25-10-2017, 01:01 PM
(25-10-2017, 11:17 AM)Bonky Wrote: Thanks Mark; all understood!
I do have a sig gen with the capacity to generate 455kHz, so will try again later today.
I can follow a CD (I think). Yes I am a beginner. I need an idiot's guide to transistors and radios in general. Googling reveals many out there!
Your admonishments are deserved.
BW
Richard
PS Re: the diode --all I was planning to do was to connect it without soldering to the copper part of the pcb. I don't fancy removing the can around the coil. R.
OK - we've got your attention
Unfortunately for you, there is a lot of bad information about transistors out there. Old text books are overly complicated and don't help understanding, and many web pages I've seen are misleading or just plain wrong. Transistors and their circuits are pretty complicated, and you won't pick up how they work in 5 minutes. Before attempting, a solid knowledge of DC theory and signals is needed. I'm not trying to put you off, but just explaining that you need to be in this for the long haul. Perhaps a good place to start is here: https://www.vintage-radio.com/repair-res...index.html
Can your signal generator do AM? If so, that makes life a lot easier. Set the modulation to 1kHz, 30% or thereabouts.
As for the diode, it is inside the IFT. So this means that you have to remove the IFT from the PCB, then take apart the IFT, then remove the old diode and replace it with a new one. Then reassemble it, and reinstall the IFT on the PCB. Quite apart from all the risk involved (the wires on those IFTs is incredibly thin!), it's a half hour job at least - let's hope it's not needed!
Looking forward to hearing how you get on with the signal generator test...
Mark
