I bought a really beautiful brand new Magnavox 25" Star System console TV in June of 1978, and with only two visits from the repairman (one was a close lightning strike), it has always worked great. A few months ago, I turned it on and no video. The tuning and audio work fine, just no picture. Thinking back, the picture lately had some lines at the bottom and top of the screen (I think) and looked like it was a little smaller vertically. Bummer.

I can't give this great old TV up without a fight. The last service was in March of 1998 and needed a transistor for the green drive. The tech said it was a T995 chassis and the CRT was in fanfastic shape with no leakage at all (it had a good vacuum). In fact, up till the time the picture went out, the color was real good. And then it just quit.

The first thing I think I need is a service manual. My guess is that some of the electrolytic caps have dried out and/or a transistor has given it up. Although I have a good deal of experience working on circuit boards and replacing components, TVs are a whole new bag for me. I'd bring someone in but everyone I call says it's not worth it. Yea? Like hell.

Any help is greatly appreciated, but remember, Flyback? What's a Flyback?

The TV's made during the 70s would display a blank picture if the x-ray protection circuit was on. You may want to start looking in the power supply first.

I believe I have some modules for that chassis if you need one. Can you tell if the set has high voltage? If there is no HV; it could be a power supply problem, a problem with the horizontal oscillator or drive circuits, or horizontal output circuit (tripler, flyback, etc). If you have HV, try pulling the service switch on the back of the set to see if you can get a line on the screen. Cleaning the service switch with control cleaner may help. You could also have a defective vertical module or video module. I'll see if I have a Sams Photofact for that chassis.

If the on screen channel display works then there is no high voltage or xray protection problem. Don't overlook the possibility of oxidized connectors where the modules plug into the mother board. I seem to recall there was a low level video module that would cause no pic. Be sure you get a manual that covers the Star system since the t995 chassis was also used on a non star set. The non star system set did not have the on screen display and such.

Bill R

Thanks guys for the response. I'm not getting anything on the screen, no picture, no channels, no clock. That's a great point Bill, thanks. This project will sure be a great learning experience for me. Before I do anything, I'd like to get a good book on basic TV repair so I don't drive you guys nuts with a bunch of obvious (to you) questions. I'll check out amazon. Any suggestions? Radiotvnut, I'd be interested in any modules you may have. Thanks again.

Everyone's giving you good suggestions here - Since you say you aren't very expereinced with tv repair, try cleaning all connectors, potentiometers, and switches. Keeping it simple pays off sometimes.

However, it does sound like you have a dead deflection amplifier, video amp, or bad solder joints somewhere. Many times the solder points weaken around where the modules plug-in, and more often than not, around high-heat areas.

Since you have no video and possibly no HV, try reflowing solder around the Horizontal output transistor (on a large heatsink), and around the HV section, but ONLY IF YOU ARE COMFORTABLE WORKING NEAR HIGH VOLTAGES.

These voltages remain even when the set has been unplugged.

Hey, I'm not the greatest tech, but I have revived many, many tv sets, so shoot me a private msg. If you have some questions. Take care and good luck/ Tom

No video, or on screen display. Problem is likely in the sweep section. I would resolder all the connections to the Horizontal sweep modules connectors, and around the flyback. Next I would check and or replace the Horiz. output transistor. I do not recall a lot of flyback problems with these.

Bill R

Thanks for your posts guys. The biggest question I have right now is whether I have HV. I think I do, because when the set goes on, the front of the picture tube will pull the hair right off your arm with the static that's there. Also, there is a thin flash of white light at the very top of the screen when first turned on, and then all darkness. I have a ticking that comes from the back of the tube that goes away when the service switch is moved from normal to service. I did measure some voltages on the main board at the TP's and everything was normal (80v, 125v, 24v, etc). I stayed away from any high voltage for now.

Some more info, this is chassis number T995-02 DC. The final unit number is RH4847PE01 and was made in Jan of 1978.

I ran across a web site (www.euras.com/english) that listed this tv in thier database of common problems. They say that vertical deflection is a common problem with this set. Sounds like what I might have (or as Bill says, horizontal sweep problems). I will have to join them to see what thier fix for the problem is. Anybody ever heard of them? Does this make sense? Thanks for your time guys.

