The other thing i should mention is that when I got this chassis, it had a #78 tube in the socket marked 6D6. Is this acceptable? i took all of the tubes in the radio and had them tested, they're all acceptable. Now if I could just find what ballast tube to put in this thing.. and if I should replace the 78 tube with the pencil marking 6D6.
Sorry, a beginner here.. I can handle the recapping, cleaning, cabinet refinishing, and can read schematics, but this thing is driving me crazy!!
Thanks for any help people can give! Don.
Don,
The ballast is probably a 140R8 which I believe is rated at 140 Ohms at .3Amp. Probably equivalent to a 13 Watt wirewound resistor of the same resistance. The 78 tube is an acceptable substitute for the 6D6. The 25Z5 is a 25 volt tube as is the 43 tube, the others are 6.3 volt tubes. The voltages of the tubes and the ballast in series should add up to the line voltage of 117 volts. The radio is what is called an AC/DC set, that is, one without a power transformer. For safety, I would suggest using a 1 to 1 isolation transformer in the line while testing is done.
Radiodoc
Don,
The ballast tubes are almost as scarce as chicken teeth. You may have to use a wirewound resistor in its place until you get the radio chassis restored and maybe find one or a substitute one later. Oh, as for driving you crazy right now - I betcha when you get the radio working, THAT feeling will make you almost forget all the craziness.
Radiodoc
Check with AES, www.tubesandmore.com . They presently have a 140R ballast on sale for $7.16. This one is electrically the same but with a different base. Might send them an email. AES has too many ballasts to list all of them.
#78 is acceptable as replacement for a 6D6.
Norm
:::Still no luck on this chassis... unidentified maker & model number.. I cleaned up the top of the chassis and underneath STRONG light was able to make out some old pencil marks left next to some of the sockets. So far the I'm able to make out a 25Z5, 6A7, #76, #43, 6Q7, 6D6, plus the tuning eye. The empty 4 pin socket for the ballast tube has two pencil marks on it.. one just says "140", the other mark says "140-B-8" any of these markings make any sense to anybody?
:::
:::The other thing i should mention is that when I got this chassis, it had a #78 tube in the socket marked 6D6. Is this acceptable? i took all of the tubes in the radio and had them tested, they're all acceptable. Now if I could just find what ballast tube to put in this thing.. and if I should replace the 78 tube with the pencil marking 6D6.
:::
:::Sorry, a beginner here.. I can handle the recapping, cleaning, cabinet refinishing, and can read schematics, but this thing is driving me crazy!!
:::
:::Thanks for any help people can give! Don.
::
::Don,
::
::The ballast is probably a 140R8 which I believe is rated at 140 Ohms at .3Amp. Probably equivalent to a 13 Watt wirewound resistor of the same resistance. The 78 tube is an acceptable substitute for the 6D6. The 25Z5 is a 25 volt tube as is the 43 tube, the others are 6.3 volt tubes. The voltages of the tubes and the ballast in series should add up to the line voltage of 117 volts. The radio is what is called an AC/DC set, that is, one without a power transformer. For safety, I would suggest using a 1 to 1 isolation transformer in the line while testing is done.
::
::Radiodoc
:: I did a google search on 140R8 ballast and came up with no results.. any idea where I could find one of these?
Norm,
Thanks I forgot about AES.
Radiodoc