Correct, that mystery broken coil part does look like it is from the convergence PCB, but all of them are intact! :thmbsp:
one must have been broken and replaced in the past, no telling HOW LONG that piece has been in there!

DAMN! there is NO ROOM to reach under the chassis to change out C1, it's just too tight under there.

Why did they design the chassis to tilt that capacitor? Was it to tilt it away from the isolation transformer’s heat?

I.m gonna have to do something drastic to replace it, cause I have noise in the B+ line :(

https://www.youtube.com/watch?v=QFl25sRnB0E

many weak tubes
most are still the original.

gonna have to check all the resistors as well

but FIRST video

Those Standard Coil tuners always needed cleaning.
They used to sell a kit that had a special cleaner and lube, plus a foam pad that went on the cover with the lube. After a while, the pad deteriorated and cruded up the tuner more. :thumbsdn:

Yeah, the tuner was very dirty, it was a bitch to get out because of the silly front screw in system they use that you have some odd key to unscrew.
Even after cleaning the contacts for chan 3, had problems getting a clear pic due to what I believe to be tired/ worn tuner tubes, only after hooking in a 15db rf amp was I able to tune in a clear video w/o snow.
Cause as mentioned, it seems that almost every tube is OEM and most likely worn/ tired.
I did try a couple of 6GH8As in the V19 socket ( h-blanker / bandpass) that were of unknown state, the first one made no change in the picture at all, the other must have been VERY bad, cause something smoked as soon as it was turned on, but STILL WORKED when the previous tube was put back, will no doubt find what it was when I check resistors, most likely many will be out of tolerance and need to be replaced.

Tubes ordered so far, based on what was observed, both tuner tubes, video output tube ( the video was being overpowered by color ) and the R-Y B-Y G-Y compactron, what color there was , is very off balance like one of the Y-amps was weak, though this could be bad resistors, but a 50+ year tube can also do it.

As mentioned, C1 is going to be a big pain to replace, C2 C3, are not so bad, but it looks like C1 was put in first, soldered in a very tight area, and then everything else wired in neatly and tightly in layers under it, there is no way to reach the bottom of C1 w/o ripping it all up.

What I may end up doing is attacking C1 with a dremel cutting wheel, won't be pretty but should work, cut around the base remove can and guts, work down to attach 3 new caps using solderable base of old C1 while leaving wiring to it under it undisturbed. ( idea anyway ).

But for now, gonna start with checking resistors on the chroma / luminance board.

Another annoying thing with this TV, is that “Instant On” was enabled, most likely for a very long time, which must have cooked the heck out of these poor old tubes.
Also, not seeing full vertical deflection, and linearity is a tad off, also a sign of bad caps and resistors in the sweep PCB.

I found out why that one 6GH8A made something smoke like it did, I really don't think the getter is supposed to upside down in there like that... it broke off!

Can you post a video and/or more pictures showing how to disassemble a tuner and clean it?

i did find what smoked.
http://suzaku.live-evil.org/smoke11.jpg

R164 went up in value R165 went down. :o

both replaced.

One thing about the PCBs used in this maggie TV, they are much more dense / thick than the ones used in RCA, GE and others I have worked on in the past, example, previously I have been able to take my work light (halogen hand lamp) and point it at the top of the board, and see light through the PCB, along with the shadow of the offending component from the bottom side, but not with this Magnavox :O no light at all gets though the board!

The cause was a short in the tube that causes excessive cathode current?

Yes, the getter completely come off, stand and all, and was loose in the top, I had not not noticed it, was only on for about 30-40 sec, before i saw smoke and shut it off, resistors may have already been weak, not sure.

Are you sure that the metal getter didn't short the elements in the tube when it was flopping/flopped around? Short between elements might have caused the problem.

I'm sure it did, but it was only on for 30-40 seconds with the bad tube, how fast do resistors fry?
There was also heat marks on the PCB under these 2 parts already, I suspect they were already on the way out, and putting in the bad tube did not help it! :P

Half a minute is plenty long enough to fry resistors, given the right (wrong?) set of circumstances.

I noticed that too. I like my T931’s build quality. 2000s solid state TVs have PCBs that are as thin as two sheets of paper.

