but do check the coil, if you have not yet, especially resistance between the windings and the windings to ground.

Then I have to cut all the connections the coil is wrapped on a plastic bobbin if I check resistance with connections on it will seek ground but with connections off there is no path to ground. The only ground is the .001 to ground I checked already.

Ok here’s what I came up with weather or not it turns out to be true I don’t know yet but obviously there is something invading the negative side so if it were shorting it would trip the breaker or burn the fuse wire so I’m thinking it’s something with cushion like a .1 or ,01 some or any cap to ground that is starting to short like the 2 in the power supply one on negative and one on positive there are 2 .01 caps there and several others I haven’t changed. After all the positive output diode is getting very hot and this is not right my other Motorola diodes never got hot it was a 908 chassis.

you dont have to cut anything

http://suzaku.live-evil.org/resist111.jpg

measure the resistance between pin 7 of V1 and pin 2 of V2, it should test very high, if not infinite in resistance.

That is the most important thing to test.

It measures 23k and those coils did measure.1 ohm each.

seems OK, for reference, the same test on L5 should test about the same IMOH, if there was a coil short, the reading would be low.

So what do you think of the idea of a cap being a cushion.01 ?

or that 800pf?
but if it is one of those, as mentioned the alignment will be disrupted if replaced, so damned if you do or don't it seems.

your best way forward may be to rig for direct video input.

I don’t think it’s the 800pf because there is no power source with it removed from pin 8 as long as the 6.8 is connected to the 8.2 and then grounded that’s when the voltage is lost

Hi

I believe measuring resistance from one side of the IF Coupling Transformers, or IF Coils
is not necessary, and you can achieve better results measuring voltages, like for example
Pin 7 of V1, and and Pin 2 of V2. If the Primary, & Secondary had some short, or leakage
it would show itself with 200V on one side, if the insulation were to break down at the
200V operating voltage it would show on grid of V2, and be more telling.

I'm wondering what the voltage on pin 8 of V2 is...? They are almost the same circuit,
and with almost the same voltages on all the same tube pins......
Same resistor voltage dividers too......

I'm also wondering if these voltages are a result of no signal from the tuner....

Have you tried hooking up your tuner subber to this tv & putting a signal on it
and leaving the tuner power plug hooked up to the tuner, but just removing the RCA
plug to the IF, & putting the Tuner Sub box in..... And then measure these voltages...?

.

V2 is not the same with the voltage divider the 8.2k on v1 goes to ground but the 8.2k on v2 does not go to ground that’s the difference the ohms check perfect on v2 but v1 the only pin that was wrong was pin 8 and I have tried with the tuner plugged in and out with the subber and the voltage only went up like 4 volts. It’s something on the ground pulling the voltage down take the 8.2 off ground and voltage is good and also the x2 diode getting really hot not right. Iirc pin 8 was little higher then what sams says. Again pin 8 v2 don’t go to ground like v1 does.

Hi

Timmy, I understand what your saying about the 8.2K resistor. I Don't see any reason
for it except possibly biasing, or absence of signal from tuner.... If pin 8 on V2 has
100V on it, or 63, I'm just wondering what might be going on there that's all....

I don't have a good idea at this time for what you have now.... As for the hot diode,
if the power supply voltages are normal, I'm not sure I have an idea about that....


.

Well maybe I’m wrong completely about the voltages all pins hooked up pin 8 v1 63v v2 pin 8 55v maybe the voltages are supposed to be that until it conducts then it becomes 100v. Maybe it is a biasing problem I did check current with the resistor to ground versus not on ground and ma only went up 1ma with resistor on ground so I guess it’s safe to say it’s really not shorting.

As for the hot diode, if you have the replacements in there, as i pointed out before, there is a good chance they are counterfeit diodes, do not rely on them.
like seen here
https://www.eevblog.com/forum/projec...e-real-1n4007/


It would not hurt to put in 2a diodes like these,
https://www.mouser.com/ProductDetail...2F4Otccg%3D%3D
they WON'T get hot on you!

Originals are in the chassis.

then get 2 fresh 2A ones and then they will never get hot again! :D

$.70 each is worth it!

.70 is good yes but 7.50 shipping is not.

.


HOLY CRAP ! 50 Freakin' Pages !

Yah, gotts love under a dollar items & 10X that for shipping......


.

That’s for sure thing is I have bigger diodes but the numbers are worn off is there anyway to tell what they are

Pin 3 v1 64 volts add antenna 74 volts and if I up the gain the voltage drops highest voltage is with the gain at min I think this subber clock wise is low gain. I think I’m going to focus on v1 because voltage does go up on both v1 and v2 with antenna on so it is working but not enough. There are a few resistors a 22 ohm that measures 25 ohms don’t seem to high and the 18k measures 17.40k I’ll have to double check the 2.2k.

Good Morning!

I think you should try setting a goal of fixing this tv before this thread hits 60 pages!

Anyway.... Since you have that tuner subber, and it puts out TV type IF signal,
I think you should take the signal that comes out of it, and make a nice little
poker probe, with a coupling cap of course, and poke it around in the IF section
and see if you can narrow down where it works and where you loose it....
You did that video injection at Test Point 'B' a few pages back, so why not
take that IF signal from the tuner subber and poke it into each of the 3 IF
stages and see what you get...?
Don't forget to ground the ground part of the output cable, then just turn
the center wire into a capacitor coupled probe....

