56? packard bell 21" tv scored

[jbivy]

So I just picked this up for free, supposedly working. I brought it up with a variac and she works. Though the horizontal is messed up. The picture is at about a 30 degree tilt to the lower right.

I cant wait to get started in on this old girl tomorrow.



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[DaveWM]

so is it just the yoke?

if its working I would go slow on the caps, just one or two at a time and then recheck. I don't know that era but maybe not a lot of paper caps?

[jbivy]

Well the yoke itself is loose, the piece of rubber used to hold it in place has disintegrated. Oddly this has mainly paper caps in it, id have assumed by 56 it wouldnt be.

Whats a good way to secure the yoke?

[Eric H]

The back of the Yoke disintegrating is a common problem on sets of that era.

You could just glue the yoke to the bell of the tube with some low acid Silicone, the problem with that is of course you would have to get it perfectly level since you couldn't easily move it later, also the centering rings are usually located on the back of the yoke too so if the mount had rotted they're hanging loose also.

People have made new Yoke covers, takes a little time and ingenuity.

[jbivy]

Originally Posted by Eric H

The back of the Yoke disintegrating is a common problem on sets of that era.

You could just glue the yoke to the bell of the tube with some low acid Silicone, the problem with that is of course you would have to get it perfectly level since you couldn't easily move it later, also the centering rings are usually located on the back of the yoke too so if the mount had rotted they're hanging loose also.

People have made new Yoke covers, takes a little time and ingenuity.

maybe inner tube rubber and sillicone?

please, ANY advice is welcomed. im a novice.

[Kevin Kuehn]

Originally Posted by jbivy

Well the yoke itself is loose, the piece of rubber used to hold it in place has disintegrated. Oddly this has mainly paper caps in it, id have assumed by 56 it wouldnt be.

Whats a good way to secure the yoke?

Nice TV. Maybe you could post a picture of the yoke issue? I've made a replacement yoke back cover out of wood for an RCA set (don't laugh it works), but it sounds like you may have some other problem.

[jbivy]

Im currently having a load of issues with this lap top, one of many is that it now wont let me upload new pictures, an uncle who is rather computer savvy is coming over tomorrow to hopefully help me with this.

The "stopper" for the yoke has seemingly shrunk and become solid as a rock, after it apparently came loose and wont even try to reform.

This tv was continuously used untill the mid 80s (when it developed this problem). The man i got it from was given it by his grandfather, its always been kept in the house. Perhaps that why it still functions today, a controlled climate. None of the hot to cold youd experience in a garage or shed.

Oh well, i had a lazy day and did not end up building the chassis stand for this. Hopefully on sunday ill be able to do this.

[jbivy]

Well i went and built a tilt chassis stand for this. Im doing like you said and replacing a few caps at a time, so far so good. I found that the rubber "yoke holder" out of a zenith with a busted crt seemingly works well, the picture is nice and level when its in there (taped on, soon to have the stopper siliconed in place).

But ive yet to screw up! *crosses fingers*

[Eric H]

The original cover was made of plastic, I think someone has said it was Soy based and that's why it rots.

Someone here made one, can't remeber who, maybe they'll chime in and fill in the details.

[Aussie Bloke]

Nice lookin set! It kind of looks like some of the B&W TVs that sold in Australia around the 1958-59 period, I personally have a 1959 His Masters Voice set that's made in slightly similar style http://www.troysvintagevideo.741.com/hmv.html . Anyways best of luck with the restoration!

[DaveWM]

with a lot of papers I am suprised its still working. Must have been kept in a air cond enviroment its whole life (I think humidity is a big factor in paper cap deterioration). Anyway being that you are new to this my advice on only a cap or two at a time holds true. If you goof something up it is much easeier to fix if you only touched a couple parts vs many. You are replacing caps to add relialbility not to fix a problem. Of couse evertime you pull a chassis out there is risk of breaking something. this is where a test CRT would be handy. you setup the chassis on a stand to hold it secure with the underside exposed, and have a small CRT installed so you can check it after each change. the kinds of problems you risk are:

wrong value cap replaced (you replace a .001 with a .01)

wrong voltage rating cap replaced (a 600v replaced by a 400v)

bad connection made (new cap lead not properly secured and poor connection results).

wrong connection made (disconnected from point A reconnected to point B)
(easy to do, take lots of notes and only remove and replace one cap at a time)

polarity not correct (on polarized caps that is).

solder splash (too much solder applied drips off, spashes on parts under it).

Damage to parts around the cap. Esp important around delicate coils. Ham hands not allowed near the underside of a TV.

Damage to term strips/coil lugs/tube sockets, too much heat and phyical stress can ruin your day, esy true on coil lugs and tube sockets. On those if it looks tough I just cut off the old part and pig tail on the new. Not as neat looking but MUCH less stressful to the other part.

Heat damage to early diodes (not ofter used on old stuff but not impossilble, esp around the video detector) Germanium based solid state devices are damaged by heat, proper heat sinks must be used when soldering near them.

induced shorts, some chassis can be very dense with parts (any color zenith as an example) if you are not careful its easy to push a part like a disc cap and move it so the leads short out (been there done that). So care must be used in how you hold the chassis and what its set on top off (shop rag under chassis balled up pushes part when chassis is set down on it, causing short).

thats about all rookie errors I can think of off the top of my head.

be extra careful on reading the cap values they are often not spelled out the way the old cap is, exp old cap .01 new cap 103.

I use a cap tester to check whats coming out to whats going in just to avoid that one mistake.

[cwmoser]

Its more a love of the art. Not like an old lawn mower you want fixed so you can get the yard done and back in to watch the game.

I like that comment that recapping is not so much about replacing the bad part but instead about making the set more reliable.

I've only done two TV restorations and I did wholesale replacement of all the .0001 uf and higher values before I applied power. You have to be meticulus and careful or you will have a big problem.

Check those resistors too.

Carl

[Electronic M]

The two silver bands confuse me as there should be only one silver band on any resistor to indicate a 10% tolerance (on those resistors that are 10% tolerance only).

If you have or can get a schematic it might be simpler to just look up the resistor in the schematic if the color code is illedgible IMO.

Tom C.

[jr_tech]

Perhaps Grey, Red, Red, Silver... 8200 ohms 10% ?
jr

[jbivy]

well it looks silver red red silver, but maybe one is grey. I ordered the 8200 ohms resistor and ill see if that helps.

Im having another problem i just found out about. With the tv on its side in the stand i built to recap it on, it plays okay, sans the top wavering. when its upright.. only the top 1/4 gets a pic, then that stops, then its a horizontal line which quickly becomes an off centered dot and dissapears.

Ive just.. no clue here guys.

Ive checked and every cap ive done is right.

Any clue what this is? It seems like maybe something is shorting out or touching another thing when it gets put right side up. Frankly this was going so well and now its driving me crazy.