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#16
07-06-2008, 12:16 AM
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Well, it's here....
The set, cosmetically, exudes coolness. Beyond the knobs (which, I'm in need of an assist on - the on/off/volume's warped, the channel's numbers are gone, and the contrast thingie is broken...), the safety glass is a conformal type like on later color sets. There's a mask behind it, giving it a kind of 15GP22 look to the whole thing. The changer's weird, but looks functional. It'll need a clean/lube though, bigtime. The hold/size/lin/focus and even brightness, controls are hidden. And the fine tunning. At first, I couldn't imagine that Motoroller would have hidden these all over the chassis. Pulling the on/volume knob gave a hint: a little lever behind there. Sure enough, flipping it allowed the metal piece around the knob to slip off, revealing ALL of the needed adjustments! Here's the trick part: The pilot light serves double duty when the casting's off, allowing you to see the controls (which are marked via a decal). The fine tuning's the same way - with a 70's zenith style adjuster thing that spins around with channel changes. Neat! The radio is weird - ho hum front end but push pull output. The rectifier's a locktal (!). The radio's amp doesn't serve duty as a TV amp - the TV and radio are almost totally independent of each other. The TV chassis? Bonkers. Vertical output's a 25L6. Series string, right? Nope - it's transformer, with a second transformer for just that tube. There's 2 5U4s, a bunch of other tubes, and 3 (!) stages of video amp. The HV box has two doorknobs in it, in a doorknob - resistor - doorknob, like a power supply filter. The HV lead unplugs from the top of the box, and the yoke and focus coil unplug, too. The tube's got a plastic apron over it, which got scuffed by one of the CRT support springs - there was a few layers of tape there. Now, the bad news: the yoke was stuck to the CRT! Freeing it also freed the tube socket, but thankfully NOT the air. There's enough lead to reglue the socket, but it might not even be worth it: There's a brightener on the tube and the gun assembly looked a bit discolored. And the yoke might be wasted (it's pretty ratty looking, but I might be able to salvage it). So, we've got a bum CRT, it looks like  But the rest of the set is in good shape and looks like it'll clean up and work. There's surprisingly little evidence of repair in the set.Anyone have any success at rebuilding a 19AP4? Oh, BTW, it's a freaking heavy tube for some reason... 
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#17
07-06-2008, 09:54 PM
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Quote:
Pick up a spare while you can: http://cgi.ebay.com/ws/eBayISAPI.dll...m=230267586559
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#18
07-07-2008, 06:11 PM
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I still can't believe this went for $1000. I have turned down many of similiar units for next to nothing rather recently.
__________________
julian
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#19
07-07-2008, 08:38 PM
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Quote:
__________________
 Do not attempt to adjust your set.
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#22
07-08-2008, 05:37 AM
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Yeah I saw that 19AP4, but didn't get it
Well, it's not the ONLY one out there and this tube's still got a vacuum. Can Hawkeye rebuild this type? Once I get the set rolling, I'll see just how good/bad this one is. I always seem to get sets with oddball CRTs anyway - I've got two sets with 21EP4s, a set with a 21MP4, and now this. With my luck, it's amazing I haven't found a CT-100 yet :/
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#23
07-10-2008, 04:19 PM
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Hawkeye can rebuild it , using the modified 6 hour reduced temperature oven cycle we developed for the 15GP22 rebuild. This minimizes the thermal stress on the large glass-to-metal seals on theCRT. But it will probably be a bit expensive. I will let Scott at Hawkeye quote you a price.
There are 19AP4s out there, you would likely find one if you keep looking.
__________________
John Folsom
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#24
07-10-2008, 05:48 PM
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That thing is beautiful!
Unfortunately here in ZA we only got TV transmissions in 1976, so theres ZERO chance of finding anything that looks like that locally. MORE photos please!
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#25
07-10-2008, 07:35 PM
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Pictures will be coming once I theft the digicam from the parents. They bought it for 'vacations' and haven't been on one for a while but get upset when I borrow it anyway. I don't think I want to know (I have my own SD card for it)....
The turntable's cleaned up, though the turntable platter bushings are a bit...wobbly. I'll have to get new ones machined eventually. I'm up to the radio, which needs a bit of work, but it's not very complex. Once the radio's going, I'll do the TV set. I've seen a few things online for reviving a CRT, most seem to suggest somewhat higher filament voltage, and a few suggest putting a hundred or two volts between the cathode and grid, too, with a meter to watch current. Might try these - I doubt it can make things worse.
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#27
07-12-2008, 12:22 AM
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Well, I've got a brightener on the filament plus my trusty Heathkit regulated PS, and with 100 volts on the grid, the current flow DID increase slowly for a while tonight (10 minutes). I'll put this back on tomorrow and see how high it goes with time (don't want to leave it on all night!). Maybe I'll bop enough life back into the tube to get a 1/2wy decent picture for testing and setup...
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#29
07-12-2008, 08:15 PM
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Well, the radio's alive
 I got the AM band working, and the first thing that came up was WABC, right during their Saturday night oldies show! That just added to the cool of getting the thing going. The antenna needs work and the FM's still dead and oh man will it need an alignment, but it's getting there
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#30
07-13-2008, 03:16 PM
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I brought the TV up on the variac today. With just the octal (sweep section) tubes in, I got a horizontal and vertical sweep! The HV is only 7kv, so I'm 10 short (!).
The HV box was dirty, with the fine black HV box dust - the HV rectifer/filter unbolts and comes out, and the cleaned up well. The design looks like it could have taken a second tube for a doubler - wonder if that was another model or a planned change for the upcoming 21 inch sets? The HV box is easy to work in, which is nice cause this one's had issues over the years... This set's got a few bizzare features, most bizzare is the 25L6 as a vertical output - there's an autotransformer to jump the 6.3V to 25 volts under the chassis. I'm guessing Motoroller used a boatload of 25L6s or something, and needed to dump a few. There's also a squelch on the audio, for zero-signal situations. And the HV lead unplugs, allowing you to work on this set with the HV lead gone (and the CRT gone). It looks like the basic stuff's working, I might put the balance of the tubes in and see if it picks up any stations - I suspect the set was stored after the CRT took a dump, or it was simply replaced by a newer set - there isn't anything obviously wrong with it other than age. Oh yeah, there's a zillion caps in this thing. Motorola must have owned a capacitor company too....
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