Maggie Home Entertainment Center

[holmesuser01]

Rechecked the AM-FM section... It is stereo.

Having to wrap it up on the covered front porch for a few days. They expect snow here. Dont want the cabinet to get wet.

[DaveWM]

good on the stereo, you need to make sure it has the MPX unit (this is all tube set right), it is a separate chassis that connect between the tuner and the amp, at least on the tube sets that is. They all have the stereo selector but I think the mpx unit must have been an option that could be order with the unit or added later. If you dont have one, just look on ebay, they come up now and then, 20-30$.

[holmesuser01]

Thanks for the heads-up Dave. I'll check for the MPX unit. And yep, its all tubes. I look forward to seeing it turned on and lit up!

[DaveWM]

I would be interested in seeing the tuner, Magnavox had a couple tuners but basicly two kinds, inductor tuned FM and VC tuned FM. If your lucky you will have the VC tuned FM, its a triple ganged AM and FM tuner so the AM gets an RF section as well. The VC has a MONSTER wheel on it so you get great tuning and it very smooth. On the tv sets I think they had the inductor tuned tuner, its a German made tuner with a variactor for the AFC all built into an alum box with a string that is wrapped around the shaft of the VC for the AM.

It works fine, I just prefer the smoother feel of the VC with that huge wheel.

Those tuners are both pretty much touble free, you may have to repalce the can, but I would hold on that until trying it, or you could do a cap check if you have a old school cap tester. I think all the coupling and HF bypass caps are ceramin or the intgrated networks that rarely fail.

the most likey problem will just be dirty pin contacts. There may be a couple cathode bypass electros on the preamp tube which is a dual triode. seem to recall they had a dual electro tubular down there.

ALL the audio coupling caps are ceramic, so no audiophool caps used at all in the tuner and mpx.

If you get the MPX it will be a 2 or 3 tube unit. If its a 3 tube you should check out the 1uf cap on one of the coils, it is prob open and will account for a very hollow sounding MPX. I think the 2 tube did not have this.

There is no MPX indicator on tube magnavox's at least on the early ones with the separate mpx. I seem to recall the last versions had a MPX intergrated into the tuner chassis.

[holmesuser01]

I checked for the MPX module. No go, here. Checked all of the tubes. The tuner mixer-osc is dead, along with all very weak, and leaky I.F. stage tubes. The vertical oscillator is barely reading at all. Vert output checks VG. Horizontal output is VG, along with the damper. The 1B3GT is barely reading. All weak tubes, except for the vert oscillator are in my junk box. They are old common B/W TV tubes.

There's an original 6GH8 AGC tube there, and believe it or not, it checks 100%! It was made by GE, btw, and no shorts! I've replaced lots of these in RCA sets!!

The 23MP4 kine is really weak, as in barely moves the meter needle. I'm hoping that raising the heater voltage will help get its emissions going. I'll deal with that when I get a warm day to work on it. Giving it the hot-shot would be a totally last resort.

I ran the set using my variac and kept an eye on the amperage between the diodes like you said, Dave. At 70 volts, I started hearing noise from the tuner. I started hearing FM at around 100 volts. I got the set up to 110 volts, and could hear the vertical running on the TV chassis. I got brave, and installed the Hz output, and fired it up. I got a dim raster, with vertical that doesent fill the screen for now. I've got to get a few tubes found to go in there first.

It took almost 4 hours to bring the set alive.

I didnt have anything to check out the little amplifier on today, so, and I hope I didnt do anything to it, pulled the outputs, and used its power supply to run the tuner module. I fed the output from the tuner to the amp into an older Magnavox amp that I recapped years ago that uses SE 6BQ5's like the set amp does. I got sound from the tuner on both AM and FM, but after awhile, the sound quit suddenly, like I had disconnected something. I can turn the set off for a minute, then back on, and get some radio sound for a moment before it cuts out again. I turned it all off for now.

My old Sencore tester cant check the 6EU7 preamp tube on the amp, and the tuner, but I did swap them and got no change. Suspect the cathode bypass caps?

I was impressed with the amount of sound that I have coming from these 49 year old speakers.

I'm not going to do anything until I get the caps done in the amp and/or tuner. The TV needs alot, too. I havent pulled the AM-FM tuner assembly out, yet.

This TV was owned by a smoker. I cleaned the front of the CRT, bezel, and safety glass. Just doing this makes the set look so much better, and keeps me focused on making it run.

Oh yeah, I dont own a cap tester.

It's been a really long time since I worked on any B/W TVs at all. 35 years, I think.

And this is my first attempt using a variac on a TV. Batting 1000 right now!