Aim for the G1's of each stage, put up some screen shots

1. no signal anywhere,
2. 1St, IF right at G1
3. 2Nd IF right at G1
4. 3Ed IF right at G1.

Naturally the signal will not be strong enough to produce a picture as you
get closer to 3ed IF, but the signal is what those circuits are tuned to
respond to, so I think it's your best bet to see at what point you might be
loosing your juice at...

Oh, and congratulations, your tuner subber is now also an IF section analyst
you can rename it later......


..

I have the chassis on the bench and I’m going by voltages and pin 2 of v1 I get same result nothing further up other then pin 2 I get the same with the subber plugged in. I have to check the 2.2k resistor again.

Does it appear that the k1 agc network would have anything to do with the IF functioning because I put together k1 and the only thing left that the IF would be lacking is the .4 source from the tuner because I have the chassis on the bench. Can’t find anything else obvious here.

in order to do that, you need to put the chassis in the " service position " as seen here.
http://suzaku.live-evil.org/0417191838b(1).jpg

OR pay way too much for a tube test socket like this
https://www.ebay.com/itm/36352391049...N2AYQ&LH_BIN=1

I know I wish I had those sockets and there is no way I can stand the chassis up to get access to the underside I tried already the harnesses are just to short

Can see an image. I can see words but video is just out of reach.

Well, I never had those fancy tube sockets.... I use to take 30 Gage wire & wrap it
around each tube pin I wanted to measure something on, then plug the tube back in
and I had access to whatever I needed on that tube....

But it would be best if you had a nice little bench you could put the chassis on, flipped
like that and make all your measurements....

Just build one, it's not like it's going to add significantly to the time it's taking to get
this tv working anyway..... And with all you spent on caps, precision resistors, tubes,
diodes, & thermisters, flyback transformers, you cudda just took out all that stuff and
put a flat screen in it already..... So just build a nice chassis table, put some movable
arms on it, mount a few lights, do it up nice!

Oh, and don't forget add one or two cupholders.....


.

Lol

The resistors I got I didn’t use the 2.7k because I got 2.7k 3watt but the voltage says they are rated for 135v so I’m not sure if it’s good to use them being there is 275v at one end. But I checked the 2.7k ones left in there and they show good however the others did not.

Problem here is I only put 2 resistors in v1 after not seeing a positive result got discouraged so after making a new k1 with the new 680k I put the chassis back in and was surprised to see an image and words I can read didn’t have that befor so now I put the other 2 resistors in v2 and I’ll try it tomorrow I still didn’t change the 2.7k in both because I screwed up when I got the resistors the 2.7k 3watt are only rated for 135v not sure if I should use them I don’t want to use them to have to pull the chassis again because they couldn’t handle the voltage and went high or opened.

I don't know where you got the 135v rating, but forget it.

It's a 3 watt 2700 ohm resistor, and will dissipate 3 watts when the voltage is 90 volts DC. (P = (V^2)/R). So, if the specified wattage rating is 3 watts, the circuit was designed to apply less than 90 volts to that resistor. Of course, a circuit fault might put more voltage across a resistor than intended, and that would have to be fixed, and the resistor would indicate that by overheating and smoking.

Edit: resistor voltage ratings are usually for momentary voltage that might cause the resistor to arc over. Typical max voltage rating for discrete resistors might be 200-600 volts, but as you see, for DC, the wattage rating may be exceeded long before the voltage is. AC or pulse current will be different, as r.m.s. current determines the power while the peak voltage determines whether the voltage rating is exceeded.

The voltage rating was listed on the mouser site where I got it and this voltage is 275 dc from the power supply so I just want to make sure because these resistors get hot but it is 3 watt same as what was in there. And it’s a wire wound. These resistors are small bearly half inch.

Was the original wirewound?
Can you post a link to the mouser page?

the resistor types I mentioned a few weeks back were 750v type metal film ones.

https://www.mouser.com/ProductDetail...Wwtn4Z2Q%3D%3D

perfect for this situation. :O

which DID you order?

Well it turns out that I never used that site before so the 6.8 and 8.2 were metal film and the oxide the 2.7 is a wire wound.

All the power resistors were wire wound.

Here’s the 2.7 3 watt wire wound

please post info links of the Mouser parts that were ordered, you should have gotten this info in a confirmation e-mail when the order was placed.
:yes:

Here’s the resistors I got

The only one in doubt is indeed the wire wond one.
https://www.mouser.com/ProductDetail...0BKWoLFQ%3D%3D
https://www.mouser.com/ProductDetail...1SlkNR2g%3D%3D
https://www.mouser.com/ProductDetail...Mm2017zw%3D%3D
https://www.mouser.com/ProductDetail...FaCwg9Xg%3D%3D


The 750v ones I had shown on page 46 were a good match and even cheaper, :/

https://www.mouser.com/ProductDetail...Wwtn4Z2Q%3D%3D

As a general rule, I try to get a voltage rating that is 2x above the circuit the resistor is to go in, not that a lower won't work, it's just for better longevity.