11-09-2013, 08:09 AM
I got this TV in the other day, after a 2 month plus sojourn through the postal system by Parcel Select (HAH!). It made it mostly intact, but the cabinet has some minor damage that I'll have to deal with.
The electronics were a bit more fun. Several caps to replace, along with several out of tolerance resistors (two were actually broken in half.)
For the longest time, I was getting good voltages pretty much everywhere, except for the HV. Eventually I found that there was a problem with the LV power supply (amazing they could make the thing work on 120V at all.. not even a voltage doubler.)
Anyway, I added a 300mH choke into the power supply filter chain (I had replaced the selenium rectifier with a silicon, so needed a resistor in there anyway. I used the choke because I had a lot of them around, and it did such a nice job of both bringing up the B+(the few volts made all the difference!) and cleaning up every last bit of hum that I decided to leave it instead of a resistor.
Well, the HV came right up after that... but still no visible signs in the CRT. I had left the yoke and ion trap off the CRT so I would have a better chance of seeing when I had HV up enough for the CRT. I had nothing. I held the ion trap up near the neck, and a spot appeared. Moving it around got a brighter spot... then it got TOO bright.
Before that, the CRT face was perfect. This was the first case of INSTANT ion burn I've ever seen
So now, I have this set with a nice bright picture, and two nice dark ion burns right in the middle.
The electronics were a bit more fun. Several caps to replace, along with several out of tolerance resistors (two were actually broken in half.)
For the longest time, I was getting good voltages pretty much everywhere, except for the HV. Eventually I found that there was a problem with the LV power supply (amazing they could make the thing work on 120V at all.. not even a voltage doubler.)
Anyway, I added a 300mH choke into the power supply filter chain (I had replaced the selenium rectifier with a silicon, so needed a resistor in there anyway. I used the choke because I had a lot of them around, and it did such a nice job of both bringing up the B+(the few volts made all the difference!) and cleaning up every last bit of hum that I decided to leave it instead of a resistor.
Well, the HV came right up after that... but still no visible signs in the CRT. I had left the yoke and ion trap off the CRT so I would have a better chance of seeing when I had HV up enough for the CRT. I had nothing. I held the ion trap up near the neck, and a spot appeared. Moving it around got a brighter spot... then it got TOO bright.
Before that, the CRT face was perfect. This was the first case of INSTANT ion burn I've ever seen
So now, I have this set with a nice bright picture, and two nice dark ion burns right in the middle.
