View Full Version : National TV-7W


bandersen
01-24-2014, 08:18 PM
Seeing a National TV-7W on ebay (http://www.videokarma.org/showthread.php?t=260590) got me thinking it was about time I took a closer look at mine.

I got it from the Elli Buk auction last spring sandwhiched between a Clifton and bakelite Emerson.

http://farm9.staticflickr.com/8115/8684124139_131378a57c_c.jpg (http://www.flickr.com/photos/70039806@N00/8684124139/)

I suspect it was that very heavy Emerson that caused the top to mush down and front to pop out. Hopefully, it can be jacked up, glued and clamped back in place.
http://farm6.staticflickr.com/5531/12126341515_2351e86bbe_c.jpg (http://www.flickr.com/photos/70039806@N00/12126341515/)

I'm pretty sure only the fine-tuning knob is correct. I suspect it will be very hard to find a full set of correct knobs.
http://farm4.staticflickr.com/3685/12126444115_615f555216_c.jpg (http://www.flickr.com/photos/70039806@N00/12126444115/)

There seems to be two versions of this set. This being the early with series string tube filaments, logo above the screen and no holes for a magnifier.

The only good picture I could find online was from the ETF

http://www.earlytelevision.org/images/national_TV7W.jpg (http://www.earlytelevision.org/national_tv-7w.html)

Here's an example of the other version.
http://www.myvintagetv.com/national_tv7w%20.jpg (http://www.myvintagetv.com/national_tv7w.htm)

I'm pretty sure that's a homebrew back.
http://farm4.staticflickr.com/3768/12126573513_ed8dcca3b8_c.jpg (http://www.flickr.com/photos/70039806@N00/12126573513/)

It kinda looks like two labels were removed and this one applied.
http://farm8.staticflickr.com/7305/12126572343_844693a7ae_c.jpg (http://www.flickr.com/photos/70039806@N00/12126572343/)

Two fuses are a nice touch :)
http://farm8.staticflickr.com/7422/12126693394_13376bf98e_c.jpg (http://www.flickr.com/photos/70039806@N00/12126693394/)

mpatoray
01-24-2014, 10:33 PM
Looks like an interesting set. Is this an Electrostatic one?

David Roper
01-24-2014, 10:36 PM
Definitely yes.

bandersen
01-24-2014, 11:06 PM
Yep, 7JP4 electrostatic CRT.

Now for the inside.
http://farm6.staticflickr.com/5536/12126696294_51f7a5393b_c.jpg (http://www.flickr.com/photos/70039806@N00/12126696294/)

The AC line voltage selector is a nice touch.
http://farm4.staticflickr.com/3730/12126692114_c86047f164_c.jpg (http://www.flickr.com/photos/70039806@N00/12126692114/)

Solid plywood bottom.
http://farm4.staticflickr.com/3763/12126325905_514bfbbb7b_c.jpg (http://www.flickr.com/photos/70039806@N00/12126325905/)

Simple cabinet interior.
http://farm4.staticflickr.com/3741/12126602393_d66ccc1e64_c.jpg (http://www.flickr.com/photos/70039806@N00/12126602393/)

Finally, here's the chassis with dual speakers :music:
http://farm6.staticflickr.com/5520/12126726614_5364a89438_c.jpg (http://www.flickr.com/photos/70039806@N00/12126726614/)

http://farm4.staticflickr.com/3824/12126345855_59292fb8b5_c.jpg (http://www.flickr.com/photos/70039806@N00/12126345855/)

Loads of room underneath. Should be a piece of cake to work on :yes:
http://farm8.staticflickr.com/7431/12126619303_626585d259_c.jpg (http://www.flickr.com/photos/70039806@N00/12126619303/)

bandersen
01-24-2014, 11:11 PM
I like they way the constructed the HV section with clip-in doorknob caps the horizontal deflection coupling.
http://farm6.staticflickr.com/5508/12126984696_7260e9d377_c.jpg (http://www.flickr.com/photos/70039806@N00/12126984696/)

http://farm8.staticflickr.com/7350/12126728444_86c9863030_c.jpg (http://www.flickr.com/photos/70039806@N00/12126728444/)

