Desperately need help on Raytheion model M-1602
 

This is an old project I started years ago, then, it went untoubhed for 18 years.
As it stands now, I've don a complte electrolytic re cap, replaced a number of off value resistors, and, bad tubes.
I get reception with audio, and, picture from cold start.
Vertical is still short, but, stable. I have horizontal discriminator issues.
But, that's not the worst of it.
After it's on a few min. the picture starts getting darker, and, shorter on right hands side.
Then audio volume goes down, and, picture turns negative, and, much darker.
Soon, my raster goes complletely dark, and, sound is very weak.
I removed the high voltage cage today in desperation. I felt the flyback. Core, and, hv donut were warm to the touch. Does this mean the flyback is failing, or, what? If not that, can anyone help me on what's going on here??
No wax has melted yet, but, I'm worried about flyback getting warm, and, the fact that raster completely dies out.
Please help, guys.
Thanks.
Bill Cahill

It sounds like the B+ is slowly taking a dump as the set warms up... because you are experiencing audio, video, and HV problems altogether. If your B+ is going down, your flyback could start to get warm. Connect your meter to the B+ and watch it as your symptoms develop.

The electrolytics you installed... are they fresh stock? What kind of LV-rectifiers is it using?

Maybe its Haunted !

youll have to call ghost adventure's and have zack run around your house . lol

Is there any whiff of scorched scent coming from the flyback? (Old servicing adage: "the nose knows."):D Any sign of red plating in the H output tube?

Those stupid jackasses wouldn't know a ghost if one came up & went "Boo !" at 'em....And what's the deal w/the guy's HAIR ? Didn't his mommy ever show him what a hairbrush is for ?!? Him & that Giorgio Tsoukalos character on "Ancient Aliens"....Sheesh !

By its model number I assume that you have a 1950 or 1951 16 inch set.

The only schematic for Raytheon from that era that I have is the M-1612B or 16AY28 chassis.

Lets think about this problem one step at a time.

If the vertical height is stable, that tells you that your B+ seems stable.


OK, this probably is not an high voltage issue, but lets eliminate that first.

Put a HV probe on the HV from a cold start and see if it drops.

If you don't have a HV probe, use a plastic ruler and a grounded jumper and measure the length of HV spark to determine if the HV is dropping.

A horizontal sync issue might lower the HV a little but probably not over 20%.

(The reason for eliminating HV issues first is, depending on how the set gets its keying signal, sometimes an AGC issue can be traced to a corrupted keying signal due high voltage sweep issues. This probably would not happen on the M-1612B chassis as the schematic indicates that Raytheon gets the keying info from the video amp which is typical of the era.)

Correction: Oops! Had a disconnect between the brain and fingers. The keying pulse comes from a winding on the flyback while the reference pulse comes from video amp.

Now let us get to the issue of:

Your set is talking to you and screaming "AGC overload!"

First step turn out the lights and see if the any tube in the IF, tuner, vid sep, video amp, horiz sync and horiz osc start to glow purple when this happens.

If no result, recheck the tubes in those circuits for gas or grid shorts after they have warmed up in your checker for much longer than you did the first time.

If nothing is noticed, disable the AGC output and manually control the AGC with a battery and fader. This may better help you isolate the problem.

If you have a scope, check wave forms in AGC, horiz sync, horiz osc, and on AGC line.

Hope this helps.
James.

I have a similar Raytheon, but with with the metal round crt... I think the 16AP4. Mine had a lot of tired parts, but the thing I remember most was the 3 resistors in the IF section... each IF stage had a resistor in the same spot (can't remember at the moment what it was) and each one had gone way up in value the same way causing a very weak signal.

The tuner is built like a tank... you have to have a really good grip to crank that knob, and when each channel "clunks" by, you can feel it in the floorboards!

Re-capping this chassis is pretty easy... plenty of wide open spaces under the chassis to work with.

Curious... you said you started this project 18 years ago.... is that when you changed those lytics? Or did you change them very recently?

i know me and my wife laugh at that guys hair everytime we see it ,its like he was in a explosion or something and zak cant make up his mind what dew to were,its probley who's ever is incharge of that they think its in style or what hollywood thinks is . lol:screwy:

Charlie, I too have a Raytheon that uses the 16AP4.
I need to pull my chassis and check the resistors in the IF.
Thanks for the heads up.

These Raytheon portholes have pretty neat chassis layouts. Its the easiest chassis I have ever recapped.

