Duncan's 1960 Magnavox
 

Picked up this beautiful 1960 Magnavox Console.

I've restored a few vintage tube radios in my past, but never a TV before!

Everything, and I mean EVERYTHING appears to be original and untouched.

A few tubes have been replaced with GE units, and the 5U4GB is labeled "Japan"

I'm still learning here on my end, so any helpful advice, corrections, or input is always welcome!

A quick power up shows a decent picture!

I'm re-capping this set because the C2 4 section capacitor did blow out (overheated, swelled up, and popped) - causing loss of picture. The whole process took 2 seconds, and I shut the set off while the cap popped.


Year: 1960
Model # 1MV354 R
Chassis: V30-15-00

Some photos of the unit below:

https://live.staticflickr.com/65535/...e8e7f0f3_c.jpgPXL_20240720_162133024 by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...0f3c6c3a_c.jpgPXL_20240720_164751604 by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...80a821f5_c.jpgPXL_20240720_164740585 by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...41fe5719_c.jpgPXL_20240720_163335964 by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...eeb406b3_c.jpgnight photo by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...73663c55_c.jpgPXL_20240722_011714175 by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...e17347b7_c.jpg262429057_7107277319290335_6646583959770188826_n by Thomas Duncan, on Flickr

Dude that thing is a real time capsule, all I can say is WOW! Very nice catch.

Thank you! I will take good care of it.

Recap amp
 

I started with replacing all the wax/paper capacitors & large 4 section capacitor in the audio amp.

I used slightly higher rated film caps inside the chassis (factory is 400v, I used 630v)

As I understand film caps are not polarity senstive and can be installed in any direction.

Multi-section can cap was replaced with a unit from Hayseed.

Re-installed the amp and everything still worked great!

https://live.staticflickr.com/65535/...1b03a2dc_b.jpgPXL_20240722_210024262 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...8bcd7817_b.jpgPXL_20240722_210111542 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...b6d5ab72_b.jpgPXL_20240722_211318305 by Thomas Duncan, on Flickr

New film caps (yellow)
https://live.staticflickr.com/65535/...bc4ed5d2_b.jpgreceived_2499329160274717 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...0aa5dfb3_b.jpgPXL_20240726_223320695 by Thomas Duncan, on Flickr

Removing TV chassis
 

I wore 15,000 volt gloves, and safety discharged the high voltage lead on the CRT.

I then removed the TV chassis for inspection.

The flyback transformer looks a little melty. Some of the wax fell off / melted off. I don't see any signs of arcing inside the metal case of it.

I contacted Moyer for a replacement / spare and had no luck.
If anyone has a good used / NOS one let me know! - I'm looking into how to re-coat the flyback?

Flyback Part#: 360779-1
Other part #s:
Merit HVO-172
Thordarson FLY-179

https://live.staticflickr.com/65535/...36f1a12e_b.jpgPXL_20240723_230154818 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...85034223_b.jpgPXL_20240723_232412518 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...e51d5169_b.jpgPXL_20240723_232419443 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...bda259dc_b.jpgPXL_20240723_232757786 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...4e083749_b.jpgPXL_20240724_204340786 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...9f58eb5e_b.jpgPXL_20240724_204344225 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...75f3500d_b.jpgPXL_20240725_011805289 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...08b002b6_b.jpgPXL_20240725_011814477 by Thomas Duncan, on Flickr

TV chassis re-cap
 

I removed each paper/wax cap and started replacing them with film caps.

Again, I heard and read the diagrams online, it seems these yellow film caps are not polarity sensitive?

Most of the caps were rated to 400v, the replacement caps I used were around 600-630v. Same uF factory rating with a tolerance +/- 10%

https://live.staticflickr.com/65535/...d21a4619_b.jpgPXL_20240730_204949224 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...99bab2a9_b.jpgPXL_20240801_010015986 by Thomas Duncan, on Flickr


https://live.staticflickr.com/65535/...d9cd3e81_b.jpgPXL_20240801_010041094 by Thomas Duncan, on Flickr

Cap C4
 

I know any normal electrolytic capacitors ARE polarity sensitive, and should never have the + terminal installed to chassis ground.

I don't understand why the diagram shows Cap #4 with + to ground.

I thought it was a typo, but the OG capacitor was installed in the same way.

