|
|
|
#33
04-24-2009, 05:31 PM
|
||||
|
||||
|
I got this back together. The 2 problems it has are with the color and the power tuning. It works on all 3 guns, and does sync the color, but a resistor burned out on the convergence board when I first turned it on, I tried replacing it, but the convergence is still way, way off. I can't even get good separate red, green and blue lines when I flip the service switch. I mostly get a thick bright white line that won't even go away if I turn the controls all the way down. The power tuning is a mechanical problem, I hear something going in there when I flip the switch, but it doesn't actually move the tuner.
|
|
#34
04-27-2009, 03:26 PM
|
||||
|
||||
|
I picked up an SC400 remote off of ebay, it arrived today. http://www.audiokarma.org/gallery/sh...php?photo=5480
|
|
#35
05-04-2009, 10:04 PM
|
||||
|
||||
|
I made some progress on this today. I replaced 2 bad resistors on the convergence board, R192 and R193, if you're following along in the sams. Also replaced the 2 paper caps on the convergence board C124, C125. And replaced the selenium rectifiers (even though they tested ok) Now the convergence is basically good (it still needs adjustment, but it's not way off anymore) That solved one problem...
But the picture was still way too blue. And I still had a large thick blue line in the setup mode, red and green lines were ok. I started checking voltages at the crt. I checked the G2 voltages, all good. I checked the voltages at the cathodes, and they were ok. Finally, I went to check the G1 voltages and noticed that the blue wire was loose in the crt socket, I stuffed it back in the socket, and that fixed it. But I suppose I should take the socket apart (you have to drill out 3 rivets to get in this one) and solder it back on... I still haven't looked at the power tuning. Last edited by Adam; 05-04-2009 at 10:25 PM.
|
| Audiokarma |
|
#36
05-06-2009, 07:03 PM
|
||||
|
||||
|
I figured out what's wrong with the power tuning. The plastic gear on the end of the shaft coming out of the motor separated and broke in three pieces, allowing the motor to turn inside it without actually moving anything. I might try to glue it on there with some kind of heavy duty epoxy or something, but I don't have anything like that on me, I'll have to make a trip to the hardware store tomorrow. Here's a pic. http://www.audiokarma.org/gallery/sh...ze=big&cat=503 You can see the upper part separated from the lower part on the shaft. It's not visible, but the lower part is also separated into 2 pieces.
|
|
#38
05-08-2009, 12:55 PM
|
||||
|
||||
|
The sams has a part number for the entire motor, but not just the gears.
I glued it back together, and it seems to be holding. I glued not just the plastic bits together, but also glued it all to the shaft, thinking that would make it hold together better. Like I said, it seems to work, but if I ever do need to replace it, now it won't come off so easily. The range on the remote is greater than any other I've had, with the set in the livingroom, I can walk to the back of the kitchen (more than 20' away where there's no direct line between me and the set) and it still works. And I actually kind of like having the transistorized remote receiver, I don't have to turn it on and let it warm up before I can use the remote to turn on the set. The reception on this set is also better when hooked to the antenna in comparison to my other roundies. But, the uhf doesn't work at all. Turning the uhf tuning knob has absolutely no effect on the picture. Now I checked to see if there was power getting to the uhf tuner, and there was. I also plugged and unplugged the wire carrying the signal from the uhf to vhf tuner, and this does cause effects in the picture. So I'm thinking the problem has to be internal to the uhf tuner. ... The problem with the uhf also appears to be mechanical. The tuner was frozen stuck, and rather than turning it, when I moved the controls, it just pushed the tuner at a slight angle to the gear turned by the control. So when I turned the knob, it wasn't actually moving the tuner. I won't know if there's anything else wrong until I take this apart, clean and lube it up so it turns easier, then put it all back together, but I suspect that this is it. I also need to replace the light bulb for the uhf. Last edited by Adam; 05-08-2009 at 01:30 PM.
|
|
#39
05-08-2009, 02:09 PM
|
||||
|
||||
|
I have the same problem with the gear being broken in my avatar set, I have a SC 400 black and white with a rotted cabinet that is to be the donor of a "new gear". If I run across two in my storage area that I am cleaning up this weekend, you can have the extra but there is no promise, I can't remember if I have two or not. When the motor shaft jumps out to turn the tuning gear, sometimes the teeth don't align and it breaks the gear that is now getting brittle with age. I wonder if there are any NOS replacements out there. Good luck with your set, it is a beauty.
