Television Repair

Tube monitors work with a beam that is projected towards the inside of the glass face you look at. This beam needs to move as it has to "paint" the whole of the picture (to put it a bit simply). If the image suddenly covers only in one direction but is narrow in the other direction, it normally means that the electro magnets next to the beam are broken. This could be the coils itself or the variable power supply to the magnets. Without these magnets the beam is not "deflected" properly and thus does not cover the whole of the screen.

A bit of it is like in this wiki page for you to read.

With regards to the second failure it is most likely down to the control circuit board as the signal to the beam deflecting magnets must be stabilised. All this could be a potentiometer on the board and need not be broken.

For both what you do is find a tv repair free lancer and just ask him the questions to see if it is financially viable.

Good luck.

If you have the gumption and the test equipment needed you can try and repair them yourself. There are plenty of old college texts on TV repair - this used to be a integral part of the electronics curriculum back in the day. Outside of the tuners that are a pain to service or get parts for the old style TVs are relatively straight forward to service.

The previous posts explanation though correct is inaccurate - best to get a book from the library and do some scrounging for the TVs electrical schematics - if you can dig up a copy of a service manual then all the better - Don't trust the Wiki.

1 - This is a problem in the vertical deflection circuit. If you are lucky its only a leaky capacitor or bad resistor and if unlucky may be the flyback transformer itself.

2 - This one is not as bad it seems. Again its a failing component but this time in the horizontal hold section of the circuit that is drifting into failure. it will be one of the dozen components in that section of the circuit. Again a schematic and / or service manual is a great asset.

Now the test equipment you will need will basically be a multimeter and an oscilloscope. Component testers are nice to have but not a needed requirement. You just have to have some idea at what you are looking at.

If you are not a hands-on electronics person - and that 15-35KVolts on the tube/flyback does make some people nervous - then finding an old time TV repair person may be the answer, but good luck finding one these days, most are retired or doing tube sets as a sideline these days.

Guest,

The problems you describe are both pretty common:

The old Philco sounds like it has a defective vertical deflection amplifier and/or "leaky" capacitors in the vertical output stage. This should be able to be repaired fairly easily. Maybe only a couple of dollars on a new mylar or ceramic cap or two...

The RCA set sounds like its vertical deflection IC has a bad stage in it, probably the vert. oscillator. Depending upon the degree of "modularity" to which the set was constructed, the replacement part(s) (i.e., the entire vertical sync. circuit board) might not be so readily available; therefore requiring identifying, pulling & replacing individual faulty circuit board components.

WARNING: If you are not familiar with working on TVs, BE CAREFUL...

The average TV flyback transformer can zap you with over 30,000 volts when the TV is plugged in, and even when off (& unplugged), the caps can store up a pretty good whallop.

=======================================================================

Just my $0.02

Quite true about the whallop from the capacitors. You need to look up a proper grounding procedure for the TV and do that before you start working with the guts.

#1..frame scan problem...probably output transistors...?

#2...sync prob' could be anything form a capacitor to a dry joint...come to think of it add 'dry joint' as possible to #1...

Both are eminently repairable...the question is...are they economically repairable?

Try you local TV repair guy..but get a quote first. Much as I disslike our thow away culture a new set may be cheaper in the long run.

( Don't try and do it yourself unless, as you obviously don't have the necessary understanding)

Del

( Don't try and do it yourself unless, as you obviously don't have the necessary understanding)

That's right, and the reason why I did not go into much detail.

A little knowledge is dangerous, look at any government.

To All:

Thanks to everyone for all the good diagnostics. I am sort of attached to these TVs and see them as a little part of history which is soon being swept away, although I was still using the RCA up and till 2 weeks ago. I am going to check out a book on TV repair and try to follow the advice given and fix both of the sets. They should last me for a while.

Look for my postings as I require advice during this process. I am really pleased that all of you offered your knowledge to help me out.

(I have a healthy respect for electricity and I am going to be careful when I work on it.)

Thanks!

Rmilo, a good source for information on these old TV and other HiFi systems are the forums on the internet, i'm a member of one which purely deals with repair of old valve (tube) based TV,Radios and assorted other electronic instruments...

