Teletone verticle size

[timmy]

the 6x5 rectifier is a full wave rectifier so im wondering if this tube goes bad can it be replaced with a resistor for the heater if its in a series string set and placing 2 diodes in place. this tube is from a teletone tv 208 and it also has a 25z6 positive i think half wave and i know 1 diode can be used in that place with IIRC a 50 ohm resistor for the heater. please correct me if im wrong.

[rca2000]

I would leave the tube in place, and disconnect the plates, and bypass it with a pair of diodes, maybe with some series resistance added to each one. This way--the tube is still there--and LOOKS like it is working--but is bypassed.

[TUD1]

I drew a diagram of that very thing for a Zenith radio.

[jr_tech]

6X5 in a Teletone 208? where? I don't see it on the schematic:

http://www.earlytelevision.org/pdf/T...Sams-90-11.pdf


jr

[timmy]

Yes teletone 208 but the schematic shows a ballast tube in place of the 6x5 is that I have on this set. Maybe the schematic is an early one with the ballast and mine a later.

[dieseljeep]

Originally Posted by timmy

Yes teletone 208 but the schematic shows a ballast tube in place of the 6x5 is that I have on this set. Maybe the schematic is an early one with the ballast and mine a later.

Possibly the other way around! The later production set probably uses the ballast tube.

[tom.j.fla]

Timmy most have a very early production set, 1st run tv-208's were a tv-149 in the suitcase housing. The tv-149 does have the 6X5 in the circuit. All the best, Tom

[jr_tech]

Originally Posted by timmy

Yes teletone 208 but the schematic shows a ballast tube in place of the 6x5 is that I have on this set. Maybe the schematic is an early one with the ballast and mine a later.

Interesting! Does the set work with a 6X5 in that position?

jr

[walterbeers]

If you want to replace the 6X5 (the easy way) with a solid state replacement here is a link to one that you just plug in.

http://www.tedweber.com/wx5

Trouble with those tube's is that they are known for heater to cathode shorts, and when they short it takes out the power transformer. Also Using diodes and resistors should work as well, but you might want to leave the filament in circuit for appearance. Not sure what value resistors are needed as I would assume it depends on the current draw of the radio.

[jr_tech]

Originally Posted by tom.j.fla

Timmy most have a very early production set, 1st run tv-208's were a tv-149 in the suitcase housing. The tv-149 does have the 6X5 in the circuit. All the best, Tom

Wow! How did they make that fit? Never have seen one... could you post a few pictures of this rare beast?

jr

[tom.j.fla]

Ok jr tech I was not very clear on my comment. 1st run 208 used the 149 circuits, 2ed run and later use the circuits you see in Riders and Sams. Hope I made myself more clear on this. I worked on 1 or 2 of run 1 tv-208 but don't own 1 do own a run 2 set. All the best,Tom

[timmy]

The 6x5 is in the exact spot where the other run chassis has the ballast. So I'll have to keep in mind that these tubes are known for heater cathode shorts and there is no power transformer to worry about cooking in the event the tube goes bad. What ohms would be ideal to replace the heater loads on the 25z6 and 6x5 tubes, would 15 ohms 10 watt for the 6x5 and 50 ohms 10 watt for the 25z6 be close ?

[jr_tech]

Not real close... R=E/I

for the 6X5, I get R= 6.3 volt / 0.6 amp. so R = 10.5 ohms. 15 ohms is a little high, but with todays higher power line voltages will likely work ok.

for the 25Z6 I get R= 25 volt / O.3 amp , so R = 83 ohms. I would not use a 50 ohm resistor there.

10 watt resistors should be adequate.

jr

[timmy]

Well ok but again with the higher line voltages I may try a 100 ohm resistor should I need to for the 25z6 . So I guess it's safe to say that any 25 volt tube that resistance should apply to all. What's odd about this teletone is the schematic for the tv208 is identical to the set I have but there is a lot that's different between the SAMs and what I have . Early television only has the SAMs I have but clearly it is very different , the ballast I don't have and the amount of power supply caps, I only have half the caps that the SAMs shows so there must be an early and late and the tv 149 is totally different then what I have which is what the SAMs shows from early television.

[old_coot88]

Could somebody post a schematic of the circuit area where the 6X5 is used?