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1961 Coronado Capri
The zenith I worked on earlier in the year has a bad CRT, so I tucked that away and am going to try to get this one running 1st. Its a 17"B&W, chassis #TV2-9402H. Sams set 553, folder 1. I'm still a rookie at this so please bear with me.
This is full of bumble bees, but there arent a terrible amount of parts in it. Its a hot chassis set. Im adding a few pictures and have a few questions; 1. The crt back side is peeling. Is this going to be an issue and is there anything I can do about it? Hot chassis is one of my concerns with that. 2. The flyback has one crack. The pic looks like 2 but there is only the one. Should this be coated somehow or should I just go ahead and try it after I recap? I did try a slow power up with no results except squeeling from the speaker. 3. If you notice anything else on the chassis feel free to comment. It has a 20W resistor way over tolerance so I know that needs replacing too. The CRT tests good, at least with the tester I bought. I do have a schematic. I also have isolation transformer. I can add pics of if needed. Thanks! |
#2
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The 20 watt resistor is probably OK. The resistance is probably high, because the set doesn't have a UHF tuner. It's a heater dropping resistor. It's either good or bad, they don't increase in value. You mentioned, the tubes light! I would be more concerned about the high-value electrolytic, as the set doesn't use a voltage doubler. Then you could start recapping in stages. |
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Wow, that is one of the cheapest built portables I've seen....I'm surprised that it only seems to use three sections of lytic.
You can clean the flaking aquadag off the back of the CRT (taking note of what the original border of it was), mask the areas it does not belong off, and re-coat it with "Slip-Plate" (spelling?) or "Areodag". I have not had arcing/corona issues with cracked tires in monochrome TV so I usually get the set working before worrying about the tire.....YMMV.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
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I'm glad to hear it is a somewhat decent quality. The 20W tests at 330 and is supposed to be 36 ohms. this wont matter? Yes, it has a 200 and a 250uf electro's. They'll be one of the first things replaced. I think they will both be replaced with 220's unless thats a problem.
Can the chassis safely be started without the CRT, speaker, etc not hooked up? Too test voltages. The less times I have to pull it apart the safer the crt neck will be. Thank you for the reply. |
#5
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Could I slip a piece of intertube between the tube and metal to keep it from arching? At least until its working. Sorry but I cobble a lot of old cars and cant help but think like that LOL |
Audiokarma |
#6
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#7
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What does the Sams say about the resistor ??
Looks like it goes to the rectifier. If so normally its a 5.6 ohm 5 watt fusable or there abouts. Also its a wire wound & I have NEVER seen one change value only open. If it is open change the rectifier too. For testing you can pull the chassis & yoke then put the HV lead in a glass jar. OR get a test CRT. OR get test sockets that plug in between the tube & socket. The dag thats flaking needs to be fixed. It acts as one side of a cap along with the inside coating & needs to be grounded. Last thought is BEFORE a recap get a picture on the set. Many reasons why........ 73 Zeno |
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He did say he brought it up on a variac and only got squealing from the speaker.....If it powers up like that he will have to replace caps to get a picture on it....Maybe go a few caps at a time and test the set after each 1-3 caps, but if it ain't showing a picture with all those bad plastic caps in it there is NO way it will get better with all those caps there.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
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Im including a pic of that part of the schematic. It has a 5.6 ohm fuseable installed (R57) and that is fine. Its the other one (R58) that tests so high. I circled them in red.
Thanks again for the advise. I will recoat the CRT, clean sockets and tubes, put in new electros and see what happens. (maybe other things that I spot) All the tubes did light up when I had it powered, but several were bad so I will replace those too. I guess I will just put it all back together before trying it. It wasnt t too bad to take out, I just worry about the neck. Edit: electric M, I posted before seeing your last post. I dont mind switching the caps if I need too. They are all bumble bees so I figured there may be bad ones anyway. |
#10
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You could probably get away with gluing aluminum foil to the glass to replace the flaking stuff. Avoid the high voltage connection and the yoke area. And be sure the foil is connected to the set's ground.
You'll need to replace the usual wax caps, bumblebees and electrolytics.
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Audiokarma |
#11
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Being a rookie on tv's, I probably better not try the tin foil as I may damage something or do it wrong. I painted for a living many years and understand that. Is this the correct slip plate product? There are a couple varieties and this one has a G on the end. http://www.ebay.com/itm/SLIP-PLATE-3...4AAOSwnipWYodd
At the very least, I'll test the bumble bees and replace the bad ones, after it being suggested now a couple times. Maybe I'll just do them all as its good experience anyways. Thanks! |
#12
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Don't bother testing them, they're all bad.
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#13
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Regarding the heater dropping resistor, what kind of meter are you using? The reading is off, by a factor of 10. The resistor looks original, with a W-G part number. As before, the tubes wouldn't lite, if the resistor is 330 ohms, instead of 33 to 36 ohms. |
#14
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It may be an error in Sams. If its a say 33 ohm & you add
a zero its a 330 ohm.......... For now just check for APX 95 vac on pin 7 of tube V7. You do not want to put a 33 ohm in if its a 330 ohm. NOT good for the filaments............ Why get a pix first ? 1) to be sure you got a good CRT. Even if it tests good it still can be bad & visa versa. 2) check to see that all MAJOR parts are OK. Even 40 yrs ago you couldnt get some of this stuff. 3) you learn by troubleshooting NOT shot-gunning 4)re-caps need to be done a few at a time followed by a test. If you do something wrong its easier to find if you just gotta look at a few things. Nothing worse than finding a self induced problem. Sends techs running if its "been somewhere else" & never fixed. And you never get the truth out of the customer !! good luck Zeno |
#15
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This works great for coating the CRT.
http://www.amazon.com/MG-Chemicals-C...+Chemicals+838 Tinfoil can come loose and short out the chassis. The flyback isn't bad enough that I would mess with it, you risk more damage by tinkering with it. |
Audiokarma |
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