View Full Version : 66 motorola contrast issue


timmy
02-17-2015, 09:28 AM
i have a 1966 motorola 23 inch and if i turn the contrast to make the picture sharp the screen pulls in on one side. this set was recapped and works great its just the contrast if i want to make it sharper and as i turn it in that direction the screen pulls in. any ideas ...... :scratch2:

zeno
02-17-2015, 10:21 AM
Color or B&W ? chassis ## ( ts### )
a screen shot also if possable

AGC ( aka optimizer) too high
Weak hoz out or other sweep tube.
Try adjusting hoz hold.
HV regulator, color only.

73 Zeno:smoke:

dieseljeep
02-17-2015, 10:22 AM
i have a 1966 motorola 23 inch and if i turn the contrast to make the picture sharp the screen pulls in on one side. this set was recapped and works great its just the contrast if i want to make it sharper and as i turn it in that direction the screen pulls in. any ideas ...... :scratch2:

I sounds like a HV regulator problem. What chassis number is it? A TS914?
Did you check the 3AT2? It might be blooming! It's been ages, since I worked on one of them. Also, the 6LY8 was overworked in that chassis. Try replacing it.

timmy
02-17-2015, 10:52 AM
it is a color set and there is no 6Ly8 maybe a different one ? the chassis is a 908 and i have the schematic that covers both aets908ye and the ets908ye. this is the set that uses 2 hots. it does seem to bloom when the contrast is turn to make it sharper.

DaveWM
02-17-2015, 05:09 PM
I would start with a check of the HV regulation, see if it vary's as the sides pull in.

dieseljeep
02-18-2015, 01:14 PM
I would start with a check of the HV regulation, see if it vary's as the sides pull in.

The ETS908 chassis was really an overbuilt chassis. That was my first color set, bought brand new.
One day, it started blooming and going out of focus. Both the 3AT2 and the 6BK4 were weak. That was when the set was around 7 years old.
We only ran it for 10 years, until the original 23EGP22 got too weak to produce a decent picture. The video output tube in that chassis is a 6HB6.

timmy
02-18-2015, 02:11 PM
yes this chassis does look over built and it does look like the hv is not regulating and this is the cause but for now it has a great picture even when certain scenes show the hv dips to 19kv but is still bright and clear and dont bloom. maybe because the crt is in great shape as it was replaced in december 1980. i did try another rectifier tube and hv reg tube no change . so one day maybe ill tackle it but for now it only goes on maybe 3 times a year.

DaveWM
02-18-2015, 02:27 PM
if a new HV rec and HV reg do not fix, then I would look into the horz out, could be weak. Is this the set with two horz outs?

DavGoodlin
02-18-2015, 02:29 PM
Timmy ,
Please post a picture of this set. I had a metal cabinet TS914 once but this is a bit older. Mine had the color indicator light and the "tint" control. It had a good 23EGP22, rare as they are.

timmy
02-18-2015, 02:53 PM
if a new HV rec and HV reg do not fix, then I would look into the horz out, could be weak. Is this the set with two horz outs?

yes its the one with 2 horiz outs.

timmy
02-18-2015, 03:13 PM
Timmy ,
Please post a picture of this set. I had a metal cabinet TS914 once but this is a bit older. Mine had the color indicator light and the "tint" control. It had a good 23EGP22, rare as they are.

ok heres the overbuilt beast, with the really good 23egp22 this one has the color light as well. this one is the 908 chassis.

Username1
02-18-2015, 05:55 PM
-WOW- That is a nice tv ! !

I think the problem is that Timmy sucks HV right out of whatever tv he is next to- :)

A good 23EGP22............... Timmy has a time machine too..........?

That is a really nice cabinet...... Real wood....?

.

DavGoodlin
02-18-2015, 07:29 PM
-WOW- That is a nice tv ! !

I think the problem is that Timmy sucks HV right out of whatever tv he is next to- :)

A good 23EGP22............... Timmy has a time machine too..........?

That is a really nice cabinet...... Real wood....?

.

