I found that to be true using my other dvm but I use the new one that does give better reading. Well this IF is far from active.

I find it kind of odd that if I pull v3 tube the voltages on the b+ comes up nice and the 4.7k resistor that feeds v3 is a 5 watt and it only calls for 2 watt but this 5 watt resistor i put in gets really hot v1 and v2 don’t do this with the voltage drop I would think that v1&2 are conducting but maybe v3 is not causing the tube to be full on drawing down voltage if this is the case why is v1&2 not pulling voltage down IF signal goes down the line 123 then out to video amp.

V1,V2,V3 are tuned RF amplifier circuits, and are always active as long as the tubes are inserted and power is on, regardless of if there is any tuned signal or not, it is still active, the only way to render it not active is to remove a tube.

The tuned circuit is comprised of the tube, the adjustable coil, and capacitors primarily, and secondly resistors.
This area is extremely susceptible to external influence, as in anything hooked to any of the pins of the tubes will alter how it is working and change what you are trying to measure, this includes the meter and even the length of the test leads used.

Therefore, do not be fooled by these readings, because they can't be trusted, in this situation.

Known good, 275v source, R54 (4.7K 5w), R53, R52, C27,C28.
Variables, the overall out of aligned state of all 3 amps, any one or more of these can alter voltage readings, hooking a meter to the grids or plates of the amps under test, this will also change the state of them, like adding a resistor to ground, and change the voltage readings.

So how can I use a vcr with a tuner built in to be hooked up to the sets video amp

Don't digital meters have a 10M input impedance same as a VTVM?

First you will have to build the video amp, this should be easy, I have made 2 before.
https://www.electronicsforu.com/elec...ideo-amplifier
Suggested parts are.
This includes replacing r5/r2 with trim pots to adjust gain and black level.
Also is suggested a 7805 regulator, for stable 5v power.
https://content.instructables.com/F2...bounds&frame=1

all mouser parts.

637-BC558A
512-BC547B
512-1N4148
531-N6S25T0C103-3030
531-PT6KH502A2020PM
511-L7805CV
594-MAL203851229E3 x2
647-UBX1V010MPL
854-SB404

here is v1 of the amp i made.

https://imgur.com/xYoNZOY

was unstable w/o the regulator.
thus v2

Some, not all.
a high $ fluke or similar type would tend to be more trustworthy in testing an IF than one that's 15-20$.

for example, I did alignments with my Micronta FET Analog Multitester / fluke 77 multimeter, and not the cheap ones I have cause I knew they were not suited for the RF area.

Once you've built and installed the video amp connect the composite video output (yellow RCA cable) from your VCR to your amp, and the white audio output cable from your VCR to a point between the audio detector and the volume control through a .1uf 600 cap (you add that cap), power on the VCR and tune it to the channel you want and it should appear on screen.

R22 is an RF trap that is listed as being 200 ohms I get no reading whatsoever do these traps go bad ? And really what happens when they do go bad ?

41.25mhz trap, (sound modulated carrier), blocked in L6 and tuned by R22, after sound is taken off for process at V3 pin 7, if not working/ faulty, sound may be seen in the screen.

R22 can be tested by resistance check from L6 pin 3 and the junction of C30/C31.

I tested there and I don’t get anything so I’ll lift L6 leg off to be sure but I don’t think it would show 200 ohms if it’s adjusted to something else.

Lifted one leg off the trap get zero no ohms ready at all.

If it does not read somewhere from 200-0, you may be able to clean it to get it working.
But you will have to pay close attention to where it's set before you start, get it really soaked in some kind of contact cleaner or isopropyl alcohol, so that the insides get good and soaked, then rotate it back and forth to each extreme several times, making sure it's put back in the original position, this SHOULD bring it back if it's not working.

but if that fails..
https://www.vivatubes.com/vintage-ma...ohm-shaftless/

0 ohms?

This is OK, then, it has been adjusted to it's far extreme.
as long as you get a reading between 200-0, it is good.

So really it’s just a 200 ohm pot nothing special just a variable resistor and that part number you posted is the same as in sams except the sams has a 1 on the end. I didn’t turn it but I get zero

it's OK, all as it should be! :D
Take a look at L6 as a whole, and the alignment procedure, L6 has 2 parts in it, the 3rd if transformer, (A4) and the sound trap, (A1), both having tuning cores, the sound trap has a 2nd adjustment which is R22.

A1 & R22 interact with each other when adjusted to suppress the sound after takeoff so it does not get to the video amp.

Either way shouldn’t this trap have some sort of resistance reading?

It can be set anywhere from 0 to 200 ohms, depending on what is needed to get correct operation of the 41.25mhz trap, as set in step 2 & 4 of the alignment.

Well I took the trap out it’s completely open tried alcohol no good but I put a pot together and it’s no where near 200 ohms just a test but this is the result it came alive still have more to do but this trap caused a lot of headaches for me a scope would have picked this up right away.

Why would the mtc22L1 have a wiper but the 22L4 don’t and matches what’s in the set already.

This is getting confusing...

You said you got a reading of “zero” which I interpreted zero ohms or dead short, or zeroed out as in closed to the extreme, but did you really mean it was open or a reading of infinite resistance?
If so, you really did not get that across well, and the trim pot is indeed bad, and the one listed is a replacement as shown on the SAMS.

The trap shown on sams is 22L1 but the one you found looks like the right one without the wiper. and yes I found that the trap was open from 57 years of vibration wore down the connections on the porcelain base so I took the cap off and put a bead of solder on each one and now it’s 200 ohms and it’s good now I put it back in. What is color bands across the screen when the color is turned up ?

PIC?

The correct setting for R22 is someplace between 0 & 200 ohms, but setting it has to be done in the alignment setup with a RF generator and scope, trying to do it visually most likely wont work very well.

