Fleetwood model 4068... Advice?

[electroking]

Wall voltage should be fine. Tube heaters do increase in resistance when the
voltage goes up, so the added dissipation is less than could be deduced from
a simple calculation.

The coil tuning slug should be inside the cardboard form. Did you reuse the
original form or did you make one yourself? It may be lost due to the damage
you observed on the coil. Maybe you could find something compatible in your
junk box. You might also find a useable slug inside a discarded IF transformer.
The slugs in your IF transformers should not be disturbed.

I don't thinkg replacing good resistors is a great idea if the soldering is half-decent,
even though it may not look that good. Some of the parts in there (coil, IF
transformers, etc.) are too easy to break.

Pending the fix on the coil, you may start adjusting the oscillator trimmer capacitor
just a bit at a time, and seing how you have to readjust the tuning knob to get
back on the station. That will tell you which way to turn to move the oscillator
in the desired direction. Good luck!

[VintagePC]

Ok, I'll leave the resistors alone (but for $6, I'm still ordering a spare set just in case...)

There was nothing in the original cardboard form (which I re-used). You can see it in 1040.jpg ( http://vintagepc.co.nr/radio/IMG_1040.JPG - not posted in the build log b/c of fuzziness). That picture was taken as soon as the chassis came out of the set and the mouse fluff removed.

You can also see the inside of the coil is shiny; I would assume the slug was threaded for positioning; it looks like there may never have been one... (also note the schematic doesn't show the "adjustable" symbol on L2 like it does for the IF cans)

I should have something in the parts box; I know for sure that I have the core from an old antenna (that can be cut to size), but that's too long. Roughly what size am I looking for?

[Reece]

If there is no slug, then the oscillator would be adjusted with the trimmer capacitor screw on the small section of the tuning capacitor. Find a station at the high end of the dial that you know the frequency of. If you tighten the screw 1/8 of a turn, this will move the station up the dial. Turn the dial higher and find it. If you turn the screw out 1/8 of a turn, the station will move down the dial. Continue "walking" the station either up or down the dial, whichever applies in your case, 1/8 turn at a time, until the dial pointer is at the correct frequency.

Each little trimmer cap is in parallel electrically with its tuning capacitor plate section. Together they act as one capacitor. When you tighten a trimmer, its capacity goes up so to keep the same frequency the large cap plates have to open up more, and vice versa.

After you get the stations at the high end of the dial where you want them WRT to the dial markings using the trimmer, then on a weak station around 1400 or so (can be WAY down in the mud weak) peak it for max volume using the trimmer on the other, larger section of the tuning cap, which is the antenna section.

Holy mackerel, it just dawned on me that you rewound an oscillator coil, and made a pretty one per the picture at that. Ain't a whole lot of newbies to tube radios that have done (or would even try) that! That's the fun of this stuff to me: making something out of nothing!

[VintagePC]

Emmm.... you sure that's right? In my case, the smaller one is the one ID'ed as C1A, which is in the antenna circuit.

The larger one (more plates) is C2A, which is in parallel with the oscillator.

The alignment instructions also contradict you; they say to adjust C2A first (bigger) and C1A last (smaller) (then again, they also say to adjust L2, for which there is no evidence of adjustments ever having been possible).

Holy mackerel, it just dawned on me that you rewound an oscillator coil, and made a pretty one per the picture at that. Ain't a whole lot of newbies to tube radios that have done (or would even try) that! That's the fun of this stuff to me: making something out of nothing!

Awesome feeling, isn't it? Excuse me while I laugh maniacally while I power up the set, the lights dim, and lightning flashes in the background.... "IT'S ALLLLIIIIIIIIIVEEEEEEEEEEE!"

[electroking]

The instructions we have (see the second figure in post number 20) do call for
adjusting the oscillator at two points with both the trimmer cap and the coil.
The manufacturer may have dropped the adjustable coil in production, in which
case the oscillator would be aligned only at the high end of the band, and
some error would have to be tolerated at the low end.

Typically, you will find a hole in the chassis above the coil so the tuning tool
can be inserted from the top. Do you see the hole?

Note regarding the alignment instructions: I don't see any contradictions.
Items 1 to 3 refer to the IF alignment (which can be left out). Items 4, 5 and 6
are the steps for aligning the oscillator to get the stations on the right
spots, with 7 telling you to repeat 5 and 6. Finally item 8 is the peaking of
the input circuit resonator, using the trimmer on the RF section of the variable
capacitor, that is the section that is NOT part of the oscillator circuit. Regards.

P.P.S.: the variable capacitor section for the oscillator may be bigger or smaller
than the RF section, depending on the coil used. Tracing the leads to the proper
circuit (and also checking the labels C1/C2 on the alignment drawing) is the
best way to determine which section is which.

[Reece]

I've never seen a two-gang tuning cap where the oscillator section was larger than the antenna section. Doesn't mean it couldn't be. On some very older sets they were the same size.

You can easily find out: tune in a station at the high end and tweak the screw on the smaller gang of plates. The station should move either up or down the dial.

The schematic may not exactly match your set. Does this set have FM? Those would be the really small gangs with just a few plates. For AM I'm talking about the plates that look about like this: scroll down to the picture of the dual gang air variable, with trimmer screws on the side. I couldn't quickly find a picture of a typical cap with the oscillator section smaller than the antenna section, but they used to be the "standard" in most radios.

http://www.midnightscience.com/catalog5.html

[VintagePC]

Apart from # of plates, that's exactly what I have. Take a look at http://vintagepc.site50.net/site/ima...e/IMG_1025.JPG

You can see it there; it turns out you're right and there's an error on the tube layout diagram; the tuning caps are mislabeled there, which is what threw me off.

