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COBRA

HH-70 RV-4
7 PLUS VR4 or CUT D8 L11, L12, L13
10 PLUS VR4 or CUT D8 L11, L12, L13
18 LTD CUT D13 or CUT R84 L7, L6, L5
18 PLUS CUT D12 L 7
18 RV RV501 or CUT D502 L304, L305, L306

19 CUT D11 L5, L8, L9

19 GTL VR6 or CUT D9 L15, L16, L17

19 LTD VR6 or CUT D9 L15, L16, L17

19 LTD CLASSIC VR4 or CUT D7 L7, L8

19 M REMOVE C73 L8, L5, L3

19 PLUS RV501 or CUT C511 L305, L306

19 PLUS (Plastic Case) RV4 or CUT D8 L11, L12, L13

19 XS CUT D105

20 B&K CUT CD20 & CD21 T11, T10, C60

20 LTD CUT D13

20 PLUS RV501 or CUT C511 L305, L306

20 PLUS (Plastic Case) RV4 or CUT D8 L11, L12, L13

21 REMOVE C105 & C106 T11, T10, C60

21A (Old) CUT D24 L9, L8

21 GTL VR5 or CUT D9 L13, L10, L9, L8

21 LTD VR5 or CUT D9 L13, L10, L9, L8

21 LTD CLASSIC VR4 or CUT D7 L7, L8

21 PLUS CUT 1.5K res. next to TR34 L12, L10

21 X VR207 or CUT D212 L212, L214

21 XLR RT4 or CUT D13 L15, L12, L11

23 PLUS RV501 or CUT D502 L304, L306, L307

25 GTL VR5 or CUT D9 L13, L10, L9, L8

25 LTD VR5 or CUT D9 L13, L10, L9, L8

25 LTD CLASSIC VR5 or CUT D9 L10, L9, L8

25 PLUS CUT 1.5K res. next to TR34 L12, L10

26 CUT D24 L7, L8

28 A CUT CD28 & CD29 T12, L2, L5

29 A (OLD) CUT D24 L7, L8

29XLR VR5 or CUT D14 L15, L12, L11

29 GTL VR4 or CUT D11 L14, L13, L12

29 LTD VR4 or CUT D11 L14, L13, L12

29 LTD CLASSIC VR4 or CUT D11 L14, L13, L12

29 LTD GOLD VR4 or CUT D11 L14, L13, L12

29 PLUS CUT D20 L12

31 PLUS CUT D19 L13, L12, L11

32 XLR CUT CD11 & CD12 L5, L3

33 PLUS VR4 or CUT D17 L11, L9

39 LTD (S.O.S.) RV1

40 PLUS RV104 or CUT D203 L305, L306

40 X RV201 or CUT D203 or C215 L304, L305, L306

41 PLUS VR4 or CUT D21 L19, L20, L21

45 XLR VR105 or CUT D119 L113, L109

46 XLR VR105 or CUT D119 L113, L109

47 XLR VR105 or CUT D119 L113, L109

50 XLR VR5 or CUT D119 L109

55 XLR VR5 or CUT D119 L109

62 XLR VR3 or REMOVE C67 L16, L15, L12

63 GTL VR3 or CUT D11 L11, L10, L9

66 GTL VR2 or CUT D4 L14, L15, L17

66 LTD CUT R54

67 LTD RV4 or CUT D212 L306, L307, L308

77 X VR207 or CUT D212 L211, L212, L214

78 X VR6 or CUT D9 L11, L12, L15

85 REMOVE Q17 L3, T4

86 XLR CUT CD9 L3

CAM 89 ADD 1K res. in series with C110 L13, L12, L9

87 GTL VR6 or CUT D16 L17, L16, L13

89 GTL VR6 or CUT D16 L17, L16, L13

89 XLR VR5 or CUT D14 L15, L12, L11

90 LTD VR201 or CUT D203 L304, L305, L306

93LTD WX VR-3 L16, L17, L18

132 (OLD) CUT Q25 T14, T15, L3, C116, (ssb) R136

132 A CUT CD39 & CD40 R79 (ssb) R87

132 XLR R134 or CUT R125 L3, (ssb)R130

134 CUT D40 & D41 L8, L10 (ssb)VR15

135 (OLD) CUT Q25 T14, T15, L3, C116 (ssb)R136

135 XLR R134 or CUT R125 L3, (ssb)R130

138 A (OLD) CUT D40 & D41 L8, L10 (ssb) VR15

