Stanley Meyer tec devices test and debugging suite

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 - done

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0

OBS1465#1: at phase shift 0 5645 hz at U4 pin1 is minimal spike from VCC to 0.4V. at the same time there is an instant edge at C10 from 1.94V to VCC decreasing back to 1.94V within 50΅Sec (I think C10 gets reloaded because of losses thru U4 pin9)

[Tecstatic]

MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0

until proven otherwise

OBS1465#1: at phase shift 0 5645 hz at U4 pin1 is minimal spike from VCC to 0.4V. at the same time there is an instant edge at C10 from 1.94V to VCC decreasing back to 1.94V within 50΅Sec (I think C10 gets reloaded because of losses thru U4 pin9)

What are the values of R12, R13 and C10 now ?

You could consider increasing C10 for a longer time constant. I don't like the regulation spike changes C10 voltage so much. if 10nF try 47nF.

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R13 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V

[Tecstatic]

R12 = 0 Ohm, R13 = 10k, C10 =10 nF

There we have a troublemaker R12 = 0 ohm, that is no good.

I expected it to be 390kohm as shown in diagram Test 0.1.

Correct to R12=100kohm, that should stabilize a lot.

Luckily we had the 10K R13 between C10 and U4 pin 13.

[bussi04]

correction R12=30k instead of R13=30k

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R12 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R12 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V
MOD1470#1: R12 = 100k same like MOD1486#1, OBS1486#1
SUG1471#1: for determination of lock in state an XOR gate for U4 pin1 and pin2 might help

[Tecstatic]

SUG1471#1: for determination of lock in state an XOR gate for U4 pin1 and pin2 might help

MOD 1473#1 connect U4 pin 2 to U7 pin 1 (as in SM 0.5)
MOD 1473#2 move R15 from U7 pin 11 to U8 pin 4 (as in SM 0.5)

Now D6 should be on when locked.

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R12 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V
MOD1470#1: R12 = 100k same like MOD1486#1, OBS1486#1
SUG1471#1: for determination of lock in state an XOR gate for U4 pin1 and pin2 might help
MOD1472#1: R12 = 30k for long time stability, when R12 was 100k there was not always lock in when SW9 = on
MOD 1473#1 connect U4 pin 2 to U7 pin 1 (as in SM 0.5) - done
MOD 1473#2 move R15 from U7 pin 11 to U8 pin 4 (as in SM 0.5) - done

Now D6 should be on when locked. – works: when lock in it΄s permanently on, when unlocked (disconnecting feedback wire of tank circuit) it noticeable varies / glimpsing.
I think I can realize a more exact version:
OBS1472#1: at lock in U4 pin 1 is constant 1. indicating a non-lock condition means to retrigger a monovibrator with inverted pulses so that indicator led is off whenever there are inverted pulses at pin1.

[Tecstatic]

Now D6 should be on when locked. – works: when lock in it΄s permanently on, when unlocked (disconnecting feedback wire of tank circuit) it noticeable varies / glimpsing.

Here you see why I did not like the switchover circuit.

Now you have to put the resistor correctly at C11 correctly

MOD 1475#1 Break connection between new resistor and C11
MOD 1475#2 connect the new resistor so it is the only signal way from R14 to U8 pin 5,6
MOD 1475#3 connect C11 to the right side of R14

Now U8B is protected against C11, and maybe even the spikes disappear on D6, lets see.

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R12 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V
MOD1470#1: R12 = 100k same like MOD1486#1, OBS1486#1
SUG1471#1: for determination of lock in state an XOR gate for U4 pin1 and pin2 might help
MOD1472#1: R12 = 30k for long time stability, when R12 was 100k there was not always lock in when SW9 = on
MOD 1473#1 connect U4 pin 2 to U7 pin 1 (as in SM 0.5) - done
MOD 1473#2 move R15 from U7 pin 11 to U8 pin 4 (as in SM 0.5) - done

Now D6 should be on when locked. – works: when lock in it΄s permanently on, when unlocked (disconnecting feedback wire of tank circuit) it noticeable varies / glimpsing.
I think I can realize a more exact version:
OBS1472#1: at lock in U4 pin 1 is constant 1. indicating a non-lock condition means to retrigger a monovibrator with inverted pulses so that indicator led is off whenever there are inverted pulses at pin1.
MOD 1475#1 Break connection between new resistor and C11 - done
MOD 1475#2 connect the new resistor so it is the only signal way from R14 to U8 pin 5,6 - done
MOD 1475#3 connect C11 to the right side of R14 – done
OBS1475#1: D6 on at lock in condition, D6 flickering (less than at post#1474)

