Just picked up this 1965 magnavox 546 console tv...need some help!!
 

Hey guys, we just picked up this console tv from a local thrift store... stereo and phonograph worked great, TV would turn on but would shut off after a few seconds. We tracked it down to a cracked board... looks like someone pushed down too hard on one of the tubes. We pulled the board, re-soldered the bad connections, and that fixed the short. The tv now stays lit, and we are getting audio, but we cant get any video... just a bunch of lines.

Judging from an ad we found posted online we figured the tv is a 1965 magnavox eastern contemporary theater 546, but I don't know the chassis code... I dont even know where to find it on the tv.

Anyone have any thoughts on what we might need to look for? All the tubes appear to be lighting up except for the video and sync amp, which is shielded and we cant get the shield off to see if its lighting up. We are new to this whole vintage tv thing and are at a loss. We ordered both of the tuner tubes as well as the one for the amp to be safe, but we might be missing something simple. Any advice? Thoughts? Information on this particular model or something close? Any help would be much appreciated.

Thanks!!

Steve

http://dl.dropbox.com/u/13671936/65mag.jpg

I have 2 very similar to that one U45 If I remember correctly I think Dave WM identified mine just by looking at my chasis picture. I am clearing some of my inventory BTW. I have mine in my album, take a look

I wish I could find a roundie Magnavox like that. I only seem to find 23, and 24 inch black and white sets. Not that I am complaining.....

what is the video source?

My advice: don't operate anything in this set until you at least replace all the wax and electrolytic capacitors inside it. There is the very real possibility of them exploding from the stress of being used suddenly after years resting, ask me how I know. After you do that, then you should investigate the loss of video. On the plus side, you already have a raster on the screen so that means 99% of the set's electronics are already good.

HI,
I have a unit similar to yours, mine is 1963 or 64 with vhf only. On the chassis for the tv you should see a unit number similar to u43-01-00/10 or something similar. Go the the Sams photofacts web site and then you can use this chassis number to get the photofact number, my tv was in Sams set 708 folder 2.
Mike

These model Magnavoxes will put out a nice picture! They will also cook Flybacks so Horizontal Output Tube Current is critical...but you've got some work to do before getting to that point. As mentioned, I would not power this up any more until you recap it and give it a good visual of all connections and components.

The tubes that are PC mounted may be hard to pull after years of being inserted so do take your time wiggling any loose, especially if there's some heat damage. I would remove the chassis before removing any of the tubes and check those areas where the tubes mount as it would be a good idea to test them too.

The last thing you want to do is induce more cracks!

A little De-oxit at the base of tubes on a board will make them come loose without stressing the board. VERY nice set BTW:thmbsp:

Just picked up this 1965 magnavox 546 console tv...need some help!!
 

Hey guys... thanks for all the responses. We replaced the video and sync amp tube as well as the RF amp and the osc & mix tubes in the tuner... those were the original primary culprits... no difference. the Z Demod tube is bad... we are ordering a replacement for that one...would that cause the issue we are seeing? We have scrolling horizontal lines on every channel. Im attaching some pics of the board as well as the sockets for the Z and X Demod, which look bad. Also, can anyone tell me where we should start with replacing the caps?

Or possibly anyone in the sacramento, CA area that may want to come take a look at it and provide us with some assistance?

http://dl.dropbox.com/u/13671936/TV/...206_104833.jpg

http://dl.dropbox.com/u/13671936/TV/...206_104907.jpg

http://dl.dropbox.com/u/13671936/TV/...206_104914.jpg

http://dl.dropbox.com/u/13671936/TV/...206_104933.jpg

http://dl.dropbox.com/u/13671936/TV/...206_104946.jpg

http://dl.dropbox.com/u/13671936/TV/...206_105317.jpg

The tube sockets were a common problem with that chassis.

For best results, break the socket apart. Heat one pin at the bottom tip and push it out gently. Do not heat the PC board. It cannot stand much heat.

Replace with new PC sockets and apply heat to the socket pin.

Also, no matter which channel we turn to, we get the same thing... brightness doesnt seem to change anything.
Our video source is a laptop: vga --> rca video --> coax --> antenna, but we cant even get snow. just the horizontal scrolling lines on every channel.

sorry not up to laptop speed, it is an RF signal correct? out to channel 3 or 4 or what ever the RF is at? oh and a matching transformer to get to 300ohm.

yeah I am running through a RF converter out to channel 4... we get beautiful audio but no video. When disconnected fromn the RF source, I can hear snow, I just cant see snow. So I'm thinking somewhere along the way it's losing the video signal?? How do I trace down the video signal?

messed with the fine tuning I presume? just need to cover the basics.

I would look at the video amp tube, maybe an open plate load resistor however with out a schematic its hard to tell exactly where to start.

if you have a scope you would need to trace the signal at the output of the video detector, looking for a composite video signal.

yeah messed with the fine tuning... has zero effect. We are probably going to start testing the signal at various points and hopefully chasing down where the bug is.

The only code I was able to pull off the chassis was R315... does that sound like a possible chassis code for the tv? Sams does have a listing for a magnavox R315, but before I jump to buying it, I thought I would check with someone to see if that sounded right?

Looks like in the last photo of tube sockets, you have a broken circuit board around the socket for V708 - lots of visible breaks around the socket area. You'll need to tackle that when you replace the socket.

Cheers,

yeah unfortunately someone in the last 45 years decided to push the tube in really, really hard :/ ... we flipped the board and re-bridged all the busted circuit connections. We have 2 more tubes on order, then we are going to stard replacing caps and the brokensockets... hopefully we will be able to trace down the video signal issue once thats done.

what caps? I would not just go shot gunning them, most are prob ok. Maybe the can caps, but then again, often they are fine, esp if you started it easy (unless it had been in service recently).

The down side of a PCB is the breakage factor, the upside is with a good solder sucker iron you can quickly replace parts very neatly.

On those I generally lift one leg of a suspect cap (low volt, high value and any non dipped caps) and check with an old school cap tester (can test at rated voltage for leakage).

Same for can caps, disconnect and check with cap tester. Lately I have found a lot of the can caps test just fine, so I leave them be. I also fuse the B+ with a fast acting fuse that is just a bit over the rated current draw. That way if for some reason a cap does short the fuse will blow.

Of course for complete peace of mind it does not hurt to replace all the filter caps, I just like to introduce as few changes as possible, until I have a working set. Then go and replace old working parts (like can caps) if you feel new ones are better. With the way some new caps go bad, I am not as sure as I used to be that is the case :)

The chassis in that set is a derivative of the U920 series, and I believe it is a U918.

The schematic for a U908 or 920 will tell you all that you need to know.

Hey Steveo,

I live in Folsom and have been working on these beasts for a few years now and have gotten fairly aquanted with the in's and out's of color tube sets. And of course with alot of help from the folks on this site. I actually own about 6 or 7 tube sets now and most of them were broken when I picked them up. You most likely have IF or AGC issues. I had a Maggie u919 I believe it was. The first rectangulat CRT combo unit with the lovely 23EGP22 CRT. Yours looks to be a year earlier. I had to replace tube sockets due to brittleness as well. Im certian that you have connection issues and or out of tolerance caps in the AGC or IF.

hey guys... thanks for all the input on this!! We spend the last few days getting the phono to work, and got it going fine, so we are now just left with our tv issue.

@freakaftr8... interested in taking a road trip to our office in rancho cordova and taking a look? :)

Would love to, have to find the time after the holidays of course.