138 XLR VR7 or VR6 VR8, (ssb)CT7

139 VR12 or CUT D63 L12, L10, (ssb)VR15

139 XLR VR7 & VR6 VR8, (ssb)CT7

140 GTL CUT R104 VR6, (ssb)VR7

142 GTL CUT R104 VR6, (ssb)VR7

146 GTL VR5 or CUT TR29 VR10, (ssb)VR6

148 GTL CUT R131 VR10, (ssb)VR11

148 GTL-DX (early prod. model) VR5 VR11, (ssb)VR7

148 GTL-DX (late prod. model) REMOVE VR14 or CUT TR32 VR13, (ssb)VR12

148 GTL-B VR14 RV15, (ssb)RV13

148 GTL-DX (copy ver.) RV12 RV11, (ssb)RV6,RV3

1000 GTL VR6 or CUT D16 L17, L16, L13, (ssb)

2000 GTL CUT R131 VR10, (ssb)VR11
GTL 150 RV14 RV13, (ssb)RV12,RV4




Cobra Power Mods
Radio Try This2000

GTL,2010 CUT TR24 Change R126 to a 2.2k resistor Change R124 to a 4.7k resistor Tune L47,L48,L46,L45,L38 for max RF output AM Carrier Power VR10 Mod Meter VR7 AM Signal meter VR1

142GTL CUT TR32 Change R99 to a 2.2k resistor Change R94 to a 2.2k resistor Adjust L36,L37 for max RF output AM Power VR6 SSB Power VR7 VR1 "S"Meter VR2 Squelch VR3 TX Freq VR12 Mod Meter VR10 TX Power Meter
148GTL+F CUT TR24 Change R126 to a 2.2k resistor Change R124 to a 2.2k resistor Tune L37,L38 for max RF output

29GTL/LTD/CLASSIC CUT D11 Adjust L17,,L20,L21,L16{Some Models},L14 for max RF output Modification: Change stock final to a 2SC1969 Change stock driver to a 2SC1957,{some model use a 2SC2028 rf driver}Remove it Change R123 to a 0.47 ohm resistor Change R58 to a 2.7 ohm resistor Put a jumper across D8{by audio transformer} Change C71 to a 33uf 16volt polarized electrolytic capacitor Put a 47pf disc cap across C57 Put a 47pf disc cap across R55 For a higher dead key place a 100pf disc cap across C62{by rf driver} Key radio and say HEEELLLOOOOOO while adjusting L17,L20,L121,L16,L14 Some models dead key 8-10 watts swing 40-50PEP VR1 rx gain VR2 rx signal meter VR3 squelch VR4 AMC VR5 tx power meter VR6 antenna warning light

25GTL/LTD/CLASSIC CUT D9 Change R76 to a 1k resistor Change R43 to a 2.7 ohm resistor Change R108 to a .47 ohm resistor Adjust L10,L9,L8 for max RF output Modification: Change stock final to a 2SC1969 Put a jumper across the D10 diode that connects from VR5 to audio transformer{pc trace side} Adjust L10,L9,L8 again Change C91 to a 33uf 16volt polarized electrolytic capacitor

Cobra 18RV, 23 Plus Change R505 (3.3k) to a 1k,
Change R310 (2.7Ohm) to a .47Ohm, Retune L305, L306

Cobra 90LTD Cut D203, Change R320 (5.6Ohm) to a 1 Ohm, Change C335 (100pf-NPO) to a 150pf-NPO, retune L304,L305,L306


Receive Boost

Cobra 29
1. Locate pin 14 of the PLL chip, and the Positive (+) side of C-12. 2. Install a 22k-220k ohm resistor between these two points. The smaller the value, the more the receive is boosted. 3. If desired, this mod may be wired through a switch.





