ฝัง
- เผยแพร่เมื่อ 10 ก.ย. 2024
- Philco Radio Model 53-956 - Finding a reliable 150 ohm filter resistor on the third attempt, replaced the selenium rectifier with a 1N007 diode which had to be a knock-off since it wouldn’t work. In Part-2, I will attempt to use a silicon diode/rectifier which will act just like a selenium rectifier by dropping the voltage down, hopefully by 7 to 10 volts. If this works like I think it will, we can do away with adding dropping resistors forever when replacing a selenium rectifier. This and more in-A Place To Happen!
How are you?
I hope you are very well. You are an inspiration to me, I watch every video of your channel. I think you are an inspiration name right so I think your videos should be released regularly which inspires me a lot. stay well Weren't you uploading videos to Facebook❤❤❤?
Thank you Ken for your effort, but we want more of crt tv from 80s 90s
Thanks for the request; I plan on doing some more TVs in the future but their hard to come by, especially when I prefer them to be color TV’s and in non-working condition.
One of the few mistakes not caught by Philco and republished in Rider's. Look at the two E cap connections on the parts
location diagram for under the chassis called Figure 5. It is where C28A and C28B have nothing connected to them! C28B should have a connection to pin 6 of the 35C5 and a wire from C28A should go to ground. The wiring diagram itself is
correct. Just like to vet information thrown at restorers just to see if we can realize that people made mistakes, even back
then. Can't recall how many times I found diode symbols in reverse in circuit diagrams by Howard Sams over the years.
Thanks Steve, I did use the Rider’s schematic and all E-Caps connections were spot on as you mentioned. The green negative wire was wired to all E-Caps internally when I re-stuffed it. I agree about the mistakes made on circuit diagrams, I have found mistakes on Rider’s and even the actual PhotoFact’s over the years to include alignment instruction. It’s always nice to get heads up on possible issues. God only knows how many mistakes I made myself.
@@kenslab1973 Ï HAVE 300 BELLY BUTTONS
Some interesting issues there Ken. The bubbling resistor was cool, I thought it might pop. Looking forward to Part 2
It seems like the radio is drawing very excessive current if the B+ voltage is dropping and the rectifier is getting hot. Also, if the sound is clear at first and becomes garbled after the radio has been on for a while, most likely, the audio output tube has grid emission, and the grid voltage drifts positive as the tube warms more. Try a new tube. Also, check the grid resistor for proper value and the coupling capacitor from the plate of the first audio tube for leakage. This is a common problem with paper capacitors.
Thanks, Michael, for your informative comment, always great to get them from my viewers. I replaced all film capacitors and resistors that were out of tolerance, shown in this part 1 video. The selenium rectifier being old had very high resistance and was causing the 45% drop in the B+ voltage. Were on the same page here and by replacing the 19V8 first audio tube, that corrected the distorted sound issue after the radio got to operating temperatures. So, the plate from the first audio tube was causing the voltage variation to the control grid of the output tube. Can’t depend on tube testers at times where they respond differently under a real load. All the best.
@@kenslab1973 Selenium rectifiers do degrade with age, and they should be replaced with silicon types. You may need to add 47 to 100 ohms in series with the silicon diode to match the normal series resistance of the selenium rectifier and keep the B+ voltage from getting too high. Use a flameproof or fusible resistor, because if the silicon diode, or anything else in the circuit, shorts, this resistor will be the fuse to protect from further damage or even fire. The first audio tube itself will not cause the output tube to draw too much current; how much current this tube draws is determined by the voltage on its control grid relative to its cathode. With most radio output tubes (such as 35B5, 35C5, 50B5, 50C5, 35L6GT, 50L6GT), the cathode bias resistor is usually 150 ohms and drops about 7.5 volts, making that cathode 7.5 V positive relative to 0V circuit common. The control grid is biased at 0 volts by a large value grid resistor, usually 470K ohms, also connected to 0v common. If the output tube grid is more than one half volt positive, the coupling capacitor from the plate of the first audio tube is leaky, the grid resistor is open or very high in value, or, especially if the current climbs and the sound degrades with time after the radio has been on for a while, the grid of the output tube is contaminated with some of the cathode emissive coating material and is trying to become like the cathode. As this happens, the output tube plate may start to glow red. Obviously, the tube is bad and must be immediately replaced.
hehe cool, for a second i thought that was a working radio circuit, and the sound came out of the speaker eyes. That would have been something else. Maybe in the future even AI powered so they can move around and talk. How could you be sacred of AI robots if they looked like that? They could teach us electronics.
I don’t exactly know what you’re referring to; if it’s the 3D woman character, I always like to add something different in my videos from time to time. Thanks for your comment.