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#17
05-05-2010, 01:06 PM
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replaced all the weak 6GH8's (4 total)with some nice strong ones (hard to find) also some 6Lm8's (3)as well, weak.
found one way out of spec resistor on the chroma board a 330k testing like 700k+, and a 4.7 ohm 2watt that was at 9+, both where 5% tol so they will get replaced next. Picked up some sheet copper, will try to build a tuner cover. been cleaning the smokers tar off the pcb during down time. 
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#18
05-05-2010, 01:30 PM
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Most of the time if the tuner cover is missing, some "TV Repairman" had spray cleaned the tuner and left it off! Sometimes they can be a little tricky to snap back on but jeez....
If you were lucky the cover was left inside the cabinet. Some of the dirtiest/nastiest tuners I'd see were with missing covers..Duh!! That tuner looks like it may be a "Sarkes Tarzan". They manufactured tuners for various manufacturers including GE, etc., and would also have their own branded tubes installed with them originally. They made that style of turret tuner.
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#19
05-05-2010, 01:53 PM
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Oops, forgot to mention that an easy fix to that tuner is to gently pry up on the channel strip contacts. If you notice they are shaped like a sideways question mark with one side open..(for prying up on!). You'll see some are laid down more than others so the trick is to get them about the same height as the highest. That way you're not prying up too much! Just use a real small blade screwdriver inserted as square as possible to avoid contact with the coil windings.
You can also easily remove the whole turret assembly if you'd like, but shouldn't need to. What I did to clean those and not make a spray mess was to saturate a Q-Tip and clean/wipe those contacts. You can then take another Q-Tip or your finger and apply a little Vasolene to those contacts. As long as your tubes are ok I bet your tuner problems will "clear up!" (Sorry, couldn't resist!!)
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#20
05-05-2010, 04:15 PM
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I cleaned them with a big eraser, and then did as you described, Q tip with cleaner/lube.
Its a hybrid that has transistors in the tuner, so I hope they are not noisy, would be a mega PITA to replace them. If the problem persist I will break out the B&K 1076 and feed an IF signal in to see if the snow is a tuner or IF issue. I hope the clean up will resolve. I cant get at the fingers on the tuner with out major surgery, so I kept cleaning the turret nobs and rotating. The fingers are next the the UHF tuner and it is hard to get a good shot at them. I tried prying up the tuner stips but they did not want to budge and I did not want to push it. If I can get 2 or 3 in a row out I would have an easytime getting the qtip at the fingers. Pulling the turret also looks like a pita due to all the hardware hanging on the front. Normally I can just jiggle the snow out, if no change by jiggling then I figure its not the contacts.
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#24
05-05-2010, 08:41 PM
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whew....
ok put it all back together and crap hold issues color sync issues crud... but the snow is gone  so I start tube swapping, a combo of the old and new tubes gets it going again, I thought I was playing it smart by replacing the old 6GH8's with new ones that tested stronger, Now I am begining to wonder if the new ones were gassy. I will try them on my cheap emission tester for grid emissons. I tested them on the hickok 533 but not sure about how to do a gas test. anyhoo pic is looking good and I am sweating like a stuck pig (tv is out in the garage, to heavy to move by myself). So will pick it up again tomorrow after work and see if I can get some screen shots. I just hope that color and sync issues dont come back. I only replaced the tubes since I was getting the one of the guns intermittently, and just shot gunned the chroma board. There was no excuse for messing with the sync tube, my bad, it was fine.
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#26
05-05-2010, 09:29 PM
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Swapping is the best if you have the spare tubes. Recently, I was working on a couple AA5 radios from the 1940s. Once I powered them up, they both had horrible hum even though I had changed the filters. I had checked the 50L6 output tubes on a late 1940s Hickock GM tester that uses a neon light for shorts test. They both looked ok. However, if I used a different 50L6, the hum went away. I then tested the humming 50L6s on my more modern Eico tester that applies 70 volts between the heater and cathode. They humming 50L6s leaked horribly. Goes to show that the old Hickock is not the best in at testing all possible issues.
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#27
05-06-2010, 07:04 AM
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what bugged me was I had some NOS radio shack lifetime tubes (the 6gh8's) that seemed to cause the problem.
Now that I got a pic I will do a one at a time swap and see if its a particular tube. another issue vert centering off, there is a pot that is labled vert centering. I figure is just bias the yoke, but have not traced the wiring yet. I will need to get a schematic of this chassis. if its a bias then I need to see what the B+ that feeds it should be. Just for fun I will put the set on a variac, I have one that can handle the load. See what happens when changing the line voltage. I has the orig can caps, maybe a weak one in the B+ doubler (again I am assuming it uses a doubler, there are a couple diodes in the PS, guess it could be a centertaped PT and a full wave rectifier). This set does not use a HV regulater either, almost a muntz color tv (I wonder if muntz ever did color?).
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#28
05-06-2010, 08:40 AM
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About that vertical centering...many times I would see it way off, as well as height and linearity being misadjusted. I believe most of us understand the relationship between the vertical pots and how the top or bottom of the raster moves with it, how they interact with each other.
What I'm getting at is take the normal-service switch and put in the service position and establish your center line. Can be tricky if the convergence is off though. Now you can adjust the other pots for a good, (more) centered and linear picture. B+, B+ Boost, and High Voltage can affect just about everything so good to check voltages...as you mentioned. These Old Philco's are fun!!
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#29
05-06-2010, 08:45 AM
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yes,muntz did color.we saw a scant few back in the day.muntz also was a pioneer in the big screen early projection sets.philco s are well known to have electrolytic problems.those cans leak like like a sieve.as in an earlier post,our families first color set was a philco ford roundie.pretty good set with a nice picture.much better than the higher level rca s in the store.good luck with yours
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#30
05-06-2010, 09:11 AM
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did the service switch, did not note the center position, will do later tonight.
in service even with brightness all the way down and the red drive all the way down I had a red line, could not make it just go away. The green and blue I was able to make just go away but since I was stuck with the red, I just adj the green and blue to the same approx brightness. after the above adj the overall brightness in the norm position seems about right and grey scale seems good. it did not converge either on the center line in the service postion. The pic looks fine in normal viewing. I will put a dot and cross hatch on it later to see how that shows up.
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