CTC177AM2 Chassis
 

My 1997 RCA Set with the CTC 177AM2 Chassis is once again starting to act up. Late last year had it in the shop and replaced the Eeprom IC and repaired soldering connections. I have been noticing for several days now that on a cold start up using a OTA Converter Box and TV Set on Channel 3 I am getting waving lines horizontally and sometimes a solid line across the screen horizontally. It even sometimes has a real loud shrill or buzz sound through the speakers on startup. It even sometimes is as bad as an issue to give you a picture like if you have the TV on the wrong channel number for the converter box. I think the problem is worse with TV Set on Channel 3 than Channel 4. If you use the RCA Hookups instead of the RF Coax Cable the TV has no of the above mentioned issues. To me it sounds like a soldering issue in the tuner again. I'm interested to see what anyone else has to say about the issues.

I remember working on those..rca used the tuner shield as common ground point.
I would take a small solid 24wg wire and connect all ground points.
I ran the wire thru the top side and back down. Also soldering the ground wire to the shield frame.
Very time consuming. Rca was trying different types of shield material on being copper. All were plated zinc . I don't know if there was one better than the other.
I left the tv repair trade in 1999.
But your issue sounds like connections.
If u move the connection we're the antenna wire goes in it should make it act up
Hopefully someone here knows more about the improvement rca was trying to make with the shield

Dittos on Dougs comment. I also ran a ground from tuner - Eprom -
front heat sink. If its cold PC cons lightly tapping the TNR will make it
come & go. RCA tried many fixes including special solder & removing
old solder first. Since the tuner has very close SMD's its dangerous
to do removal. Also if you havnt done it wright down the Eprom
parameters incase they get corrupted for any reason.

73 Zeno:smoke:
LFOD !

Did the special solder help any?
I still have the chipper checker . Was that to set up the eprom or other adjustments?
Its been too long for me to remember.I read his other posts he has had on this set and the epom was replaced before.

It's definitely a ground issue inside the tuner. There are connections around the perimeter of the tuner wrap (shield, but RCA called it a "wrap") that are problematic, but there are several connections (four I think) in the middle of the tuner that also need to be soldered.

But here's the issue - if you elect to use the RCA composite inputs instead of the tuner, the ground issue will still at some point take out the eeprom or at least corrupt many of the internal settings.

If you want to avoid using the tuner, you should still run a ground wire from the cold side of the power supply to the computer and T-Chip area directly and bypass the tuner's structure. Also solder the heatsink tabs on both the STK power regulator and the horizontal output transistor.

John

I took the back of the TV off and tapped the tuner shield several times and I could not get the picture to act up. However, after tapping on the shield and removing the tuner shield cover. I so far have not had any issues of the picture acting up after shortly turning on the TV. I found the Tuner Shield Cover not securely locked down.