How to make Cobra 29LTD,Classics slide on TX & RX

1)Remove D-18 , R-110 , C131 and R-112. 2)Put jumper were R-110 was. 3)Take orange wire from delta tune and unsolder it from board then resolder it to Tr-23 (Solder to the pin closest to front of board. It should have around 8 VDC on this pin.) 4)Put radio back together and if all is done right you should slide transmit 5-6 KCs up and down. For more slide change D-16 to a 1N-4007



Cobra 2000
No Audio on AM Transmit with good Carrier
The Fix: This problem is more common in the "older" 2000's but is relatively easy to fix. Look for the collector of TR-23, you should read about 4.5 V with a dead key. If you find that this voltage is not present, check on the opposite side of R-120 for 6.5V. Most likely this voltage will not be present; if this is the case, C18 has shorted and needs replaced. This is a 330uf, 10V electrolytic capacitor beside L31. To prevent "future" problems, replace with a 16V.




UNIDEN
PowerPRO 510,520XL CUT D14 Adjust L6,L5,L4 for max RF output
PC66XL CUT D9 Adjust L10,L9,L8 for max RF output
PC76XL CUT D11 Adjust L17,,L20,L21,L16{Some Models},L14 for max RF output
PC122 Adjust VR5 AM Power VR10 SSB Power VR11
GRANT XL & MADISON{UNIDEN 8719PLL} CUT TR24 or R131 Tune L37,L38 for max RF output
GRANTDX EXPORT CUT TR32 AM Power VR13,SSB Power VR12
ZACHARY T.(2816 pll) VR6 or cut D16 Adjust L13,L12,L11 for max RF output
WASHINGTON (858 pll) VR7 or cut D23 AM Power VR8, SSB Power CT7, TX Coils L32,L30,L29,L28
WASHINGTON{MB8719} CUT TR32 AM Power VR6, SSB Power VR7, VR1 "S"Meter, VR2 Squelch, VR3 TX Freq, VR12 Mod Meter, VR10 TX Power Meter


Uniden Power Mods
Radio Try ThisWASHINGTON{MB8719} CUT TR32 Change R99 to a 2.2k resistor Change R94 to a 2.2k resistor Adjust L36,L37 for max RF output AM Power VR6 SSB Power VR7 VR1 "S"Meter VR2 Squelch VR3 TX Freq VR12 Mod Meter VR10 TX Power Meter
ZACHARY T(2816 pll) VR6 or cut D16 Remove C128 (.47uF). Remove TR16. Replace R132 (1k) with a 470 Ohm. Replace R50 (3.9 Ohm) with a 1 Ohm. Re-tune coils L13,L12,L11 for maximum forward power output. Jumper C61 with a 67pF capacitor. Replace TR10 (2SC2029) with a 2SC1969 then tune L16,L17 and spread L14 For even power across band. Remove D13 and replace with a jumper.
GRANT XL & MADISON{UNIDEN} CUT TR24 Change R126 to a 2.2k resistor Change R124 to a 2.2k resistor Tune L37,L38 for max RF output
PC76XL Change stock final to a 2SC1969 Change stock driver to a 2SC1957,{some model use a 2SC2028 rf driver}Remove it Change R123 to a 0.47 ohm resistor Change R58 to a 2.7 ohm resistor Put a jumper across D8{by audio transformer} Change C71 to a 33uf 16volt polarized electrolytic capacitor Put a 47pf disc cap across C57 Put a 47pf disc cap across R55 For a higher dead key place a 100pf disc cap across C62{by rf driver} Key radio and say HEEELLLOOOOOO while adjusting L17,L20,L121,L16,L14 Some models dead key 8-10 watts swing 40-50PEP VR1 rx gain VR2 rx signal meter VR3 squelch VR4 AMC VR5 tx power meter VR6 antenna warning light
PC66XL CUT D9 Change R76 to a 1k resistor Change R43 to a 2.7 ohm resistor Change R108 to a .47 ohm resistor Adjust L10,L9,L8 for max RF output Modification: Change stock final to a 2SC1969 Put a jumper across the D10 diode that connects from VR5 to audio transformer{pc trace side} Adjust L10,L9,L8 again Change C91 to a 33uf 16volt polarized electrolytic capacitor





MIDLAND

79-290 Q-24 Audio limiter RV-7 AM Power RV-8 SSB Power

MIDLAND 77-285
There are two printed ciruit boards for the 77-285. You must first determine which you have. Circuit board "A" This board can be identified because D18 has been cut.To restore full power simply resolder D18 or replace it. Circuit board "B" On the "B" circuit board D18 is intact (has not been cut out).To restore full power, locate D18 and trace the etch. Put a solder bridge between the open pads.





