a real challange?

[Electronic M]

Originally Posted by JohnCT

Update: I took an NOS RCA peaking coil from my parts supply and measured it. On my Z-Meter, it reads 5.8uh (marked 5.6 on the bag).

On my cheapo mega328 tester, it reads as a 0.2 ohm resistor... I tried several times and did the calibration procedure, but it won't read inductors - it sees them as resistors. Now, this tester is at least three years old and it's possible that this early version didn't read inductors while the later ones (which still look identical) purportedly do.

Incidentally, on the Sencore Z-Meter this 5.6uh peaking coil shows 5 rings.

Lastly, this is an RCA part number 119590. Judging by the part number, I'd say this is an early 60s to mid 60s coil for a color TV, but it likely covered many years.

If anyone wants this, it's theirs for the asking. Email me at delstv@aol.com

John

My 328 based tester (which died on me a while ago) couldn't read inductance that low. Also the lower the inductance the higher the series resistance of the coil had to be to be for it to NOT register as a resistor. It is a quirk to be aware of. These meters are useful (why I'm going to replace mine again) but not as good as a pricey dedicated inductance tester, didicaed cap/ESR tester or dedicated Solid state devices tester...it's only good within it's range limits.

[JohnCT]

Originally Posted by Yamamaya42

Well the thing I got ( when ever it gets here ) was only about $6.50, and they say it does coils, and 5.6uh is kinda small

Yep. Just checked, it will read as low as 10uh. The one I tried was 5.6uh. I'll pick a higher value tomorrow and see how it compares. I did try some capacitors today while I was playing with it, and it's pretty accurate with capacitors, and the ESR values were very close to what the Sencore Z-Meter says they are. The only thing it can't do is leakage.

Originally Posted by Yamamaya42

... on the slow boat from China...

The longer it takes to get here, the better...



John

[Kevin Kuehn]

Originally Posted by Yamamaya42

there are 21 of those little bastards in there.
all still orig, I was hoping they would not be a problem, but if the new 6.750 k bleeder does not bring up the 135v to around where it should be, they are next on the list, might as well get them all, they are cheap enough.
I just hope that the resistors IN the tuner are OK, for I really don't want to go in there or have to take it out to get to them, but with the way that I have found some resistors that were almost 2x over what they should be, I DO wonder...
But finding resistors that far off does not surprise me, given that this thing spent 2/3s of it's life neglected in a dark, dank musty basement in Pennsylvania.
And I know that carbon resistors HATE THAT!

How difficult is it to lift that 3 section candohm from the chassis, assuming it's riveted on. Doing so you may see your low resistance section move back closer to 6.750k. If that holds true, then leaving it isolated from the chassis it's likely you'd also see your 107V B+ come closer to 135v, as well as your 265V increase to 275V. It's something you could do while waiting for the replacement resistor to arrive. Keeping in mind the Candohm will heat up much more so than normal when it's physically not being heatsinked to the chassis, so this is only a short test to see if the B+ increases.

The above scenario is all based on my hunch that the one section has burned through the fish paper and is partially shorted to ground. And also requires that there's not a wire physically connecting the Candohm housing to ground.

[Yamamaya42]

I will have the new resistor today, and be able to try it tonight and see how things work.
I will most likely replace the 1500pf caps this weekend as well, but I'm not sure if I should touch those silly 270pf domino mica capacitors yet or not. :/

[Yamamaya42]

yop. those damn 1500pf caps are no good.

put in the new resistor the 109V came up to 112V. not much better.

unhooked R39 (R130 on riders/RCA) the one feeding the voltage to the IF, and it came up to 139v.

they all gotta go.

[Kevin Kuehn]

Originally Posted by Yamamaya42

yop. those damn 1500pf caps are no good.

put in the new resistor the 109V came up to 112V. not much better.

unhooked R39 (R130 on riders/RCA) the one feeding the voltage to the IF, and it came up to 139v.

they all gotta go.

Similarly you could remove R26 feeding B+ to the tuner, reinstall R39 and get an indication of whether it's mostly in the tuner or IF section. Of course there's the possibility that more than one caps are leaking. You can even go so far as to put a dc ma meter in series with R39 and you'll see the accumulative draw from each progressing stage. What would be very interesting is to see current draw with and without the RF and IF tubes installed. If it's the caps you'd still be seeing significant current being drawing without the tubes in. Time consuming work but very rewarding if you can narrow down the point of failure.