Carl

Darned! I'm not getting e mail notices from this site.

Here's the scoop.
First, it was a total recap 18 years ago, including electrolytics.
At the time I re started it a couple of days ago I found my electrolytics had gone south. Some were oozing, and, bulged.
I re replaced electrolytics.
Just discovered this morning, two things...
1 a low voltage electrolytic on the vertical osc. had openned up.
2 I had missed the 10 mf 160 volt capacitor going to damper for boost.
That cap was also bulged, and, electrolyte had oozed out.
I will be replacing those today.
I will also probably re replace the cathode bypass on vert. output.

Thanks. I'll look into those I F resistors. I'm noticing now that some channesl are somewhat snowy, and, that's on cable.
With that bad damper cap I'm sure it wasn't helping matters any....

Vert. started out full two days ago, but, was working its' way down hill.
It's now over two inches short on the bottom.

No, i think it's 1949. I'll look at sams on it to see when it was produced.
And, model is C-1602. It's in the same sam's at the M-1601.
I'll be back on the set this morning, and, will let you know the results.

And, though not that much, the power supply voltage had been dropping a little.
Thanks, guys.
Bill Cahill

By the way... ON scope. I have one, but, still don't know how to use it.
On the hv probe, I have one, but, didn't think of checking hv on this set. If I had, I might have been elnlightenned that something else was going on.
Stupid me..................
One of my sprague orange drops had also gone bad, and, I re replaced it two days ago.
It was quite leaky.
Hmmmmmmmmmmmmmm.
Bill Cahill

I also had tubes failing almost everywhere, and, apparently had missed one while originally working on set.

Reason for all those years. Life. I was working in a high pressure job.
At that time my gull bladder failed, and, I had major health issues for a year while they were messing around trying to find the problem,a dn, kept telling me that though it had a dark spot, men don't get bad gull bladders.
8 months, and, one week later the surgeon removed it.
It took a year to recover from that.
16 years ago I had to have surgery for chataracts in both eyes.
Then 15 years ago I had to have laser surger for glaucoma.
Then, I lost my job, and, was doing volunteer work.
Eight years ago volunteer work ended, and, I started getting hip problems.
I'm now on forced retirement.
Oh, boy, has this been a fun life!
Not complainnig, but, just felt you needed to know why this project, and, manny others were put on back burner for years.
Bill Cahill

Well, my luck ran out.
I re replaced the two electroytics.
Started trying set. For a brief moment I saw a picture come on. I had full vertical height, and, width was nearly full. I had variac set at almost 90 volts.
Suddenly, I heard a Pop, and, raster went out. Set started making noises I didn't like.
I shut it down, and, examined parts. Couldn't find anything.
I slowly brought variac back up.
Iwas getting very low B+ at that point.
I heard another pop, and, sizzling. I quickly turned it off.
I smelled around, and, didn't like odor.
I put chassis back on its' bottom, and, pulled hv cage. Instantly I was rewarded with some smoke, and, the acrid smell of burnt transformer.
The smoke stopped, and, I smelled around. The flyback is toast.
It is history!
Now, my entire house smells like a burned transformer.
Flyback is cooked!
Oh, 589^%T##%#T%T$#!!!

Anybody got a good flyback for this set?
Until then, I've pulled all tubes out.
It's a special transformer.
Bill Cahill

Sorry to hear that; major bummer.

Thanks. I made a confirmation by semtlling around, again, and, flyback is definately it. To confirm it I put my ohmmeter accross hv winding. It is bunred open.
Apparently, that's why the flyback was getting hot yesterday.
I guess that permanently ends that project!!!!
My house still smells like buned transformer.
Bill Cahill

Maybe one of the tubes in the HV circuit went bad.
My flyback has a fuse to protect it - did yours have a fuse?

Carl

Does Sams give a cross-ref for an aftermarket tranny? Seems many of those black and white flybacks cross over for many sets. I recall a tranny box with a label on it saying "for b&w 16 inch and similar sets" on the label. I'll look when I get home in a few days. I'm sure we can find a cross-ref part number if we all put our heads together... and 1950's b&w flybacks are usually pretty easy to find. I know I have a few... I bet one will turn up.

