Good point regarding internal vs external arcing. Though if the fly does end up being bad with no easily found replacement, I think I'd source some fine wire and try my hand at rewinding it just to say I tried. If it works, bonus :D Maybe overambitious but my 4068 track record of 1 for 1 at rewinding doesn't exactly deter me yet.

Finished my recap yesterday night. Was definitely a challenge getting at some of the caps, but it's all done and I've double-checked my electrolytic polarity already :)

Probably going to assemble a dim-bulb tester w/isolation transformer (have parts, just not assembled) at some point over the weekend and will try for a powerup after that. May give the chassis a good cleaning/polishing before I reinstall the CRT though since it is easy to get at now. Fingers crossed!

Any additional recommendations to beware of for a TV newbie besides the standard monitoring of B+/bad noises/smells/don't burn the CRT if no horizontal or vertical, and the staged supply mentioned earlier? (I've done a tube radio before and am familiar with basics, and have watched all of bob andersen's stuff, just not whether there's anything particular about this chassis design to beware of. I do know the risks/safety for HV, line voltage and hot chassis stuff.)

IT'S ALIVE!

First powerup today, nothing caught fire so I wired up the cable and switched her on. BOOM, picture and sound first try! (Will edit post and provide a picture in a little while, camera is on charge right now)

A couple of things need doing though... and I'm not sure where to begin on some of these... Any advice?

1. B+ seems a little high. Schematic calls for 260V, I'm getting around 310 with the variac at 95%.

2. Am hearing some soft ticking coming from the HV area. I think it may be a bad HV cap connection as I lost HV after nudging it while the set was off. Will investigate further.

3. On switch-off, vertical and horizontal collapse as is expected... but there is a REALLY bright spot left over gradually expands and fades away over about 30 seconds or so... this seems far brighter and more concentrated than seems healthy, and something I do want to resolve asap before I run the set too much more for testing.

4. Vertical height is about 75% of the screen space with the control at maximum. Probably something to do with the bodge job on that control. Again, something I need to investigate after #3 is done.

Good start though, I can smell the victory coming!

As promised, here we go:

http://vintagepc.site50.net/site/fle...v/IMG_1519.JPG

Congrats! Looks like you did a good job.

1.) Adjust the voltage from the variac to what the schematic specifies as the line voltage present when the authors of it took their chassis voltage measurements if the B+ is within approximately + or - 20%(I probably would not worry if it were within 30%) of the listed B+ you should be fine. The grid in many rural parts of the USA(and I'd guess Canada too) were not designed for loads such as many large kitchen and home appliances, and at different times a day the grid(and thus the B+ which varies in direct relation with the power grid) could be below 100V or well above the 117 that was the common standard then....TV makers were aware of this and made sets which could tolerate a fairly wide range of power grid voltage. If your set's B+ runs more than 30% high when plugged directly into a wall outlet then I'd do something to lower the voltage coming in. A few things you can do to lower the power grid voltage reaching it(that don't involve tying up your variac constantly) are to use a 100'+ long extension cord(it's resistance will lower the voltage some) or get a 120V to 2-20V stepdown transformer and wire it up as a line bucking transformer(there are threads on this if you search).

3.) This could be normal for this model... You may be able to dim of suppress the spot by adjusting brightness or contrast after shutoff. I have sets that do this which are fine, but there is one where there is a small black dot in the center of the screen where this effect burned the phosphor clean off at some date prior to my ownership of it. There are threads and IIRC even vintage electronic magazine articles on how to modify sets to not produce the spot.

4.) Look for out of tolerance resistors, wiring mistakes, and test the tubes. Some sets(Muntz was infamous for the degree to which this applied to them) will sort of work with tubes that test in the lower end of good, but only work well with a VERY strong example of a given tube type. You may need a tester and a source of several samples of the given vertical tubes, from which to choose the strongest, in order to get enough oomph to get the vertical to fill. Running the set with high B+ should also help with shrunken vertical.