From what you say, there is HV present. That ticking you hear is probably the Vertical windings of the deflection yoke singing for you. When you pull the service switch; that will kill vertical drive to the yoke, thus, eliminating the fast ticking sound. I suspect the vertical and horizontal / HV circuits are functioning. That low level video module would probably be my next place to look for trouble. Give me the number of that module and I'll see if I've got it. Also, make sure the filament is lit in the neck of the CRT. No filament voltage will give you a black screen. I do hope you can get that set up and running again. That set is 1000 times better than most garbage currently available.

No doubt about it, the vertical adjust will speed up or slow down the ticking that comes from the back of the tube. The low level video module number is 703640-5. However the neck of the tube is dark, I don't see anything glowing inside it. With the set on or off, it looks the same. Could this mean the picture tube is shot? I hope it's just not getting any voltage because that could be fixed.

I'd really like to save this TV, it has so much more class and style than the black boxes of today. Thanks for your comments.

If the CRT is dark at the neck, there are two possible causes:

1. CRT filament is open (bye bye CRT)
2. filament supply voltage is not present.

If its the supply voltage, then go to the power supply. If this set has a filament transformer it may be bad. If this set has a filament winding in the flyback, you will either need to purchase a new flyback or add a filament transformer .

Another thing that may cause the filament to be dark is a poor connection at the neck of the CRT. If possible, remove the connector from the CRT neck. Whether its just a connector, or a circuit board is attached to it, make sure nothing is securing it to the neck before removing it.

What you are looking for is corrosion or carbon on the pins of the tube and the socket it fits in . It will be green and powdery looking or black if its carbon. If any exists, use a pipe cleaner with a good contact cleaner (I like caig De-oxit) in the socket. Use very fine sandpaper (1000 - 2000 grit) to burnish the pins of the tube.

Also, if this has a circuit board attached to the CRT connector, check to make sure there are no bad solder connections. The solder connections are the silvery dots that have a pin or wire attached to. if there are any cracks in the solder around where the CRT socket is it may be the cause of your dead tube.

I hope this of some help. I'm more of a techy guy, and not that good at explaining these sorts of things. Good luck on getting your vintage set running. Sounds like it has served you well up until this point.

I pulled the Sams (1815-1) on this set, and, there is a two amp fuse in the CRT filament circuit. It's very possible that this fuse is open. The CRT gets it's filament voltage from the main power transformer. It's either going to be a blown fuse, an open filament winding, or an open CRT filament. Even if the CRT is bad; don't scrap the set just yet because I'm sure a good used tube can be found.

Thanks radiotvnut, I found the 1815-1 on sams last night. Would it be worth my buying it from them? I've seen the fuse you mentioned on the circuit board but it looked good, not dark and all. I'll pull it and put the ohm meter to it. I want to test the voltage at the 2 wire connector that goes up to the tube. What kind of voltage should I get if the power supply is OK?

I think the lack of the filament firing up is my basic problem. Whether it can be fixed or not, we'll see. Thanks for your comments.

Wow! Here's a surprise. That 2A 250V fuse for the CRT fiament that looks like new when taken out of the circuit and cleaned up had failed. Not blown mind you, just failed. This is one of those fuses that has a spring in it for slow blo action. In the circuit it looked just fine, knowing what a blown fuse looks like and all. But upon close inspection, the spring had just pulled away from the other internal part of the fuse. The glass is crystal clear. I think this means that no other TV part pulled to much current causing the fuse to fail. If that's right, a new fuse should put me back in business. I've never seen this before. I'll report back when a new fuse is in place.

That style of fuse is prone to fail that way, The spring gives a pull on the solder connection all the time and sometimes they just separate on their own with no fault in the circuit. Back when I worked for a Magnavox dealer we'd also see the solder connections of the crt socket to the PC board become faulty, look close and see if any seem to have a circular crack in the solder. IMHO the T995 was the best color chassis Magnavox ever built.

