a real challange?

[Yamamaya42]

Originally Posted by Notimetolooz

The contacts for channel 7 may be damaged and no amount of cleaning will fix it. I don't see why you couldn't use another channel for alignment but I don't know this set.
From the video it looks like you might have a noise or interference problem in the video signal.

I took it off a crappy cellphone cam, it does not work very well for this, the noise is the cam trying to auto adjust

[Kevin Kuehn]

Per Sams have you tried injecting your test signal direct to the mixer grid? With the oscillator tube removed and signal connected to the mixer grid there should be no reliance on channel selection, because the mixer is post any channel tuning. You could also inject the signal to the shield of the mixer, keeping the shield insulated from contacting the chassis.

[Kevin Kuehn]

If your rf generator is not perfectly calibrated to your sets IF you should be able to rock the generator tuning and find out where the signal gets through to the detector. You know the IF is working at some frequency or you wouldn't have been able to watch channels 3-4.

[bandersen]

Like Kevin said above, when you align the IF, you inject the signal after the Rf front end. The tuner won't have any effect. The typically have you disable the local oscillator or switch to an unused high VHF channel to avoid an external signal getting in. Probably why they suggest channel 9.

[Yamamaya42]

Originally Posted by bandersen

Like Kevin said above, when you align the IF, you inject the signal after the Rf front end. The tuner won't have any effect. The typically have you disable the local oscillator or switch to an unused high VHF channel to avoid an external signal getting in. Probably why they suggest channel 9.

https://imgur.com/HpMK2wJ

the 2 times i tried, I tried going in via the ant input as it said, after the 2nd try, I found that having the freq generator hooked up had no impact on the voltage level at the point being measured, nor did changing freq slightly.

i did not however try as Kevin mentioned, tapping it in on point E, if I do try again, I will most likely go that route, but as mentioned, my contacts for chan 7 are most likely damaged, and to make things work I have to go with a mod I can pic the chan output on to get the most clean pic,, 3-4 DID work, but had a lot of RFI, most likely all the computers i have
so hopefully once I can get the IF setup ( mostly the 1st IF and traps ) i can use a modulator like this,https://www.amazon.com/fosa-Modulato...07G9ZYXW9?th=1
and find the best working channel
till then, I will use direct input, will try to get a better video tonight.

[Kevin Kuehn]

Originally Posted by Yamamaya42

https://imgur.com/HpMK2wJ

the 2 times i tried, I tried going in via the ant input as it said, after the 2nd try, I found that having the freq generator hooked up had no impact on the voltage level at the point being measured, nor did changing freq slightly.

i did not however try as Kevin mentioned, tapping it in on point E, if I do try again, I will most likely go that route, but as mentioned, my contacts for chan 7 are most likely damaged, and to make things work I have to go with a mod I can pic the chan output on to get the most clean pic,, 3-4 DID work, but had a lot of RFI, most likely all the computers i have
so hopefully once I can get the IF setup ( mostly the 1st IF and traps ) i can use a modulator like this,https://www.amazon.com/fosa-Modulato...07G9ZYXW9?th=1
and find the best working channel
till then, I will use direct input, will try to get a better video tonight.

Speaking of computers generating RFI... everytime you bring in another modern signal processing device you'll more than likely be dealing with yet another switch mode power supply and micro controller generating even more RFI. Something to think about.

[Notimetolooz]

Originally Posted by Yamamaya42

so hopefully once I can get the IF setup ( mostly the 1st IF and traps ) i can use a modulator like this,https://www.amazon.com/fosa-Modulato...07G9ZYXW9?th=1
and find the best working channel
till then, I will use direct input, will try to get a better video tonight.

I've never noticed that modulator before. Are you sure it doesn't output a digital modulated signal. The ad does mention NTSC but the device also looks to have a RF input that it may apply to. The display shows 5.38 which is too low to be in MHz, so it looks like it is set to digital channel 5.38.

[Yamamaya42]

here it is on a webcam
https://youtu.be/HgqNDAEh-Wc

a bit better.

for that modulator, the question was asked,,, digital or analog

and the reply.
Analog, NTSC Mono. The Information Sheet that comes with the unit includes a Frequency Table for the channels used with USA cable systems, of which, the first 13 channels are the same as over-the-air broadcast analog channels.

