RCA/GE CTC175-CTC203 TVs

[radiotvnut]

Yes, I know I'm getting old and it's hard to believe that it's been roughly 31 years since we were exposed to a radically different TV chassis design from Thomson Consumer Electronics, who owned the rights to the RCA/GE consumer electronics brands.

What made these sets different from everything else is they used what Thomson called a "tuner on board", which was simply a tuner circuit that was an integral part of the main circuit board. If something failed with the tuner, one couldn't just simply pull the tuner and replace it. Instead, they had to fix the tuner and with all the tiny surface-mount parts, that wasn't always easy. The main problem these gave was faulty ground connections around the tuner shield. This caused intermittent problems that included a snowy picture and intermittent vertical size issues. If the issue wasn't soon corrected, the EEPROM would become corrupted, with the most common effects being a dead set or a set with the horizontal so far off frequency that it would shut down.

The other radical change was that all service adjustments, except for the focus and screen controls that were on the flyback, were made via an on-screen service menu.

Even though those tuner problems made TV repairmen a bunch of money, it was a very stupid design and they should have used a stand-alone tuner, like everybody else did. To my knowledge, nobody but Thomson used that integrated tuner crap. You would have thought that Thomson would have gotten a clue after the CTC175/76/77 chassis, but they continued to use that type of tuner until later production CTC203 sets. Earlier CTC203 sets had the integrated tuner, while the later CTC203 sets had a standard tuner that could be replaced.

Other than the tuner issues, these sets were generally reliable (especially the CTC175/76/77/87). I recall replacing several STK regulators in the 177 and 187 and a small 10meg (I think) resistor off of the regulator that would result in a dead set. Flyback transformers were generally reliable, except for the 185 chassis. I've had to replace a few of those big blue capacitors in the HOT and pincushion circuits. The biggest issue on the 203 was cold solder connections on a coil in the horizontal driver circuit. If this wasn't fixed quickly, it would short the HOT and this would sometimes blow up the switching power supply. The jugs in those sets had a bonded yoke and usually held up, but I don't think I've ever had any luck rejuvenating a weak one.

I recall these RCAs having lousy audio quality and if you had a set with audio output jacks, you were better off connecting the set to an external amplifier and speakers.

[Blast]

Indeed!

Don't forgot the need for 'Chipper Check', the interface required to service many of those sets, not to mention having to use that system just to get the serial number of the set to make a warranty claim.

Throughout the nineties I worked in a major shop in Kansas City that was RCA/GE authorized and the guys there did a LOT of tuner shield/eeprom repairs.

I was the VCR/camcorder guy so I stayed away from much of that but I probably did a couple dozen of those tuner shield and associated eeprom repairs. Did you ever do the trick with the eeprom by unsoldering one pin? I don't remember how it was done.. But, if the eeprom wasn't too far gone you could still get the data off of it and not have to go through an entire time consuming alignment process.

I left consumer electronics repair in 2001 so the CTC203 was barely an introduction by the time I left. Doubt if I ever had my hands on one.

How Thomson didn't have close to 100% failure of that CTC17x through 18x chassis series would be beyond me.

[zeno]

Heres the trick. Works most of the time.
1) remove e-prom & install socket
2) put OLD IC back in & turn on set.
3) while still running swap IC's
4) turn off then on. Should work now.
The old data is mostly good & at turn off it all reloads to memory.

At the CTC175.... seminar they showed the chipper checker. IIRC it
was abt $400 & you needed a laptop too ! He made it sound like you
HAD to get one. I thought they were gonna drag the trainer out
back and lynch him. Subject never came up again. Wise......

73 Zeno
LFOD !

[Blast]

Originally Posted by zeno

Here's the trick. Works most of the time.
1) remove e-prom & install socket
2) put OLD IC back in & turn on set.
3) while still running swap IC's
4) turn off then on. Should work now.
The old data is mostly good & at turn off it all reloads to memory.

At the CTC175.... seminar they showed the chipper checker. IIRC it
was abt $400 & you needed a laptop too! He made it sound like you
HAD to get one. I thought they were gonna drag the trainer out
back and lynch him. Subject never came up again. Wise......

73 Zeno
LFOD !

That's it! That was the procedure. Memories return...

Got a chuckle out of "I thought they were gonna drag the trainer out back and lynch him".

As memory serves (which is infrequently) the "requirement" to have Chipper Check MAY have finally surfaced at the introduction of the CTC203 (or other at that time) where getting that 10th digit of the serial number was what kept the authorized servicer from getting paid (or not) for work on a given set. No, Chipper Check most likely didn't involve the CTC17x or CTC18x series.

Good times, good times. Nowadays I pull my hair out repairing print finishing equipment.

[radiotvnut]

I don't think it was mandatory to have the software until maybe the CTC195 chassis.

[Blast]

Originally Posted by radiotvnut

I don't think it was mandatory to have the software until maybe the CTC195 chassis.

I'll buy that.

[JohnCT]

I don't recall what I paid for the Chipper Check interface (still have it), but I seem to recall it was less than $200, but I could be wrong.

Another useful tool was the tuner alignment generator (also required). This is a very cool frequency agile generator that would generate a carrier on any channel in the VHF bands, UHF, and cable bands. It had RCA composite inputs to modulate. The alignment was done by using the generator and a DC voltmeter, although to be honest because it had built in attenuators, I'd align them by eye. A full tuner alignment took 10 minutes which was required if the eeprom was corrupted. Still have that as well.

John

[Blast]

Originally Posted by JohnCT

--snip--Another useful tool was the tuner alignment generator (also required). This is a very cool frequency agile generator that would generate a carrier on any channel in the VHF bands, UHF, and cable bands. It had RCA composite inputs to modulate. The alignment was done by using the generator and a DC voltmeter, although to be honest because it had built in attenuators, I'd align them by eye. A full tuner alignment took 10 minutes which was required if the eeprom was corrupted. Still have that as well.

John

Ah... more memories. Yes, I remember the generator. We had one of those, as well.

And, also remember how the generator would receive the IR signal from the remote control transmitter, as would the set under test, and both change channels together during the alignment.

10 minutes was a lifetime to me.

[JohnCT]

Originally Posted by Blast

10 minutes was a lifetime to me.

LOL, I might have snuck a couple in under the 10 minute mark!!

John