The advantage of joining one of these groups is that there is ALWAYS someone who either has had the same problem or has a complete set of drawings and advice as to your model etc...

http://www.vintage-radio.net

Is the one I'm a member of its primarily UK biased but they may be able to point you in the right direction.

Good luck!! ........ John. (aka Marconiman on that forum!!)

Boy I can see there aren't many TV technicians out there! No surprise since who fixes TV's any more? Most people just throw them out and buy a new one.

If your set is from 1970, just about the time I was working in a TV repair shop in high school, it might use vacuum tubes. If so, look for a tube on the "Tube Placement Diagram" indicated to be the "Vertical (Sweep/Deflection) Amplifier". Statistically this would be the most likely cause. Tap it lightly with a small screw driver and if it affects the height of the picture that may be further confirmation.

The flyback transformer has nothing to do with the vertical deflection circuit but there may be a small iron core transformer between the tube and the vertical deflection coils though it is unlikely to cause the gradual degradation you note.

The other problem is actually more difficult. Again, if it is a tube set look for a tube labeled "Sync Separator" or something of the like. Synchronization is done by picking the imbedded sync pulses out of the composite video signal and is usually done with an RC high pass filter and then an amplifier to drive the horizontal oscillator and keep it in sync with the video.

If all else fails, buy a nice small LCD unit, save energy and enjoy a beautiful picture or just read a book. Good luck!

<Waiver of responsibility>

The writer of this post assumes no responsibility for any damage or injury however caused by either following or not following the above instructions.

The ideas in this post are not the view of the forum moderators but the explicit view of the poster and the poster alone.

<end of waiver>

Unfortunately, disclaimers of liability don't usually hold up in court. The courts don't want people to act with free license of consequence and so no matter how thoroughly you attempt to, in advance of the event, exclude yourself from liability due to negligence, it probably won't hold up in court. And of course lawyers know this and so guess why Johnny got hurt? Of, course, you were negligent.

Here is a better one:

By acting on said advice, you thereby agree to be bound contractually by the following terms:

In consideration of my utilization of advise as I may receive herein, said advice itself constituting good and valuable consideration, the receipt of which is acknowledged: I hereby for myself and my heirs, personal representatives and estate forever discharge, release from liability, covenant not to sue, and agree to indemnify and defend the provider of said advice for damages for and against any personal injury, including death, or property damage suffered by me or by anyone to whom I may pass said advice from any cause whatsoever arising from or in connection with the use of said advice. I further agree to hold harmless and indemnify the indemnified parties from and against any and all damages, suits, causes of action, claims, demands, liabilities, penalties and costs, including reasonable defense legal fees for property damage or personal injury, including death arising from or proximately caused by me through any use of said advice.

I also hereby understand and agree that I am freely waiving my valuable right to claim for damages which I may have now or which arise in the future by reason of any act or omission including but not limited to negligence, of any entities or person or their agents, representatives or employees and that the consideration of this waiver is the right to use said advice. If any provision herein is determined to be void or unenforceable, such determination shall not affect the validity or enforceability of any other provision.

How's that? The key is the indemnification and hold harmless covenant. So sue away but you have agreed in advance to cover all my costs associated with such actions. The courts won't disallow you to enter into such a contract. They only disallow me to be fee of any responsibility for liability. Lawyers, you gotta hate/love 'em.

Not all you said will stand up either I am afraid.

<<The Unfair Contract Terms Act

Transactions between businesses are covered by the Unfair Contract Terms Act 1977 (UCTA). In general, businesses are assumed to be free to enter into whatever contracts they agree between themselves - so you should make sure you're happy with the contracts you agree with other businesses.

