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Old 09-12-2017, 07:48 PM
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Radiophile2001 Radiophile2001 is offline
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1967 Color Sylvania video died (Mod. CF16W)

Hi--

I probably do not run my TVs enough...turned them on today and came back down in an hour or so and the Sylvania's raster was out. Opened the can and found some evidence of smoke. Seemed to center around 3CU3A tube, which I removed.

Nothing melted...a resistor(?) was blackened a bit but not melted.

Is it possible that if I just get a new 3CU3A and plug it in, this might come back to life? Cheap on ebay.

Screen was fine when I turned it on today initially, but I left the room. Was viewing via UHF mini transmitter attached to cable box.

Thx!
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Old 09-13-2017, 12:49 AM
old_coot88 old_coot88 is offline
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First rule of operating any vintage TV: never, ever leave one running unattended, especially a color set.
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Old 09-13-2017, 09:13 AM
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Radiophile2001 Radiophile2001 is offline
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I have certainly learned my lesson.....I heard some unusual buzzing sound while listening to an old AM radio....one I had never heard before in the sound of AM interference.....and I immediately suspected one of the TVs....
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Old 09-13-2017, 09:55 AM
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If it still has sound then it probably has B+ (if not check the B+ supply circuits).
Without the HV rectifier (3CU3) installed, and with the room dark does the Horizontal output tube plate (different from the heater which is supposed to glow) start to glow (red/orange)? If the plate stays dark that is good, but if the plate glows do NOT let it run for more than 1 minute (or damage to that expensive tube may result). If the tube plate glows (commonly called red plating), measure the grid bias. If the grid bias is somewhere around -50 to -75 volts DC then you have proper grid drive (if not the H oscillator needs work). look for shorts on the secondary side of the flyback.

Do you have the schematic for this set? If not look for the Sam's photofact for it. Schematics are essential for troubleshooting/finding your way around in a color TV.
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Old 09-13-2017, 01:23 PM
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Radiophile2001 Radiophile2001 is offline
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Hi there--

I tried what you suggested, but unlike yesterday with the 3CU3A still removed, its connector was sparking like Frankenstein's lab....and making sparking noises. I turned it off soon thereafter. No smoke or anything. All other tubes looked like they were heating up.

I have attached a pic...the connector is circled in red. Also circled is one pin hole that oozed a little bit of oily stuff. It is also on that pin of the removed 3CU3A.

My problem--do not have a schematic and do not have any diagnostic gear. More of a hobby that a specialty for me. I can solder, replace tubes, wires, diodes, resistors, capacitors, etc, but most of all I am a TV idiot who is much better at restoring transistor radios.

Thanks again, though, I am willing to try to fix it as much as my skills will allow ;-)

I had this crated and shipped from the Chicago area years ago from one of the major collectors in this forum,...can't remember his name but he had a basement full of TVs and was a real pro at repairing 60s sets, along with Lawn Boy mowers!
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Last edited by Radiophile2001; 09-13-2017 at 01:30 PM.
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Old 09-13-2017, 01:27 PM
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Oh yeah -- also, the set still has full sound. I also have a new 3CU3A on the way from ebay....about $9 shipped.
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Old 09-13-2017, 02:08 PM
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If the top connector is creating a healthy arc like that then all the troubleshooting advice I gave is likely irrelevant. Try it with the old HV rect tube back in and see it it produces a raster. If not then you definitely need that tube you ordered. If it does produce a raster as bright as before with the old HV rect in it then there was some other issue that has it has temporarily recovered from.

There should not be anything in the pin of that tube socket to produce an oily substance...That oil is probably grease/dirt that found it's way into the set from outside. It is not bad (and sometimes necessary such as when dirt becomes a conductive path for arcing) to clean HV cage areas.

If you plan to fix the set your self/own it for the long haul you really should pick up a copy of the schematic/service data and keep it with the set.
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Old 09-13-2017, 02:29 PM
zeno zeno is offline
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I am with Tom C. Discharge the CRT & pull off the anode lead.
Pull the 3CU3 socket & clean it with 91% isopropyl alcohol.
Clean all the wires to it & the "cup" also. Put back together with
the new 3CU3 & try it.
BTW dischage the CRT AGAIN before reassembly !
BTW #2 most HV rect tubes DO NOT have a filament glow !

