TV repair books

[kx250rider]

The RCA Pict-O-Guide series is very detailed, and simple. It discusses TV on a circuit-by-circuit basis, and has schematic drawings for understanding throughout. I don't know how many there are, but I have a late 1940s edition, and also two mid 50s to late 50s editions with color.

A much more in-depth, but still geared toward the basic electronics tech who wants to go into TV in the 1950s, is the Video Handbook by Morton Scheraga & Joseph Roche. It is basically "the original" TV repair school textbook.

And for the benefit of anyone reading this thread who is not a general electronics tech already, I strongly recommend any book by Art Margolis. He wrote about a dozen TV repair books for the household do-it-yourselfer and the novice radio hobbyist in the 1950s & 60s. He had a few (slightly) more advanced editions with a little more technical theory and explanation, but his best for the beginner in repairing old TV sets is probably "Professional TV Repair Secrets". It's about 1960.

Originally Posted by DaveWM

The one thing I have not tried is to clean the grounding points of the PCB to the chassis (a 63 magnaox)

I had that problem in a Magnavox; a vertical snaking with dark hum bars moving up through the picture, but not exactly like a filter cap. It would pause and be OK in between "cycles". That was a 21" round color set. I had a terrible time finding it, and I couldn't see it on the scope either. It was, if I recall, the ground points! That set is actually still in use, and I did that job for the owner about 10 years ago. I really don't remember the details, but it seems to me it was on the video & chroma board, near the demod tubes. I may be way off on that memory, though. I'd just pull it and resolder all of them, as they're notorious for those cracking. You can probably get away with murder and just superheat and solder from the top of any of the ones you can't reach from below.

Charles

[DaveWM]

this one is odd, its a very slow moving snake on vertical line only, no hum bars at all. takes about 15 seconds to cycle thru (beat freq of 60hz and the video sync).

I even have a nearly identical chassis that I have scoped the B+ and see the same low freq beat on top of the B+ ripple (you can see the slow wave work its way thru the B+ on both sets).

I am not sure why it effects one set but not the other. The set with the problem even has a 30mf 220ohn decoulpling off the yoke that the other set does not (this is the only diff beside the audio section between the two sets, the audio of the good set does not use the audio output, it is a console with a sep audio amp). The schematic does not show this decoupling, if just has the yoke connected directly to the B+.

I am tempted to bypass the yoke decouple and make it the same as the non snake set.

No joy finding that book close by or for sale, library of congress was the closest. I will keep trying.

[Phil Nelson]

Here are a few books that I've found useful:

Basic Television Principles & Servicing, Bernard Grob

Elements of Television Servicing, Marcus & Gendler

Mandl's Television Servicing, Mandl

Popular authors like Marcus or Grob had books that went through multiple editions. Mine are from the mid-1950s. If you find an edition published a few years after the TV you're working on, it will mention common problems of the time or with particular models, etc. There are a couple more kicking around here somewhere . . . a Coyne book and at least one other.

It's nice to have a handful of books, since each will have somewhat different approach & coverage. For instance, the Mandl book is not my favorite overall, but it has the most detailed explanation of Barkhausen oscillations.

I have the 1957 Pict-O-Guide for color TV and it's a great piece of writing. Doesn't cover everything, but no book does. My other color TV books are mostly solid state and I can't recommend one in particular.

These books typically sell cheap thru used booksellers, Amazon, eBay, etc. Not much demand for tube TV repair books these days

Phil Nelson

[Einar72]

I vote for resoldering the board grounds too. I have fixed plenty of those when working on Maggot-boxes (term of endearment here) in a TV repair shop. Seems to me every ground-return shares those little eyelets on the perimeter of whatever PCB you are having trouble with. Those fingers that reach up through the eyelets from the chassis-stamping can get corroded also, so take the extra time to clean them when you suck-out all the old solder. Use silver-bearing solder if you can find it, always worked well for me.

[cbenham]

Originally Posted by kx250rider

The RCA Pict-O-Guide series is very detailed, and simple. It discusses TV on a circuit-by-circuit basis, and has schematic drawings for understanding throughout. I don't know how many there are, but I have a late 1940s edition, and also two mid 50s to late 50s editions with color.
Charles

I have a set that 'breathes'--an RCA 9T-256. I also have a 9T-246 that DOES NOT breathe. ??? I can't see any ripple on the B+ lines anywhere in the sweeps or the power supply. The only difference between these two sets is that the 256 has a relay with a wired remote switch to 'expand' the size of the image.
It works fine but the picture breathes in both modes. Could this be caused by the power transformer radiating magnetically into the yoke? I tried placing a steel panel between the yoke and the xfmr but this didn't do anything to reduce the breathing. Any help is greatly appriciated. Thanks, Cliff

[marty59]

I have a Howard Sams publication #20361 "TV Servicing Guide".."Arranged by Trouble Symptoms" by Leslie D. Deane and Calvin C. Young, Jr.
It's nineteenth printing was in 1973 that appears to have been around since 1956. Does not cover anything with color but goes over a lot of the older designed B&W circuitry in a straighforward manner, with lots of pictures and covering all the stages.

[DaveWM]

Originally Posted by cbenham

I have a set that 'breathes'--an RCA 9T-256. I also have a 9T-246 that DOES NOT breathe. ??? I can't see any ripple on the B+ lines anywhere in the sweeps or the power supply. The only difference between these two sets is that the 256 has a relay with a wired remote switch to 'expand' the size of the image.
It works fine but the picture breathes in both modes. Could this be caused by the power transformer radiating magnetically into the yoke? I tried placing a steel panel between the yoke and the xfmr but this didn't do anything to reduce the breathing. Any help is greatly appriciated. Thanks, Cliff

if the freq is slow, then like mine it may be a beat freq of the AC line and the vert sweep. If that is the case you could do like I did and see if running the vert tubes on DC filaments makes it go away, or better yet, just make sure you have a good ground return on the filaments (which was the cause for my breathing issues).

[cbenham]

Originally Posted by DaveWM

...just make sure you have a good ground return on the filaments (which was the cause for my breathing issues).

Yep it's the vertical beating against the 60 cycle line. Thanks very much. I had not thought of it being a heater circuit problem, but I'll sure take a close look at that wiring.

Cliff