Would you be able to send specs on your microphone element 90A2263?
This element is also called the R132 and is used in the model 527C. It is a dynamic mic element.
Nominal impedance at 1 kHz: 150 ohms
Nominal output at 94 dB SPL (One Pascal) at 1 kHz: -51 dBV (2.8 mV)
Specified frequency response range: 300 Hz to 5,000 Hz