There was a fuse. But, it's not directly in the flyback circuit.
On the replacements, this set uses a special flyback with quite a few windings. One special winding is for afc, and, agc voltage.
Half the hv doubler circuit is mounted on this flyback.
Sam's shows no cross reference.
This set is really dissappointing.
I was getting the thing to finally work right. When the picture came on the last time, the vertical was finally full, and, stable.
Then, it popped, and, I lost my raster.
The rest you know about.

My house smells awful from that set.
I think when I finally gave up the flyback was starting on fire.
HV donut winding is burned open.
This one went up in a big way.

I want to give all you guys a fair warning.....
This is the second Raytheon that I've found flyback failure on. I suspect this is going to be more common, now. I have a 12" that I need to do repairs on. The flyback was good at last I knew, but, I'm beginning to think these are another one of their problems in design. If someone has the proper flyback working properly, I'd love one.
Bill Cahill

Sorry to hear that your worst case scenario happened. Your AGC keying or signal overload could well have been related to the bad damper 'lytic.

I'm not surprised that your electrolytics failed in 18 years, as 18 years ago, most can types being sold were old stock.

What did surprise me was your orange drop failure.

The black-molded RMA-banded Spragues and their printed-value replacements were good for about 5 to 7 years. The brown drops were usually good for 15 years, but I'd never seen an orange drop fail, unless the leads were bent too sharply and the coating cracked at the lead and this allowed moisture to penetrate.

Jas.

Never used them. The failed cap was an orange drop.
I didn't use cans. I used brand new individual Japanese electolytics.
Thanks .
Bill Cahill

Well, the Sam's was written while the sets were still under warranty and until the warranties expired, the service men got their flybacks for free from Raytheon.

Thordarson - Meissner says that 4 different flybacks were used in the Raytheon C-1602 sets:

For Raytheon part number C-12M-18689-1 and C-12M-18689-1 use FLY-35 (chassis 12AX26, 27, 14AX21)


For Raytheon part number C-12M-19407-1 and C-12M-19407-2 use FLY-36 (chassis 14AX21)

Now at least you know what you are looking for.

Jas.

Since you had an almost normal pic at 90 volts, and lots of trouble at full voltage I would say you have a bunch of bad caps. Or you replaced a bunch of caps with too low voltage ratings, or if you re-stuffed the old cans, you got the polarity backwards. I would re-check all those caps. I can't see all the bad caps you say if they were all just replaced 18 years ago and never used.... Just a squirrel's view... I'll shut up now....

Moyers was able to get Flyback for my Raytheon, it wasn't exact, I had to swap the tire onto the old core but it worked.

Strike 3. Yer out! Eh, no, this isn't basebball.

No, wasn't any of the above.
The electrolytics just plain went bad from non use....
And, leaked, and, bulged.
They wouldn't reform.
Can you tell me the number of theglyback you used?
Did it also have that special tapped winding for the afc, and, agc?
What model of Raytheon was yours?
Was it this one, or, something else??
This is a special flyback in all ways....
Bill Cahill

Bill, I don't know the number, it probably wouldn't apply anyhow because mine is a 12" set.

It did have some extra windings, one for the Phase I know for sure because the polarity was backwards and it had to be reversed to work correctly.

Bill, scratch the above, it was a Sonora I got the Fly for, I got a couple transformers from Moyer for my Raytheon.

Eric, does this mean what I think it means? That there is nothing to do????
It is a very weird flyback.
Bill Cahill

Bill, was your Flyback protected with a Fuse?

There are still some junker Raytheon TVs out there.
Hang on to that project until one turns up.
All of us can keep a look out for one.

Carl

Well, I had cut second anode lead, and, power cord off, but, they are repairable.
I'll leave it together, minus tubes for awhile, and, hope you guys have good luck. I don't know how long my new filters will last, though.
If you find one, I need other parts, as well. I seem to have lost the screws that hold the assembly together, the front door, and, the speaker board. I have the brass fret work. I coluld use a better spkr., and, a back cover.
Also, if it has good a c connector, that assemblly. I had to hard wire mine as it got broken.
Thanks. I'll keep it together for now in hopes you have good luck.
I moved chassis on bench. Working on new old project.
A rare RCA Victor 1939 table victrola that uses PP 2A3's for audio output, and, has neat chrome plated grills in front.
It's a neat machine, and, I've had it for over 30 years.
I'm doing a complete restore. Two of the transformers are actually chrome plated, as are some chassis hole caps.
This will be nice when finnished. I'll post it in antique phonographs soon.
Bill Cahill