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Bronzepony
Junior Member
Username: Bronzepony
Post Number: 23
Registered: 12-2005
| | Posted on Saturday, February 18, 2006 - 10:06 am: | 
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I have a Madison with the 8719. I have done the tune up on it with a d-104 it will swing 10 watts but acts like it hits a brick wall. With a 636L it will only swing 6 watts this off a 3 watt dead key. I also have a 148f gtl not dx it has had the same tune up and will swing 12 watts with both mics. What is the diff? I have clipped r 131 what about removing tr24 and the resitor change will this give me more swing it only says adj. for max. am. and how do you adj. L37 with it being a coil of wire?? |
Hotwire
Advanced Member
Username: Hotwire
Post Number: 938
Registered: 1-2005
| | Posted on Saturday, February 18, 2006 - 2:34 pm: |
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The Astatic 636L is like that. I have owned many. I believe its because of the type of noise canceling involved. You have to hold the mic to your mouth with the lip gaurd touching your lip. Talk a bit louder too. I use the 636 with a connex 4800 and it works great even as I speak softly. Don't mess with L37 it will only fool the meter into more watts with harmonics! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1201
Registered: 9-2004
| | Posted on Saturday, February 18, 2006 - 8:46 pm: |
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bronzepony,
do not remove TR24, this will cause distortion on SSB.
instead put a 1.5K resistor in series with the middle leg.
L37 is not the coil you want to turn.
to tune the transmitter for max. audio output; key the mic, and while saying,"aahhhhh" into the mic, turn these coils: (USE THE PROPER TOOLS!!!) in this order:
radio on ch.19- L47, L48, L46, L45, L38.
do not do this while dead keying or you will have lots of carrier and little modulation.
if you want the radio to swing much past that 12 watts, you have to volt the final. do a search on this forum for "adshare64 NPC mod". you will find his method for volting the final on the 148/2000gtl chassis which is the same as yours.
some people dont like this mod, and their reasons should be heeded. in the end its up to you.
here are some things i would recommend doing to your radio. these are things that i consider upgrades, not "mods".
remove c207
change R206 to 35-39K
remove c232
Q41(AM regulator) probably 2sc1419, change it to a NTE152
C18, change to 680uf 16volt or bigger
change C172 to 3300uf 50volt
change C163 to 3pf
change R114 to 10k for wider audio response(you can experiment
to see how much lower you can go) i use 10K.
put R131 on a SPST switch.
take a 10uf 25volt electrolytic cap & solder across spst switch,
find C23 & run leads from + & - to same polarities of cap
soldered to switch, fast & slow AGC for SSB.
replace Q14 with a 2SC2999(that's the best choice,
but i think NTE107 works also)for at least 3 db gain
on weakly received signals!
take the Q14 you removed & use it in place of Q19(2SC945).
that will be a major upgrade to SSB detector.
for even more increased AM sensitivity(& less noise)
replace D1, D2, D21, & D22 with NTE583 schottky diodes,
or SK9975 diodes.
remove R95 to broadband VCO.
these mods will not stress out your radio; they will make it better.
R131 is a modulation limiter for the AM mode. its up to you if you want to remove it, put it on a switch (my choice), or leave it alone.
its all about personal preferrence.
have fun with these,
matt
i replace all the electrolytic caps in my radios as they are getting old.
big difference in audio quality on both RX and TX with the new caps. |
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