So, I installed the replacement 2uF / 50v cap with the + terminal to chassis ground.

https://live.staticflickr.com/65535/...4218069f_b.jpgPXL_20240803_005803186~3 by Thomas Duncan, on Flickr

OG cap:

https://live.staticflickr.com/65535/...1b6bf9bb_b.jpgreceived_1052973953063467 by Thomas Duncan, on Flickr

New cap:

https://live.staticflickr.com/65535/...9a3cf871_b.jpgreceived_1249401692693103 by Thomas Duncan, on Flickr

I ended my day with a visit to the local Houston EPO store.

Picked up a nice looking, and working! Tube tester.

https://live.staticflickr.com/65535/...977bd245_b.jpgPXL_20240803_141622095 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...aabf8512_b.jpgPXL_20240803_153220060 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...12327d1c_b.jpgPXL_20240803_153226760 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...9a82e518_b.jpgPXL_20240803_163259167 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...0d55d56d_b.jpgPXL_20240803_164418694 by Thomas Duncan, on Flickr

.

Very Nice TV! My Parents has a set like that - but only a tv. I spent many many nights
in front of it as a kid.... Watched till the stations went off the air at 3AM.
I would like a parts store like that near me......

.

Only lytics and IIRC Tantalums are polarized.

Your flyback is probably fine if it makes the screen light up that well. Many flys would normally drip some wax or tar (depending on what they're made of) over the course of their service life....It's also not uncommon for some of the tar to chip or peel off with age....the flyback doesn't need replaced it just needs recoating with wax, tar, corona dope or sensor safe RTV (which one is a matter of personal preference).

The positive grounded lytic probably filters a negative voltage rail. All tube gear has positive rails, but some have negative rails too. Some sets connect the can lytic capacitor negatives to a floating negative rail separate from the chassis, and if you change that bad results tend to occur. Another thing that can be confusing when you see it for the first time is a voltage doubler circuit.

Don't replace paper caps with ceramics in TVs, ceramics aren't stable enough for video and sweep applications that originally called for paper.

Thank you for the info, I'll keep that in mind. I didn't know that about ceramics.

I'll pickup some blue sensor safe RTV from the store this weekend.

Out of the TV Chassis capacitors I replaced so far:
13 replaced with Film caps
1 with a Lyitic
2 with Mica (Hard to find value & tolerance) - Mica seems to be okay? - From what I can find online its not considered a ceramic.
.0039 uF @ 200v +/- 10% (Part of the Horizontal Hold Circuit)
.0051 uF @ 400v +/- 5% (Sits between the Sync Phase inv & AGC Clamper)

Micas are fine...expensive, but fine. Those 2 caps you changed should also be available as film capacitors (I don't think I've seen 5100pF used anywhere before and haven't looked for new parts that value) and I probably would have used Panasonic or Illinois Capacitor brand red film caps in those locations for budget reasons.

RTV for Flyback
 

After reading multiple forum posts about re-coating the flyback, i've settled on the following RTV.

Brand name: Momentive / SNAPSIL

Model RTV: RTV-133 Silicone Rubber

It's been reported good to use on flyback transformers, and carries the following traits:

• It does not produce acetic Acid .
  
• It utilizes an atomospheric moisture cure system, which releases an
  alcohol vapor from the sealant surface during cure.
  
• Dielectric Strength: 20kv per 1mm layer.

I've got a MSDS sheet listed here for more reading/ spec.

The new can caps arrived from hayseed.

I installed one, and have one left to replace.

That just about does it for all the capacitor replacements.

The old can cap that was replaced was VERY leaky and way out of spec. It was reading 80-100% higher uF ratings than listed on the can.

https://live.staticflickr.com/65535/...61c87b09_b.jpgPXL_20240806_020045066 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...1f7f3f94_b.jpgPXL_20240806_020145917 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...ece988f2_b.jpgPXL_20240806_025948971 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...4523f9f9_b.jpgPXL_20240806_030359626 by Thomas Duncan, on Flickr

Today's the day!

Finished replacing the last multi sectional capacitor.

The old one was VERY swollen and leaking fluid.

I powered the set up slowly with a variac.

At full voltage I'm pulling 2.5 amps which seems to be normal. No abnormal sounds, no arcs.

