TV repair books

[DaveWM]

I have a fair understanding of electronic circuits, I am looking for some books that help with diagnosis of tube type (vs solid state) TV problems.

What I am hoping to find is sort of like this:

Dark bars on screen check filter caps along with pictures.

One of the problems I have been chasing is vertical snaking. Been a real pita trying to figure it out. It seems like a decoupling issue with the vertical osc/amp mixing with the AC ripple in the power supply. But I checked all the decoupling filter caps. Checked HK shorts. Checked just about every darn part on the sweep board.

I did have some sucess by running the sweep board on pure DC for the filaments, but that is not a perm fix. I tried new tubes, cleaning the board etc...

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

anyway I figured I need to expand my troubleshooting skills and was hoping there were some books out there that may help.






I find the service manuals helpful but I dont have ready access to them.

I found on book TV repair for beginners but it focused on solid state and color.

any suggestions please?

[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.

[Dan Starnes]

A tech school book I own has been very helpful to me. Profitable Televison Troubleshooting by Eugene Anthony is a great study book and has tons of info. I have the 1957 copyright and it is a McGraw Hill book.

[DaveWM]

great info guys, I am noting and looking

keep them coming if any others can think of good books.

I bought "basic electronics" published by the navy from amazon, great basics on vacuum tubes and transistors, mostly as it related to radio transmission.

What would be great is a online library, not sure how copyright stuff works so that may be a problem.

[mattdavala]

You call it snaking, I call it breathing!

I've got a 58 Setchell carlson that the entire left side seems to "snake". When I bought the set it had a serviceman modified vertical section and still snaked. I reverted it back to origional and just ignore it. The filters are all as they should be accorording to the schematic. It bugs people after I mention it to them. Why'd you tell me! I never noticed it before till you mentioned it! Doh!

-
Matt Davala

[DaveWM]

got some books off ebay, I will keep checking to add to my library..

[kx250rider]

I just had a thought on the Magnavox... Have you thought of the degaussing coil thermistor being bad? Try unplugging the degaussing coil. I've seen those change value, so that they keep recycling. Usually it will burn out the coil, but I suppose not always. That will definitely cause a snaking or breathing of the picture, and load down the B+

Charles

[DaveWM]

not color, I did not think B&W had them?

there is a thermistor in the yoke, now sure why its there.

Its a very regular pattern, I can see it in the B+ and it matches the screen wave in frequency.

if you look at the ripple of the B+ you can see a rolling wave that is on top of the regular ripple, it takes about 15's to go one full cycle.

You can really see it when the horz id adj so you can see the black of the picture just beyond the scanning on side. Its a low amplitude low freq wave that works thru the whole picture. At 1st I was willing to just say it is a weakness in the circuit design but the other chassis with the same design does not do it.

The only other thing is the fly back is really really bad looking on the set that works. I figured it is making HV so I assume it is ok. I have a spare yoke that I may try just as a process of elimination

I need to get the sets side by side and scope them with a dual trace scope and see if anything shows up.

[bandersen]

If you'd like to go really old school, try to track down this set from Philco published in 1947


It outlines basic TV troubleshooting with some focus on the Philco 48-1000.


I love this illustration of how an ion trap works

[jeyurkon]

Those guys doing the sorting out of the ions must be related to Maxell's Demons.

[DaveWM]

I may have the horz prob licked,


It seems to have stopped but I need to get a fresh look at it later.

The pcb has little solder fingers on it that touch the bare metal chassis, on the sweep board

The horz osc has a solid wire ground, while the vert osc and vert amp use pc traces that go to the ground thru these little fingers.

I was able to clean up the wave by running those two tubes heaters on DC, the horz osc did not need the DC hmmmm.

anyway all the sweep board tubes now have a solid wire ground returns, AND cleaned and tighted up the pcb mounts to make sure the little solder fingers are firmly attached to the chassis.

I got a couple books so far, one is a waste of time, the other mentioned horz "weave" and went on about filament grounds

Not sure if the "weave" is the same symptom as I have be trying to describe, but it was nice to see a meantion of the same solution.

[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