EDIT: BTW the program you have on looks to be a letter boxed program(google that if you don't know that term in this context) letter boxed programs naturally don't fill the screen vertically so when adjusting the screen use a native 4:3 aspect ratio test pattern or program. Despite the program being letter boxed I can still tell the vertical is too small because the two horizontal Closed Captioning dashes well above the rest of the image, which should be JUST above the the top of the viewable area of the CRT, can be seen on screen.

Good luck!

Thanks for the reply. Last I checked having the variac around 90% gave me the recommened 117V, but that was a different location. Will re-check and decide what to do. It's not so much the operating B+ I'm concerned about as the initial jump up which goes to 400ish volts when the caps are rated for 450. Probably still okay but I like large safety margins ;)
I am familiar with the transformer trick to drop line voltage, IIRC you anti-phase the primary with the secondary and drop the total voltage by the amount the secondary is rated for.

I'll also see about some circuitry to kill that dot; perhaps it is normal but I'm pretty sure it's way too intense to be good for the phosphor... and that's with brightness and contrast at minimum when I shut off the set.

Edit: What kind of keywords should I be using to locate a circuit to fix this? I tried a few things that immediately came to mind but I'd imagine there's a specific term I don't know that would help immensely... and I did try "afterglow" without much luck) Could it be cured with an appropriate resistor to bleed off the HV quickly at poweroff?

Edit2: seems like the magic words are "spot killer". Mostly patents and unhelpful passing references, but this gem did turn up:
Looking at my schematic I think I do have a cathode-driven set... so what type and size of capacitor would I be looking at?

Edit 3: More looking at the schematic... looks like G2 is AC coupled to B+ already... which would presumably achieve the same effect vs G1. The spot doesn't immediately appear when power is killed... the raster collapses and fades but then the spot comes back. Perhaps upping the value of this capacitor (C70, .03µF) would do the job?

Will venture into vertical height land shortly. I don't _think_ there's a miswire as it all made sense when I was verifying the schematic against the chassis and hunting caps to replace... but you never know. I very much suspect it's related to the replaced VBO and height control bodge job though; the control is definitely the wrong value called for in the schematic and some other resistors in that chain were replaced too because I noticed they didn't have a full 360° wrap around the lugs like the factory ones do.

On that note... is it a good idea to run these sets tilted on their sides for access to the underside while working? I recall reading that it's generally not good since it means any sag in your filaments will result in a heater->cathode short.

Last thing for now... I pulled 3 bumblebee caps from this set... are audiophiles still going nuts over those? If so... where's the best non-fleabay place to sell them? :D

I've ran several sets on their sides and nothing bad has happened.

The bumblebees are still in vogue, but I've only seen them sold on ebay...I bet the guitar nuts that use them have a forum with a classifieds section.

Hi,

Congratulations for the progress. The only tube that is sensitive to position is the
power rectifier. Typically, vertical operation is preferred but horizontal is acceptable
if some pair of pins is in a given plane. Just check a data sheet for the proper tube.
Bye for now.

Right you are, 5U4 and it looks like pins 1 and 4 need to be in the vertical plane.

I can't imagine it being a design oversight that techs wouldn't tip these on the side for service and testing... so fingers crossed the socket is turned in the correct direction ;)

http://www.triodeel.com/5u4_p1.gif

Definitely some weird stuff going on in the vertical height section. Control is too low value (2.5M vs 4.7M) and it seems that someone shoved a higher-value resistor (3.5M vs 2.2M) before the wiper to compensate... which would likely be the culprit as the minimum value of the control is now much higher. I conveniently happen to have some 2.2meggers on hand... no replacement control, but I'd only need to worry about that if I get excessive height after replacing the resistors & with the control turned up.

Any comments on the spot killer capacitor from G1 to B+? I don't think B+ to G2 will work as G2 is driven around the same as B+ and wouldn't go sufficiently negative to clamp emissions. Would anything catastrophic happen if I just picked a value and tried it?

Good news! I replaced the suspect 3.5meg with a 2.2meg as specced and height seems to be adjustable to something a little more normal. The flyback also sounds a lot happier now, there was a bit of transformer noise that went away after adjusting the control and the linearity to something reasonable.

