Somehow I posted this in the wrong section... twice I've done that?? Copy pasted and deleted from other location:
OK. I now have 2 of these radios, one bought new (MFR FEB 13) and an eBay special (MFR July 04).
Both have had the Cobra TSB for diabling the Soundtracker done.
My setup, a Radioshack 4' mag mount (about the equivalent to a Wilson Lil Wil) on my filing cabinet, SWR 2.0:1. Temporary test load until my MFS 300W dummy comes in Tues (Oct2). Computer 13.8V 30A Power supply. Main antenna I am working on putting up is a Solarcon A99 on a 30' pole, 100' rg8x coax.
----------------------------------------------------------------------------------------------------------------------------------------
1. The '13 radio I have added a RCI EB-2015 echo to, the 2nd one I want to but have a question on doing it. I would like to remove the Dim/Dyna knob and put the echo there. What does it take to eliminate the knob for the Dyna side? I plan to set the dimmer, measure the resistance, and just install a fixed value resistor there in place of the VR. Looks like there are 3 wires to each part of that control set...
------------------------------------------------------------------------------------------------------------------------------------------
2. OK. Another thing. I opened the 04 radio, D9 was clipped, (I think it is L10) was turned out fully, the ceramic cap from the 8 or 9 pin chip on the side wall of chassis to chassis was clipped. I cannot see any other obvious changes. I put it on my Dosy TC, modulation swung high, dead key about 6W, but here is my observations...
Modulation pegs meter, but then drops to about 75% without changing my "auuuudio".
Deadkey 6, but only swings to maybe 7 or 8.
I turned L10(?) slug in, dk dropped, but still no matter how I adjusted it it only went maybe 2w swing.
No wire coils spread, all are tight and still glued (thankfully! No harmonics measured.)
Soldered D9 back together. Adjusted VR5 to the "Set" lone on the meter for a solid reference point. Still drops with voice. Read somewhere about finding a 1kHz audio online, played it thru the mic. Modulation held steady. Maybe my voice gets weak after a moment...
Resoldered ceramic disk cap to chassis. No difference. Thinking it is a filtering cap??
Is the 2W swing normal, and is that sufficient to sound strong and clear? I always see 1:4 ratio, I am nowhere near that.
----------------------------------------------------------------------------------------------------------------------------------------
I am planning to use this thread for any questions I may come up with with these 2 radios. I have searched a lot, only found a few things on the modulation, and they were mostly add a "swing kit" cap and resistor. I kind made notes of what and where I found some info:
Copper:
Modulation: VR5 or Cut D9
AM Power: L10, L9, L8
Notes: VR1 Squelch Adjustment VR3 Transmit Meter VR4 Squelch VR5 Modulation Meter VC10 = 10.240 Xtal Adjustment POWER MOD! #1 - Change R76 (3,3K) to a 1K (located near Mic Socket} #2 - Change R43 (10 Ohm to a 2.7 Ohm #3 - Change R108 (1Ohm to a .47 Ohm #4 - Re-Tune L10, L9, L8 for MAX Forward Power
WorldWideDX.com:
(Thread about more audio)
Loosecannon: you can also try changing C91 to a 33uF electrolytic cap.
this affects the AMC attack time.
CBTRICKS.COM:
Secret CB:
1. R76 (3.3K), Change to 1K
2. R53 (47K), Change to 22K
3. C89 (.033mfd) change to 2.2mfd (Note: makes sure + side is not next to IC)
4. If more drive is needed the final may be changed to 2SC1307 or ECG-236
CBRADIOTALK.COM:
Pokeyman:
install 2SC1969 power transistor. Exchange D10 with Schottky diode.
Exchange R43 (at driver) with a 1.5-2.2 ohm 1/4 watt resistor. (Stock unit is an 8.2-10 ohm)
Exchange R40 (at final) with a 8.2-10 ohm 1/4 watt resistor. (Stock unit is a 22 ohm)
Optimize output for each radio by bridging a 33, 47, or 68pf at C46 and C42
OK. I now have 2 of these radios, one bought new (MFR FEB 13) and an eBay special (MFR July 04).