Multi-deck rotary tuner switch.
http://farm3.staticflickr.com/2819/12126740564_f688b81b19_c.jpg (http://www.flickr.com/photos/70039806@N00/12126740564/)

Cast aluminum fine-tuning gears.
http://farm4.staticflickr.com/3822/12126989186_a3228e1860_c.jpg (http://www.flickr.com/photos/70039806@N00/12126989186/)

Crappy old repair.
http://farm8.staticflickr.com/7374/12126332195_e86ace5cbd_c.jpg (http://www.flickr.com/photos/70039806@N00/12126332195/)

HV oscillator coil. I sure hope it's still good :ntwrthy:
http://farm3.staticflickr.com/2866/12126729914_5d67c78ed7_c.jpg (http://www.flickr.com/photos/70039806@N00/12126729914/)

bandersen
01-24-2014, 11:15 PM
Now for a bit of cleaning.
http://farm6.staticflickr.com/5528/12126343395_9cb671df86_c.jpg (http://www.flickr.com/photos/70039806@N00/12126343395/)

http://farm4.staticflickr.com/3749/12126610933_217c7b3cb1_c.jpg (http://www.flickr.com/photos/70039806@N00/12126610933/)

Chunky piece of safety glass.
http://farm6.staticflickr.com/5488/12126615433_9c84fd0efb_c.jpg (http://www.flickr.com/photos/70039806@N00/12126615433/)

http://farm4.staticflickr.com/3823/12126735344_459d9dbcbc_c.jpg (http://www.flickr.com/photos/70039806@N00/12126735344/)

Ceramic sockets for the hor/vert oscillator and output tubes.
http://farm8.staticflickr.com/7351/12126992026_3a34b27830_c.jpg (http://www.flickr.com/photos/70039806@N00/12126992026/)

It's a guaranteed electron tube :)
http://farm4.staticflickr.com/3670/12126990936_f56e1c223a_c.jpg (http://www.flickr.com/photos/70039806@N00/12126990936/)

That's better
http://farm4.staticflickr.com/3804/12126994096_021cd66811_c.jpg (http://www.flickr.com/photos/70039806@N00/12126994096/)

mpatoray
01-24-2014, 11:24 PM
That set is looking nice, the chassis is in great shape! Dual oval speakers, that should put out some dB's :) Looks like it is going to turn out to be a nice set.

Phil Nelson
01-24-2014, 11:47 PM
That is just about my favorite 7-inch set. Only National would give you ceramic tube sockets!

http://antiqueradio.org/art/NationalTV-7W19.jpg

That chassis will polish nicely, too, if you're into shiny.

If I could only keep one 7-inch, it would probably be my Admiral 19A12, though. Performs very well and it just looks so darned cool.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

bandersen
01-24-2014, 11:55 PM
Very nice :thmbsp:

I think my favorite 7" is the Airline 94GSE31088, but then I've never owned one and probably never will.
http://www.tvhistory.tv/1949Airline94GSE31088.JPG

Phil Nelson
01-25-2014, 12:39 AM
I should have said, "of the 7-inch sets that I own," the National is one of my favorites. I'll probably never run across one of those Airlines, either.

I'll be curious to see what you think of the National's performance when you're done. I think it's a pretty good set, but there are lots of things I haven't seen (and I did the restoration on mine a long time ago).

Regards,

Phil Nelson

bandersen
01-25-2014, 12:54 AM
The schematic in Riders #2 shows a dedicated AGC and DC restoration rectifier so I expect it will work fairly well :)

TV'S&MORE
01-25-2014, 09:31 AM
Hi Bob,

This is going to be a great project. I look forward to seeing you do a full restoration. I have this same model only mine has channel 1 Most of channel selector knobs I have seen are chicken head knobs. On the chicken head version the fine tuning knob is the size as the volume knob. Based on your photo it looks like yours is the chicken head version because of the size of the fine tuning knob. On the other version the fine tuning knob is smaller. I usually only see the knob that covers the fine tuning in the later version models like the photo you show with the magnifier option. I am sure either would be appropriate. Hope this helps.