CHEROKEE

AH-100 RV14 SSB ALC RV4 AM Carrier
CBS-1000 VR5 VR14 SSB ALC VR4 AM Carrier
CM-10 VR103(On the circuit board it's just labeled 103) VR502(On the circuit board it's just labeled 502)







GALAXY

Radio DX 2527 VR 1....AM/FM S-Meter VR 2....SSB S-Meter VR 3....SSB Squelch Range VR 4....AM/FM Squelch Range VR 7....SSB Carrier Balance VR 8....RF Meter VR11...Driver Bias VR12...SSB ALC VR13...Hi Power VR14...AMC VR15...AM Low Power VR16...SSB Low Power VC 1....10.240 VC 2....10.240

DX 2517 VR 1....AM/FM S-Meter VR 2....SSB S-Meter VR 3....SSB Squelch Range VR 4....AM/FM Squelch Range VR 5....FM Deviation VR 6....SSB Carrier Balance VR 7....TX Offset VR 8....CW Beep Level VR 9....RF Meter VR10...Final Bias VR11...Final Bias VR12...Driver Bias VR13...SSB ALC VR14...AM/FM High Power VR15...AM Modulation Meter VR16...AM Modulation VR17...SSB Power VR18...AM/FM Low Power VR601..13.8 Volt Power Supply

DX 22B VR 1....AM/FM S-Meter VR 2....SSB S-Meter VR 3....SSB Squelch Range VR 4....AM/FM Squelch Range VR 7....SSB Carrier Balance VR 8....RF Meter VR11...Driver Bias VR12...SSB ALC VR13...High Power VR14...AMC VR15...AM Low Power VR16...SSB Low Power VR21...TX Offset VC 1....10.240 VC 2....10.240
DX 11B VR 1....AM/FM S-Meter VR 2....SSB/CW S-Meter VR 3....SSB Squelch Range VR 4....AM/FM Squelch Range VR 5.....FM Deviation VR 7....SSB Carrier Balance VR 8....RF Meter VR10...Final Bias VR11...Driver Bias VR12...SSB ALC VR13...AM/FM High Power VR14...AM Modulation VR16...CW Tone Level VR20...Final Bias VR21...TX Offset VR601..13.8 Volt Power Supply VR803..AM/FM Low Power

DX 77HML, DX 88HL, and DX 99V VR 1....AM/FM S-Meter VR 2....SSB S-Meter VR 3....SSB Squelch Range VR 4....AM/FM Squelch Range VR 5.....FM Deviation VR 7....SSB Carrier Balance VR 8....RF Meter VR10...Final Bias VR11...Driver Bias VR12...SSB ALC VR13...AM/FM High Power VR14...AM Modulation VR16...AM/FM Low Power VR20...Final Bias VR21...TX Offset Unmarked VR in R189..AM/FM Medium Power for DX 77HML only

DX 33HML, DX 44V, DX 55V, DX 66V, and DX 73V VR 1....AM/FM S-Meter VR 4....AM/FM Squelch Range VR 5.....FM Deviation VR 8....RF Meter VR12...Low Power AM Modulation VR13...AM/FM High Power VR14...High Power AM Modulation VR16...AM/FM Low Power Unmarked VR in R188..AM/FM Medium Power (DX 33HML only) Unmarked VR in C139..Med Power AM modulation (DX 33HML only)

DX 949,DX 959 VR 1....AM S-Meter VR 2....SSB S-Meter VR 3....SSB Squelch Range VR 4....AM Squelch Range VR 6.....SSB Carrier Balance VR 7....TX Offset VR 9....RF Meter VR10...Final Bias VR12...Driver Bias VR13...SSB ALC VR14...AM High Power VR15...AM Modulation Meter VR16...AM Modulation VR17...SSB Power VR18...AM Low Power VC1....10.240

DX 2517 and DX 2527 Symptom:Buzzing or motorboating sound in either the transmit or receive Problem: TR602 is oscillating Cure: Replace C602 with a .01uF cap {Cap is located in the power supply board}
RG 66,99,DX2517 Replace Q54 2SB754 60watt 7A with a higher power 2SB817 100 Watt 12A. Derating of this component will cool operation, provide better voltage stability,decrease wobble, allow voltage increase to 14.5 volts comfortably. (replace 10 volt caps in this section of the radio to a minimum of 16 volts before increasing supply voltage to this level)and provide faster swing rise time, Replace Q37 2SA473 to a 2SA1012-0 or ECG153 this will improve the clarity and volume of the modulation and it will also run a lot cooler.