I'm sure a new fuse will fix the problem. There should be 6.3 VAC across pins 1 and 14 of the CRT. Use caution as there is 132 VDC potential between pin 1 and ground. I believe the reason that they placed a high DC potential on the filament was to minimize tube arcing. I also agree that this was one of the best Magnavox color sets made. Would your tuner by chance be the type that has those three colored levers and a yellow knob for programming the channels. One would almost have to have a degree in rocket science to program that thing. It would probably be worth getting that Sams for that set; but, I wouldn't be too quick to pay the $20 something Sams wants. I'll look through my extra Sams and if I have an extra copy; you can have it. You might check epay as well as some older TV shops. Most shops would probably be glad to sell you a Sams that old because most of them would laugh if someone brought a set that old in to be repaired.

Well the fuse brought back the video. I'll remember that one. Now that I have a picture, but it looks like I might have to go back inside to make a few adjustments. The verticle was rolling a bit and I used the external knob to stop the rolling, but it's stable with the black line in the middle of the picture. I can't get it stable with the external knob like it should be. What concerns me more however is a very pronounced strobe effect going on with the picture. It's like the picture is going on and off many times a second (that is, much less than it should to look seemless). Could I have changed the horizontal? I was real careful not to touch things inside.

Radiotvnut, if you find and extra copy I'd be happy to buy it from you. You've been a great help already. The lack of the glowing filament was key to seeing the real problem.

Thanks for everyone's help. I'm a whole lot closer to TV bliss than I was yesterday. The next time I take the back off I'll look for those levers, but I don't recall seeing them. Thanks again.

The levers will be on the front behind a little door over the keypad. Your set may not have them. If it does not, be glad!! I think those hard to program tuners were on the circa. '74-'76 models. A good vertical module would probably solve the vertical sync issues and maybe the flickering. The problem with your module is probably bad electrolytic capacitors, dirty controls, or bad solder connections. I have an '82 Magnavox console that uses the modular T815 chassis that I think uses the same or similar tuner. Mine does play; but, the CRT is not too good. I rejuvenated it but I know it won't last long. I'll probably end up finding a tube for it and keeping it because no one around here wants it, not even for free.

Well guys, the project is all wrapped up. I found out that I was trying to set the vertical hold way to slow. I'm surprised the TV stoped rolling even with the bar in the middle of the picture. When I turned the vertical way up where it should be, the vertical locked in like it should and the flickering went away. The only adjustment in the back I made was to increase the vertical width a little bit so that from top to bottom, nothing but picture. A little tweak of the front panel controls and wow, what a beautiful picture. Great color, nice and sharp. If it weren't for you guys, some service tech could have taken me for a ride, a real long ride. After 30 years, this beautiful Magnavox is 100%. It's the center piece of my living room.

Radiotvnut, I don't have any levers, just the star system keypad on the console, and an identical keypad on the remote which works fine. And I am very glad!

I want to offer my heart felt thanks to everyone that was kind enough to post suggestions. If I had half a clue what I was doing, I'd be dangerous.
You guys are the best. Thanks again.

I think the best way to thank old TV nuts is with a picture! I know I want to see it!

The star system was my favorite. While mine did still work, it was used so much that the crt is really soft. It was turned on from about 5 am until sometime after midnight 7 days a week, with very few exceptions. Glad you got it working.

Bill R

Glad to hear you got it going!
I have a circa 1978 Magnavox (non Star) that has that odd tuning system with the levers. I WAS able to get it tuned in on channel 4, and run it off the cable box. However I can't figure out how to tune the other channels. If you get one tuned in, it throws the others "off". How the hell does one tune these? I thought my parents 1979 Sony was a bitch to tune, but this is WORSE.

fff

Yes indeed, I am happy and pleased to share some pictures of the Magnavox Star System that you great guys helped me save. It is working like a charm and all for the price of a fuse (a 5 pack of fuses actually). For 30 years old, this thing looks better than I do! Thanks again. :banana:

I love the look of the set!! I don't know much about these, so what does it mean that it's a star system? And, 5 stars for having a doilie on top of the set--it's a must!!!

Glad to hear you got it going!
I have a circa 1978 Magnavox (non Star) that has that odd tuning system with the levers. I WAS able to get it tuned in on channel 4, and run it off the cable box. However I can't figure out how to tune the other channels. If you get one tuned in, it throws the others "off". How the hell does one tune these? I thought my parents 1979 Sony was a bitch to tune, but this is WORSE.

