U8 pin 5 reconnected to U8 pin 6
Pin 2 of RV7 connected to VCC
U2 in circuit again
Set center frequency to 5600 hz
R15 = 4.7 KOhm
R15 cut off from U8 pin 4 and connected to U7 pin 11
C10 = 500 nF
C10 connected to pin3 of U6B
R14 = 100 KOhm
C11 = 30 nF
D5 in series with Resistor 1 KOhm
Inserted Resistor 1 KOhm between C11 and pin5/6 of U8
Added capacitor 100 nF between pin 14 (VCC) and pin 7 (GND) of U6
MOD 1415#1: Connect the wire going to U6 pin 3 to U4 pin 9, being the only connection to U4 pin 9
OBS1420:
Repeating power up once more there is another situation:
U4 pin 4 135 kHz at duty 50% 5V SS
U4 pin 3 4215 hz duty 50% 4V SS
D6 on
U4 pin 5 (INH) constant 0V
U4 pin 2 5V SS rectangular duty variable
U4 pin1 5V SS variable frequency around 4215 hz duty 15%
U4 pin9 0 V with spikes up to 0.6V
u4 pin13 0V with short spikes to 0.6V
u4 pin14 4215 hz duty 50% 4V SS rectangular
u4 pin16 VCC no spikes
u4 pin7 GND no spikes
Pin 2 of RV7 connected to VCC
U2 in circuit again
Set center frequency to 5600 hz
R15 = 4.7 KOhm
R15 cut off from U8 pin 4 and connected to U7 pin 11
C10 = 500 nF
C10 connected to pin3 of U6B
R14 = 100 KOhm
C11 = 30 nF
D5 in series with Resistor 1 KOhm
Inserted Resistor 1 KOhm between C11 and pin5/6 of U8
Added capacitor 100 nF between pin 14 (VCC) and pin 7 (GND) of U6
MOD 1415#1: Connect the wire going to U6 pin 3 to U4 pin 9, being the only connection to U4 pin 9
OBS1420:
Repeating power up once more there is another situation:
U4 pin 4 135 kHz at duty 50% 5V SS
U4 pin 3 4215 hz duty 50% 4V SS
D6 on
U4 pin 5 (INH) constant 0V
U4 pin 2 5V SS rectangular duty variable
U4 pin1 5V SS variable frequency around 4215 hz duty 15%
U4 pin9 0 V with spikes up to 0.6V
u4 pin13 0V with short spikes to 0.6V
u4 pin14 4215 hz duty 50% 4V SS rectangular
u4 pin16 VCC no spikes
u4 pin7 GND no spikes
Comment