Yes, exactly what squirrel said! Nice one- really!:yes:

Electronic M
02-18-2015, 07:52 PM
Yeah, from what I've red here I'd estimate the number of good 23EGP22s known to exist at around 10.

timmy
02-19-2015, 07:03 AM
well this motorola has been for sale if anyone may be interested, i would let it go for what i have in it. i bought this from a VK member a few years back and i got 225.00 in it , tubes, caps and the price for it, it may be more but i dont remember. this problem with the hv regulation in the beginning i thought it may have been the flyback and or the yoke so i got both from moyers the yoke i didnt put in but the fly i did so now i know what the problem is and its got a new fly and a spare as well as a spare yoke and i didnt add these items to what i have in this set. so if someone offers 225.00 for it i will take it.

oldtvman
02-19-2015, 08:05 AM
During my years of tv service I never saw a Motorola 23" that had a good picture. Not until Mashushita took over the Motorola name.

dieseljeep
02-19-2015, 08:39 AM
During my years of tv service I never saw a Motorola 23" that had a good picture. Not until Mashushita took over the Motorola name.

They only took over the Quasar name. They also had the Franklin Park and possibly the Taiwan plant.

dieseljeep
02-19-2015, 08:43 AM
Yeah, from what I've red here I'd estimate the number of good 23EGP22s known to exist at around 10.

Make that nine. I regret to say, I bought one last fall, that went to air before I received it.

timmy
02-19-2015, 09:14 AM
a few pics...

Username1
02-19-2015, 09:29 AM
I wonder if after that tv is fixed, running it at just above minimum bearable brightness
and possibly adding a 2 to 3 ohm 10 watt resistor in series with the picture tube
filaments - reducing the voltage 2 to 3 volts may just add several years to the
life of a 23EGP22.......?

It sure looks like a nice bright tube now....

.

dieseljeep
02-19-2015, 05:47 PM
I wonder if after that tv is fixed, running it at just above minimum bearable brightness
and possibly adding a 2 to 3 ohm 10 watt resistor in series with the picture tube
filaments - reducing the voltage 2 to 3 volts may just add several years to the
life of a 23EGP22.......?

It sure looks like a nice bright tube now....

.
The CRT was designed to operate on 6.3 volts. I don't think, running it on a lower heater voltage, would extend the life of the CRT.
That CRT, like the mid-90's Zenith CRT's were just a bad situation. It was all, the luck of the draw.
In the mid-60's, when rectangular CRT's got popular, there was common failures in the other manufactures CRT's. I saw bad CRT's in Zenith's, RCA's and Sylvania's, where the sets were only 14 to 18 months old.
Guess what, the set owner, had to pick up the tab for a CRT replacement.
A little later on, most manufacturer's increased the warrantee to two or three years.

timmy
02-19-2015, 06:26 PM
oh so maybe the 23egp22 i have in there now is a much better one since it has a date of december 1980. but even a 10 year warranty would be up by now, lol lol :D

Electronic M
02-19-2015, 06:36 PM
oh so maybe the 23egp22 i have in there now is a much better one since it has a date of december 1980. but even a 10 year warranty would be up by now, lol lol :D

Odds are it's a rebuild, and probably a LOT better off in terms of reliability because of that rebuild...

IIRC the electron guns in the EGP were essentially the same as those in other tubes, but the early EGP cathodes did not last as long as they should...So a rebuild with better made cathodes should be every bit as good as a properly made non-EGP.

dieseljeep
02-20-2015, 09:45 AM
oh so maybe the 23egp22 i have in there now is a much better one since it has a date of december 1980. but even a 10 year warranty would be up by now, lol lol :D

Here, I thought that the 23EGP22, I bought was a real gem. Rebuilt by Video Display Corp in the mid-80's, with a 2 year warranty on it. It's even a rare-earth.
I thought to myself, This set's going to have a great picture. I checked the tube before installing it. Zip, nutin, nada, not even a heater glow. I even started it at a lower heater voltage. Looked like it went to air, but no white on the getters.
When sent, it was packed very well and shipped by Fed-Ex. Both boxes were in good condition, so it didn't appear to be mishandled.
I don't think the tube was checked before it was shipped. :thumbsdn:

DaveWM
02-20-2015, 11:01 AM
I still have a VDC 23vecp22 in the box, have not checke it BUT I did recently install one that a got a couple years ago into a zenith.

has a purity issue that can not be worked out. you can see it with the hand held degausser as what looks like a pinch or some other defect in the shadow mask in one corner the other issue is some purity in the top middle that shows like a purple stain. Its more noticeable on some background colors that others.

