PLL problems! fun! fun!
drinking a few Guinness' here and downloaded this schematic.
I watched the video. I noticed TP2 voltage never goes up much
over 3.2V it should lock up at times to over 5 volts while
messing with L17, to pull the VCO freq up higher.
it is best viewed with an Oscilloscope, as it changes.
what is the supply voltage to IC011-LM358 at pin 8?
it should be around 7.5 V.
on band D can you go to 26965 kHz, or lower to say 26905 kHz.
adjust L17 for a TP2 voltage of around 2 volts.
see if it stays locked.
also I would double check VCO BUFFER tuning of L18 and L22.
also in the VCO filter network, I prefer to use "real"
capacitors, that is a stable film type, not an electrolytic capacitor
as used at C101 and C102.
Capacitor C101 looks like it may be marked "T" as a tantalum type. (yikes!)
with an oscilloscope, you can see what is going on
with the signal to the VCO. a shallow sawtooth signal.
it is sunny and 84 degrees F outside now down here
on this bayou in southern Louisiana, so grabbing another
beer, and going outside.
drinking a few Guinness' here and downloaded this schematic.
I watched the video. I noticed TP2 voltage never goes up much
over 3.2V it should lock up at times to over 5 volts while
messing with L17, to pull the VCO freq up higher.
it is best viewed with an Oscilloscope, as it changes.
what is the supply voltage to IC011-LM358 at pin 8?
it should be around 7.5 V.
on band D can you go to 26965 kHz, or lower to say 26905 kHz.
adjust L17 for a TP2 voltage of around 2 volts.
see if it stays locked.
also I would double check VCO BUFFER tuning of L18 and L22.
also in the VCO filter network, I prefer to use "real"
capacitors, that is a stable film type, not an electrolytic capacitor
as used at C101 and C102.
Capacitor C101 looks like it may be marked "T" as a tantalum type. (yikes!)
with an oscilloscope, you can see what is going on
with the signal to the VCO. a shallow sawtooth signal.
it is sunny and 84 degrees F outside now down here
on this bayou in southern Louisiana, so grabbing another
beer, and going outside.