73 Zeno
LFOD !
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Old 09-13-2017, 03:09 PM
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Radiophile2001 Radiophile2001 is offline
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Thanks--!!

I will take all of these steps when the new tube comes....figure I will try it with a good tube first....

Also, discharging the CRT--is that basically just turning on the set without it being plugged in before reassembling with new tube hookup?

Will QD electronic cleaner work as well as 91% alcohol? I have both.

Thx again
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Old 09-13-2017, 03:44 PM
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To discharge the CRT take a screwdriver with a well insulated handle connect it's metal shaft to the TV chassis with a clip lead and slip the blade of the driver under the HV connector on the top of the CRT bell until a spark is heard or you know your hitting the metal connector.
The best way is to use an HV probe instead of the screwdriver/jumper method, but I'd guess you don't have one (that is another important tool for TV work). Second best is to put a high value (meg ohm and up) resistor in series with the clip lead.
If you don't have a resistor (the HV probe has one inside) in series with the ground the stored HV will tend to bounce back within 30 sec to 1 min of discharge.

Failure to discharge the HV stored in the CRT may result in one heck of a nasty static jolt.

Alcohol is best for HV cages/hardware. If you want to use the cleaner on the socket electrical contacts it should not hurt there.

The guy you got the set from is probably Doug Harland DRH4683 is his handle here and on you tube. Nice person I've bought stuff from him too.
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Old 09-13-2017, 04:06 PM
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Radiophile2001 Radiophile2001 is offline
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I will follow these instructions....thanks....! (don't need to damage the thing any more than it is)

Yes, Doug was his name and he was nice enough to give me the set....just as long as it made it to a good home that would not trash it. It has lasted a long time.

The same kind of thing had happened to my Zenith 1968 color TV.....but that involved much more smoke and melting. I was in the room for that one. All I did is turn it on, with the others.

Amazing how ghosts get in these machines! ;-)
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Old 09-13-2017, 04:58 PM
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Ill look up CF16W/DO9 issues in my book but PM me with your personal email and I will scan you the schematic. The 3CU3 should have you back up but take all the good advice here on cleaning things.
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Old 09-14-2017, 11:46 AM
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Radiophile2001 Radiophile2001 is offline
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Sure, it's sent, thx

Last edited by Radiophile2001; 09-14-2017 at 11:49 AM.
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Old 09-14-2017, 12:18 PM
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Findm-Keepm Findm-Keepm is offline
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Quote:
Originally Posted by zeno View Post
I am with Tom C. Discharge the CRT & pull off the anode lead.
Pull the 3CU3 socket & clean it with 91% isopropyl alcohol.
Clean all the wires to it & the "cup" also. Put back together with
the new 3CU3 & try it.

BTW dischage the CRT AGAIN before reassembly !
BTW #2 most HV rect tubes DO NOT have a filament glow !

73 Zeno
LFOD !
I'd also clean the regulator socket and cap above the cage - it has full 25KV on it and looks as though it may be just as dirty, judging by the plate cap.

HV loves and attracts dirt - it's a much lower resistance/impedance and may be your only problem.
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Last edited by Findm-Keepm; 09-29-2017 at 07:39 PM.
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Old 09-14-2017, 09:51 PM
walterbeers walterbeers is offline
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A couple of thoughts: Quite frequently the HV (red) wire that wraps around the core of the flyback that supplies the filament voltage to the HV rectifier tube 3CU3, breaks down and arcs to the core of the flyback. There is usually 2 or 3 turns around the core of the flyback and they go down into the HV cup that the tube sits in and is connected to the filament pins for the 3CU3. If it breaks down it arcs, smokes, and grounds out the HV, usually ruining the HV rectifier tube. Simple fix, just get some good 30KV or better HV wire, take the socket out of the cup and replace the wire, paying close attention to the number of turns around the flyback core. Yes, there is at least 24KV between the wire and the flyback core. Also another thing that i have seen happen is that the HV cup itself develops a crack or a spot in which the HV will arc through to the chassis. In this case you just need to replace the HV cup. Of course clean all the gunk off of the wires, socket, etc. Sometimes this gooey residue will also cause arcing. Since you get a good healthy arc off the connector to the 3CU3 coming out of the flyback with the rectifier tube removed, I think your flyback transformer is ok. Although the 3CU3 could be weakened or bad and also possibly the horizontal output tube.
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