Senior Member
Joined: 13/08/2024
Location: NetherlandsPosts: 104
| Posted: 04:55pm 15 Oct 2024 |
The Sony infrared sensor is a SBX1619-52 with TTL level output. The transistors on the right side are Q209, Q210.
The transistors Q206, Q208 and IC202 will be removed. The two transistors Q209 and Q210 will be reused as level translators for the control of the LB1641. I have to test how these transistors behave when they are driven by the Pico with 3.3V. When the amplifier is switched on in the normal usage situation, pins 4 and 11 of IC202 are low. In the new situation, these are connected to 5V and R213 and R214 serve as pull-up resistors. LB1641 is on brake when both inputs are low or high.
When IC201 pin 1 is connected to ground, the system goes into standby. In normal operation, there is 3.4V on this pin. I have to check whether this can be solved with a voltage divider or whether a transistor must be used, for example Q208 when the amplifier is switched.
To be continued.