That's the same problem I ran into. I recently saw one of these sets at a thrift store and the owner had me playing with it trying to set the channels. After about a half hour; I gave up. I also remember having a T991 19" when I was a kid. I never got it powered up; but, it had the same goofy tuner and a soldered in rectangular battery inside the set. I know a retired Magnavox repairman; and, he hated that tuning system!

That looks very much like my Star set. The star system set had a direct entry tuner with on screen channel display and a on screen clock. When you changed channel the channel number would fill the screen then shrink to the center of the picture and then disappear. As far as picture control the set used seperate presets for picture prefrences. To change the presets you pull the small silver knobs off the front control panel and then you can use a long thin screwdriver to change the presets. When the star system came out it was indeed state of the art. The original star sets, I don't recall the exact date around 1972 or 1973ish, did not have any tunning controls on the set. You had to have the remote to operate the set. After the first year they added the keypad on the set. 1978 was the last year for the star system. In 1979 they offered their frist inline large screen crt, and completely changed the model lineup. They also changed to ir remote control, and introduced "total automatic color". I think that is what they called it. My 1984 set also works, but as with the star set it had a lot of hours and the crt is weak. It had remote control, but I do not remember any special designation of the set.

Bill R

Bill, that's just how this set works. The channel numbers appear on the screen and then shrink in size till they are gone. The clock will appear in the lower left cornner when the channels are displayed, but will just disappear, not shrink.

I was told by a service tech that this technology was known as the "Random Access Tunning System" at Magnavox. It truly is random since you key in the channel you want without going through all the ones inbetween. When it came time to market it however, Magnavox decided not to call it the "RATS" system, but turned it around to make it the "STAR" system. Good move. With this system, there is no building a favorite channel list as we do today (adding or deleting channels). As a result, there is no "Up" or "Down" channel button. You must key in each 2 digit channel yourself. The Star System was without a doubt the first of its kind TV.

It was my first color TV I ever bought. I had gotten a good job and wanted to replace the 13" BW with the best there was ($875 at the time). It has moved from the southeast to the west coast, to new england and back south with me. It outlasted two wives and many cars. I won't let it go until I do!

List price on that set here was $1250, so $875 was a good deal at the time. I paid $850 for mine, but I bought it through the service center/warehouse for the local Magnavox Home Entertainment Centers. So it never made it to the store. Mine was to replace the Philco roundie that is in another thread in the early color forum. While mine was under warrenty I had 2 problems, one was with the tuner. They sent a tech out and he just changed all the boards in the tuner. There is like 4 or 5 boards in the tuner cage. Later the set lost blue in the picture. There wasn't a tech available to make the call at the time so Rudell, the tech who knew I repaired sets, said you can do the same thing we would do and gave me a stack of modules and said just keep the one that solves the problem, and bring the rest back. I replaced the chroma processor module, and never had any other problems.

Bill R

That looks very much like my Star set. The star system set had a direct entry tuner with on screen channel display and a on screen clock. When you changed channel the channel number would fill the screen then shrink to the center of the picture and then disappear. As far as picture control the set used seperate presets for picture prefrences. To change the presets you pull the small silver knobs off the front control panel and then you can use a long thin screwdriver to change the presets. When the star system came out it was indeed state of the art. The original star sets, I don't recall the exact date around 1972 or 1973ish, did not have any tunning controls on the set. You had to have the remote to operate the set. After the first year they added the keypad on the set. 1978 was the last year for the star system. In 1979 they offered their frist inline large screen crt, and completely changed the model lineup. They also changed to ir remote control, and introduced "total automatic color". I think that is what they called it. My 1984 set also works, but as with the star set it had a lot of hours and the crt is weak. It had remote control, but I do not remember any special designation of the set.

Bill R

A friend just brought me his 25" Magnavox console from the early '80's (date sticker missing) that uses the 25C1 chassis. That's the set that has the two large PC boards in the bottom of the cabinet that comprise the main chassis. The CRT is an inline type similar to what Zenith used in the System 3's. His TV has "STAR" on both the set and remote. His set has the Hi-Fi audio system feature. He claimed he paid around $1200 back then for the TV.

