View Full Version : Magnavox T-940 Astro Sonic journey.


ARC Tech-109
07-28-2024, 04:37 PM
The beast has been released from it's 18 years of captivity inside a large refrigerator box and is now parked in my home. I will say it weathered the storage well despite the temperature extremes but only on the surface. Two hours were spent cleaning off the grime while I ran the heaters up with the DC breaker locked in, once cleaned up I released the breaker for some B+ and the damper failed with a gassy pink flash and promptly died forcing me to the dungeon for another 6DW4. Once in place the HV came alive but the screen is blank and I have no vertical... the adventure begins. Supply voltages all test within spec and I have good anode with a two inch spark, did an arbitrary check of the voltages going to the blue gun and they're all within spec but I suspect just off enough to cut off the gun. Tube checks strong on my 467 so it's time to pull the chassis and take a hard look around.

I've attempted to post pictures but keep getting caught up in the file size limits, I don't have the time to crop them down at the moment in GIMP but they're posted on another unrelated forum of which you will have to ask me directly for the link. I will say the file size limits are a major disservice to the members of Videokarma in this day & age where the average camera is greater than 10 megapixels in a 4:3 aspect ratio. Personally I'm willing to support the site as I have when it was still part of audiokarma however there has to be some give with the take on the part of administration.

ARC Tech-109
07-30-2024, 07:28 AM
So an update on the progress; the set is working as well as I can remember but it was a battle. Numerous bad resistors and a wrong tube in the video amp socket, once I got that squared away and the video IF aligned everything came to life. A few nagging issues remain one of which is the IF AGC seems to be hunting and it needs a purity & convergence alignment. The FM tuner works well but is having a hard time keeping up with some of the IBOC and other digital crap of our modern stations, the AFC wants hunt and the sound itself has this subtle midrange "twang-y" edge to it on the local iHeart stations, I don't hear it on the NPR or college stations.

Here are some of the images I promised, you can click on them at your leisure.