[Electronic M]

Originally Posted by Notimetolooz

I've never noticed that modulator before. Are you sure it doesn't output a digital modulated signal. The ad does mention NTSC but the device also looks to have a RF input that it may apply to. The display shows 5.38 which is too low to be in MHz, so it looks like it is set to digital channel 5.38.

ATSC and QAM capable modulators are $1K at cheapest and only used by broadcasters and some Ham radio opperators with deep pockets.

[Yamamaya42]

Oddly enough, the RFI that is seen on chan 3-4 on the FADA, is also seen on my CTC-16XL, but not the CTC-90.
If it is, it's not noticeable.

[Kevin Kuehn]

Originally Posted by Yamamaya42

Oddly enough, the RFI that is seen on chan 3-4 on the FADA, is also seen on my CTC-16XL, but not the CTC-90.
If it is, it's not noticeable.

I'm not sure what you find odd about that? At any rate you should not consider it a fault of your vintage TV. The fix is unplugging the offending modern noise sources.

[Yamamaya42]

Originally Posted by Kevin Kuehn

I'm not sure what you find odd about that? At any rate you should not consider it a fault of your vintage TV. The fix is unplugging the offending modern noise sources.

I'm not trying to fault the vintage stuff per sey, just more sort of curious, is tube tech more susceptible to RFI? Or solid state less, or a combo of both?
I have only had the 2 recent tube tech ones to reference recently so I'm not sure.

And since my computers ( main systems & server & home ent system ) are part of what I use on a day to day basis, it's unlikely they will be shut off any time soon! :p
Not to mention the networking systems, both wired in wall and wi-fi, modem, router,hubs etc :0

Anyway, so far my FADA has been run now for about 16-18 hours w/o any problems, the last few with direct input.
Aside from perhaps making another stab at IF alignment someday, the only other thing I'd like to try again is vert blanking mod, after I was not happy with the first 2 tries.

Looking at the SAMS for the SC x21 the I will be getting, I thought perhaps I could use the circuit they have.
https://imgur.com/gVpu2B8

As this sort of worked, but had a black band at the top of the screen.
===
1. Place a 47k resistor between pin 11(cathode) of the CRT and ground.

2. Connect a .05uf, 630v cap from pin 3 and 4(plate) of the 6K6 vertical output
to pin 11(cathode) of the CRT.
======
the RCA manual shows it to be 700v there on the plate of the vertical output, ( a bit high I would think to use here ) and 60v in the yolk.

If I were to try to use the input signal to the yolk as source, do I still use 47k to gnd on the cathode?
or perhaps a 100k pot, and adjust for best results?
and the cap, use one? and just try diff values to see what works?
or more like above in the x21, 2 in series with a pulldown midway.

So many choices

[old_tv_nut]

"... is tube tech more susceptible to RFI? Or solid state less, or a combo of both?"

If it is radiated RFI, sets with 300 ohm twin lead feeding the tuner will be more susceptible than sets that are 75 ohm coax all the way. Beyond that, it depends on a lot of little tuner design differences that could go either way.

If it is conducted RFI, it all depends on individual chassis design, old or new. This can be reduced with an AC line filter.

[Kevin Kuehn]

Originally Posted by Yamamaya42

I'm not trying to fault the vintage stuff per sey, just more sort of curious, is tube tech more susceptible to RFI? Or solid state less, or a combo of both?
I have only had the 2 recent tube tech ones to reference recently so I'm not sure.

And since my computers ( main systems & server & home ent system ) are part of what I use on a day to day basis, it's unlikely they will be shut off any time soon! :p
Not to mention the networking systems, both wired in wall and wi-fi, modem, router,hubs etc :0

I suppose it all comes down to priorities then. It's technically possible to both transmit and receive a high fidelity AM radio signal, but you probably wouldn't ever consider it enjoyable while listening during a lightning storm.

[Yamamaya42]

ooops!
I missed a couple

I thought they were Mica :/

I plugged it in tonight and it went FOOM! :O

https://imgur.com/5O76o0O
https://imgur.com/N9UhRBD
one of the 2 input caps went up in smoke, and took the input plug with it, unwelded it from the back.

https://i.imgur.com/xaPGUjl.jpg
so I had to feed a line direct in and add new caps

https://imgur.com/8XubId2

back running again