__________________
My TV page and YouTube channel Kyocera R-661, Yamaha RX-V2200 National Panasonic SA-5800 Sansui 1000a, 1000, SAX-200, 5050, 9090DB, 881, SR-636, SC-3000, AT-20 Pioneer SX-939, ER-420, SM-B201 Motorola SK77W-2Z tube console McIntosh MC2205, C26 
|
|
#40
05-08-2009, 09:45 PM
|
||||
|
||||
|
I fixed the uhf, it was just the mechanical trouble with the tuner. But the uhf light wasn't going on, not because the bulb was bad, but from dirty contacts in the switch that turns it on.
I often wonder what will happen when the parts for these sets dry up. Now I may be in trouble if I need something like these plastic gears, but stuff like tubes are still readily available. But it's not like they're making more of many of the tubes our sets use. I want to keep using my big old color roundie consoles as daily watchers, but eventually we're all going to run out of 6GH8s and we'll all be in trouble.
|
| Audiokarma |
|
#41
05-09-2009, 10:15 PM
|
||||
|
||||
|
pictures of the Zenith working...
http://www.audiokarma.org/gallery/sh...=5493&size=big http://www.audiokarma.org/gallery/sh...&size=big&cat= http://www.audiokarma.org/gallery/sh...=5491&size=big http://www.audiokarma.org/gallery/sh...=5490&size=big http://www.audiokarma.org/gallery/sh...=5489&size=big http://www.audiokarma.org/gallery/sh...=5488&size=big Last edited by Adam; 05-10-2009 at 08:26 AM.
|
|
#43
05-13-2009, 07:51 AM
|
||||
|
||||
|
Thanks. Unfortunately it only worked that good for about a day and a half.
Now what it's doing is, when I first turn it on, it pops out of focus about every 2 seconds (out of focus so slightly that I can't really notice it unless there's writing on the screen). When it pops back into focus I see very briefly a single white horizontal line flash across the screen (not always in the same place). After the set warms up for about 10 minutes, it stops going in and out of focus, but the white horiz lines start flashing across the screen at a much faster rate, until it appears that there are several of them at once. (The lines aren't that bright, not really brighter than the rest of the picture, and they don't stay on the screen for long) After the set warms up for 30 minutes or so, the problem becomes intermittent and it will do it for several minutes, then quit for a few minutes, then start up again. Now I won't have time to work on this again till the middle of next week, but anyone have any thoughts on this? My first thought is to start checking out what's going on around the horiz output tube, but then I've never seen anything like this before. There is no problem with horiz hold, width, linearity, etc. The vertical appears a little jittery in the first couple of minutes the set is on, then stops. But the vert sync is never weak, even when it first comes on. Vert size is fine, vert linearity is not totally perfect, but it's really close. The color is good, the problem occurs exactly in the same way on a color and a b/w picture. It does not effect the sound. Last edited by Adam; 05-13-2009 at 07:59 AM.
|
|
#45
05-13-2009, 02:43 PM
|
||||
|
||||
|
Check your focus lead where it goes into the crt socket. These are known to arc, crumble or corrode right at the pin in the socket. I had the same problem with mine and the problem was where the focus wire was connected to the focus pin in the socket was badly corroded. I fixed mine by taking the cover off the back of the socket. I then removed the focus pin and wire. After that I removed the wire from the pin, I cut about an inch off the wire because the corrosion had wicked back into the wire some. Then I cleaned the corrosion off the pin and soldered the wire and pin back together and reinstalled it. I also cleaned the focus pin on the crt and the crt socket while i was at it and checked for carbon trace. It took care of the problem and has been working great for almost two years now.
To get the cover off the back of the crt socket, get a 1/8 drill bit and just drill enough to remove the revit head. There are three of them. Pop the cover off and repair. After the cover is removed, you can remove the rest of the revit by pushing it through to the other side. To re-attach the cover, just find some small screws like you would find in a transistor radio or vcr and screw the cover back on using the original revit holes. Take your time putting the screws in to avoid cracking the bakelite socket. Some of these small screws have cutters made into the tips that will self tap the threads when installing. The good part about doing this is you can install the socket on the crt first and check for any arc's before re-installing the cover and coat with silicone or similar first. Remember that the wire leads just sit in the socket and use the cover to hold them in, so pay attention that the leads stay in the socket while your handling it with the cover off. -Tony Last edited by Tony V; 05-13-2009 at 02:58 PM.
|
| Audiokarma |
 |
|
|
Linear Mode