Roy

TV’S&MORE

rld-tv01
01-25-2014, 11:36 AM
I was thinking you could get knobs off an old National TV signal booster but it appears they only have one knob. You could use that knob to make your own. Sometimes you can get these boostewrs cheap on eBay for $5-$10. http://tv-boxes.com/boosters/natl-tvb2.jpg

rld-tv01
01-25-2014, 01:49 PM
It seems National couldn't decide whether to put their logo on the top or bottom of the face. A picture of one of two that I have with the logo on the top.

earlyfilm
01-25-2014, 08:42 PM
I'm pretty sure only the fine-tuning knob is correct. I suspect it will be very hard to find a full set of correct knobs.

The only good picture I could find online was from the ETF


Bob, go to closed ePray auction 231124855530 , and select "see original" and you will find two original adverts for this set, one (or both?) which seem to show a modernistic brown chicken head, instead of the later style knobs.

The pictures of the restored set in the auction show the more common knob. The seller is the green pool table guy in Florida.

Jas.

bandersen
01-25-2014, 11:04 PM
Thanks for the info. I'm sure I can dig up a chicken head knob.

I was thinking you could get knobs off an old National TV signal booster but it appears they only have one knob. You could use that knob to make your own. Sometimes you can get these boostewrs cheap on eBay for $5-$10. http://tv-boxes.com/boosters/natl-tvb2.jpg

Good idea, I'll keep a look out for one.

Tim
01-25-2014, 11:48 PM
It is not really a generic chicken head. Here is a photo of the one from my channel 1 set.

TV'S&MORE
02-09-2014, 08:26 PM
It is not really a generic chicken head. Here is a photo of the one from my channel 1 set.

Tim you are correct in your responce. I should have been more specific about the chicken head knob. I just learned how to post photos today. Here is a photo of mine

bandersen
02-09-2014, 10:50 PM
Thanks for the great closeup photos. I'll dig through my stash and see what I can find.

snelson903
02-10-2014, 02:27 AM
Very nice :thmbsp:

I think my favorite 7" is the Airline 94GSE31088, but then I've never owned one and probably never will.
http://www.tvhistory.tv/1949Airline94GSE31088.JPG

about 2 months ago i was looking around on craigslist like i do everyday when i check my email ,and i seen a lady with a airline like that one for sale . her son couldnt make it work so he took a 80's model tv out of its plastic enclosure and fitted inside the airline cabinet and thought it was made good that way and was selling it after he moved out . i contacted her and asked if she had all the parts and she said thinks so ,but i would have to look at it . after along trek to no-mans land with my G.p.s i made it up to here house ,i had to talk the airline out of her house ,dealing with some of these craigslist people is getting stressful, i had the airline in my trunk with 90persent of the parts.

dieseljeep
02-10-2014, 08:53 AM
The schematic in Riders #2 shows a dedicated AGC and DC restoration rectifier so I expect it will work fairly well :)
I have to look up my Riders. My Sams only covers the transformer model completely, with a small addition, covering the transformer-less model. They also don't show the voltage selector switch.
The model I would really like, would be the metal cabinet one, with the transformer power supply. Dream on! :sigh:

bandersen
02-10-2014, 11:39 AM
You can download a scan of the Riders at the ETF: http://www.earlytelevision.org/tv_schematic_diagrams_postwar.html

The voltage selector switch is shown right on page one. I think it works like a buck boost transformer.

TV'S&MORE
02-10-2014, 12:53 PM
My metal one with has the power transformer on the outside with no switch. The wood cabinet has the switch.

dieseljeep
02-10-2014, 01:00 PM
You can download a scan of the Riders at the ETF: http://www.earlytelevision.org/tv_schematic_diagrams_postwar.html

The voltage selector switch is shown right on page one. I think it works like a buck boost transformer.

