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-   -   Dead Haviland (http://www.videokarma.org/showthread.php?t=267200)

stromberg6 06-12-2016 04:08 PM

Dead Haviland
 
2 Attachment(s)
:tears:
I fired up my Haviland this afternoon, and after about 90 minutes, the screen "flickered" and went black. Upon checking, found all heaters dark, so probably not a HV failure, but could be a power xfmr. Checked continuity across the cheater cord, and found none. Hoping for a bad solder joint, or a failed switch on the volume pot. Need to clean up some other repairs before I get to the CTC-4, and I can use my 100+ pound Kron-Hite supply to power it up if the xfmr is toast, at least to be sure nothing else fried when it shut down.
Always something interesting when "playing" with vintage electronics.
A couple of pics from happier days attached. The avitar is also from the Haviland.
Kevin

oldtvman 06-12-2016 06:36 PM

there may be a fuse in the filament circuit.

oldtvman 06-12-2016 06:40 PM

Nice to see a picture where the contrast isn't driven up all the way. Those sets were never designed to look like the HD's of today. Back off the contrast and the colors blossom.

dieseljeep 06-12-2016 09:28 PM

Quote:

Originally Posted by oldtvman (Post 3164504)
there may be a fuse in the filament circuit.

The O/P stated, there was no continuity across the power input. I don't think the power transformer primary would open, without making a burning smell. I don't remember a line fuse but it might have one of those surge limiting thermistors.
What is the chassis number of the set? :scratch2:

Electronic M 06-12-2016 09:50 PM

It is a CTC-4 judging by cabinet name.

One hack way of dealing with open primaries of power transformers that I like is to take a similar sized xfmr and jumper it's heater winding (assuming both use the same heater voltage) to the heater winding of the one in the set.....If only the line winding is bad then the set will come to life with the "helper" transformer connected.

Zenith26kc20 06-13-2016 08:43 AM

I vote for the switch on the volume control. Way too small in capacity. Changed countless numbers on color and B/W sets in the past.
I use a variac today to prevent killing the switches today. Just leave them on and ramp up the voltage.

dieseljeep 06-13-2016 10:38 AM

Quote:

Originally Posted by dieseljeep (Post 3164509)
The O/P stated, there was no continuity across the power input. I don't think the power transformer primary would open, without making a burning smell. I don't remember a line fuse but it might have one of those surge limiting thermistors.
What is the chassis number of the set? :scratch2:

I, personally don't go by model names! RCA seemed to use the same name, years later, on a different set. Chassis numbers are all that count to me. I looked up the CTC4 schematic and there's nothing in the primary circuit, but the switch, transformer primary and the AC input, plus a couple of line filter caps across the input connector. :scratch2:

stromberg6 06-13-2016 12:54 PM

Thanks for the replies. It's a 4A, late run with all the mods done at the factory.
Hoping to get to it as soon as I finish restoring my daughter's HH Scott 130 preamp. Not much between the line cord and the xfmr, just the switch and associated wiring. Needed to do a sound trap and ratio detector alignment anyway.
Kevin

miniman82 06-13-2016 05:59 PM

Audio is funky in mine too, like it has an intermittent connection somewhere.

rca2000 06-13-2016 10:01 PM

Is there a thermistor in the primary ckt--like on some sets? They like to crumble and fall apart..

zeno 06-14-2016 08:06 AM

IIRC those may have used fuse links. Its nothing
more than a thin wire like #22 a certain length. Usually
right at the interlock & sometimes covered with spaghetti.
It was commonly done.

73 zeno:smoke:

jr_tech 06-14-2016 12:58 PM

Odd as it may seem, the two fuse links on a Ctc4 are in the heater circuit.
All that is in the primary is the power cord, interlock, 2- 56k resistors to ground from the 2 sides of the line, power switch and power transformer. Thats it.

That's according to the schematic, of course sombody may have added a fuse or thermistor later.
jr

Penthode 06-15-2016 08:16 PM

I know it appears obvious, but have you checked the power switch? The switch is a bit small for the power requirement of a color set and I have replaced a few in my time.



Quote:

Originally Posted by Zenith26kc20 (Post 3164524)
I vote for the switch on the volume control. Way too small in capacity. Changed countless numbers on color and B/W sets in the past.



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