
You can check with the ohmmeter if you have a short circuit between 0V and +16V (finger #12 down).

873

First Aid / Re: Infos soudures

« on: January 23, 2022, 08:58:57 AM »

Non, il ne faut pas souder le boîtier des transistors. Seulement les pattes.

874

CP4500 Stereo Bus Compressor / Re: No LED or Meter Light

« on: January 23, 2022, 08:56:18 AM »

Congratulations!

875

CP4500 Stereo Bus Compressor / Re: No output on L-channel when engaged ("In" pressed) - right channel fine

« on: January 23, 2022, 08:54:44 AM »

Congratulations!