Thanks!
Another set with a strange IF frequency.
The last time I saw one of those sets in the flesh, was 1959. I didn't have the money to buy it. :sigh:

TV'S&MORE
02-10-2014, 04:27 PM
Hi Bob,

If you have difficulty finding the original four center knobs you might want to try and fabricate some using grey National NC radio knobs painting them the appropriate color and gluing in a brass insert. If you look at the center knob in the first photo and compare it to the outer knobs you can see they are the same except the center knob does not have the insert and the outer ones do. The center knob is the same knob used in many National NC radios. I have seen these on ebay quite frequently also at ham swap meets. The inserts are actually pretty easy to make. I took a jewelry/ metal fabrication class at the local community college a couple of years ago we made something very similar these. If you end up going this route I will check to see if someone in the class would make some. I could get the brass at Ace hardware.

snelson903
02-10-2014, 09:40 PM
about 2 months ago i was looking around on craigslist like i do everyday when i check my email ,and i seen a lady with a airline like that one for sale . her son couldnt make it work so he took a 80's model tv out of its plastic enclosure and fitted inside the airline cabinet and thought it was made good that way and was selling it after he moved out . i contacted her and asked if she had all the parts and she said thinks so ,but i would have to look at it . after along trek to no-mans land with my G.p.s i made it up to here house ,i had to talk the airline out of her house ,dealing with some of these craigslist people is getting stressful, i had the airline in my trunk with 90persent of the parts.

it also looks like there was a small record player in the top compartment ,but thats the only part i never got, does anyone have a picture of it.

Celt
02-11-2014, 06:30 AM
The size and shape suggests that it was an RCA 45J changer.

snelson903
02-11-2014, 09:04 AM
thats what i thought to ,and still a tight fit for a 45 thats why i like to a picture of it . it must have been a early compact tv/radio/phoneo /combo in its day.

Eric H
02-11-2014, 10:43 AM
it also looks like there was a small record player in the top compartment ,but thats the only part i never got, does anyone have a picture of it.

It's an RCA RP-168 changer, this one is correct for the set:
http://www.vintagetvsets.com/temp/airlinechanger.jpg
.
Did you get the radio chassis? There's a bunch of wires under there that don't belong.
I can also send you the art work if you want to get a new dial scale printed out for it. Kinkos can do that on some clear plastic but you have to reverse paint the gold on yourself.

This is basically a Sentinel TV-400 with an added radio chassis.

I should probably split this off into a separate thread so we don't hijack Bob's post?

snelson903
02-11-2014, 12:40 PM
It's an RCA RP-168 changer, this one is correct for the set:
http://www.vintagetvsets.com/temp/airlinechanger.jpg
.
Did you get the radio chassis? There's a bunch of wires under there that don't belong.
I can also send you the art work if you want to get a new dial scale printed out for it. Kinkos can do that on some clear plastic but you have to reverse paint the gold on yourself.

This is basically a Sentinel TV-400 with an added radio chassis.

I should probably split this off into a separate thread so we don't hijack Bob's post?

yes i got both chassie and the crt all she had, the kid put in a 80's model tv in the cabinet .good thing he dint drill or cut on the cabinet ,for now i just put it on the shelf for later. the reason i posted it here they saying they never ran across one before ,i thought i would show the one i found. apart from that i dint think anyone would be interested.

decojoe67
02-11-2014, 04:27 PM
it also looks like there was a small record player in the top compartment ,but thats the only part i never got, does anyone have a picture of it.
I've been into vintage TV's for years and can tell you that you have a VERY rare set there! I can only remember seeing one other in a photo. It's easily as rare as a pre-war.
It would certainly be worth the time and expense to restore it!
I'm envious! :)

Eric H
02-11-2014, 04:39 PM
I picked up mine on eBay for what I thought was a fairly steep BIN price, the next one that turned up went for twice as much! They are a sought after set.

snelson903
02-11-2014, 06:37 PM
the reason i posted it was early on in this thread Phil nelson and Bandersen was talking about how rear this airline model was, when i seen the picture bandorsen posted i said thats the tv i picked up 2 months ago, so posted 2 pictures of it on the ad he posted. i thought he like to see there was another one out there .i was able to get every part from the lady while i was there ,but the record player and was glad to be getting what i did and getting out of there.

bandersen
02-13-2014, 05:54 PM
I found a TV-2 booster but it's so nice I'm going to keep in intact rather than scavenge the knob.