As for the bright spot... Noticed today that even after poweroff I can still control the brightness of the spot with the brightness control. Control is attached to the secondary supply line coming off the audio amplifier, which feeds into the video amp output to bias the cathode. Logic dictates something is up with that and [maybe the voltage isn't decaying quite as quickly as it should] edit: voltage seems to decay too quickly. I had that backwards -> K emits electrons, if it's closer to ground there are naturally more of them present.... There seems to be about 120VDC present on the staged supply line during operation, but it spikes well over 200V when powered on. Interesting, given that the caps are only specced for 200v in that area. Tube spec says max H-K voltage is 410, I think we're still below that though.


Picture is nice and bright and definitely watchable as-is with some tweaking of the fine tuning. Most enjoyable/challenging $20 I've ever spent so far... but not counting the $60 worth of caps that went into it :D

Had another idea whilst observing the spot... Noticed that when it expands, it gets a shadow along one side that looks like a neck shadow... which reminded me of how an ion trap works in a CRT.
Here's a picture of the yoke assembly from earlier:
http://vintagepc.site50.net/site/fle...l/CAM00041.jpg

There's no "traditional" ion trap, but there is a giant magnetic ring, with an inner sleeve which rotates by the grey knob behind the deflection coils... the focus assembly. Is it possible that on correct centering (the bright-dot is off center) the field is such that it aims the gun beam just off to the side when the deflection assembly isn't running?

Ok, I had another poke around today. After attempting to get the raster to fill the screen, it seems it is excessively wide. It goes beyond the edges of the screen even with the width control completely backed off.. and sliding the yoke assembly backwards only results in neck shadows at the edges of the screen.

I did notice that on pin 6 (the cathode of the HOT), C65 in the schematic is a 0.22 µF cap, but in actuality was a .47. I replaced it with a .47, but ordered a .22 just in case.

Is that something that would cause excessive width, or should I be looking elsewhere around the HOT and oscillator?

Did some more poking around today. Seems the dot issue goes away when the brightness is left up before poweroff; then when the sweep decays, most of the remaining emission has already gone and a fuzzy spot is all that's left.

Still having issues with foldover on the left hand side though. I tried subbing out the cap on the cathode of the damper tube (schematic gives option for .1 or .03) but no change. Same with the .47 vs .22 on the cathode of the damper tube.

Apart from desoldering and checking every single resistor in the horizontal section, does anyone have any tips as to specific things to test? I also note there's a resistor buried somewhere inside the horizontal yoke... Hope that's not the problem.

Once the tubes are confirmed good, caps are changed, and all relevant adjustments have been tried my default is to check every resistor in the circuitry that is potentially related to the symptoms...In sets I really care about I may even go through the resistors in some sections before first power up.
Some sets will have most resistors out of tolerance while others will have almost none. I'm restoring a Sylvania in the rectangular tube section that seems to have nearly ALL resistors in any given section I go over in detail out side their specified tolerance. :sigh:

I think it's a descriptor of the environment the set was in. Those carbon ones deteriorate pretty quickly given the right conditions.

A couple borderline ones but they're still pretty close to within 10%... but I'll replace them anyway.
Will have to see what I do about the one in the yoke though... accessing it to check it is gonna be a PITA. Wouldn't be surprised if it was the culprit either since it's an asymmetric foldover - left side has it but not the right (and the poweroff dot is now centered)...

One of these days I'll have to try locating a tube tester. Haven't seen anything good locally that isn't exorbitantly priced though.

Whelp... two steps forward, one step back.

I now no longer have a picture after changing 2 resistors. One of them was between phase detector and horizontal osc, and since I do still get a raster that's not the culprit.

The other one was B+ to the tuner, specced for 1.0K (R1 in the schematic), drifted up to 3 K and is in really poor shape.

I double checked that last one, and it is connected correctly. I'm also not getting any audio, just static so it's localized to before the audio gets tapped off... Haven't touched anything in that area though. Hope I haven't lost a tube, I will investigate more tomorrow.

