View Full Version : Need a road map for a Panasonic CT101


Richard D
12-25-2004, 08:31 PM
Hello all, I could sure use a schematic for a Panasonic CT-101 micro crt color tv I am having trouble with the Audio, It sounds just like a voice coil going bad, yet when I plug a small speaker into the headphone jack it sounds fine. When I replaced the original speaker with a new one it behaved the same way! When I hooked up the original speaker to the earphone jack it sounds fine but at low volume. The phonejack and speaker both come from a small circuit board with no amp chip on it, just the vhf/uhf selector and channel indicator button.
Excuse me while I go pound my head against the wall some more.,
Richard.

Doug
12-25-2004, 09:41 PM
Since the cabinet is plastic maybe it's warped a little causing a bind on the speaker when mounted which causes in the voice coil to rub.

Richard D
12-25-2004, 10:28 PM
Thanks for your tip on speaker warping. I thought that too so I directly hooked the mounted speaker to the solder connections where the headphone jack is soldered to the circuit and the audio is good, just very low level and I can't find a chip amp on this little board. How can it be good there and not at the speaker out. I t would seem to me that the speaker would get the full output then after the headphone jack perhaps a small resistor as to not be able to play it too loud through the headphones, Thanks for your help.
Richard.

Doug
12-25-2004, 10:49 PM
With the resistor in series on the headphone jack the circuit has less loading. Possible
coupling cap from audio circuit to speaker leaky and the speaker would pull down the DC voltage on audio output(s).Also weak output(s) could be effected by loading.
Yep you need a print. I may have one but can't get to were there stored till the snow melts down some. Maybe next week. Temperatures are forcasted to be in the 40s this week.If your still looking for a print later this week send me a PM.
Doug

kc8adu
12-26-2004, 06:36 AM
the last ct101 i repaired had crummy sound due to bad lytics.
had short vertical and weak sync due to the same.
just got a binoc with the same low distorted sound and it likely means time to dig in the cap bucket again.