The one thing I do not lile about the T931 (and the T933 as the same design) is that it doesn’t use DC reinsertion, but instead uses partial DC coupling of the DC bias from the video detector. This causes inconsistent black levels, especially for super bright scenes, which cause black crush.

I am tempted to add a diode clamper to make brightness more consistent between scenes.

Well, all the others in the area seem to check OK, it was most likely being fed by the big 4w resistor on the triode plate P1.

Yeah, the tuner was very dirty, it was a bitch to get out because of the silly front screw in system they use that you have some odd key to unscrew. >>>>

The screws with 2 holes come out with long needle noses. They also
used 2 sizes of inside out nuts. I saw everyone fighting them so called
Maggy FS to get part ##'s & ordered 2 sets. I told the techs if they lost them they will build stands for 60 days:tears:

BTW many sets had a 'lytic on the conv PCB, causes bad V lin. IIRC
this had it ?

Zeno

It has two lytics on the convergence PCB. They tested bad on my T931, and so I replaced them with 105c lytics.

i replaced them on mine as well.

BOY the new ones are tiny!
http://suzaku.live-evil.org/0525232112a.jpg

also replaced the cap on the contrast pot, i don't think the old one is very good!

http://suzaku.live-evil.org/0525232112.jpg

IIRC my Maggie roundy is still running original lytics on much of the TV chassis (the remote and amp chassis got full recaps) with the exception of the contrast lytics section of a can which was completely open. I just added a new cap at the pot and brought the set from weak unadjustable contrast to plenty of contrast with good adjustability.

The multi lytics in the set are as such.

C1-A&B (80uf@450) are impossible to reach cause of no room, (filters)
C1-C is 20uf @ 350 and may be able to isolate and relocate as it's for the grid of audio output.
C2A 80uf @ 450 filter
C2B 50uf @ 450 filter on vert output
C2C 30uf @ 450 filter
C3A 20uf @ 450 filter bottom of voltage divider
C3B 20uf @ 450 filter video amp 1
C3C 20uf @ 450 audio out xformer

Just can't do anything to C1 w/o destroying it. :no: :tears:

For my Magnavox T931, I used an oscope to measure the ripple voltage on each lytic that is used as a decoupling capacitor. They all measured good. I also did in-circuit ESR and capacitance tests and all measured good except those 2 on the convergence PCB. I bet after reforming, most are still within specification.

Perhaps they are OK, but I don't know yet, in most sets I have done so far many were bad, C4 was definitely bad and leaky testing a 2x norm value, C5 was also too high @ 81uf, (cathode cap vert output ) , now has new TVA1414-E3 Sprague ATOM.

I don't have one of those old fancy vintage cap leakage testers, wish I did, but from what I have seen, if the testers I DO have (I have 2) show the value to be way WAY above the posted value, chances are it's leaky and not to be trusted, like the example of the 100uf testing a 208 on both testers.

If you want your restoration to look OEM on the inside, you can get newly manufactured multi section can lytics from CE Manufacturing. I bought a new capacitor from them to replace C1, just in case it failed to reform.

Only 2 new tubes have come in so far, the mixer/ osc for the tuner, and the video amp V6 12GN7A, no change in the picture yet, VERY weak luminance that is overpowered by color.

In grayscale setup it does not take much turning up of the screens at all to make a bright line on all 3 guns, but when in normal mode, nothing is seen on the screen cause luminance is so low getting to the CRT. You have to turn the screens up too see anything at all.

3 good 6GH8As are coming, as is the 1st video amp cathode follower tube 6LM8 (V6)
I have not found any other bad resistors so far, hopefully this is just a case of tired tubes, as mentioned, they seem to be all original.

12GN7A tubes are one of the most impressive vacuum tubes to have been mass produced. It has a very impressive gain, and its plate can handle 12 watts. Not bad for such a small tube.

I think the luma issue is due to the weak 6GH8A blanker.

some sources say that 6LM8 and 6GH8A are compatible, but i am getting a new one of each anyway.