The photo below kind of exaggerates how bright the tube filaments are glowing. Much more mellow in person.

I'm getting just a non-adjustable horizontal line across the screen.

So I'll need to do some reading as I have no clue what controls the vertical movement of this line?

**I only ran the set for about 30 seconds with the screen set to minimum brightness** - didn't want to burn the CRT.

https://live.staticflickr.com/65535/...d2ed640f_b.jpgPXL_20240806_221113960.PORTRAIT by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...e95f4e2b_b.jpgPXL_20240806_225509131 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...350b5bf2_b.jpgPXL_20240806_230959278 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...cb1a6c02_b.jpgPXL_20240806_230953330 by Thomas Duncan, on Flickr

The safety glass in the display makes the line look much thicker than in person.

https://live.staticflickr.com/65535/...fc083603_b.jpgPXL_20240806_225528496 by Thomas Duncan, on Flickr

Upon checking both these tubes, one BARELY shows good on my tube tester.

6BF6 - Pass
Vert OSC & AGC

6DT5 - Fail? - Readings are poor.
- Labeled as VERT output.

Photo of 6DT5 test below.

https://live.staticflickr.com/65535/...afe81382_b.jpgPXL_20240806_234132521 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...486d16b5_b.jpgPXL_20240722_010820973 by Thomas Duncan, on Flickr

A vertical output tube can cause the collapsed raster that you show but I would be looking more at capacitors in that section first.

Will do! All the small capacitors were replaced, new capacitors were checked before & after install.

I see that the old multi-section can C2 capacitor was in circuit with the Vertical output tube. And that capacitor was leaking fluid/swollen/ejecting a black foam type material?

Marginal tubes can cause issues like lack of oscillation, but usually there should be some deflection especially if you had deflection before the recap.
Recheck your work in the vertical circuit and make sure you didn't install any end of any vertical stage cap to the wrong terminal in the set. Also check B+ voltages to the vertical. If you lost a power supply rail that feeds the vertical that could cause no deflection too.

One thing you can do as a troubleshooting measure on a transformer powered set like that is connect the grid of the output tube to the heater line with a .1uF cap and see if you get some deflection.

Will check tonight an update.

I forgot to mention the whole reason I'm re-capping this set is the C2 4 section capacitor did blow out (overheated, swelled up, and popped) - causing loss of picture. The whole process took 2 seconds, and I shut the set off while the cap popped.

Looking at the diagram 6DT5 tube is connected to one section of C2.
(20uF Square) - I assume when C2 blew out, it could have damaged that tube.

I'll dig more into it tonight.

https://live.staticflickr.com/65535/...d01cec4e_h.jpgtube by Thomas Duncan, on Flickr

WAG...perhaps R-50 opened when C-2 blew. :scratch2:

jr

So far all replacement capacitors and old resistors are testing fine, and are in the correct locations.

I'll dig into it more tomorrow to double check as I'm getting a bit tired.

I did notice on 6DT5 that pin #8 (empty) was barely touching pin #7 wires.

Not sure if that had to do anything, I bent it out of the way.

https://live.staticflickr.com/65535/...b0ed205c_z.jpgPXL_20240807_223523011.PORTRAIT.ORIGINAL by Thomas Duncan, on Flickr
https://live.staticflickr.com/65535/...cff8c538b5.jpgimage by Thomas Duncan, on Flickr

Unlikely C2 damaged the output tube, but R50 that JR Tech mentioned could easily have been damaged if there was excessive leakage or shorts on that section of C2.

I agree, so far R50 and R51 tested fine. But I may replace them just incase.

R50: Measured 232. Spec is 220
R51: Measured 328 Spec is 330

I'm really enjoying following your journey here. That set is a copy of a unit I was looking at in NY state... but was about $2000 overpriced. I'll be following along as I begin the recap of my Silvertone this weekend. What CRT does that use? It's the same size as my Silvertone. Oh, and someone said they wished they had an electronics parts hous like that nearby... same here!

In my opinion, replacing common resistors that are in spec "just because" is a waste of time if you have operational problems that you need to get fixed, unlike certain capacitors that could be eventual failure points.
Did you know that 10% or 20% carbon composition resistors were often near the plus or minus limit of value because the production line output of a particular value covers the whole range of +/- 20% and then the 5% parts are selected, and then the 10% parts are selected from the remainder, and then the over 20% parts are culled from the final remainder? So old tube-era sets were expected to have resistors that are towards the ends of the spec and still work. The time to replace resistors "just because" is after all the real problems are fixed.

