Problems with a Piedmont - Videokarma.org TV - Video

Carmine · #1 09-17-2011, 08:23 AM

If anyone was wondering what ever became of Doug's giant Zenith console, the Emperor-like mega console; it landed on its feet (casters) in a loving home just outside of Toledo, OH. The set's real name is "Piedmont".

However, it has recently developed an annoying audio hum. The hum is not related to signal level or input from the converter box, it's present with/without a signal, even with snow. Interestingly, I can modulate the frequency of the hum by using the brightness and contrast controls, but not its volume.

The obvious conclusion is a shorted cap, I would think somewhere in the video or HV circuits. There is no degradation in picture quality.

Anyone have an idea where I might want to start poking around with a dull stick? Haven't bothered to remove the back because short of an exploded cap, I know this isn't going to be something visually obvious to solve without a schematic (or the help of someone who has one).

BTW, I love having this set as a daily-driver in the living room. Strangers really freak-out when they see this huge console as your "main" TV. Little do they know that as crappy as modern programming has become, investing in a fancy HD flatscreen makes about as much sense for us as buying a Lamborghini strictly to drive to church on Sunday.

Carmine · #2 09-22-2011, 08:33 AM

Problem has been solved, and I also touched up the gray scale and convergence while I was back there. It appears the CRT was being overdriven, causing some blooming in white lettering. All of the screen drives are fully counterclockwise, as is the brightness range control. Amazing CRTs, those Chromacolors. Much improved picture now.

holmesuser01 · #3 09-30-2011, 10:59 AM

Hi. Looking at the pictures of the set, and what a nice set it is, I have to comment on the ASPCA commercial playing on the TV behind that beautiful dog... That commercial about kills me when I see it. I couldn't imagine doing things to an animal like that.

I adopted an orange cat a week ago that was mistreated for several years. He was coated with fleas, and had a terribly tight collar that was strangling him. After a $200 vet charge, he's doing great, and keeping my other 2 kitties on their toes. This little kitty is a real stinker, and wants to eat everything, including the other kitties stuff.

Back to the TV: When the OP was talking about the buzz in the audio, I was thinking overdriven CRT, and thats what it turned out to be. Those old sets are incredible, and with a bit of TLC, they are proving to be some of the best sets ever built.

Username1 · #4 10-05-2011, 11:24 AM

Yah hum and brightness is an overdriven crt..... Very nice tv, I have been thinking the same thing along the lines of one nice combo with stereo and record player..... Me and the wife's only charities these days are the Animal Charities, like the one on tv there and our local animal shelter. I sure would hope everyone here would support animal protection groups. I wonder if the ASPCA'S big ad blitz on antenna tv got them a lot of new members??? I know off topic.... Anyway very nice tv! I bet the sound is G-R-E-A-T !