First Restoration - 50s RCA 14PD8055 - Videokarma.org TV - Video

#1 10-03-2003, 10:13 AM

Just got my first TV restoration running after a full recap and some resistor replacements.... a little knob twiddling and things looked great, with good brightness and contrast. I have a couple questions I thought someone here might be able to help with:

1) horizontal width is too wide even after using all the adjustment. To compensate for squatty images , height must be over set resulting in loss of the extreme edges of the field. I checked anode voltage and it was fine at 14.5kv. How should I approach correction? UPDATE: Current in horizontal output cathode is about 30% higher than SAMs spec and I do hear some fizzling that might be coming from horizontal output transformer... I noticed wax was pretty soft and warm after shutdown..normal???

2) there is some visible (but very tiny) continuous arcing going on inside the neck of the CRT within some glass rods. Is this normal and will it hurt anything over time?

3) I haven't done an alignment. If I am getting good reception, will I have much to gain? I have been accumulating lots of test gear (all vintage tube) and restoring to good working condition, but what is really going to be needed for TV alignment? I have Tek 545a, HP606a, Measurements 80, old Hickok sweep generator, vtvms, TV2a, etc. I am unclear about the "marking" signals referenced in the Sams to do the alignment.

I hope these questions aren't too stupid... I am a newbie to this and really to any formal electronics training beyond my USAF experience in the early 70s. Been devouring old tube reference materials and that has really helped. This is FUN (most of the time)! I am a nostalgia nut and love just about anything with tubes. I have a dual chassis Admiral TV from 1948 and that "cool Zenith" mentioned on the forum waiting on me next, along with some radios.

Thanks,

Dan

jstout66 · #2 10-03-2003, 01:54 PM

Hi Dan! Did you get the "cool Zenith" that the eBay seller was worried about plugging it in to "todays" electricity? LOL! If that's the one, it is a GREAT looking set. Good luck with your restorations. I'm sure you'll get some good postings with great hints and advice.

#3 10-03-2003, 03:39 PM

Yes that is the Zenith. I have been searching for a vintage generator so that I can supply the "correct" old analog power to it.... maybe someone has some NOS electrons in storage somewhere LOL!!

rcaman · #4 10-03-2003, 04:40 PM

i had plenty of old electrons for you. but i used them all up restoring my color roundies. if i run across any more i will send them to you asap. steve

Rob · #5 10-03-2003, 08:43 PM

Geojunkie,

Welcome aboard and congrats on your first restoration. That arcing in the CRT doesn't sound right. Does the CRT have an ion trap? You may have it set wrong and the beam is burning an oversized beam clearance hole in one of the disc grid elements. Just an idea. If this is so it will not take long to toast your CRT.

I have three different models of those two chassis admirals. Two different wooden case ones from 1947 and the bakelite from '48. Which do you have? 10BP4 CRT right? They are great vintage sets.

Marker signals on sweep generators are generated to place a pip or brightness spot along the sweep at the points in the response curve where the key frequencies are to represent the beginning of the skirts (tapering response at the edge of the passband). This lets you do the alignment with a detector diode probe on an uncalibrated oscilloscope screen.

#6 10-04-2003, 09:12 AM

On the RCA, there is no ion trap that I can see... only a deflection yoke as the focus is non-adjustable electrostatic. The "arcing" or more like a continuous tiny "fizzling" in the neck of the CRT seems to be around some tiny metal plates within some internal glass rods, not the beam electrodes themselves.

The Admiral is a wood cabinet model with a wooden X over grill cloth. Chassis is 30B16S and CRT is 10BP4 as you surmized. I purchased from the original owner... set sat in a basement since the late 50s unused. It worked when they put it away, but didn't when they checked again before selling it. Hope no serious damage was done in repowering. Looks like a fusable resistor is gone, perhaps that protected things. Appears to be completely unmolested, but I have a thick layer of dirt to remove. I love the dual chassis setup and it looks like it will be far easier to work on than the RCA... which forces you to become a contortionist with the soldering iron and solder.