https://v4s.yimg.com/so/7344/12506742675_4479eb7bf5_c.jpg (http://www.flickr.com/photos/70039806@N00/12506742675/)

https://v4s.yimg.com/sk/3746/12509950663_15328ae279_c.jpg (http://www.flickr.com/photos/70039806@N00/12509950663/)

bandersen
02-13-2014, 06:11 PM
Here are some more photos of the booster I took while cleaning it.

http://farm4.staticflickr.com/3725/12510029823_9f17fbfd8a_c.jpg (http://www.flickr.com/photos/70039806@N00/12510029823/)

https://ycpi-farm8.staticflickr.com/7289/12509907515_c7b18dfaf3_c.jpg (http://www.flickr.com/photos/70039806@N00/12509907515/)

It has a turret tuner with removable sections inside.
https://v4s.yimg.com/so/7426/12510031173_9d171963a4_c.jpg (http://www.flickr.com/photos/70039806@N00/12510031173/)

https://s3.yimg.com/so/7305/12509912265_445ca96576_c.jpg (http://www.flickr.com/photos/70039806@N00/12509912265/)

http://ycpi-farm6.staticflickr.com/5538/12509920345_f7575ddb97_c.jpg (http://www.flickr.com/photos/70039806@N00/12509920345/)

Neon bulb pilot lamp
https://s2.yimg.com/sm/5487/12510039373_68436aebde_c.jpg (http://www.flickr.com/photos/70039806@N00/12510039373/)

http://farm8.staticflickr.com/7293/12509916525_2b5fd481b7_c.jpg (http://www.flickr.com/photos/70039806@N00/12509916525/)

TV'S&MORE
02-13-2014, 06:19 PM
Nice score. I always thought the National emblem was a nice touch these boosters. They made 2 versions of this one with the knob and one without.

TV'S&MORE
02-16-2014, 02:15 PM
When I first purchased this set the previous owner he told me when had plugged it in and turned it on and he said it started smoking. Needless to say I was concerned but, not discouraged. Hopefully the smoke was friendly smoke and not the transformer or filter choke. When I got home and pulled chassis from cabinet I found that the brightness control and the on-off / volume controls were frozen and they had been turned around and around pulling the connecting wires from there connections wrapping the wire with a resister attached into a ball around the pots. It appears that what ever was used to lube these controls has a tendency to dry up freezing the controls in position. On my other National TV-7M all of the controls in the front are very stiff and frozen in the rear probably because those are seldom adjusted. I was reading a very early videokarma post from 2003 where the owner of the exact same TV needed to disassemble clean and reassemble his controls because they were frozen solid. I am hoping I can get by just using Deoxit to loosen these controls without having to open them up. I saw on Phil Nelson’s website he had to take one of these controls apart to make a repair. From the picture I saw they seem to be the friction pad type. Are these more fragile than other types? What’s the best type of lube? I have some dielectric silicone compound would that work? I think I have everything I need to get started. I am curious see Bob’s restoration of his TV when he gets time to start on it. I am sure it will be very informative. Maybe we can compare notes. I Don't want to hijack Bob's post but,my question seems related to the topic. Any advice or comments would be greatly appreciated.

Regard’s

Roy (TV’S&MORE)

ChrisW6ATV
02-23-2014, 11:54 AM
It would probably be good to try your Deoxit on the controls a couple of times, particularly the shaft areas, to see if it will soak in over a period of time. If you have no success, try WD-40 on the outside of the shafts. When you get done (whether you succeed without disassembling the controls or not), Deoxit has another product called Fader Lube that should be good for the interior parts of the controls (particularly after using WD-40). I think I bought mine at a Guitar Center store.

TV'S&MORE
02-23-2014, 12:46 PM
Thank's Chris. I will go get some today. I have seen this deoxit product before. I quess I should have read the can.

bandersen
01-05-2015, 07:10 PM
I finally got around to working on this TV :) I decided to restuff all the caps since most of the originals were still present. I also used carbon comp resistors as much as possible.

