E F Johnson Viking Ranger - 1st Stage Modifications. The Johnson Viking Ranger transmitter originally sold in the 1950s is perhaps one of the most popular "Boatanchor" AM/CW transmitters today. I've seen mint examples go for over $400.00 at Dayton but they range from $100.00 to $250.00 at flea markets or on the air swap nets. The kit sold in its time for $214.50, or $293.00 factory assembled. It covers from 160 to 10 meters (including 11!). A later model, The Ranger II dropped the former 11 meter ham band in favor of 6 meters. This discussion is limited to the Ranger I improvements. The transmitter has 14 tubes: 6AU6 VFO, 6CL6 buffer, 6CL6 multiplier, 6146 final RF amplifier, 12AX7 audio amp, 12AU7 audio driver, pair of 1614 modulators, 12AU7 keyer, 6AQ5 clamper, 5R4 high voltage rectifier, 6AX5 low voltage rectifier, 6AL5 bias rectifier and OA2 voltage regulator. None of these are hard to find nor expensive. The stock audio is quite constricted but can be modified to sound quite good. There are other mods that may be performed to improve the power supply, keying/push-to-talk circuitry, etc. However this document will cover modifications to the audio circuitry and a few others as well that may be performed to any Ranger transmitter without any irreversible mods in the (unlikely) event anyone would want to restore the transmitter to its "original state". These mods are as performed by Tim Smith, WA1HLR, aka The Timtron. Any of you who have heard The Tron on the air or one of the many transmitters he's built or modified will know that these mods make a BIG difference in the way the radio sounds. You will need some technical skill and knowledge of boatanchor technology to perform this work. As a caveat I offer these instructions only as a guideline without any warranty or guarantee of results. Although I have tried to maintain a high level of accuracy here I will accept no responsibility for errors or omissions that may cause damage to your radio if you follow them. These mods are gratuitously offered and you must agree to accept them under the above conditions. Remember folks, we're living in the 90s! I refer to components by there reference on the schematic in the Ranger I manual. You should have a copy of this schematic and know how to physically identify components from their position in the schematic. Also your Ranger may have been modified in the past and that will be for you to figure out. Looking at the schematic diagram, the following mods shold be made to the coupling and bypass caps around V-7 (12AX7) - 1st and 2nd audio amplifier. C-57 replace with .1 at 400 VDC C-50 (both sections) replace with 150 mF electrolytics C-53 remove this mica cap from the top of the audio gain pot C-52 replace with .1 mF 400 VDC cap C-56 replace with 8 mF 400 VDC electrolytic C-55 remove C-59 (both sections) replace with 2 - 330 mF 400V electrolytics C-60 replace with 1K 1 Watt resistor R-20 replace this 220 K resistor with a 68 K resistor R-27 replace this 158 K resistor with a 330 K resistor R-17 replace this 1 megOhm resistor with a 15 megOhm resistor Other modifications include: C-69 remove R-35 modulator screen dropping adjustable resistor (this is the big adjustable wire-wound resistor) Add an 8 mF 400 Volt electrolytic capacitor from the wiper to ground R-28 change this 820 Ohm resistor to 680 Ohm 2 Watts C-66, C-67, C-68 remove these .002 ceramic disc capacitors. They are connected from pins 1, 2 and 3 on the accessory socket to ground. C-47, C-48 Change these two .002 disc ceramic caps near the final plate choke to .001 C-90 bias supply filter capacitor (under the keyer sub-chassis). replace with a 50 mF 250 Volt electrolytic capacitor If you need to reduce the audio amp gain replace V-7 (12AX7) with an 12AU7. You may wish to replace V-8 (12AU7) with a 12BH7. Its a direct plug-in replacement. Should you experience a "motor-boating" effect when you raise the audio gain, add a 500 pF mica cap across the primary of the audio driver transformer T-3. These modifications should produce a much higher quality audio. It is best to use a high-impedance crystal or ceramic microphone. If possible a graphic equalizer and other external audio processing equipment should be used. Of course the FCC rules clearly prohibit playing music, but the frequency response of the audio circuitry is greatly increased and experimentation is required to suit individual voice characteristics, etc. Other mods mentioned but not covered include changes to the keying circuitry using several relays, modifications to the modulator, including changing the 1614s to 6550s, solid-state the power supply, remove the two rectifier tube sockets and install strapping filter can electrolytics in their place. Also a muffin fan should be placed on the top so it will draw air through the PA section. I would like to thank Tim WA1HLR for designing these mods for the Viking Ranger and sharing them with the amateur radio community. COPYRIGHT 1996 Michael Crestohl, KH6KD/W1 mc@shore.net