Garey, The reason i mentioned the final filaments is I found one set with only one of the filaments not working . It allowed the receiver to function, but not quite up to par. You seem to be very knowledgable on these, so I have a problem maybe you can help me with. I have an eary TR4- SN 23470. The on board PTO will not function, but the external vfo will function fine. It has the 3 section filter cap instead of 4 like the later models and a bunch of stand up component boards unlike the later ones. What do you normally find wrong in that situation ? I have fulled out the PTO and the circuit if different than my schematic. It only has one diode instead of two and the components are located in different places. Any help would be appreciated. Boyd W0BUW
Garey Barrell <[EMAIL PROTECTED]> wrote: Garey Barrell made an utterance to the drakelist gang ---------------------------------------------------------------------- The final filaments are in series with most of the receiver tube filaments, so if the receiver is working, that is not the problem. The bias supply should be variable from approx -45 to -85V. The screens should have approximately 250 VDC, current limited to less in X-CW. The plate voltage is 650 VDC. IF these voltages are present, and the cathodes are grounded through the 15 ohm cathode resistors, you should be able to adjust the bias for the 0.1A idle current. The system is the same as the T-4XC, just one more tube. Same rules. 73, Garey - K4OAH Boyd Van Horn wrote: > Carl, Check the filaments on the finals. They are all three in > parallel and drop the 12.6 volts to 6.3 for the remainder of the > tubes. The wires to the filaments are small and brittle. Measure the > Bias voltage coming out of the power supply- should be at least -65 > and you should be able to reduce it to zero. When you go to X-CW you > should have 350 volts on the final screens and when you go to ssb the > voltage should go to 650 volts. Be Careful !!! Also the sealed > transmit /receive relays are known to go bad. If you need one you can > order from Mouser in Texas- the manufacturers part number is > R10-EIY4-V2.5K. Good Luck, Boyd > > */Garey Barrell /* wrote: > > > Garey Barrell made an utterance to the drakelist gang > ---------------------------------------------------------------------- > Carl - > > No. No modifications are necessary to use the 6GJ5. Pin 8 is no > connection in the 6GJ5, and is the suppressor grid on the 6JB6, > which is > grounded. > > You say NO plate current. Do you have bias current? > > Garey - K4OAH > St Charles, IL > > [EMAIL PROTECTED] wrote: > > [EMAIL PROTECTED] writes: > > abbreviated excerpt below > > > > The 6GJ5's will work fine....... Garey - K4OAH > > > > Hi, TR4 will not tune up...no plate current...have been advised > that > > 6GJ5's may have to have pin 8 cut off. > > Your thoughts. > > Carl Hibbard WD8NHK > > > > ---------------------------------------------------------------------- Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
