a real challange?

[Yamamaya42]

Well, the caps are already ordered, so I might as well put them in, for better , or worse.
I now see why they have 2 220pf caps in series, cause 110pf seems to be a VERY odd cap, and is hard to get, even now, not in stock with very long wait time to get if you try.

[old_tv_nut]

Putting two in series may be a voltage stress thing too, so better to do it their way.

[Yamamaya42]

I decided to haul out the LD payer and run a movie or two.

https://imgur.com/Z28QFrd

Today's test

[Yamamaya42]

One thing I have noticed running this set, the audio on it can get VERY loud, surprisingly so.
Also, tuning is quite finicky, always having to tweak fine tuning to get best picture as it warms up, (herringbone patterns that never fully gos away ), not sure if this is a tuner problem ( age/ dirty contacts ) or if it's IF related, namely the new 1st IF coil 23.3mhz and trap 27.25mhz, which I was unable to get good results the first attempt going by the book to adjust it, and did it by “eye'..

[Electronic M]

One thing that will help is to eliminate the color sub carrier from the video going to your modulator.
On an LD player if there's an S- video output make an RCA adapter cable that only connects to the monochrome coax in the S-video coax pair. Newer component video sources just use the green Y video cable.
Many monochrome sets made before color TV was standardized had video response out to 4.5MHz later sets limited the video IF bandwidth to ~3MHz to hide the chroma dot crawl.

[Yamamaya42]

Originally Posted by Electronic M

One thing that will help is to eliminate the color sub carrier from the video going to your modulator.
On an LD player if there's an S- video output make an RCA adapter cable that only connects to the monochrome coax in the S-video coax pair. Newer component video sources just use the green Y video cable.
Many monochrome sets made before color TV was standardized had video response out to 4.5MHz later sets limited the video IF bandwidth to ~3MHz to hide the chroma dot crawl.

not on my player

http://www.laserdiscarchive.co.uk/la...r_ld-v8000.htm

edit- notice the wt... almost 35lbs

[Yamamaya42]

But I do have one of these...
https://i.ebayimg.com/images/g/grkAA...tC/s-l1600.jpg

I can cut the color out completely.

[old_tv_nut]

Originally Posted by Yamamaya42

But I do have one of these...
https://i.ebayimg.com/images/g/grkAA...tC/s-l1600.jpg

I can cut the color out completely.

It would be interesting to know how it adjusts the color level; specifically, does it involve a low pass filter that also attenuates high frequency detail?

[Yamamaya42]

another day, another LD.

https://imgur.com/mMXcECv

I def have to clean that tuner dome some
And I am betting sound in the picture still.
I did try to clean the tuner a while back, with deoxit, and ran through the channels a few times, but it was obviously not enough, for example, with the BT modulator, (CH7) , when I tune to 7, I get nothing when it "clicks" into position, I have to turn it slightly out of position to get it to get the signal in, so it seems the contacts are still dirty for chan 7, and who knows about chan 9, the IF alignment instructions said to remove the OSC tube and turn to chan 9, so perhaps 9 has dirty contacts too still.
and that's why I had problems with the IF setup

I do have I can of RadioShack Control/Contact Cleaner and Lubricant coming, that I hope to clean it up better.

and then perhaps I can try to adjust the 1st IF again

[Yamamaya42]

it seems that once I cleane the tuner a bit more, I will have to adjust more than the new 1st IF coil and trap...

as mentioned. I have seen sound in the picture.
but that trap has nothing to do with that.

https://imgur.com/p7bwi4X

this info is only in the RCA guide, the sams does not say what the traps do.

the trap on the 1st IF is for adjacent channel sound, of which there is none...

the sound trap is an another adjustment :/

[Yamamaya42]

today's movie

https://imgur.com/mPmo6pq

and as I guessed (and was told ) , trying to adjust the traps by eye does not really get me anywhere :/

so will have to wait till later after I get the cleaner, and I recover from shoulder surgery and can lift things again

[Yamamaya42]

I now have a RF generator that I can have precise control over , freq and amplitude, unfortunately, the tuner cleaner did not come today as hoped, meaning it will be here Monday or later, (USPS is very slow lately ) meaning I won't be able to attempt to do it until Aug, most likely after I have recovered and can lift things again w/o risk of ripping the things they are trying to fix in my shoulder

there is still one thing about the alignment setup I am unsure of.
where as it says Channel 9, in though the aut inputs and gives exact setup for setting RF gain via "contrast " at -3 volts, and what freq to use for each coil trap adjusted, it does NOT mention what amplitude to use, I can select any range from 00.000v to 10.000, so what would be needed to do this?
has anyone done this before and know the right range to use?

screenshot of the PC interface for the RF generator
https://imgur.com/lwu3fZK

[Kevin Kuehn]

Originally Posted by Yamamaya42

there is still one thing about the alignment setup I am unsure of.
where as it says Channel 9, in though the aut inputs and gives exact setup for setting RF gain via "contrast " at -3 volts, and what freq to use for each coil trap adjusted, it does NOT mention what amplitude to use, I can select any range from 00.000v to 10.000, so what would be needed to do this?
has anyone done this before and know the right range to use?

In general the lowest amplitude that allows you to make a reliable measurement. Since your TV doesn't have AGC you don't have to worry about that messing with your signal level. The one thing you want to avoid is overloading the IF amplifiers.

[Yamamaya42]

Originally Posted by Kevin Kuehn

In general the lowest amplitude that allows you to make a reliable measurement. Since your TV doesn't have AGC you don't have to worry about that messing with your signal level. The one thing you want to avoid is overloading the IF amplifiers.

I'm going to start with the traps only, cause the RCA service manual says to do them first, and I'm mostly seeing sound and noise in the pic.

[old_tv_nut]

For RF input, a couple of millivolts up to a tenth of a volt should do. If the instructions say to set the contrast/gain to a certain fixed value, do that and adjust the input level up from zero until you get a few volts (2 to 4) out of the video detector. If you have information on what the usual video amplitude is out of the video detector, go for that instead.