Thank You!

This one uses a 24AHP4 tube.

This question of resistor tolerance reminds me of the question of whether the major brand TVs were actually better quality than second tier. In terms of component tolerance the answer is yes, since the high volume of Zenith or RCA meant that they could get parts cheaper. At Motorola, standard practice was to use 10% resistors in designs unless 5% was absolutely necessary, while Zenith used 5% as the default until analysis showed 10% would not reduce final yield. When I moved from Motorola to Zenith I was surprised to find the lab stocked with 5% resistors instead of mostly 10%.

I think I may go that route "just because" once I solve the vertical circuit problem. I'm still struggling to find the error, so far all replacement capacitors are wired correctly & test correct.

When able, I've been buying higher spec replacement parts.

For example if it called for a 20% +/- tolerance I'd replace it with a 10% tolerance part capacitor. (plus slightly higher voltage rated capacitors 400 vs 630.)

As for resistors, that does make sense!

If we look at R50 for example, it should be 220 ohm @ 1watt.

Does anyone have a recommendation of what TYPE to buy?

When looking at that spec resistor with a 1% tolerance rating I have Wirewound vs Metal Film.

If I go to 5% tolerance "Metal Oxide Film" shows up.

What's best? - I really don't mind paying extra for higher quality / better parts.

https://live.staticflickr.com/65535/...836c5c8f_b.jpgoptions by Thomas Duncan, on Flickr

I forgot to mention, I have a set of these coming in the mail so I can finally test voltages with the chassis installed.

https://live.staticflickr.com/65535/...5e5d5823_b.jpgtubes by Thomas Duncan, on Flickr

I general, don't replace composition resistors with wirewound, because they may affect frequency response of high frequency circuits. Replacing wirewound with wirewound is a good idea.

1% tolerance is a waste in consumer tube sets, because the variation from tube to tube in a circuit will completely swamp that out. The exception is test equipment where multiple low-gain feedback stabilized sections are used to make the gear maintain calibrated state at least for a while.

In transistor circuits, variations due to the transistor itself are usually much smaller than variations due to passive components.

5% film resistors when replacing other than wirewound are usually not a bad idea.

Checking ESR on both capacitors on the vertical circuit.

Both these new capacitors are .1uF @ 400volts.

I checked and found ESR ratings of:
C40: 16.6
C39: 16

I de-soldered them, and got the same ESR ratings, with the same .1uF.

I cant seem to find a chart/data on ESR ratings for high voltage, low uF capacitors. Are these ESR ratings bad? The uF test shows the correct uF value.

https://live.staticflickr.com/65535/...a564f4c4_c.jpgtube by Thomas Duncan, on Flickr

C40
https://live.staticflickr.com/65535/...fe686c5f_c.jpgPXL_20240810_233255415 by Thomas Duncan, on Flickr

C39
https://live.staticflickr.com/65535/...0d62445d_c.jpgPXL_20240810_233312649 by Thomas Duncan, on Flickr

According to this page
https://www.eevblog.com/forum/beginn...ll-capacitors/
your ESR meter may be reading the capacitive reactance of small capacitors in series with the resistance.

In fact, if you plug in 0.1 uf and the frequency of your tester (100 kHz) on this page
https://www.omnicalculator.com/physi...tive-reactance
You get 15.9 ohms

square root [16^2 - 15.9^2] = 1.79 ohms ESR

I rarely test new film capacitors, but when I do I use my Heathkit C3 which will tell me if they're going open or if they leak at full rated voltage.
I only use my ESR tester on solid state stuff.

For high voltage low current circuits, the leakage is the most important parameter. For high current low voltage PSU's, the ESR can play a important role.

Exactly, for what it's worth I agree, it is the way to do it.

Picked up a 1950's (i think) antenna for the TV, matches well.

https://live.staticflickr.com/65535/...ed622418_c.jpgPXL_20240813_203405669 by Thomas Duncan, on Flickr

https://live.staticflickr.com/65535/...b5b14d64_c.jpgPXL_20240813_203410786 by Thomas Duncan, on Flickr

Great!