[Tecstatic]

MOD 1477#1 Replace C10 with a 100nF capacitor

[bussi04]

MOD1428#1: swap of feedback wires of tank circuit at P3-P4
MOD 1436#1: Be sure midpoint R12, R13 only have one connection: U4 pin 9 - done
MOD 1436#2: Be sure U7 pin 1 and 2 are connected (no connection on the diagram) – pin 1 is put to GND, done
C12 = 1.1 nF
R14 = 5.7k
Set center frequency to 6240 hz
At VCO = 0V freq = 4875 hz
At VCO = VCC freq = 7280 hz
At 4875 hz phase of feedback signal advancing phase of oscillator signal
At 7280 hz phase of oscillator signal advancing phase of feedback signal
MOD 1446#1 Break connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 Connect RV7 pin 1 to U4 pin 9 - done
MOD 1446#3 Connect one led to VCC having light on when connected to GND via a 10K resistor (test it), but the resistor is instead of GND connected to U4 pin 2 - done
MOD 1446#4 Connect one led to GND having light on when connected to VCC via a 10K resistor (test it), but the resistor is instead of VCC connected to U4 pin 2 - done
0 LED on = midpoint at GND
1 LED on = midpoint at VCC
Regarding the LEDs something is not right – correction done
MOD 1451#1 connect U15 pin 5 to midpoint R12-R13 (no longer to GND) - done
MOD 1451#2 connect U15 pin 4 to midpoint of LED resistors – done
Correction OBS1451#1: 1 LED bright, 0 led off at whole frequency range 4877 to 7280 hz

MOD 1454#1 Swap P3-P4 - done
if COND 1454#1 is false then
MOD 1454#2 Swap U4 pin 3-14 - done
if COND 1454#1 is false then
MOD 1454#3 Swap P3-P4 - done
MOD 1459#1 move R12 wire from U4 pin 2 to U4 pin 13 - done
U4 pin 9) 0V with 0.2V ripple 1 LED=off, 0 LED=bright
Then revert back – all done

MOD 1446#1 reestablish connection between R12-R13 and U4 pin 9 - done
MOD 1446#2 disconnect RV7 pin 1 to U4 pin 9 – done
MOD1464#1: adjusted pot R12 to finetune threshold voltage at C10
MOD1464#2: doubling tank circuit capacitor 1nF to 2 nF reduces frequency from 5647 to 5471 at phase shift 0
OBS1466#1: at power on the lock in doesn΄t lock every time (maybe only every 5 th time). Better power on freedom circuit with tank circuit switched off (SW9 off) and then switch on SW9. works fine.

R12 = 0 Ohm, R13 = 10k, C10 =10 nF
MOD1486#1: R12 = 30k
OBS1486#1: no more spikes at U4 pin1, at C10 = 2V with minimal spikes +- 0.4V
MOD1470#1: R12 = 100k same like MOD1486#1, OBS1486#1
SUG1471#1: for determination of lock in state an XOR gate for U4 pin1 and pin2 might help
MOD1472#1: R12 = 30k for long time stability, when R12 was 100k there was not always lock in when SW9 = on
MOD 1473#1 connect U4 pin 2 to U7 pin 1 (as in SM 0.5) - done
MOD 1473#2 move R15 from U7 pin 11 to U8 pin 4 (as in SM 0.5) - done

Now D6 should be on when locked. – works: when lock in it΄s permanently on, when unlocked (disconnecting feedback wire of tank circuit) it noticeable varies / glimpsing.
I think I can realize a more exact version:
OBS1472#1: at lock in U4 pin 1 is constant 1. indicating a non-lock condition means to retrigger a monovibrator with inverted pulses so that indicator led is off whenever there are inverted pulses at pin1.
MOD 1475#1 Break connection between new resistor and C11 - done
MOD 1475#2 connect the new resistor so it is the only signal way from R14 to U8 pin 5,6 - done
MOD 1475#3 connect C11 to the right side of R14 – done
OBS1475#1: D6 on at lock in condition, D6 flickering (less than at post#1474)
MOD 1477#1 Replace C10 with a 100nF capacitor – done
OBS1477#1: in unlock state D6 = off, in lock state D6 = on