Huge magnavox Combo roundie Warren MI
 

I own that as of today, it was tested by a fellow smarter than me, he said it has a bad thermistor and a weak green and blue, but can be brought back up slowly.
The player works and the radio did tune in when I got it home, however there is no sound in any mode, first of all where should I begin in this process of restoration?

radio tuned it based on the tuning meter?

does it have a remote, look on the back for a large metal switch

Yes it was moving and stabilizing as I moved the tuner on stations in my area and some I know where in Indiana as well it was able to pick up on the dial

on more what is your experience level in electronics?

yes it does have the switch, there are two of them

make sure you have the remote off.

speaker switch to internal

modern electronics fair to average this old stuff I know where the on off switch is lol and I do know basics

ok it is on internal and I can hear scratching sounds out of the speakers when I adjust volume but no output sound

pm me with your phone and I will call you gotta go off line for a bit but can talk

make sure your not on stereo, that is phono, select fm mpx

ok I sent my phone number to you I will check my settings

Can any one point out?
 

I have some pictures the thermistor is suspected bad where do I find it and how can I tell?

not on those pics, those look like signal pc boards. FYI I did see at least one likely electrolytic caps on one of those board that prob should be replaced. It looks like a paper tube on laying on the side, about 1.5 inch long and .75 inch wide. should have a + marking on it some where. Any of those are suspect.

if they leak they can throw off the tube bias and cause the tubes to pull too much current. you will need to locate and replace all of them. A Sams will help you find all the parts.

Maybe some more pics of the rest of the chassis.

pics
 

There is also a board right under the CRT but it cannot get a good view of it for you

sorry cant see it, someone fam with this chassis will be able to help out forsure.

DJ, one of the first things you need to do is clean that chassis up a bit. Looks like there's a decent amount of dust on there, and that by itself can cause problems. For a start, get a small delicate brush... something like a woman's make-up brush. Start dusting off those boards and have a vacuum cleaner hose nearby to suck it up as you brush the dust. Be careful not to bump any standing naked coils... there's a green one there to the left of the power tranny... those break easily. The dust on there can allow voltages and signals to jump across to parts where it's not supposed to go. You can also load down the HV section by having too much dust in there.

I'm not sure what that chassis is... looks backwards. Perhaps it was Magnavox's own design? I would have assumed this set to have a CTC15 or 16 clone in it... doesn't look like one of those.

Ok I was just wondering about how to do that cleaning, should I attempt the lightbulb test on this once it is clean? I do not have my meter with me today for testing the system ohms etc.

If that thermistor is part of your power supply, you're not going to be able to do much without replacing it first since the toasted thermistor won't allow any juice to get to the rest of the set. You might be able to jump it (especially since you'll be applying low power to the set anyway).

Until you get a Sams for the set, you're not going to be able to do a lot. You should wait till you get the Sams.

Ok where is a good source to get them?

Several choices
 

When I looked up the chassis 4251 I came up with 9 RCA options

I would second Charlie's advice to hold off until you get the Sams service manual. Poking around in the dark and powering it up a lot is not the best idea at this stage.

In the meantime, you can clean off the dust & grime and brush up on your schematic reading and soldering skills.

It's usually prudent to replace all electrolytic capacitors. This article has basic advice about recapping.

http://antiqueradio.org/recap.htm

Here's what a dead thermistor looked like in my RCA CTC-11A.

http://antiqueradio.org/art/RCACTC-11ABadThermistor.jpg

A disc roughly the diameter of your thumb, with two metal leads. I replaced it with a new type CL-90. There may be other types I'm not aware of.

Phil

Thanks Phil, I will keep looking so far nothing like that, and still having trouble with the chassis number being 9 different RCA's on Sams not sure whats going on with that

Those RCA numbers are not for you. It just so happens that those 4 digits you entered are part of someone else's model number. I just looked up 4251... online and in my own index... that doesn't bring anything up for Maggies of that time. Try and find another number. Magnavox's are sometimes a pain in the ass with model numbers. I think the number you want will likely start with a letter... like "T" or "U" for the first character... and likely several numbers to follow.

I will keep looking around in it

I have been able to re-solder two of those thermistors by scratching the disc surface clean/shiny where the original "blob" was and re-tinning them there.

Model number
 

THis is the only model number I could find but sams has no record of it.
10T558K

If we can narrow down the sams number I'm sure I can fix you up with an original copy. It's getting late tonight; if you don't figure it out in the meantime, maybe I can research it some Monday night. With a few details I bet Randy Bassham could I.D. the chassis.

Bryan, earlier I sent DJ a list of possible Maggie color chassis numbers from the 60's using my index (that took a while). He's looking to see if he can find any numbers or partials that will match up with the list I sent. I think we'll finally stumble on something. If nothing else, we might be able to get some kinda idea from a good photo of the chassis.

I never understood why it seems Magnavox numbers often turn out to be a pain to look up. I've had similar experiences with a couple of black and white Maggies

Here's a shot of what DJ has in there.

I have a very similar one with the number 4RU556K and I used the sam 746 for the chassis C/U45-01-00. Identical chassis except that the combo does not have a sound amplifier tube in it, it uses the amp of the radio.

Interesting. Thank you very much, Dom! :)

Continuing to search for numbers
 

I am still on the hunt, even if I have to put it up on wooden blocks and look under it!:thmbsp:

Dead in the water for right now I guess I cant find anything else on it anywhere.

It is a U45 chassis. The radio is an R204 chassis. The record changer is probably a W604.

Remove the radio chassis, replace six 5uF, four 50uF, and two 100uf caps on the preamp board, and the speaker coupling caps (400uF) and the radio will sing again.

Those radio and changer numbers are right on the money thats for sure as they are printed on both items you mentioned i was wondering about the radio etc the player plays good once I cleaned the volume control.

It was the right number for my Sams thanks for tht info!