The 6GH8 blanker and the 6LM8 video amp really need to be 100% in these chassis. Earlier Magnavoxs did use a 6GH8 in place of the 6LM8s. Also, unlike most all other brands, the brightness control on Magnavoxs has an effect on the set up service line adjustment. I always start with brightness, contrast, and kine bias controls tuned down. After set up and tweeking adjustments, if brightness is lacking check resistor R74, on the cathode of the 12GN7 ( shown on your post number 51). The resistor is usually underneath the tube socket on the foil side of the board. The diagram shows a 470 ohm, some sets used a 270 ohm. On sets needing more brightness range I replaced the 470 with a 270, made quite a difference.

https://www.youtube.com/watch?v=XwJplJKppqc

2nd video

its pretty clear that the filters are not up to snuff.

http://suzaku.live-evil.org/magg1-cap.jpg

going to try and replace what Caps i can C2a C2c C3a

hopefully that will clear up that noise in the screen ( bar riding up )

USPS is living up to it's reputation of reliability and efficiency as always (heavy sarcasam ), as the new 6MD8, which should have been here today, decided to take a 1,800 mile sightseeing trip from the local PO 15 miles away, to Teterboro NJ, WAY TO GO, USPS!

Ya never know, it just might show up today!

Just sharing my frustration a bit with USPS. :D:thumbsdn:
30 May 2023 14:13
Arrived at USPS Regional Origin Facility. Your item arrived at our KEARNY NJ DISTRIBUTION CENTER origin facility on May 30, 2023 at 2:13 pm. The item is currently in transit to the destination. KEARNY NJ DISTRIBUTION CENTER ← Expected Delivery by 5/30/23 by 9pm, I DON'T THINK SO-- USPS!

USPS
29 May 2023 01:12
Arrived at USPS Regional Facility TETERBORO NJ DISTRIBUTION CENTER ← leaving on a jet plane, just for fun?
USPS
28 May 2023 12:58
Arrived at USPS Regional Facility AUSTIN TX DISTRIBUTION CENTER ← 15 miles away
USPS
28 May 2023 12:57
Departed USPS Regional Facility AUSTIN TX DISTRIBUTION CENTER ← it left before it arrived!

USPS
28 May 2023 03:50
Arrived at USPS Regional Facility DALLAS TX LOGISTICS CENTER
USPS
27 May 2023 11:27
Departed USPS Regional Facility CHICAGO IL NETWORK DISTRIBUTION CENTER
USPS
27 May 2023 01:37
Arrived at USPS Regional Origin Facility CHICAGO IL NETWORK DISTRIBUTION CENTER
USPS
26 May 2023 11:49
USPS in possession of item OAK PARK, IL, 60304
USPS
24 May 2023 15:52
Shipping Label Created, USPS Awaiting Item FOREST PARK, IL, 60130

If you think that's bad it's just a part for a hobby...
Our local state farm office was not getting mail into their PO box for MONTHS.... People's coverage was lapsing and their business was a mess because of this. For several months in a row our agent kept pestering them to fix it and getting ignored, the runaround, BSed, all the above until eventually someone noticed they had been dumping checks and sensitive legal documents into the wrong PO box for months! Can you imagine getting into an accident and discovering you don't have coverage because the post office wasn't delivering your check. :yikes:

I get that they are having staffing issues, but at some point there needs to be punishment...If they have to worry about the last 2 months of their paycheck deposits being pulled back from their account or SOMETHING other than layoff that hurts then they'll be more careful.

USPS is not the only carrier to engage in long odysseys. I ordered an A/C hose from Phoenix, AZ. I live in the Atlanta, GA area. Fed Ex Ground routed it through Idaho! Come on guys - just get on I-10 and head due east.

Today, I ordered another car part which is being shipped from a town 7 miles away. DHL says it will be here on Friday. Before you ask, the company won't let me pick it up in person.

I'm just having flashbacks of when I tried to get a NOS vertical block transformer for my Arvin over 2 years ago or so from e-bay, the first one was lost when it got to the local PO, they never found it, the 2nd one was DOA, a bad one, used in a new box, which was lost on the way back RMA, the 3rd and final came from ETF, and I was very nervous tracking it all the way from Hilliard, OH, hoping that USPS would not mess it up as well.

C3 replaced

http://suzaku.live-evil.org/0530232043.jpg
http://suzaku.live-evil.org/0530232044.jpg

C2 is next.

one thing i noticed
most of the time when the set is turned on, there is no luminance at all, brightness cont has no effect, but if I switch it in and out of service mode several times, it will suddenly start working.
weird.


all it does it cut power to IF 1&2 and the pincushion amp.

still waiting for new tubes