Both have had the Cobra TSB for diabling the Soundtracker done.
My setup, a Radioshack 4' mag mount (about the equivalent to a Wilson Lil Wil) on my filing cabinet, SWR 2.0:1. Temporary test load until my MFS 300W dummy comes in Tues (Oct2). Computer 13.8V 30A Power supply. Main antenna I am working on putting up is a Solarcon A99 on a 30' pole, 100' rg8x coax.
----------------------------------------------------------------------------------------------------------------------------------------
1. The '13 radio I have added a RCI EB-2015 echo to, the 2nd one I want to but have a question on doing it. I would like to remove the Dim/Dyna knob and put the echo there. What does it take to eliminate the knob for the Dyna side? I plan to set the dimmer, measure the resistance, and just install a fixed value resistor there in place of the VR. Looks like there are 3 wires to each part of that control set...
------------------------------------------------------------------------------------------------------------------------------------------
2. OK. Another thing. I opened the 04 radio, D9 was clipped, (I think it is L10) was turned out fully, the ceramic cap from the 8 or 9 pin chip on the side wall of chassis to chassis was clipped. I cannot see any other obvious changes. I put it on my Dosy TC, modulation swung high, dead key about 6W, but here is my observations...
Modulation pegs meter, but then drops to about 75% without changing my "auuuudio".
Deadkey 6, but only swings to maybe 7 or 8.
I turned L10(?) slug in, dk dropped, but still no matter how I adjusted it it only went maybe 2w swing.
No wire coils spread, all are tight and still glued (thankfully! No harmonics measured.)
Soldered D9 back together. Adjusted VR5 to the "Set" lone on the meter for a solid reference point. Still drops with voice. Read somewhere about finding a 1kHz audio online, played it thru the mic. Modulation held steady. Maybe my voice gets weak after a moment...
Resoldered ceramic disk cap to chassis. No difference. Thinking it is a filtering cap??
Is the 2W swing normal, and is that sufficient to sound strong and clear? I always see 1:4 ratio, I am nowhere near that.
----------------------------------------------------------------------------------------------------------------------------------------
I am planning to use this thread for any questions I may come up with with these 2 radios. I have searched a lot, only found a few things on the modulation, and they were mostly add a "swing kit" cap and resistor. I kind made notes of what and where I found some info:
Copper:
Modulation: VR5 or Cut D9
AM Power: L10, L9, L8
Notes: VR1 Squelch Adjustment VR3 Transmit Meter VR4 Squelch VR5 Modulation Meter VC10 = 10.240 Xtal Adjustment POWER MOD! #1 - Change R76 (3,3K) to a 1K (located near Mic Socket} #2 - Change R43 (10 Ohm to a 2.7 Ohm #3 - Change R108 (1Ohm to a .47 Ohm #4 - Re-Tune L10, L9, L8 for MAX Forward Power
WorldWideDX.com:
(Thread about more audio)
Loosecannon: you can also try changing C91 to a 33uF electrolytic cap.
this affects the AMC attack time.
CBTRICKS.COM:
Secret CB:
1. R76 (3.3K), Change to 1K
2. R53 (47K), Change to 22K
3. C89 (.033mfd) change to 2.2mfd (Note: makes sure + side is not next to IC)
4. If more drive is needed the final may be changed to 2SC1307 or ECG-236
CBRADIOTALK.COM:
Pokeyman:
install 2SC1969 power transistor. Exchange D10 with Schottky diode.
Exchange R43 (at driver) with a 1.5-2.2 ohm 1/4 watt resistor. (Stock unit is an 8.2-10 ohm)
Exchange R40 (at final) with a 8.2-10 ohm 1/4 watt resistor. (Stock unit is a 22 ohm)
Optimize output for each radio by bridging a 33, 47, or 68pf at C46 and C42