Horizontal off frequency RCA TV

[mattdavala]

Hello!

First time posting, but I have been reading for quite awhile. I have a 21 inch RCA TV that I aquired from Phil Nelson. 21T227. The Horizontal oscillator is "locked in" at a wrong frequency. Multiple images. Phil Nelson had the same issue and scanned the horizontal part of the schematic. If you want to take a peek its at:

http://www.antiqueradio.org/art/21t227.jpg

There are multiple images on screen, but sync is locked in. I am RE- replacing C95 C96 C97 and C98. I am using orange drops for all except C96 which is a dipped silver mica.Will those capacitors affect the horizontal frequency? What about C93?

There is a resistor R105 is 10K less that its supposed to be, schematic says 5% tolerance. How does that resistor affect the horizontal section?

Here is everything Phil has done to the TV before I aquired it. http://www.antiqueradio.org/rca15.htm

If replacing those caps doesn't bring the Horizontal osc into correct freqency, I'll will be listing this great TV for sale. :-(

[mattdavala]

I can't upload because of the servers size limit. 784 KB. If you want to see the screen image email me at [email protected]

[Eric H]

Matt, I'm assuming you have tried turning the horiz hold coil back and forth through the whole range?

The coil and slug type control can be tuned through the range till the picture flops over several times at different frequencies, sometimes you have to go quite a ways to get it right, i.e you have three pictures now but if you turn it far enough it'll flop over and become two, farther still and it might flop over and become a single picture.

Edit: Never mind, I see Phil tried that.

[Einar72]

I've mentioned this in previous threads. One of the silver mica caps is a really leaky paper cap in a mica-type case. It's C94 in this chassis, across two terminals on the bottom of the H-oscillator coil. I can't tell if this has been replaced yet, an Orange Drop will do fine. I own almost the same RCA, but with the full doors.

[mattdavala]

C94 had been replaced previously. But again I will re replace all those caps in that section. I'll even replace C93, a 330 MMF cap off the bottom of the frequency coil. That one had not been replaced before.

Many thanks!
Matt D

[kx250rider]

I've seen that problem in MANY RCAs including even as new as CTC-5 color sets. It's normally the tuning caps on the oscillator transformer; often two caps in parallel. As Elinar72 says, one is a fake mica on earlier sets. Beyond that, you might have to recap more of the set. Could be that the B+ is low to the horizontal oscillator circuit due to leaky caps and filters.

Charles