UCTA places a number of restrictions on the contract terms businesses can agree to. Specifically, it lays down rules for the ways in which vendor businesses can use exclusion clauses to limit liability in certain areas:

• excluding liability for death or injury is not permitted in any circumstances
• excluding liability for losses caused by negligence is permitted only if it is reasonable
• excluding liability for defective or poor-quality goods is also permitted only if it is reasonable

The test of reasonableness

UCTA doesn't define precisely what is meant by reasonable, but courts will usually take into account:

• the information available to both parties when the contract was drawn up
• whether the contract was negotiated or in standard form
• whether the purchaser had the bargaining power to negotiate better terms

Businesses don't have the same protection as individual consumers. A consumer contract excluding liability for defective goods would be automatically invalid.>>

This was however not the point. The point was that I felt the original poster clearly showed not to be knowledgeable enough to be able to undertake such a repair or trouble shooting exercise himself without putting him or her self at risk from severe injury. I would put "gently tapping the tube with a screw driver when it is powered up" to be one of those high risk exercises.

This forum should not only be about how much do we know and how much can I display about the subject, it should be about a measured amount of assistance that depends on the posters needs and abilities.

Good point, however, I am not sure we have such a provision in the law on this side of the pond. I do know that exclusion cases have held up here in the states when the scope of the activities to which the exclusion applies was reasonably specific.

Ok, don't tap gently on tubes! Find a qualified repair shop! Though you will likely pay them as much as it would cost you to just throw the outdated energy sucking piece of junk out and get a nice new TV like a good consumer. It's a way of life, you'll love it.

1970 is good going though as consumer products go. Throwing it away now is hardly considered "bad" consumerism.

Discarding it on the grounds of "keeping up with the Jones" is entirely different.

I agree that the laws in the USA are different although I do not know how exactly. There must be something stated somewhere about reasonably accepted though. It would be unworkable otherwise.

Well aside from all else, if he is using rabbit ears and if he is in the US then he would have to do something in about a year anyway because all standard TV broadcast will cease in 2009. You will in all likelihood be able to get converter boxes but for a few dollars more...

Also what can't be factored into the legal thing is, for a few dollars more you can get a better lawyer and for enough few dollars more you can kill your wife and her lover and lead a low speed car chase and still get off. Money=legal rights. Not always, but then there are always exceptions.

"Ok, don't tap gently on tubes!"

Well, pilgrim, the entire civilized world knows that one shouldn't tap gently on those tubes with a metal rod!

I guess there are some out there who might try it though.

Yes! In my youth I have been zapped by a flyback transformer. Not a pleasant experience.

simply change your all capacitor ( eleco) in vertical section as per your comment only capacitor fail as per my geass!

Thank You All!

I am going to check out a book on TV Repair and proceed to follow your diagnostics. I will be careful, I have a healthy respect for electricity. I will repost when I need further help. These TVs, especially the Philco have more value to me than just a TV set. I want to finish out the "Old Analog Era" with my beat up 13" TV with rabbit ears. I enjoyed a lot of sports on that tube.

Look for my posting and please help again.

Thanks Again!

Buy a new 13" TV for less money then it'll cost to repair the junk sets you have! And lot faster!!

Now if you're a hobbist and like to tinker with "OLD" electronics...have fun!

That's from my E-Z BUTTON!

hello

As you may know all televisions that are not capablle of recieving the new digital signal (such as yours) will cease to operate as of the year 2009. Therefore, it would be wise to just purchase a new set altogether.

ya can go here and find all info on ya model, used them when I was in the repair business, but no more.

SAMS Photofact^® repair manuals

http://www.samswebsite.com/

the set is from 1970? vaccum tube made or transistor?

the first problem is vertical deflection part. to see if there is oscallation and the second is syc.

We can help you with them. no problem.

But I suggest you sell them as an antique. if its transistor made. 1970, rare transistor tv set on market. some collector like it very mch.

sell to them they pay money enough for you to buy 3 sets of 25" color setx.

The Philco, you can fix it with just one step, change the elecrolitic capacitor in the vertical out put, Usually a 33Mfd/ 50V.

RCA, that seams a problem with an open Zener diode some where across the hor hold control, check for it.

The answers are generally correct- here is the problem"a little knowledge is dangerous"- but we all have to learn somehow- I myself learnt & are still learning from discarded sets that tv repairers couldn't fix- but I can- make no mistake, electronic repair can be dangerous- it all seems to me to be exactly cognizant of the repairer's ability & capacity to learn- if you are not a diy capable person, don,t even think of it! That said, get as much info as you can- the feeling when the pic comes up is what keeps me going- sometimes after many hours of effort!.