Color bars

herringbone patterns again, An over all indication that the response curve of the IF is not correct, added that the sound trap may also be not right and letting audio into the video amp.

How is it that you can have a clear good b&w picture and yet it won’t accept color how does these frequency’s work for color.

You need to read on how color TV works, again. In any case, if you have the color control turned way up and the oscillator is working you should get color
at some position of the fine tuning, maybe one with a really bad B&W image,
even if the IF is badly misaligned. Last spring I worked on the CTC5 at the ETF.
I got color, in fact good color, but the B&W picture looked even worse than
yours. I didn't have time to do an alignment.

If you don't get any color, the first thing is to bring the antenna of a regular
short wave radio in CW mode up to the color oscillator and see if there is
a whopping signal at 3.58 MHz.

Problems with the pulses generated by the horizontal output transformer
can cause no color to get through the color amplifiers. The feedback in the color area is so complicated that no color is a nightmare even with a scope. Wrong color is a lot easier.

This is prof positive that the color circuits of your TV is working.

http://videokarma.org/attachment.php...9&d=1669302177

color with direct input.

I had the very same problem a few years back with my CTC-16XL.
After I spent a VERY long time getting the color circuits working again after some putz messed it all up, and I had to use direct input to do so, I still could not get stable color via the tuner cause the IF was all borked because it was messed with was very obvious as the shield for it was missing.

A telltale sign of messed up IF is getting good BW but crappy or no color, why it does this is complicated, but it has to do with how they took the normal BW video standard and crammed color info into it and still had it compatible with older non color sets.

And most of the time there is no fix other than alignment,because otherwise the color info will be corrupted by the time it gets to the video amp, even if you get a semi good BW video.

Even on my CTC-16XL I was not able to clear up the IF as good as it should be, it's like 85-90% and shows red smear, and thus I have installed bypass signal relays in the A/V lines and can change from tuner to direct input at a flip of a switch.

perhaps someday If i ever get a sweep marker generator, i may attempt to bring it up to par.
but for now, it's really good with direct, and fair with tuner.

Well at this point all I could do is blow a lot of time trying to adjust things here and if I’m at all lucky maybe I can pull this off. Even if I had the proper things to do an alignment I still don’t know how to perform it. Since finding this trap open and restoring it the b+ voltages are finally normal the 256v is now 276v where it should be. All the time trying to make adjustments with blinders on don’t mean I’ll get it right but I’ll try.

[QUOTE=Yamamaya42;3247041
A telltale sign of messed up IF is getting good BW but crappy or no color, why it does this is complicated, but it has to do with how they took the normal BW video standard and crammed color info into it and still had it compatible with older non color sets.

[/QUOTE]

It depends on what the actual IF response is on the malfunctioning TV. Generally (but see the service data first) the video carrier and color carrier are at or near the 50% amplitude point on the response curve; the 45.75MHz video carrier is there to compensate for how the unwanted sideband is filtered out at the transmitter, and the 42.17MHz chroma subcarrier point is placed there to minimize interference in the picture from the chroma information. The chroma bandpass circuits compensate for this falling response and have to be aligned with a special setup, basically the video carrier modulated by a frequency sweep at the chroma frequency range. If either or both of those carriers is significantly out of place, there are going to be problems with the picture.

Picture problems related to alignment usually end up as ghosting that changes with the fine tuning adjustment, weak or no color, excessive hue shift with fine tuning, or interference patterns in the picture, either from the sound carrier or 920kHz beat from the chroma carrier. These adjustments have to be done with test equipment, they cannot be done visually.

So agc when’s it’s turned ccw the pick gets dark and distorted then turned cw picture is stable and brighter, is this how agc is supposed to behave ?

Yes it is, read the instructions on how to set it in the SAMS, even though it only factors in with TV stations tuned in from an antenna, it will still have an effect when a signal is being fed in from a modulator, turning AGC will have a drastic effect on the video, this is normal, set it to a decent range.

The higher up cw the brighter the screen gets. At this point I don’t know anyone in my area that knows how to do an IF alignment on this Motorola so all can do is the impossible by trying different adjustments on this set one day I’ll give up or maybe I’ll get lucky I’m into now so I don’t have a choice . I could give up now and put it in a corner and let it get dusty or I could try. It wouldn’t be worth the cost of the equipment to do an alignment and I don’t know how many pieces of equipment it would take or be needed to get the job done.

Or, you can build the video amp and convert to direct input.

Or, just buy the equipment needed, and do the alignment. The Sam’s is on the ETF website and has the entire process. It’s not very involved, and actually pretty simple. Steps 1-4 should get you close, if you do it carefully a few times.

Get a perfect B&W picture, before screwing around with the color stuff. You can’t get good color until you get the B&W stuff right.

Randomly turning afjustments will just make everything worse.

This thread has gone on for 1200 or so posts. We’re going in circles now. This is, TBH, getting stupid.

I disagree. It looks like very bad purity.

Yes it is bad purity since nothing is setup.

I already have a near perfect B&W picture.

[QUOTE=trinescope;324704
Picture problems related to alignment usually end up as ghosting that changes with the fine tuning adjustment, weak or no color, excessive hue shift with fine tuning, or interference patterns in the picture, either from the sound carrier or 920kHz beat from the chroma carrier. These adjustments have to be done with test equipment, they cannot be done visually.[/QUOTE]

Ditto, well said. IF alignment rarely goes way out without HELP.
Once I changed an IF transformer in a GE. I eyeballed thet one.
The last Emerson TV's seemed to have alignment probs but they were
such POS's we never dealt with it. And had a big Admiral that an alleged
TV man got to with a diddle stick. We couldnt fix it & sent it to Admiral
of Boston. Even they couldnt fix it.

73 Zeno:smoke: