R23 is a trap but it has no wiper it’s attached at each end and would usually have a center for the wiper it has the adjustment knob but no wiper

Not with it the way it is working now, you won't see it change much.
But as suggested, if you feed the tuner subber into pin 2 of V2 as you did the other week, giving it a good source like DVD something else with good sync, the AGC should respond much better.

You won't see any change on the screen, BUT, the voltage at pin 3 of V2 should change as you adjust R14, the same changes should be seen at pin 3 of the tuner plug.

Well I already seen the voltage does change at max it’s only 135v. All 3 coils test good the only other is the 8.2pf cap at antenna input.

picture please...

if R23 is broken that is a BIG PROBLEM, and 99.9% likely you can't tune in anything.

the traps are de-tuned and nothing can get to the 1st IF to get processed.

Are you saying that they are pre-tuned I didn’t touch the blue knob.

It say it’s 15k but can’t measure it because the .2 that the coil is showing across the trap will show before the 15k. So how are they checked why would it have gone bad if it did.

Those types have brass communicators hidden under the plastic disc, they make contact with little carbon traces that are formed into the ceramic resistor base below it.

It looks fine, don't turn it cause it will make things worse.

It’s not broke in anyway if it was turned it can be put back where it was correct.

https://www.robotroom.com/Trimpots-2.html

not exactly the same, but you get the idea! :)

Well now to figure out the next step.

This trap don’t have the center lead for wiper I guess it’s done under the blue cap

they most likely did not see the need for a full 3 terminal trimmer, and just got and oddball 2 terminal one.

So if this were you where would you go at this point

When I put this chassis back in tomorrow I may try disconnecting the 2 wires from k1 that go to the first IF and see if this helps find this problem.

I also may put k1 back in the one I made up since for some reason I had a much clearer picture from pin 2 v2 when the new k1 was in but then again I replaced 2 22ohm resistors in v1 and v2 so maybe it’s the resistors letting more to get by in the iF interference to get the same clear pic Before doing the resistors I don’t know yet. And besides why is agc needed anymore anyway since there’s no more over the air broadcasting for the agc to amplify.

You could manually bias the IF...Some cheaper portables and consoles like the Philco predicta didn't have AGC and simply had a local distant switch for bias control and expected the user to adjust contrast to compensate for signal strength....There may not be sufficient contrast range on your set to give it permanent fixed bias.
Modern RF modulators vary in strength so without AGC one unit might be too weak or too strong.

You already know that you could use the tuner subber to feed in signal at V2 pin 2, but it did not work at V1 pin 2.

but I do not think you tried to disconnect L3 point 2 ( leave R37 hooked up) and try to feed it in again at V1 pin 2 with that coil unhooked, you may have to adjust R14 and the gain of the subber.

If it still does not work, the fault is L4, and is likely not passing any signal, out of tune or bad.

If you DO get a picture, the fault is l3 or L1 L2.

Do not worry about the 7v on the grid right now the 6EH7 can still work like that, V2 did just fine with 7v on the grid, V1 will also.

So try it with L3 disconnected while feeding the subber in like you did with V2 and see what happens.

I already took v1 pin 2 wire off L3 I tried the subber and the video was not as good as v2 but I didn’t try the agc while I did this.

so you got distorted video ?

that would mean that L4 is out of tune, most likely and prob L3

Ok interesting I’ll look into that tomorrow I’ll rule out everything you mentioned here L3 and 4 and I’m going to put the new k1 back in be the resistances are way out on the old one which may make a difference. I did get the new .001 mica cap but I did try a regular.001 ceramic that made no difference I don’t think a mica slim ale that much difference.

You should not have gotten a worse picture , unless somehow the signal was being overloaded, thus the reason to adjust the gain out of the subber down a bit.

but If it was messed up like feeding in from the RF input for the tuner, then L4 is suspect.

this is taken from the b&k precision 1077b television analyst manual, it's for the most part what you are doing to debug the IF

http://suzaku.live-evil.org/if-111.jpg
http://suzaku.live-evil.org/if-222.jpg

The primary of L4 has the red cap I don’t know yet if it’s a mica but maybe I can’t use a ceramic to test like I did because when I wired in 2 ceramics and had the wire off L3 and had the subber on pin 2 of v1 I took off the ground on both caps and it made no difference in the video at all so maybe while I have the chassis out I should put the mica in and the other .001 so that’s done.

So if the primary cap the red one is not a mica then putting a mica in same value should be ok.

Good Morning:

Before I run off to work today, there are a number of things I would like to
see you test if you want to & have the time......
Both at the IF section, and again at the HV section.

At the IF Section, I know this may sound silly at this point, but, I think you
should check the input RCA jack the center connector where the signal goes
in, I think you should check this to ground with the ohm meter, to be sure
it's not grounded.... Please post the actual reading as well.
I think you should disconnect R23 at pin 3 of L3, and Disconnect Pin 1 of L3
and then put in your DC AGC bias circuit for Point A. Fire it up and see if you
can feed a signal through..... Be sure to sweep the voltage on your little AGC
bias circuit. If no signal, then I think you should reconnect everything,
disconnect pins 2, & 3 of L4. Take your tuner subber and ground pin 2 of L4,
and using your coupling cap attache the tuner subber to pin 3 and see if a
signal makes it to the screen..... Without a plate voltage there I'm not sure if
it matters to leave V1 in for this part, or take it out.

Not sure how I feel about disconnecting pins on K1 because it can be
overridden by the AGC Bias thingie. But If you really want to remove
a Pin & Test, I would remove only pin 5. Be sure you use new batteries
in all of these things for testing.

Other thing I would like to see is a resistance or Ohm reading from these
points to compare against the Sams for the following areas.....

Tube | Pin | Sams Reading | My Reading |
--------------------------------------------------------------------------------
6JM6 | Plate Cap Both | 22 Ohms | ? |
3AT2 | Plate Cap | 622 Ohms | ? |
1V2 | Pin 9 | 21 Ohms | ? |
6BK4 | Pin 5 | 800K Ohms | ? |
6DW4 | Pin 2, 7 | 24 Ohms | ? |
6DW4 | Pin 9 | 240K Ohms | ? |

-------------------------------------------------------------------------------

Please double check the resistance table & be sure I did not make a mistake
here. Also observe the little caveats posted in the Sams about each reading.
I'm interested in these as a double-check for flyback wiring, just -in-case.

Don't forget to stop for coffee breaks now & Then and have
a good lunch & think about next steps.
Never Give Up, Never Surrender.....

Have an Awesome Day!


.

Sorry....

When doing this, it may be smart to put a 1K or so resistor in series
with pin 2 or 3......

disconnect pins 2, & 3 of L4. Take your tuner subber and ground pin 2 of L4,
and using your coupling cap attache the tuner subber to pin 3 and see if a
signal makes it to the screen..... Without a plate voltage there I'm not sure if
it matters to leave V1 in for this part, or take it out.

..

2 caps in L4 no mica.

Mica caps tend to be more stable than ceramic disc, and since you have already crossed the threshold of no return and removed the caps in L4, might as well put 2 new mica .001 caps in. provided they are up to the voltage rating.

Well I put back pretty much what was in there and it turns out that the 2 micas I got are to big to fit inside the aluminum housing. I got .001 500v and they were just to big.

Taking them in and out like that would have upset any alignment there may have been in the coil, if size was a problem, rather than putting the old ones back, new ones like this may have been better.

https://www.mouser.com/ProductDetail...mqNqg61Q%3D%3D

I put 2 new caps in but not the micas.

That clear pic form several posts ago from v2 pin 2 I can’t get back since I changed the 22 ohm resistors which were around 28 ohms. This is what I get wire off L3 v1 pins 2 and 7 and v2 2 and 7. Agc didn’t do anythin

what kind of dialectic disc cap did you put in?

the old ones were Z5U, had a pretty big spike.
https://www.allaboutcircuits.com/upl...captypes_1.JPG

i guess the red one was on pin 1 and the yellow RMC on pin 2? RMC= higher voltage.

At this point it don’t matter it’s the same as it was before I changed them and the next step I’ll lift number 4 from the k1 from v1.

NOT A GOOD IDEA!!

Pin 4 of K1 ( test point C / C18) is the ground ref point for that circuit, if removed, it would cause a drastic rise at all other points including the grid of V1.

Ok I’ll leave it and I plug the subber in the chassis and get the same as all before so now I’m left with either L 1 2 3 or 4 as possible culprits.

Maybe unlikely but for all I know the caps at v1 could be bad.

More likely than not, the first few stages are out of tune, be it from age, or from someone messing with it, for some reason or another, it can't pass a signal, and nothing short of someone with an alignment setup can get it back to working the way it should again.

You could try the steps that Squirrel boy mentioned, like on the top of this page, unhooking the primary of L4 to feed in the subber direct, this can help find what is out of tune, however, trying to tune without the right equipment is pretty much impossible, and you pretty much end up making it worse if you try.

At this point you have pretty much confirmed that you do indeed have an IF problem, and the best way forward is to rig for direct A/V input until you can find someone with the correct equipment and knowledge near you to align it, the chances of there being a fault in the IF is low, but there may be, but when alignment is attempted with the right equipment, any faults will be quickly found.

Or if I mark the trap and rotate it left and right and see if I get anything because at this point I’m looking at either the 3 coils before v1 or the trap and if none of this gets any results then possibly the 39pf 800pf 56pf 150pf caps.

V2 already proved to be ok the pic showed this but since changing the 22ohm resistors only 2 of them the video is the same across the board no matter why I do now.