Looks like you could use an adapter to go from an octal socket to a 7 pin and use a 6X4.

Not sure anyone has one but the picture of the set in the SAMs under teletone tv208 in early television is what I have but like I said it's clearly different. I would like to see the right schematic for this set too.

Well if they did use the circuit of the TV-149 in the 208, it should be something like this:

http://www.earlytelevision.org/pdf/T...Sams-56-22.pdf

Perhaps Timmy could trace out the circuit around the 6X5 and 25Z6 and draw a schematic showing how the power supply is wired. Again I ask, does the set actually work or at least do the filaments light up with the 6X5 installed?

jr

No it's not working yet I'm in the process of recapping so if there are any problems later I'm sure I won't be able to rely on the schematic that's out there now. I was just looking into these tubes because they are the source of b+ along with one selenium which will be replaced with a 1n4007 diode later. And now he reign that the 6x5 is known for cathode shorts so there is nothing like a reliable silicon diode and maybe leave the tube in for show, long as it still lights. This is just in case later on I will have this info to do if I could not obtain these tubes. Kind of a backup plan, alternate.

I was puzzled over the references to the 6X5 being "used as a ballast". Does that mean the diodes are paralleled and used in lieu of a nichrome wire dropper tube? :saywhat:

I don't think that anybody indicated that the tube was actually used as a ballast, only that it occupied the same socket location as was occupied by the ballast in later sets. :scratch2:
I would love to see a schematic for the set that Timmy has, but very likely the schematic is close/same as that of the TV-149, which has an 80 ohm dropping resistor in the heater circuit and also a selenium rectifer as well as the 25Z6 and 6X5.

jr

Well I looked at the tv149 schematic and it's different as it has 2 - 25z6 tubes and mine only one so I can't go by that schematic should I need to.

:scratch2: I hope this means your intentions are to get this set working perfectly in it's original configuration , and then when it's working perfectly as designed you will consider any modifications ? Restored correctly , the circuit will function as it's manufacturer intended , and that should be the baseline from where any modifications to the power supply are considered .

Myself , I'd restore it to what I'd call 99.5% original , I'd leave all the tube circuits alone modification wise and use a modern diode (with resistor) in place of the Selenium (which would remain on the chassis but with both of it's wires run to a terminal strip)

As you've already noted , this set has no power transformer to roast , so there really is no need to play "hot potato" with the 6X5 here .

Yes I always restore what was there originally including tubes however if a specific tube was not available I would like another option in place to replace a tube if possible which in this case I can do so if needed. And it's possible to just use a modern diode without a resistor because what I sometimes do is the resistor in series with ac I will up the ohms for both the diode, increased voltage which is only a few volts and also the increase in line voltage which seems to vary from area to area. The aim here for me is to always get a set working the way it was intended and what annoys me because it always has to be perfect while I don't consider myself a perfectionist , I want it right, even down to the flow of solder, it don't look right I do it again. :yes:

The TV-149 schematic that I linked to shows only one 25Z6 but each section of it is drawn as a separate 1/2 tube. Is that what you are counting as two tubes?

jr

Yes you are right it is shown in 2 sections but one tube but this is definitely not the same schematic for the set I have since the 149 is one a piece chassis and mine is a 2 piece chassis. Even the power supply caps are different.

Just for S&G's, look up the schematic for the early model, Hallicrafters T54. The power supply circuit looks very similar, including the resistor values.
The Sams for one of those models, shows the electrolytics drawn with the wrong polarity. :thumbsdn:
BTW, what's so bad with the newer issue 6X5's. I'd leave it as-is. :scratch2:

I really need the right schematic because there are resistors that don't have colors and I need to know the right value, they are bad.

Could you draw out a schematic of how the components in the circuit are connected and post it here? Perhaps we can back-enginner the circuit and figure out what the resistor values should be. :scratch2:

jr

SAMs photofact
 

I'm still looking desperately for what I believe is the right SAMs for a teletone 208 r because the 208 and the 208 tr have a ballast but mine don't. There are 2 SAMs that I know of, 90-11 and 95-6 both are not mine but I don't know the SAMs number for the 208r . Mine has the round plug that connects both chassis together like the tr and the tr also has the round plug. The 208 has the square plug and a ballast, the 208 tr has the round plug and a ballast, the 208 has the round plug and NO ballast. Does anyone have this print ?