I now see this is not true; the yellow wire runs to the lug of the coil (thus smaller section) and the green wire is bridged by the antenna (2-wire flat cable you see)

Thus, BIG=antenna, SMALL=coil, and therefore REECE=correct.

There is indeed NO hole in the chassis above the coil; the only one is a fold-out pin to which the ground lug of the coil is soldered. (and it does not extend over the center of the coil).

[electroking]

Did you look for a tuning slug accessible from below? It may be hard to reach,
but alignment is a bench job rather than an 'in-cabinet' job. If you find no tuning slug,
you will have to do with a single adjustment point as discussed above.

You're right of course regarding the mislabeling on the instructions. The antenna
lead (flat cable) is connected to the rear section (C1 on the schematic but marked
C2 on the figure). Good luck!

[VintagePC]

Did you look for a tuning slug accessible from below? It may be hard to reach,
but alignment is a bench job rather than an 'in-cabinet' job. If you find no tuning slug,
you will have to do with a single adjustment point as discussed above.

Nada. I don't see any possible way to adjust the coil.

This may well be intentional because the alignment on the set has to be in-cabinet; the dial face is mounted to that as opposed to the actual chassis itself - if it's out on the bench, you can't see where you're supposed to be!

In addition, we've already found a few differences on the schematic and the actual set, such as the line (filter) caps/resistor values and loudness taps/caps on the volume control.

Taking a pot-shot, I'd say the 4068 model is based off the 2053 and is either a later run or intentional design change, resulting from component supply issues or so (but it was either short-lived or so similar they did not want the added cost of making new schematics/layout diagrams). I'd be interested to see whether the tuning caps are also mislabeled on a "true" 2053. (note they're also mislabeled on the sheet stapled to the inside of the cabinet).

I will re-draw the schematics with the additions and upload them to the build log when I make the next update. There's really not much new going on that's picture-worthy at this point, hence the long delay in updates.

Also noticed that there's some rust on the magnets at the back of the speakers... worth worrying about, or no? It just looks like a small surface coat, not like the whole magnet is disintegrating.

[VintagePC]

WoHoo! was tuning the set and I noticed my 6AQ5s have a faint blue glow to them... looks exactly like the "flourescence" described here:
http://www.jacmusic.com/html/article...w/blueglow.htm

Only noticeable in near-blackness. Looks pretty cool, and sounds great... hope to get some pics if I can; the dial lights give off a lot of light, so I'll have to block them with some cardstock or so.

Still waiting for some fainter stations to come in so I can adjust the antenna trimmer I did, however, bump up the stations to where they belong.

[VintagePC]

Whoops... double post, but I just _had_ to upload this (click for full resolution, ~900KB)... Enjoy! (this is a 10 second exposure, BTW, will try for a better one when there's less ambient light.





Edit: and another, for good measure (15 second exposure, near full darkness):




Also, physical restoration question for you guys; how do you clean the grille cloths on these sets? I can't remove this one without completely dismantling the cabinet.

[electroking]

All right, so you just locate a station near the top, ascertain the frequency, and
then adjust the oscillator trimmer to bring it to the correct spot. A simple comment,
alignment can be done on the bench with a signal generator, just jamming the needle
at either end of the range, and using the two frequencies specified (530 and 1620),
or in fact just the higher one since the coil is non-adjustable.

I don't think you need to worry about a bit of surface rust. I think your electrical
restoration is nearly complete. Congratulations, I look forward to the update in
your site. And I believe I already got all the credit due to me, which is not that
much, after all you did all the manipulations! This thread possibly contains more
posts over its lifetime than all the rest of videokarma, and I believe this means
something...

[VintagePC]

All right... Hope to have the set fully adjusted by tonight...

A simple comment,
alignment can be done on the bench with a signal generator, just jamming the needle
at either end of the range, and using the two frequencies specified (530 and 1620),
or in fact just the higher one since the coil is non-adjustable.

Dangit... Now I'll have to build a signal generator... (just kidding.)

I think your electrical
restoration is nearly complete. Congratulations, I look forward to the update in
your site. And I believe I already got all the credit due to me, which is not that
much, after all you did all the manipulations!

True, but it wouldn't have been possible without everyone's help! Next step is cabinet restoration and detail work... I've mentioned it before that I want to put some decent veneer over the hardboard crap, and strip/varnish the maple frame.

This thread possibly contains more
posts over its lifetime than all the rest of videokarma, and I believe this means something...

...and it shall be preserved in eternal glory when I'm done. (Going to mirror it on my site)

[Reece]

Grille cloth: see if you can find a dry cleaning spray can called K2R. It's dry cleaning solution with chalk in it. Shake it up, spray it on, let it dry thoroughly for half an hour. The solution dissolves the dirt and the chalk soaks up the dirty stuff. Then you brush or vacuum the chalk off. Remove speakers first. If you can't find that you could try a spray foam upholstery cleaner. Before I used anything I'd try it on a little spot to make sure it wouldn't hurt anything.

Thinking about winding coils I remembered this video a guy made using a coil winder. The winder is really neat but what's neater is the trouble he went to making the video, coordinating the music right down to the scissors snip etc. I wrote and told him so a long time ago.

http://www.youtube.com/watch?v=FIOocMoRsYQ

[VintagePC]

My goodness, that was incredible... and all hand built by the looks of it!

Perhaps I should dig up my Lego Mindstorms kit and build something similar

Edit: Seems we can't get K2R here in Canada... I tried some PowerOut upholstry foam on a small spot, and it seems to be all right.