Disabling Talkback

DX 33HML
Disconnect wire located in TR30

DX 44V
Disconnect wire located in J15

DX 66V
Disconnect wire located in J15

DX 73V
Disconnect wire located in J15

DX 77HML
Disconnect wire from resistor R244

DX 88HL
Disconnect wire located in R189

DX 99V
(original type echo board) Disconnect wire located in TR35

DX 99V
(smt type echo board) Disconnect wire located in J15 next to R244

DX 11B
Disconnect wire from diode located in R244

DX 22B
Disconnect wire from diode located in R327






Talkback Mod

Talkback can become distorted if these radios have been "peaked," and there is no cure because the talkback just amplifies what goes to the RF section. Try adding a 470k ohm resistor from junction of C155/R207 to the junction of C187/R235 on the solder side of the board. This will also give you clean talkback on SSB and FM. Try different values of resistance to get the amount of volume you want. The less the resistance the louder the talkback will be.




DX 2517 Symptom:
Talkback squeals when mic gain is at max
Problem:
Excessive drive to IC-8 pin 4
Cure:
Replace R-221 with a 200K ohm resistor





Roger Beep Mods

The tone and time of the roger beep on the 10 Meter mobiles can be changed as follows:


The roger beep tone is controlled by R181 which is 220K ohms:
for a higher tone try 150K to 200K ohms
for a lower tone try 270K to 2M ohms
The roger beep time is controlled by C134 which is 2.2uF@16V DC:
for longer time try 5uF or 10uF@16V DC
for shorter time try 1uF@16V DC





Clarifier Mods

Some people have asked how to make the fine clarifier control track on transmit and receive like the coarse clarifier control. Below are the mods for our 10 Meter SSB mobile models (DX 77HML,

DX 88HL and DX 99V) as well as the mod for the DX 2517.


10 Meter SSB Mobiles
Remove R141
Remove D38
Solder bridge J106 pin 54 to 8 volts

DX 2517
Remove D68
Remove R113
Add jumper from R113 to 8 volts


DX 2517 and DX 2527 SYMPTOM:
Buzzing or motorboating sound in either the transmit or receive
PROBLEM:
TR602 is oscillating
SOLUTION:
Replace C602 with a .01uF cap
Remove C608





GENERAL

WARNING
I ASSUME NO LIABILITY FOR DAMAGES RESULTING FROM THE USE OF THIS INFORMATION AND IT IS NOT INTENDED TO BE USED TO EXCEED FCC SPECIFICATIONS,THIS IS FOR INFORMATIONAL PURPOSES ONLY!..



General Lee

TR32 or VR14 AMC
VR12 SSB ALC
VR13 Hi Pwr
VR16 Lo Pwr
L33 Tune For Max Swing
For The Modulator Effect Unsolder one end of R238 and solder a 1N4001 Diode {the unbanded side} to the resistor then solder the banded end to the circut board where you removed R238 from and then check out the swing and audio.
Convert the General Lee to CB Band
To Get CB Channels remove the top cover of the radio {circut board side} and with the front facing you look to the right you will see 4 small resistors soldered to the chip remove them and you will now have the cb band.


General Grant

Q39 {next to JP58}AMC
VR14 Power{note:DO NOT ADJUST THIS TOO MUCH OR YOU CAN DAMAGE THE AMP.}What i do is turn the rf power on the front of the radio all the way down then i adjust VR14 to about 3 watts dead key. Then look at the swing!
Convert the General Grant to 480 CH
1. Unplug and remove the band switch and replace with the one in the radio box.{Dont forget to put the sticker on the face plate}
2. Change J28{in the middle front of circut board} to were it shorts Pin 2,3.
3. Follow the wires from the back of the tone switch to were in plugs into the board{at J4 } then remove the plug and then find J2 {which is in behind the shorting block J28} and plug it in there.