Motorola Color Television

[Charlie]

Correct me if I am wrong, but aren't you suppose to remove the horizontal tubes before bringing it up slow???

[Stlouisian]

Eric,

You were right about the horizontal oscillator not working. I replaced the horizontal output tube that was not glowing cherry red with a new tube and now I got a picture as shown but it disappears slowly and it sounds like there is a high voltage hiss in the high voltage cage where the 3AT2, 1V2 and 6BK4 are located.

Ross

[Chad Hauris]

I personally don't use the variac trick---have not personally noticed an improvement on electrolytics using it. If you use it you should remove the horiz. output tube as there is not enough drive signal from the oscillator at the reduced voltage, therefore not enough bias voltage is developed in the HO tube and it overheats.

The hiss is probably from insulation breakdown, one likely culprit is the HV rectifier filament leads.

[Charlie]

Originally posted by Chad Hauris
I personally don't use the variac trick---have not personally noticed an improvement on electrolytics using it.

I've only been using a variac for a short while to bring a chassis up slow. So far, I haven't noticed any improvements on lytics, but, it has helped me locate a few that were evidently shorted. I would get the juice up to about 40 or 50 volts, and usually find at least one lytic to be pretty hot. I would then change the hot one before taking it any further. Probably saved me from having a nasty surprise. Before having a variac, I was usually always leery of plugging in a set for the first time.

[Charlie]

Ross,

In addition to Chad's suggestion, you might also try examining your flyback very closely. I have a flyback in a set right now that has a hissing HV leak at the flyback. There is only a tiny little pin hole in the insulation that has a slight burn mark. Wasn't very noticeable at first glance, but when I got up close, I found it. I was going to put some silicon caulk on it, but every time I go to WalMart, I forget to pick some up.

[Stlouisian]

Charlie, it looks like you are right about a hole in the flyback. I have a small cut in the flyback. However now I got a new problem from wanting to make sure the picture tube socket pins were free from corrosion. One pin broke off the socket and if you insert it in the hole it will make contact per my VTVM. How can I repair the problem? I have pics that show the damage.

Thanks,

Ross

[Charlie]

Ross,

The photo you are showing looks as if the the WIRE came out of the socket (if i am looking at that correctly)... you had mentioned the PIN breaking off.

If the wire came out, here's an idea. Take a fine hacksaw blade and try cutting the tip off the rivet from the backside of the socket. If the saw blade is to thick to work under the rivet head, you could try using a pocket knife to bend the head up just a bit so you can work the saw blade on it. Another choice might be using some small wire cutters to get up under there and snip it off (although you may end up ruining the cutters after that). Once you get those heads cut off, then you can take the two socket pieces apart to resolder the wire back in.

Once you've made that repair, you'd probably have to go to the hardware store and get some really small screws with nuts to put it back together.

If that isn't going to work, ya could obtain another socket with the wires intact and cut that old one off and splice the replacement on. If you don't have another one, I'm sure that i have one around here I could send ya.

Anyone else here have a suggestion? I would think this has happened to at least a few of us in the past.

[captainmoody]

If possible, Drill out the rivets and replace with like. On the flyback, Make sure any carbon is removed from the damaged area before using silicone.

[Stlouisian]

I might need a new socket. The wire broke off the connector that is in the socket and makes a connection with the pin on the CRT base. Likley I will need to get a new connector even if I could easily open the socket I made a crude drawing of the conector. The red line indicates where the connector broke. Thanks for all your help.

Ross

[drh4683]

To save some time and effort, strip back some insulation on the broken wire and solder it next to the connector. If you are careful, try to cut back on that pink fiberglass disk behind the socket with a cutting tip of a dremel tool to get at the terminal. Changing the entire socket for 1 wire shouldnt be nessisary.

[Stlouisian]

I used silicone caulking on the flyback and I had problems with 4 wires on the socket. A friend and I used wire spades and a pop ricket gun to fix the socket. The focus 9 pin was very badly corroded in the socket. Now I have sound plus a raster but no video.

Ross

[Stlouisian]

Looks like I was wrong about not getting video. I attached my Sencore Dot Bar/Color Bar generator to the TV and got this picture. It is a bit out of focus and after a few minutes the left side of the picture shrinks a bit. Where might I need to check in the high voltage section of the tv? Thanks.

Ross

Originally posted by jstout66
Great looking set! I haven't EVER seen a Motorola roundie. They were so quick to have a square tube that there can't have been very many sold. Does yours work?

Motorola introduced the 908-Y chassis in the fall of 1963. This chassis was an excellent performer, and used the rectangular 23EGP22 CRT, which was developed jointly by Motorola and National Video Corp (both in Chicago). This CRT was the world's first mass-produced rectangular color tube. The sets were deluxe models with Drexel cabinets, and were priced accordingly. About 100,000 of these sets were manufactured.

During this time Motorola also marketed a budget line of color sets using round CRTs & series-filament hot chassis in cheap cabinets. These were priced at about half the price of the rectangular models, and did not sell well. I was not aware that Motorola had produced a round tube model with a transformer-powered chassis in the sixties - must be quite rare.

Today it is rare to find ANY Motorola color set, including the Quasar! In the sixties, they were common.

[Stlouisian]

Here is the tube layout for you guys there are curious about my set.

Ross

[drh4683]

picture looks a bit washed out. Did you try adjusting your AGC control? If you did and it didnt help darken up the picture, test your IF tubes and that 6HS8 AGC/clipper. Should that not be the case, then check your video amplifier tubes. you should have probably 25KV on the the anode if HV is properly set. To check the HV, turn the brightness and contrast all the way down, then try to stick the HV probe between the anode cap and the CRT well and adjust your HV for about 25 KV. Your focus voltage should read at 5KV. Poor/ corroded connection to the pin of the crt can cause the focus to go off. But if you want, touch your HV probe on the focus lead (probably black) and see if youve got 5KV, if so its a connection problem most likely.


Just as a safe rule I follow, when I get a TV for the first time that I work on, I test every tube in the set, even though the set might appear to work ok. Sometimes the set is working good but the grid leakage is poor, or a life test on a tube fails indicating trouble is on the way. Its just a good habit to get into I think, it also makes you feel good as you now know ALL the tubes are good, and you feel more confident in relying on the TV to work good.

keep us posted.