I have another on from VDC in the box, maybe someday I will try it out. Too bad since both test great with emissions and cutoff.

My guess is one of them took a hit to the corner, maybe jacked the shadow mask up. I hope the other one in the box is ok.

Electronic M
02-20-2015, 11:13 AM
Here, I thought that the 23EGP22, I bought was a real gem. Rebuilt by Video Display Corp in the mid-80's, with a 2 year warranty on it. It's even a rare-earth.
I thought to myself, This set's going to have a great picture. I checked the tube before installing it. Zip, nutin, nada, not even a heater glow. I even started it at a lower heater voltage. Looked like it went to air, but no white on the getters.
When sent, it was packed very well and shipped by Fed-Ex. Both boxes were in good condition, so it didn't appear to be mishandled.
I don't think the tube was checked before it was shipped. :thumbsdn:

If the getthers are still normal, then perhaps it is just a bad heater weld. I'd consider getting something like a charged 80uF 200V cap connecting it to the heater pins and tapping on the neck with a screw driver....You have nothing to loose in it's current state.

Username1
02-20-2015, 05:04 PM
Well My 23EG was deep green in the face, Timmy's set looks like one of those grey
face tubes common in the 80's... Maybe his was not a rebuild, but a new one....
Maybe he has nothing to worry about.... One of you guys who knows more maybe can
tell more with the manufacturer code....? But then he's most likely gotta remove the
metal shield around it, maybe better leaving it alone.... Timmy, Don't go digging in there!



.

dieseljeep
02-20-2015, 07:22 PM
If the getthers are still normal, then perhaps it is just a bad heater weld. I'd consider getting something like a charged 80uF 200V cap connecting it to the heater pins and tapping on the neck with a screw driver....You have nothing to loose in it's current state.
When I first checked it with a reduced heater voltage, the neck got a little warm to the touch, but I couldn't see any glow.
I'll try the charged cap trick, as the Crt is probably scrap.
When I first received the tube, it had a lot of gray plastic tape wrapped around the front of the tube, but not covering the bond between the CRT front and the safety glass. It was appearant the the tube needed cataract surgery. I didn't care about that, as long as it showed a good picture.
A little history about this set. I bought it from Doug, drh**** on Ebay.
The set is a low hours set, that is extremely nice and appears to not ever being repaired. All original tubes, clean inside and out. That was the famous CRT that almost cost him his life. It imploded, when he was attempting cataract surgery.
I bought a conversion kit on ebay for a 25XP22 and half the parts were missing. I guess some things aren't meant to be. :D

Electronic M
02-20-2015, 08:27 PM
When I first checked it with a reduced heater voltage, the neck got a little warm to the touch, but I couldn't see any glow.
I'll try the charged cap trick, as the Crt is probably scrap.
When I first received the tube, it had a lot of gray plastic tape wrapped around the front of the tube, but not covering the bond between the CRT front and the safety glass. It was appearant the the tube needed cataract surgery. I didn't care about that, as long as it showed a good picture.
A little history about this set. I bought it from Doug, drh**** on Ebay.
The set is a low hours set, that is extremely nice and appears to not ever being repaired. All original tubes, clean inside and out. That was the famous CRT that almost cost him his life. It imploded, when he was attempting cataract surgery.
I bought a conversion kit on ebay for a 25XP22 and half the parts were missing. I guess some things aren't meant to be. :D

I'd make sure the heater is open first. If not all the cap trick will do is possibly risk damaging the heaters....Though if it is down to air and the neck is getting warm because the heaters are warming the air inside, it won't make any difference if the heaters get damaged since that is the point where only a rebuild may help.

Username1
02-20-2015, 08:58 PM
EM is right, if the tube is getting warm, then the heaters are not open....
The charged cap will just melt them right off....

You should carefully check to see what you have going on.... Check voltage and current
going to the heaters, use 4v DC if you have to, be sure they are actually good.