Thank you for your continued patronage of Ono Sokki products.
We have recently discovered that some units of the MI-3111 microphone preamplifier may experience malfunctions depending on the usage environment. We sincerely apologize for any inconvenience and trouble this may cause our customers.
The details of the defect are as follows: Because the product may not function as intended, we would like to replace the affected product with a new one.
We will strive to improve our quality to prevent such incidents from happening again in the future, and we kindly ask for your understanding and cooperation.
Target Products
MI-3111 Microphone Preamplifier
Applicable serial numbers
| Applicable serial numbers | |||
| 36664 - 36673, | 36677 - 36736, | 36742 - 36781, | 36785 - 36824 |
| 36835 - 36836, | 36907 - 36956, | 36962, | 36971 - 36977 |
| 36982, | 36984, | 36998, | 37000, |
| 37005, | 37012, | 37015 | 37020 - 37022, |
| 37024, | 37037 - 37039, | 37042 - 37051, | 37053 - 37056, |
| 37058 - 37059 | |||
(The final 'R' has been omitted.)
Details of the problem
If used or stored for extended periods in high-temperature and high-humidity environments, the function of some components may deteriorate, potentially causing waveform distortion and reduced RMS values at sine waves above 114 dB.
Based on our own testing results at 40°C and 90% RH, we estimate the probability of malfunction occurring to be 6% at 114 dB–124 dB and 12% at 124 dB–130 dB.
Cause of the malfunction
In July 2014, we revised the manufacturing process for the preamplifier and changed the circuit board cleaning method. However, the cleaning agent used deteriorated the moisture resistance of some components, leading to insulation failures.
How to respond
The problematic part has been replaced with a part that is highly resistant to cleaning, and the countermeasure has been completed.
We will replace the product with a new one in due course. Please note that the serial number will change.
We will inspect your current preamplifier after receiving it back and will report back to you.
We apologize for the inconvenience, but please fill out the customer information sheet and contact your nearest branch office.
(PDF: Please print and use this document.)
Regarding inquiries
If you have any questions, please contact our Customer Service Center or your nearest sales office.
