Fleetwood Constellation Restoration Thread

[Electronic M]

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.

[electroking]

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.

[VintagePC]

Originally Posted by electroking

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

[VintagePC]

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?

[VintagePC]

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

[VintagePC]

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:


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?

[VintagePC]

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?

[VintagePC]

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.

[Electronic M]

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.

[VintagePC]

Originally Posted by Electronic M

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.

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.

[VintagePC]

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.

[Electronic M]

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.

[VintagePC]

Originally Posted by Electronic M

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)

[VintagePC]

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.

[VintagePC]

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?