I want to get this set into the house, too. BUT, right now, there's no where to stick it. I need to get rid of a few things first. Hmmm. The other half wants all of this stuff gone!!!

My camera is traveling thru Middle Tennessee today. I forgot and left it in the back of the car. My oldest son is heading to Arkansas and will be back in 10 days.

[holmesuser01]

I replaced all of the weak/leaky tubes in the TV section this afternoon. Turned it on, and got sound and picture within a minute. The pic is very dim not sharp. I remember seeing this with other sets with rotton kine's. At least, I know the set chassis is basically OK now.

I have a blown midrange speaker. It's an odd looking oval type and is part number 584010. If anyone has something I could use, please let me know.

While I had the amp out this afternoon, I discovered that no matter which audio input was connected on the amp, both speaker sets would react. First, I found that someone had wired it so that both speaker sets were connected to the #2 speaker terminals. There was still no stereo, but if I rocked the 6BQ5's I could get some minor distortion from the dirty sockets on each channel. I pulled the amp and checked the wiring. I found a foursome of resistors between the preamp input and the 6EU7 tube that had been crushed together at some point in the last 49 years. This was causing the mono sound. Now, after carefully separating the wires, the signal is stereo.

I installed one of my spare Micromatic turntables in this set (the original is not ready to go, yet) and played a few records while testing the system. Sounds pretty good.

I appreciate all the help from you guys. Dave, I enjoyed our phone conversation this morning. I think this set will be around for awhile, bad kine or not.

[DaveWM]

if it dim it may by the magic eye, you can change settings including disabling it completly by selecting different spades to plug into. I though I had a dim raster but I was in a dark room, turned on the lights and the brightness came back.

If its out of focus you can try the focus adj, but the difference was slight.

[holmesuser01]

Im not aware of the Magic Eye function.

Through a VCR, I ran several episodes of I Love Lucy, Beany & Cecil, and 2 Ben Casey shows. As the hours went by, I was able to see a little more picture, or maybe it was because it was getting darker outside!

I left the kine turned on all night on my Sencore tester. I ran the filament at 7 volts. It still checks bad, but not quite as bad as yesterday. How long should I let this tube sit and run? Thanks a ton for all the offline comments, and your help here, DaveWM.

[DaveWM]

it may or may not have it, but its a a sensor (light sensitive resistor) prob on the lower left side looking at it from the front.

it controls the brightness to adjust to ambient light. By selecting the different voltages you can adjust how much it adjust by. It sorta looks like a pilot light (which will be on the other side) just bigger.

I would just keep running it and see if it gets better. Can you check the HV?

I think you should be around 15-16kv does it bloom or is it just a focus issue?

If it was mine I would just keep looking for a picture tube. Then when you get one, try rejuv the old one with the CR-70 (I dont like to do that with out a backup). In the mean time just get all the other stuff working and replace all the paper caps.

[DaveWM]

a screen shot would be nice to see what you are getting. Take it with the flash off if you can.

[holmesuser01]

Guess what? I have a magic eye!! I thought that thing was another pilot light! No clue as to how to mess with it!

I replaced all the pilot lights tonight. Still dim picture. When my camera comes back from Arkansas, I'll post pics.

I have a HV probe. I dont think there is a problem here, as the pic never blooms.

I'm looking for a tube.

Bruce

[DaveWM]

well just for grins, take a flashlight and hold it up to the eye, see how bright it gets then. I was looking at mine in a garage with low light and thought I had a dim tube until I brought it out into a lighted room.

[holmesuser01]

It snowed about 4 inches today here in western NC. It will be a day or two, but I will do the flashlight test... also check the HV.

Right now, I am dragging it out, uncovering it, running it, covering it back up, and moving it out of the way. It's getting old, but I have found some stuff to move out so I move it in... The saga continues...

[DaveWM]

let me know how the flashlight trick works for you. I hope it is just the magic eye killing the brightness.

[holmesuser01]

A flashlight on the magic eye made no difference.

I checked the HV... right at 14K.

Applied 7 volts to the kine filament thru my tester. Slowly, the meter needle moved up toward good. Finally, it was at 80% and holding. I left it alone for a time while I worked on the tuner. Got the tuner cleaned up and now the fine tune is working. This took about an hour.

Turned my attention back to the kine, and noticed that the meter was now indicating BAD. The filament is intermittent. I can see it flickering on and off. It couldn't handle the 7 volt supply. The set will have to wait for awhile since I need a kine. In the meantime, I will get the stereo half of it running nicely. I hope I can either find a kine for it, or can get the one I have rebuilt.

Until then....