I have one I picked up 30+ years ago from the church up the block for an allowance busting $5. Used it on my bed to watch the Honeymooners, The Three Stooges and others before going to sleep.
It works, but blooms when the brightness it turned up, as well as the sound has gotten weak. I could just recap it, but would like to see some service info.
Thanks
Tony
http://techpreservation.dyndns.org/schematics/
Tony
:What is the model number? It does sound like low B+ You will need to replace the filter capacitors. Try this link for the schematic.
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:http://techpreservation.dyndns.org/schematics/
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http://www.radiolaguy.com/Manuals/Television_Manuals.htm#P
Replacing all the electrolytic capacitors though, is not a bad idea, there cheap. A voltage check on the Horz. output transistors collector, would tell you if the Horz. sweep voltage is up to snuff. I think the audio problem, may be an open germanium audio output transistor, i think it's a push pull output.
I'd like a schematic for refrence, if anyone knows which Sams folder this TV is in. I could probably go to the library to get a copy.
Thanks.
:
:I'd like a schematic for refrence, if anyone knows which Sams folder this TV is in. I could probably go to the library to get a copy.
:Thanks.
Tony, SAMS 475-2 covers H2010L and H2010BL. If library can't come up with it I can send one out to you.
Bill
Sir Anthony. . .
Some few points of interest on that set of yours:
First, that the set is using first generation gemanium transistors, almost exclusivelyPNP's.
Probably the majority of time watching the unit was undoubtedly via AC power in the past.
If to be used battery powered nowadays, the logical thing to do would be to restuff an old 7 1/2 V battery housing with Ni Cads--- or a step up, with NiMh cells, or in getting right on up into the 21'st century, use a good pair of Li- Ion cellls salvaged from an old lap top battery, using either a set of the CGR17670 or CGR18650 series, or, if you are on a roll, and wanting to additionally attact an adjunct powering project, scrape up another 600 cells to fabricate a Power Pack for your "VOLT" electric
car knock off.
For sure its time to do a sweep of the electrolytics caps in the unit, with the power supply units being the C1 and C2 units.The next most important position is the one in the sweep section as the C21 , which is decoupling the collector B+ supply buss of the Hoz out xstr, if that unit is deficient the hoz output circuitry suffers appreciably.
Looking at the sets schema, you can also see some parasitic voltage supplies derived from extra windings on the flyback.
The + and - 11V supplies and the 280 V supply for the kines grids biasing,
A goood test of the health of the sweep circuitry is to monitor that last supply and see if the power supply exhibits any
"crunching down" when you attempt any brite adjustment which you mentioned, I don't think that it will, as I really
think that the problem mentioned will be attributable to the set of pencil rectifier tubes that are hard wired into the voltage doubler section that feeds the kines ultor .
Great shades of a 555 or 562 series of Tektronix scopes HV supplies !, I'm glad my units don't use those tubes, as they have inched on up to an ~$12.00 price apiece.
If that was my set to fix I would be pulling those units and replacing them with a solid state rectifier stack that had some time periods favor of being used for supplying the focus electrode on color tv kines.
Reference the right bottom corner of the sets schema, pricing on those being on down to the $3 per copy.
On your set the most power drag is from the 3W used for the kine filament, just after that is the hoz output stage and its function, along with those parasitic supply windings off from its windings . . . .figure on 2 W there , for all.
Then comes the two filaments on those 5642's for 1/2 W.
The SS replacement would take away the filament loading on the power supply along with the 30 volt drop that they experience on the HV supply.
Do note that that they are really driving that ultor heavy in the projection use of the kine. General rule of thumb is 1 KV
per inch of screen size. In your sets situation there are two aspects to the decline of its kine, one of course being the timely deterioration of the cathode elements active coating.
The other irreversible condition is the development of ion burns on the phospor face of the kine.
A classic example that you can readily relate to is the common flourescent lamp where there is a similar phospor coating within the internal inside length of the tube envelope. The unit having electrodes at both extreme ends,
and its action dependent upon an initial flashover between electrodes and then a maintaining of a gas plasma condition
upon an initial flashover between electrodes and then a maintaining of a gas plasma condition between the electrodes and
a bombardment of the phospors with a then resultant light output. Note that with time that the phospor areas near the electrode start taking on a greying and progressively intensifying toward a black. There goes the light output downward
in that area.
The same effect is occuring on the face of projection use tubes, since they are being bombarded so much more intensely.
Its akin to a "glaucoma" onset on kines.
On modern day projection tubes, one can see the intense white areas near the edges where no display action occured,while the central area shows its timely graying.
Thats it. . . . gotta get your schema loaded now, and it had to be a BIIG one, so it might need a click on to bring the size
on up to posted size.
73's de Edd
Thank you again,
Anthony
:If you do need to use a solid state rectifier, do away with connections 9-10-11-12. Go right from 7 to the CRT anode connection. No need for C-89 C-90 & R-98 anymore.
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SIR Anthony. . . . .
No . . . nix . . . .. .nyet . . . on the use of a single rectifier unit.
Along with the adjunct info given of of :
If you do need to use a solid state rectifier, do away with connections 9-10-11-12. Go right from 7 to the CRT anode connection. No need for C-89 C-90 & R-98 anymore.
With particular respect to my earlier posts textual info of:
I don't think that it will, as I really think that the problem mentioned will be attributable to the set of pencil rectifier tubes that are hard wired into the that feeds the kines ultor .
Meaning, that the fact is, that the TWO tubes are being configured into a HIGH VOLTAGE DOUBLER CIRCUIT, and that sets performance would be DISMAL with only half of its prescibed HIGH VOLTAGE level at its kine ultor.
All the brightness possible is needed for that unit being used in a projection mode, even with the addition its mechanical design incorporation of a hood to minimize ambient side and frontal light presence.
A focus stick rectifier would be installed in place of V1 by having its anode lead going to the former V1's plate connection terminal, and its cathode connection (+) going to the #10 of the terminal board.
The other focus stick rectifier would have its anode lead going to the former V2's plate connection and its cathode connection(+) connection going to the #12 of the terminal board.
While you are on that board, before connecting in the second stick rectifier, and the circuitry is completely isolated, check out that 20 meg resistor, if it is . . .and its VERY
likely to be . . . a carbon composition unit.
Those units are real IFFY in very HV circuitry, tending to drift upwards in value.
73's de Edd