RCA 36" Problem

Guest · Posted: Fri Jan 12, 2007 2:31 am Post subject:

Thanks. I'll try that first.

bitbucket · Joined: 13 Jan 2007 Posts: 2

Frank and Minnie,

I tested the Hot at location Q14401 with a multimeter while it was still soldered on the board. The readings I got while checking for resistance where zero between any of the three leads. I desoldered it and rechecked it for resistance. I get resistance readings between each of the three leads now that it is by itself.

I tried turning the set on with the Hot removed and I no longer get the flyback transformer (Location T14404) squealing and the power light goes on. I tried seeing if I could get sound but was not able to.

Based on this what would recomend I do next? Do the resistance readings mean that the Hot is good? Should I resolder it?

bitbucket · Joined: 13 Jan 2007 Posts: 2

Correction! The squeal was coming from T14101 not T14401. I finally reexamined the numbers.

T14401 has the red cable going to the Tube and it has a visible crack on one side of the part at the top. The crack extends through label that was on the part so it is definately damage from the part failing.

To recap. Q14401 showed zero resistance when tested on the board but some resistance when tested after it was desoldered. The set does not have sound but does power on with Q14401 removed. Without Q14401 the set no longer chirps or squeals. The set responds to the TV remote to turn it on and off.

T14401 shows visible damage.

Based on this what would you recomend I replace and what further testing should I do?

For Chassis CTC203CA5 I found the following part numbers:
HOT is part# 237470
IHVT (Flyback Transformer) is part# 244247

Are these correct?

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

You got it. I'm sure of the flyback. The hot sounds correct. Compare the # on the old one with the new one that's stamped on the transistor. Take a flat screw driver with clip leads and put one side on the metal of the screwdriver and the other end to the tuner and remove the anode lead from the crt. That will discharge any voltage from the picture tube. Once the new parts are in you'll have to adjust screen and focus on the flyback. Then you should be good to go!

Guest · Posted: Sun Jan 14, 2007 7:26 pm Post subject:

Thanks. I'll order the parts. Do you think I need a new HOT as well or just the flyback?

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

You said that it had low resistance removed, so yes.

Guest · Posted: Sun Jan 14, 2007 9:37 pm Post subject:

The cheapest place so far I have found is acme-sales.

They have a non OEM part that is supposed to be compatible with the flyback transformer.

ACME-2957 (244247)
Flyback transformer
Replaces 244247

$20.95

The HOT is listed as
2SC5148
Toshiba transistor
Sony # 8-729-035-75
and RCA 237470

and it runs 2.39.

Are there any concerns about ordering a non OEM part or about ordering from the place?

Also, what would the values on the HOT read with a multimeter if it was good?

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

tritronicsinc.com or http://www.matelectronics.com/
I hate asti or generics. Original parts are always the best.

Guest · Posted: Mon Jan 15, 2007 11:17 pm Post subject:

What would the values on the HOT read with a multimeter if it was good?

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

Don't squabel over a horizontal output. Collector/emitter 0 ohms collector/base high/low base/emitter the same high/low.