08-01-2025, 09:51 PM
Hi Mike, yes, screen is now full of raster and linearity is, well, let's say somewhat better, but I'm not done with replacing resistors that have drifted high yet. Video coupling cap is now replaced along with the electrolytic (totally open) and Hunts on the IF board. Video detector diode was completely open and is now replaced. So far, though, there is no snow on the screen and no noise, apart from a slight hum, from the speaker except when exercising the tuner knob. I have a dual channel arb generator that'll go to 120MHz and it does both AM and FM modulation. I suspect that the tuner contacts are very iffy. I'm going to start with loosely coupling some sound IF to see if sound is working.
I don't have a 405 source yet. I thinking of building a Hedghog L or pressing one of my spare Raspberry Pis into service -- need to read that thread.
Re. the video coupling cap, and ceramic parallelled with it, I figured that was probably the reason, having given it some thought. I won't have much time to play with it tomorrow as I volunteer at our local air ambulance charity shop on Thursdays doing PAT testing on items for sale..
I don't have a 405 source yet. I thinking of building a Hedghog L or pressing one of my spare Raspberry Pis into service -- need to read that thread.
Re. the video coupling cap, and ceramic parallelled with it, I figured that was probably the reason, having given it some thought. I won't have much time to play with it tomorrow as I volunteer at our local air ambulance charity shop on Thursdays doing PAT testing on items for sale..
My name is Steve, but I answer to most things like "Oi, you!".
