I have some issues on rotary encoder and on function switches.
Only two first switches works (V/DIV and SEC/DIV). Instead, when I press TRIGGER or OK switch, nothing seems happening.
Similary, when I rotate the encoder, no changes are seen (sometimes, a single step of V or SEC happen). ADJ function works.
I thinked that was due to activation, but activation (SEC/DIC+TRIGGER+ADJ) isn't possible because TRIGGER malfunction (I also tried with a firmware downgrade, with same results).
Referring to this schema
if I measure
I obtain right value.1 ) Check to make sure no opens between the following pin pairs. The resistance between these pin pairs should read about 1K.
DB0 ---- to ---- encoder pin 1
DB1 ---- to ---- encoder pin 3
DB3 ---- to ---- encoder pin 4
But if
the resistance is greater than 10k (12k) only between pin 4 and ground. Between others two pins 1 and 3 (and ground) is approximately 8k.2 ) Check to make sure no shorts between ground and pin 1, 3, and 4 of the encoder. Resistance between these pins to ground should be greater than 10K. NOTE: At certain positions of the encoder pin 1 & 3 are connected to pin 2 (which is ground) internally. If you find both pin 1 & 3 read zero resistance to ground you just need to turn the encoder by one position to make the internal connections open.
About
similary, between pin 4 and +3.3V is 11k, but between pin 1 and 3 (and +3.3V) is 6.6k3 ) Check the pull-up resistors R23, R24, and R25. Measure the resistance between pin 1, 3, & 4 and +3.3V respectively. The result should read about 10K for each pins.
All 3 pull-up resistors are 01C (10k); R5, R6 and R7 are 1k (01B). How is should be.
Similary, if for the switches I measure the pull up resistance, I obtain:
DB4 <-> +3.3V 10k
DB5 <-> +3.3V 10k
DB6 <-> +3.3V 5.4k (!)
DB7 <-> +3.3V 5.4k (!)
DB4 <-> GND 11k
DB5 <-> GND 11k
DB6 <-> GND 6.7k
DB7 <-> GND 6.7k
Note:
measured with switches not pressed;
DB4 is wired to V/DIV
DB5 is wired to SEC/DIV
DB6 is wired to TRIGGER
DB7 is wired to OK
Any idea or suggestion? Some DBx I/O lines of micro that are fault?
Thanks