The first thing I did was puzzle out some old repairs like this twist-loc that had been jammed in.
https://farm8.staticflickr.com/7576/15092904033_28f454b9dc_c.jpg (https://flic.kr/p/oZH5xk)

Once I cleared out that mess, I found some NOS parts to replicate the original look.
https://farm4.staticflickr.com/3937/15092904503_b6012fcdf1_c.jpg (https://flic.kr/p/oZH5Fr)

https://farm6.staticflickr.com/5616/15713824252_01aaf1f9c0_c.jpg (https://flic.kr/p/pWzsum)

I'd never seen these SOLITE type of caps before. They turned out to be very easy to restuff :)
https://farm8.staticflickr.com/7530/15547805627_40c59222cc_z.jpg (https://flic.kr/p/pFUyWg) https://farm8.staticflickr.com/7548/15113607343_2226cb4ced_z.jpg (https://flic.kr/p/p2xbUX)

https://farm6.staticflickr.com/5600/15547116159_6008d64864_z.jpg (https://flic.kr/p/pFR2YT) https://farm8.staticflickr.com/7539/15113605713_9ebfbcfc7c_z.jpg (https://flic.kr/p/p2xbqR)

bandersen
01-05-2015, 07:16 PM
I left the ceramic doorknob type caps for the horizontal alone, but restuffed the vertical with new ASC high voltage caps.
https://farm8.staticflickr.com/7574/15564865107_a714dd57c0_c.jpg (https://flic.kr/p/pHq18e)

A few of the resistors in the high voltage divider change were out of tolerance and replaced.
https://farm6.staticflickr.com/5613/15630035808_f8d4e0ee77_c.jpg (https://flic.kr/p/pPb271)

I went with NOS for now, but have some modern high voltage resistors ready if they don't work out.
https://farm8.staticflickr.com/7565/15630589350_ec5758a18b_c.jpg (https://flic.kr/p/pPdRDQ)

https://farm8.staticflickr.com/7549/15652774240_d4d2fdb41b_c.jpg (https://flic.kr/p/pRbyrW)

bandersen
01-05-2015, 07:22 PM
The brightness and all three high voltage pots were frozen and had to be taken apart. All you need to do is carefully pry up a bit of metal and the back covers come right off. I used electrical parts degrease to clean out the old lubricant. Isopropyl alcohol works well too. After cleaning, I used white lithium grease.
https://farm9.staticflickr.com/8113/15805997241_7318547db4_c.jpg (https://flic.kr/p/q5HSiP)


Here it is all recapped and ready for a first power up :)
https://farm9.staticflickr.com/8599/15489421873_e9f70a8fdf_c.jpg (https://flic.kr/p/pAKktP)

Sandy G
01-05-2015, 07:39 PM
Didn't National make the metal-bodied set w/a big "Power" meter on the side, that was sposed to show power of the video signal ?

N2IXK
01-05-2015, 08:38 PM
Didn't National make the metal-bodied set w/a big "Power" meter on the side, that was sposed to show power of the video signal ?
Yes. It wasn't really a "TV set", but a test instrument for installing and pointing antennas. A field strength meter with a built in picture monitor. :smoke:

bandersen
01-05-2015, 09:58 PM
First power up was a partial success in that I got a picture but no sound.
https://farm8.staticflickr.com/7569/16106833102_1ac15f715d_c.jpg (https://flic.kr/p/qxiJk1)

Further investigation revealed a cracked 6AT6 that had gone gassy but still had filament continuity.
https://farm8.staticflickr.com/7491/15485232304_40d7988529_c.jpg (https://flic.kr/p/pAnS4S)

Picture was still a bit dim and weak though. Bypassing the old selenium rectifier helped a bit.
https://farm9.staticflickr.com/8606/15921693868_55e36d9e1e_z.jpg (https://flic.kr/p/qfWQTf) https://farm8.staticflickr.com/7523/15492698104_d7cf72e290_z.jpg (https://flic.kr/p/pB38oy)

Eventually, I tracked down a bigger issue - an open peaking coil. Luckily, a little soldering touch up on one end restored continuity.

That improved the picture quality and brings me to what I hope is the final issue - poor horizontal stability.
https://farm8.staticflickr.com/7482/16100767326_82ac8d6e33_z.jpg (https://flic.kr/p/qwLDbE) https://farm8.staticflickr.com/7556/16188556021_d17fb1845e_z.jpg (https://flic.kr/p/qEwzGR)

I think this series of images taken while using a 7VP1 test CRT illustrates the problems.

