I used to hate working on old tube TVs until I found a trick with a $20 signal generator

For years, I'd get these big old sets from the 70s with weak or fuzzy pictures, and I'd just start swapping tubes and checking caps, which took forever. Then about six months ago, I picked up a cheap used BK Precision 4040 signal generator at a flea market in Dayton. Instead of guessing, I started injecting a clean video signal right at the grid of the video output tube. The difference was night and day. I could see exactly where the signal got messed up in the circuit. Last week, I fixed a Magnavox in under an hour because the issue was a drifted resistor value I never would have found otherwise. It turned a frustrating guessing game into a straight line to the problem. Has anyone else had a simple tool change their whole approach to a specific repair job?

4 comments

4 Comments

william8642mo ago

Man, that's a game changer, wish I'd tried that years ago.

piperbailey2mo ago

Actually, that trick only works with newer models.

miller.emery22d ago

Wait, really? I mean, like, only on the newer ones? That's wild, I totally thought it was the same across the board for years. I've been telling people to try that trick and now I feel like I've been giving out bad info this whole time. Maybe it's just me but I feel like the older models should still have that feature built in, it's such a basic thing. Idk, that kind of bums me out because my car's a 2019 and now I'm worried I've been missing out on something. Seriously though, are we sure it's not just a software update thing?

seth_shah2mo ago

Same trick saved me a ton of headaches last winter.

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