If you did not disturb anything in the tuner or IF sections or subject the set to strong mechanical shock then your issue is likely that resistor or it's area...It also could be that if the B+ to the tuner has changed that the AGC needs to be tweaked to account for that.

Thanks for the reply. My first step will be to put the old resistor back in, that will answer the question of whether that is indeed the culprit. If the problem is AGC, then I should be able to get back some semblance of picture and sound by biasing the AGC line at -3V, correct?

Update: Replaced the original resistor, it started working again. Tacked in the replacement, still works. I'm running a 10 foot cable temporarily so I have a signal source to test, I'm starting to wonder if I just had a poor connection yesterday.

As it stands the set is definitely watchable but there area few things that could be improved; I'll have a look at that circuitry in those areas to see if I can locate the problems (namely contrast and jittery picture on some channels)

I've been hunting more out of tolerance resistors and have found a few.

One problem I'm having is a descrepency between parts though. For example, R54 on the cathode of the 6W6 vertical output tube is listed as 8.2K on the schematic, 10K in the list of resistors, the part itself measures 18K, and is colour-coded for 12K. To add to the confusion it doesn't look like it's a replacement part, the leads seem to be wrapped around the lugs much like the factory stuff.

Does someone perhaps have a Sams or a Riders (or similar) for this set which might show chassis revisions or modifications? Chassis number in the manual is 55M11, actual chassis itself is stamped 55M16, model # is 21-61. I've already tried some searching myself but there's very little on the Canadian made Fleetwoods, and anything that looks promising is usually related to the US Conrac company.

Well, this was interesting. Turns out the 680K to the cathode of V10 (phase inv/sync sep 12AU7) was off the scale of my meter (>2megOhm)

Out of curiosity, what kind of problems/symptoms would something like that cause?

I've gone through and replaced all of the worst offenders. Foldover problem is now gone, but it still seems to have an issue with excessive B+ (~290V at 117VAC in, when schematic calls for 260)

Further update here. I've replaced all of the resistors in the set (except those in the tuner). Interestingly enough my B+ is now at around 300V, and does seem to be contributing to the excessive width problem.

Apart from that, the picture is nice, but could benefit from an alignment. It's a bit fuzzy and the fine tuning is at one end of the extreme... as well as some ghosting to the right of the image and sound bleeding. I'm trying to track down some gear to help me with that now. :)

OK, I had a sit-down today and tried to see what I could get in terms of linearity and so on. (Pictures linked because they're large)

Geometry is pretty good:

https://dl.dropboxusercontent.com/u/...7/CAM00009.jpg

Picture isn't too bad but the contrast is cranked pretty high and it's not the greatest. Also you can see there's a bit of a halo going on to the right of any sharp contrast changes. The distance of the halo changes as I adjust the fine tuning, but it's not possible to completely get rid of. Looks to be some sort of ringing going on with the video signal. I am missing a tube shield on the tuner (6BQ7) and on the vertical (6W6), so that _might_ be related.

The other thing is that there's only a very small band where the picture is good. Just a touch to the left or right on the fine tuning, and the contrast is very poor. On top of that, being off on the fine gives me warping in the picture as well:

https://dl.dropboxusercontent.com/u/...7/CAM00012.jpg.
Those are standard bandwidth bars, but they probably don't say too much about the capabilities of the set given they were generated from the S-video out of my laptop into a dubious VCR RF modulator.

Sooo... I'm somewhat unsure of where to begin with these issues (well, I can apply my standard troubleshooting, but hopefully someone here can pinpoint what needs looking at). Any paper caps were replaced, as were _all_ resistors except those buried in the tuner. I was hoping these issues might go away when I fixed some of the wrong-value replacement resistors with the ones originally specced for, but I guess not :(

Whelp, I think I'm gonna call this done for now. There are a few things left to do but those will be as time permits, they aren't as critical to get things working again.

Writeup here:
http://vintagepc.co.nr/site/index.php/stuff/tv/