Adjusted for a good picture.
https://farm8.staticflickr.com/7533/16013142257_966db89793_z.jpg (https://flic.kr/p/qp2xiB)

A short while later tearing appears. Tweaking the horizontal hold will get rid of it for a little while.
https://farm8.staticflickr.com/7559/16012857159_a636ff2e54_z.jpg (https://flic.kr/p/qp15y8)

A bigger issue occurs when there are large areas of bright and dark. Seems like the video is causing a horizontal offset. This set does have DC restoration that uses an average of the video signal as a grid bias. Seems like that might be leaking in to the horizontal circuit somehow ? Tough to track down since it's not always a problem.
https://farm8.staticflickr.com/7499/16197069841_3055b4f614_z.jpg (https://flic.kr/p/qFhdyR)

M3-SRT8
01-24-2015, 06:36 PM
Check out the 800v micas and resistors in the Hor Sweep & Synch circuits.

I replaced a bunch of resistors and the micas in mine. Pic is rock steady.

The step up transformer in the HV cage will take a while to "cook" to eliminate any moisture in it. HV will climb after that. Weak selenium rectifiers held mine back. OK after replaced by diode.

When you get audio back, be prepared for a loud sounding TV. They really crank.:smoke:

bandersen
01-24-2015, 09:05 PM
Thanks for the input. I ended up replacing every resistor, capacitor and tubes in the sync and sweep circuits and it made no difference so I'm calling it done for now. Didn't notice any issue with the HV coil. Maybe because it's winter and the humidity is low ?

I'm expecting to get the metal cabinet version sometime in the next few months and will compare the performance.

https://farm8.staticflickr.com/7526/16233362862_428e140b27_c.jpg (https://flic.kr/p/qJuedA)

M3-SRT8
01-24-2015, 10:25 PM
Ah. Sorry 'bout that. These NT-7s are so simple I was sure that would cure it.

Tell you the truth, I pretty much shotgunned most of the resistors, along with ALL of the caps in mine. All the resistors on the bleeder board I replaced with 2Watters. It plays real well, aside from a slightly squished picture bottom.

My cabinet, a mahogany one, is pretty beat. Finish all faded, decals pretty miserable looking, although the "National" logo I could probably resuscitate.

I'm thinking of coming up with gold decals from a vendor that's a close/exact match, font-wise.

Good Luck with Yours;

Lee:smoke:

bandersen
02-05-2015, 09:09 AM
My decals are in fair condition with the worst area being around the channel selector. I spruced up the cabinet with a light sanding and a few fresh coats of lacquer then a rub out.
https://farm8.staticflickr.com/7445/15827675594_5f230a8d3c_c.jpg (https://flic.kr/p/q7CYww)036 (https://flic.kr/p/q7CYww)

bandersen
02-09-2015, 05:45 PM
I finally got the set all back together :) The horizontal sync seems a bit more stable receiving an over the air broadcast from a Blonder Tongue modulator which makes me think I was overdriving it on the workbench with my test signals.

That just leaves finding a few more of the correct knobs...

https://farm8.staticflickr.com/7408/16487017615_5fd4edb3be_c.jpg (https://flic.kr/p/r7UgWp)

https://farm8.staticflickr.com/7322/16486040412_9f69b269eb_c.jpg (https://flic.kr/p/r7Pgs5)

Paul Knaack
02-09-2015, 05:48 PM
Nice,
Great work as always. love that antenna.

decojoe67
02-09-2015, 06:56 PM
Nice work Bob. You really get an early set playing like new. Great seeing these more obscure TV's working.

Boobtubeman
02-09-2015, 08:25 PM
I got the same antenna... those work pretty well :D

SR

Phil Nelson
02-09-2015, 09:44 PM
Beautiful job! That National and the Admirals are my favorite 7-inch sets.

I haven't redone the cabinet on mine yet. It's presentable, but weathered.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Telecruiser
02-10-2015, 10:20 PM
Looks really good!

BigDavesTV
02-17-2015, 06:41 PM
That's one of the sharpest focus pictures I've seen on a 7" electrostatic, in recent memory! Good job.