View Full Version : My new RCA CTC-25!


TUD1
02-19-2017, 01:19 AM
I have literally been awake for 22 1/2 hours as of right now, but it was worth it. I got to go to the SARS swap meet, get some goodies, which I will show later on, and after that, went to collect my RCA GH-759F. Beautiful cabinet, one of my favorites. As usual, we had to take it totally apart to get it home, and I just got it set back up a few hours ago. More to come. I'm exhausted.

MadMan
02-19-2017, 02:20 AM
Noice.

Kevin Kuehn
02-19-2017, 02:34 AM
Boy, either that set was kept in an immaculately clean environment or someone did an excellent job of dusting it's insides.

TUD1
02-19-2017, 09:26 AM
Yep, it's nice and clean, just the way I like it. I'm sure my friend Danny cleaned it up when he got it. It had a rebuilt picture tube, but we took that out, and I put in a 1969 RCA Hi-Lite tube.

Captainclock
02-19-2017, 02:59 PM
Yep, it's nice and clean, just the way I like it. I'm sure my friend Danny cleaned it up when he got it. It had a rebuilt picture tube, but we took that out, and I put in a 1969 RCA Hi-Lite tube.

Boy, that's an ugly looking cat in that TV! :D Were you trying the old cartoon trick of trying to replace the TV show with your cat by swapping out the picture tube for your cat? :scratch2:

Also the first picture on your thread seems like sacrilige having a Zenith Radio ontop of an RCA TV. :nono:

FYI, I'm just kidding around by the way I hope you got that. :)

TUD1
02-19-2017, 03:15 PM
Ain't my cat. Mother paid $1300 for it. That's more than my car cost. Just got an email from the friend who gave me this, and he said that the Beauchamp has not been out of his basement since the mid 1980's. He told me that he bought the set from an ad in the paper in 1976, and that it was being sold because it had a bad CRT. He put in a different CRT and sold it to a high school friend who was getting married. When buyer got divorced several years later, the ex kept the set for several more years until it was replaced by a solid state set, and my set went back to Danny (my friend) and has been in the basement ever since.

Captainclock
02-19-2017, 03:22 PM
Ain't my cat. Mother paid $1300 for it. That's more than my car cost.

Wow! Anyways I hope you were able to get my joke either way. ;)

old_coot88
02-19-2017, 04:32 PM
There's a fault condition endemic to those sets that you're probably aware of already. If not, it's the two ground stakes on the far right end of the chroma board which go open and kill the heaters on the 6GU7s. They need to be re-flowed, and this should be routine on every CTC-12, '15, '16, '17 or '25 you ever run into.

What happens is - (since the 6GU7 plates are DC-coupled to the CRT grids), the plates go too positive, driving the CRT grids positive, which runs the beam current full-on, overloading the snot outa the 3A3, flyback etc. Symptoms are - raster blooms, loses focus, then fades out completely.

TUD1
02-19-2017, 06:50 PM
I cleaned the Beauchamp today. Gojo'd the entire cabinet (and it has a lot of cabinet), and used Novus on the mask, and it turned out absolutely beautiful. The picture doesn't do it justice. And I'm using my good camera.

TUD1
02-20-2017, 12:45 AM
Unfortunately, the audio in the Beauchamp just died. I turned it off to leave the room (Incase something broke while I was away) and when I got back, I turned it on, and I heard a loud 60 Hz thump, and that was it. Dead silent after that. Probably the audio out transistor.

old_coot88
02-20-2017, 01:10 AM
Probably the audio out transistor.
Yup. Very common failure on those. Also there's an electrolytic which fails, causing low volume. IIRC, it's in parallel with a low-value resistor going to the emitter.

BTW, congrads on snagging a very nice set.

BigDavesTV
02-20-2017, 12:48 PM
Very nice! I had a nearly identical CTC-25, back in the early '70's!

Kamakiri
02-20-2017, 02:36 PM
I had the identical set in 2012. In all fairness, it had not led a charmed life. The thing had no end of problems and would blow 6GH8s left and right. Ended up parting it out....hated to do it, but the set hated me.....

old_coot88
02-20-2017, 06:17 PM
We were a sales/service dealer and sold a boatload of '25s. Biggest beef with 'em was the chincy channel selector/indicator/fine tuning setup. They didn't eat 6GH8s nearly at the rate of the 'short chassis' CTC-19, 20 and their follow-ons.

TUD1
02-20-2017, 07:14 PM
Replaced the audio output transistor and now the audio is back.

dieseljeep
02-21-2017, 11:34 AM
We were a sales/service dealer and sold a boatload of '25s. Biggest beef with 'em was the chincy channel selector/indicator/fine tuning setup. They didn't eat 6GH8s nearly at the rate of the 'short chassis' CTC-19, 20 and their follow-ons.
I had cited the problem a while back, about the channel selector setup. RCA only used it one year. That and the loose P/C grounds and of course the 115876 fly. The CRT's weren't that long-lived either. :sigh:

old_coot88
02-21-2017, 12:30 PM
Yeah, they did eat flys and jugs too. Getting them thru warranty was always a challenge, but that was par for the course for with all color brands. Five years was considered reasonable lifespan for a color set.

With RCAs we routinely changed the power xfmr primary to the 'high line voltage' tap, to drop the 6JE6 cathode current a few notches, and dipped the efficiency coil. Surprizing how many were not on 'true dip'.

dieseljeep
02-24-2017, 11:00 AM
Replaced the audio output transistor and now the audio is back.

It seems that the 25A was the only RCA chassis, that used the solid state audio board. Most of the 25's I worked on had the tube audio.
I think RCA quit using it because it was more trouble prone.
I have a year newer CTC28, that uses a tube audio.

BigDavesTV
02-24-2017, 01:13 PM
The CTC-25 that I had, years ago, was identical to the one Tim "Kamakiri" has pictured! It had the fancy speaker on the left side of the CRT only, different model from Universal Dave's set, which has the fancy speaker on both sides of the CRT!

TUD1
02-28-2017, 12:06 AM
I got bored today, so I did a little dynamic convergence on the Beauchamp. I'd say turned out pretty darn good.

TUD1
02-28-2017, 12:18 AM
The CTC-25 that I had, years ago, was identical to the one Tim "Kamakiri" has pictured! It had the fancy speaker on the left side of the CRT only, different model from Universal Dave's set, which has the fancy speaker on both sides of the CRT!

The Dumas.