Truck load of "stuff"

[Charlie]

Yesterday, I had to make a drive to Houston for a work physical. After my physical was done, I made a couple of stops to investigate two sets on the H-Town Craigslist. I ended up bringing home two late-60's sets.

The first set was a CTC-38 with doors. The cabinet was in very nice condition. The owner said it was in the house when they moved in years ago. That neighborhood in Katy was built in the late-90's, so that set apparently made some moves. He turned on the set to show me it played... but just with a extremely dim picture.

The next stop was in Jersey Village (NW side of houston). The set was a Zenith SC-600 with chassis 23XC36 (1968 if I am not mistaken). The owner said it was the first color set his parents bought. He said it still played, but the picture needed some work. He turned it on and it produced some nice bright snow on the screen. Looked in the back... was a heavy smoker set and lots of dust/grime.

After leaving Houston, I drove to my parents' house on Lake Livingston (north of Houston). My mom was going to allow to leave the RCA in her living room for now. Since the set had doors, she figured it wouldn't look out of place... no one would know it was an old TV. When I got there, I took the back off to have a peak inside. There was a dreaded tube brightener on the CRT... explains the dim picture. Plenty of dust in there, but not as bad as the Zenith.

My dad pointed to some stuff in the garage. "Take that stuff home... your mother got that from the people across the street." So, in addition to the TV's, I ended up loading two 1970-ish recievers (Pioneer and Fisher), a cheesy Rat Shack cassette, and a 1960-ish Silvertone stereo record player. When you raise the lid on the Silvertone, it lifts the turntable up inside the cabinet... kinda neat.

After getting home last night, I was out in the garage connecting the DVD player to the Zenith. It's making a nice b&w picture (little bit shrunk up from bottom). I tried adjusting the fine tuner to see if I could get the color to come in, but it seems the fine tuner has no effect on the picture at all... the picture never changed... for better or for worse. But hey, it gives me something to work with. As I clean it out, check tubes, and update capacitors, it can only get better. The SC chassis doesn't seem to be working. There's a cover over the chassis.... will remove it later and see if all the tubes are lighting up. I put the tester on the CRT... tests very strong.

After reading an old thread that Doug started years ago, it sounds like CTC-38's don't generally make a great picture compared to other RCA's of the time.

[joemama99]

What a haul!I am jealous.

[snelson903]

man ! you done good

[radiotvnut]

Those are some excellent finds!

[jr_tech]

Very Nice! Is that a SX990 Pioneer?

jr

[Sandy G]

"Ahh HATE Yew..."-Yosemite Sam, Esq...(grin) EXCELLENT haul, Charlie !

[Charlie]

The Pioneer is an SX1500SD. I like the early "blue dial" receivers.

Update... been cleaning out the Zenith. Wow there was a lot of dust in there! Surprised the thing functioned at all! I got the Space Command to work... just had to jiggle the plug in the back of it a bit.

The Channel Down (and tint down) do not function. The volume works fine,,, it goes thru the 3 steps, and then off. However, once off, it's off! Pressing the button again wont make it come back on. I have to reach back there and tap the relay to make the thingy turn so the power will come back on. I did try spraying some contact cleaner on the thingy that turns, but didn't help.

So for now, most of the Space Command functions work.

[holmesuser01]

I had an RCA CTC-38A for years in my showroom for sale. It was a big cabinet, and people oohed and aah'd over the beautiful color picture it displayed, but never bought it. Eventually I took it home and put it in the den for about 15 years, then gave it to a friend who ran it until the CRT died, then I got the chassis and tubes back!

[marty59]

All the '38's I had remembered coming across back in the day actually were okay sets but always seemed weak in displaying color. You could not overdrive the color intensity for anything! Maybe I never discovered the right combination of 6GH8's! Those sets would eat 'em up!

[jstout66]

I LOVE the cabinet on the RCA. You can bet that was pricey in the day.
However... as a kid working with my Uncle in his repair shop, we had a ton of CTC-38's on the service route. ( they always ate 6GH8's and flybacks) at the time the sets would have been 10-13 years old. I NEVER saw one with a stunning picture. They had "okay" pictures, but never outstanding. I even remember 1 set that he replaced the picture tube with a rebuilt Chromacolor tube. You'd think THAT would have made a huge differance, right? Nope.... still had that RCA "acceptable" picture.......

[Charlie]

At my parents' house now for Thanksgiving. I figured I would get to play with the CTC-38 while I was here.

Can't really do what I want... I was wanting to vacuum it out. Now that I get a better look in there, I'm finding there's a lot more dirt than i initially thought. I brought the Electrolux with me, but everyone is in here watching Houston & Detroit, so, running the Suck-U-Lux would not be good at the moment. There is so much dust on the chassis that I know it's got to be straining the circuits. I'm surprised I haven't heard any HV discharge. I ran the set for about 10 minutes.

I brought the CRT tester. The red is quite strong, blue just barely into the "good" zone, and green is way into the bad. That test was with it set to 6.3 volts. Bump it up and it gets better, but nothing is even. It is apparent in the picture.... the picture is quite red right now (however I haven't adjusted anything).

I found that the centering rings are just dangling there. It appears that the extra heat from increased tube heater voltage has stressed the plastic device that holds the centering rings in place. So they are just dangling there on the neck.

If the family goes outside for a bit, I will likely get in there real fast and spend some time with the Electrolux.

Years ago, my CM roundie wouldn't produce a picture. The dust was at least a 1/2 inch thick covering everything. I had never seen so much dust on any chassis. After spending 15 minutes in there with the Electrolux and a small brush, the set a pretty decent picture.

[andy]

...

[radiotvnut]

I agree on rejuvenation, as long as you do it with a good tester. With a good tester, those old delta gun CRT's usually respond well and will often last a long time. It should at least last until you can find a strong tube.

[Sandy G]

Charlie, spend time w/yr family. Play w/the TVS & junk later...Just sayin'....

[jhalphen]

Hi Charlie,

About the Pioneer SX-1500 stereo receiver:
All of these 1972 era Pioneer receivers develop a generic fault:
the adjustable resistor to set the output transistors's idle current bias go to dust i.e. the carbon track self destroys over time.

The power amp affected then shows 2 different symptoms:
- excessive output transistor temp can go to 70°-80°C
- totally cold

In spite of the high temp, the output TO-3's aren't destroyed.

I've had the exact same failure on 3 Pioneer stereo receivers.
I therefore replace with CerMet Mil-spec resistors, problem solved (forever).

The culprit is located on the PWR amp board, one per channel.

On the SX-990 there is a second adjustable resistor, drive adjust (from memory). I replace it also with a CerMet.

Just to let you know in the event you want to use the receiver as a daily driver.

To all: If someone needs the Pioneer SX-990 schematics, i scanned them from the original service manual. Give me your Mail by PM.

See the power amp with this post.

Best Regards

jhalphen
Paris/France