| Author |
Message |
    
Possum
| | Posted on Sunday, June 23, 2002 - 10:40 pm: | 
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vr8 is the rf adjustment on the board, i piggy backed a varible resister to the vr and was able to vary the power . Is it possible to remove vr8 and mount a potentiometer on the face to vary power? |
Jyd
| | Posted on Monday, June 24, 2002 - 8:38 am: |
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yeah,use a 20ohm pot.and 2 of the wires go together and other one to other side of varible.on vr-8 it has 3 legs the 2 on the same side go together. |
Salty_bones
New member
Username: Salty_bones
Post Number: 6
Registered: 5-2005
| | Posted on Saturday, June 11, 2005 - 9:05 pm: |
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We this work for the Washington? I would like to have Variable power to run a linear. Just looking for the easyest way for the Washington. Thanks for any ideas. |
Twowatt
New member
Username: Twowatt
Post Number: 7
Registered: 7-2005
| | Posted on Wednesday, July 06, 2005 - 9:38 pm: |
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salty_bones, yes the washington can have variable pwr. the easiest i think is to remove vr6, install a 5k pot on the rear chassis and run 3 wires (shielded would be nice, twisted at least) from the vr6 holes to the pot.
now lets jack up the ssb pep: get your schematic and notice that from the on-off sw the +v splits in 2 directions. cut the circuit going to ic5, r430, s-403 etc and install a LM340-12 (1st choice) or 7812 to an insulated 2"X 3" heatsink (or to the chassis if isolation from circuit gnd is not a concern), with the output going to ic5 & etc, and appropriate caps. [.1 uf on input, 10uf on output (tantalums would be nice, but other caps ok), keeping leads as short as possible, and try to make only 1 ground connection for all 3 grounds]. an added benefit is the meter light will last twice as long now, and ic5 will run cooler now giving better results all around. next install a 6800uf 35v cap in parallel with the 3300uf cap (usually you will have to install the cap on the top side with double-sided tape or ty-wrap, and run the wires thru a hole to the solder side of the regulator board - twist the wires at least or better yet shielded). now replace the 2sd188 with a 2n3055. replace fuse with a 5a slo-blow. adjust voltage to 16 volts. re-adj bias on driver to 35ma and final to 45ma. turn up vr7 and have fun.
for a little more am modj, lift one leg of d42 and add a 1k 1/4w resistor in series with diode.
for a lower am dk, parallel a 4.7k 1/4w resistor
across r123 (4.7k).
for more am dk, first...naw lets not go there.  |
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