FM Radio

[MP1]

To All:
The project schematic is back in it's original form and is correct. Anyone making this circuit should have no problems with it's design.

Thanks Kyr, for joining the discussion and adding the additional comments about your project.

MP

 

[AVRFreakMan1]

Found another scan image of the PCB.

View attachment 39721

 

[MP1]

Excellent!
Thanks for posting.

MP

 

[Andy815]

Hi am having trouble getting the parallel port to work and i dont understand why. The radio is working purfect with the potenteomoter but i cant tune the radio with the parallel port. If anybody knws why i would really be happy

 

[AVRFreakMan1]

Hi am having trouble getting the parallel port to work and i dont understand why. The radio is working purfect with the potenteomoter but i cant tune the radio with the parallel port. If anybody knws why i would really be happy

Explain more!
Did you use a program? What program?
What OS? My program runs  only in plain old DOS environment. That means DOS, Win95, Win98(SE) but not any NT based Windows.
Have you measured the voltage in B point with a multimeter? Does it change in regular steps?(0 to 5V, @ 5V/255 steps)

If you think everything else is correct, check parallel port's settings in BIOS. Alter SPP/ECP/EPP settings and you'll see.

Report your findings and if anyone has any photos, it whould be nice to see them.

Kyriakos

 

[mvs sarma]

Fine-- there was a time lapse in my reverting back-- as i was out of station attending on a relation who was sick, thus not verymuch on net.

i went thro all the letters  and also the philips application note an192

PIn 5 of TDA7000 sits on =ve voltage thus the Varicap positioning is RIGHT

the circuit is also checked working by andy815 with potentiometer.

  i stand corrected.

sarma

 

[mvs sarma]

Fine-- there was a time lapse in my reverting back-- as i was out of station attending on a relation who was sick, thus not verymuch on net.

i went thro all the letters

 

[MP1]

Thanks sarma,
I think we are already past this. It is good to have you back. Hope all is well.

MP

 

[Andy815]

in the schematic i connected the parallel port to point "A" and removed the potentieometer. I connected r4 to c18 and r3. The program i am using is Java. I am sorry i dont understand what you mean when you want me to check the voltage. This whole time i was checking resistance and the resistance is changing. will attempt to figure out the voltage.

 

[AVRFreakMan1]

in the schematic i connected the parallel port to point "A" and removed the potentieometer. I connected r4 to c18 and r3. The program i am using is Java. I am sorry i dont understand what you mean when you want me to check the voltage. This whole time i was checking resistance and the resistance is changing. will attempt to figure out the voltage.

You should NEVER attempt to measure resistance in a powered circuit.

Anyway, remove R4 and it should work. You didn't see the scissors?