I guess they used the star name for the top of the line sets then past 1978. The star system was actually the tunning system name. After 1978 they used "Videomatic/Touch Tune" for the direct acess tunning sets. It was sometime in the early 80s that they were bought by philips. By 1984 the Magnavox, Philco, and Sylvania sets all used the same chassis. I don't think Magnavox chassis numbers ran in order. For example the t815 chassis came out after the t995 chassis and used the new inline tube in 1979. The t997 and t998 numbers came out before the t995. The t997 wasn't a color set. The t956, which was a hybrid chassis, was out in 1972, just before the t995. Looking through the service manuals it looks like the star system ran from 1974 through 1978. I know that "Total Automatic Color" was used on the late 60's sets, but I think they used it again in the 80's or 90's. I think the t809 and t815 chassis were the last of the real Magnavox color chassis since they were 1979 into the early 80's.

Bill R

Thanks for posting that picture... I love seeing old sets in use in nice houses as the "regular" TV. That's all I'll ever have... TV sucks anyways, so the damn thing might as well look cool when it's off! :D

Bill, that's just how this set works. The channel numbers appear on the screen and then shrink in size till they are gone. The clock will appear in the lower left cornner when the channels are displayed, but will just disappear, not shrink.

I was told by a service tech that this technology was known as the "Random Access Tunning System" at Magnavox. It truly is random since you key in the channel you want without going through all the ones inbetween. When it came time to market it however, Magnavox decided not to call it the "RATS" system, but turned it around to make it the "STAR" system. Good move. With this system, there is no building a favorite channel list as we do today (adding or deleting channels). As a result, there is no "Up" or "Down" channel button. You must key in each 2 digit channel yourself. The Star System was without a doubt the first of its kind TV.

It was my first color TV I ever bought. I had gotten a good job and wanted to replace the 13" BW with the best there was ($875 at the time). It has moved from the southeast to the west coast, to new england and back south with me. It outlasted two wives and many cars. I won't let it go until I do!

I attended Magnavox training when the new Star system was introduced and the Acronym for the system stood for Selective Tuning At Random, the RATS story is accurate I heard it at that seminar from the Factory Service Rep that was putting on the seminar. He said Engineering was fine with Random Access Tuning, but Marketing had a problem with it for some reason :D

The early sets that had electronic tuning were great when using off air signals but I ran into problems on small MATV and Cable systems if they weren't too careful about getting the frequencies dead on when they changed stations to another channel. With mechanical tuners it was easy enough to crank the fine tuning but these sets relied on AFC to keep them on the channel and some of the systems were too far off frequency for the AFC to pull in. There were some factory mods you could do to increase the range. I had one set that would show a picture if you tuned down but not if you tuned up to a particular channel on a really sloppy MATV system at a local resort.

Magnavox put the star system in quite a few sets, I've got a 19 " set that has the T991 chassis, it's in a very plain presswood cabinet wrapped in vinyl to look like wood that has the Star system.

Somewhere around here I've got the book that I used to carry with the instructions on how to program the 3 lever system, these had a ni-cad battery on the circuit board to hold the memory, they also had a single AA cell in a holder screwed down to the tuner chassis. When both failed the customer had to reprogram when ever the power failed. To program it you have to think of a circle like a pie, then you visualize each slice, now.......One lever selects a slice, the second lever assigns a channel number to that slice, the last lever assigns a frequency to that slice......Simple, Huh.....NO I don't know what kind of pie......

Randy, wasn't the 3 lever system used on the "touch tune" sets that came out after the original star tunning system in 1979? The only one I have seen was on a set of that vintage with the then new inline crt. When I bought my star set the 79 models had just shipped, and I could have had either the 78 model or the new 79 model. I chose the 78 model so mine will be one of the last production runs I think. I didn't like the picture on the newer set as well.

Bill R

Bill, The 3 lever and later the 1 lever tuning systems were introduced after the original Star system. I can't remember just when, IIRC the original Star system came out around 1975 and originally was put on the T995 chassis on 25" and T991 for 19" higher end sets. Truth be told the Star sets were a bit troublesome, and very expensive to manufacturer with a separate chassis with I think 3 plugged in panels, they came out with the 3 lever as a cheaper alternative and later the 1 lever. There were also some sets that had a knob tuner but all it did was select different potentiometers to change the voltages on varicaps there were also other contacts on the switch to change bands from vhf low to vhf hi and UHF. I quit working on TV full time in December 1979 but did some contract work for a dealer in 1980-1983.