[Yamamaya42]

Originally Posted by Kevin Kuehn

Similarly you could remove R26 feeding B+ to the tuner, reinstall R39 and get an indication of whether it's mostly in the tuner or IF section. Of course there's the possibility that more than one caps are leaking. You can even go so far as to put a dc ma meter in series with R39 and you'll see the accumulative draw from each progressing stage. What would be very interesting is to see current draw with and without the RF and IF tubes installed. If it's the caps you'd still be seeing significant current being drawing without the tubes in. Time consuming work but very rewarding if you can narrow down the point of failure.

well I just ordered 21 of these, https://www.mouser.com/ProductDetail/667-ECQ-E6152KF
they SAY the the ones in there are ceramic, but I am not sure what the hell they are, I tend to think they are more like the elmenco tubular ceramic shell caps bombs that were in my CTC-16LX, they went bad as well, i took one apart and it had wax seals on the ends, and to quote Electronic M, It is usually best to assume in any tube TV that any cap 1000pF (=.001uF) and up is paper unless it is flat disc ceramic or a later film type such as a Sprague orange drop.

I just should have replaced them all at first :/

[Kevin Kuehn]

Originally Posted by Yamamaya42

well I just ordered 21 of these, https://www.mouser.com/ProductDetail/667-ECQ-E6152KF
they SAY the the ones in there are ceramic, but I am not sure what the hell they are, I tend to think they are more like the elmenco tubular ceramic shell caps bombs that were in my CTC-16LX, they went bad as well, i took one apart and it had wax seals on the ends, and to quote Electronic M, It is usually best to assume in any tube TV that any cap 1000pF (=.001uF) and up is paper unless it is flat disc ceramic or a later film type such as a Sprague orange drop.

I just should have replaced them all at first :/

My only reservation on the wholesale replacement of those is it may complicate your alignment requirements, but you wanted to learn full blown alignment anyway.

[edit] Just looked at what you ordered. Ceramic NPO may have been a better choice, but oh well.

[Yamamaya42]

Originally Posted by Kevin Kuehn

My only reservation on the wholesale replacement of those is it may complicate your alignment requirements, but you wanted to learn full blown alignment anyway.

[edit] Just looked at what you ordered. Ceramic NPO may have been a better choice, but oh well.

they are unlikely to change much of anything, as they seem to be mostly noise filters on the power and ground planes, unlike the coupling caps (720 pf ) which i have, but am hesitant to put in right now, for that reason.

[Kevin Kuehn]

Originally Posted by Yamamaya42

they are unlikely to change much of anything, as they seem to be mostly noise filters on the power and ground planes, unlike the coupling caps (720 pf ) which i have, but am hesitant to put in right now, for that reason.

I tend to agree. Although I've heard others advise that they can have subtle effects on alignment.

[Yamamaya42]

Originally Posted by Kevin Kuehn

My only reservation on the wholesale replacement of those is it may complicate your alignment requirements, but you wanted to learn full blown alignment anyway.

[edit] Just looked at what you ordered. Ceramic NPO may have been a better choice, but oh well.

https://imgur.com/lswPluo

as mentioned,, the same sort of thing happened on my 16-XL and i replaced the .001 with Panasonic films also.

worked OK,

[Yamamaya42]

I'm really not that worried about these new caps, the replacement specs were 20% @ 350v, and these new film ones are 10% @ 630v.
And like I mentioned, not in a critical area where they have mica caps used.

[Yamamaya42]

I just hunted up every vintage Miller / Merit peaking coil I could on Ebay and grabbed what I could.
Still 1 short
Found, NIB, 2 120 mh, 1 93 mh, 1 250 mh, and 1 180 mh...
short 1 93 mh. :/
Now I don't know that the ones in the set are necessarily bad, but as it's been pointed out more than once, I don't know that they are good, so now I have at least 5 out of 6 NIB ones to try.

[Yamamaya42]

have started to replace the little buggers...
https://imgur.com/1As2s9h

https://imgur.com/evHg7rm

this is gonna take a while
it does look like some of them have leaked some wax

I got my fingers in on of those :p
you can see I marked all the resistors that tested OK with a green mark.

[Yamamaya42]

So, from what I understand, the cheapo mega328 tester should be able to test the coils in my tv, 93uh – 250uh, cause as mentioned, I only found 1 of the 2 new 93s needed, so I will have to re-use whichever one that's in there that tests best, and from what I read, the new ones need to be put in exactly the same way as the old ones... just how critical is that?
If coil #xx1 was ##mm on the left side with the leads, and ##mm on the right, sitting ##mm above the metal chassis, does the replacement have to be exact, or is there some wiggle room?