The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

ramblingman

check diode d-66 for open or short..d-66 is the rf meter detector...but first check vr-8 variable resistor to see if it is adjusted right..vr-8 is the adjustment for tx meter...if it has no effect check d-66..also check vr-8 for open condition..and also check to see if solder connections are good at...

ramblingman

i forgot to ask,,you did check the mic right????i have seen the shield get together with the rx or tx wire on inside of mic or at plug...and cause this sympton....always check the simple stuff first you know////

ramblingman

hi there,,it sounds like the tx rx switching transisot shorted.also should check diode d-77..the rx tx switching trans.,are tr-36 and tr-38..the part numbers are 2sa-1282.if you have a v.o.m. check the voltages at tr-36 and tr-38 and get back with us..............also check d-77 for short or open co...

ramblingman

hi there...does it register on rx and no tx..or is it not working in either

ramblingman

i did this mod on a cobra 148gtl one time.and the radio actually had more output with the 2sc1969,than with the erf2030.might have better luck on the galaxy

ramblingman

hi there,,yes, you need to replace the bias diodes with 1n4148 diodes..also remember the diodes will have to put in reversed than what the original diode are.....................ramblingman

ramblingman

hello to all,,and i would like to take a few moments to wish everyone that takes part is this forum.a very merry christmas and great new year..and to all that take time out from there busy schedule,to make this forum a success..to especally rick and other tech helpers who have been a great help to m...

ramblingman

hello,i have fixed those by just reheating the solder joints.but like they say most times you have to completly replace it..if you dont have a new one,try to find a junk radio,that they work in,and use it.

ramblingman

will it transmit in ssb.or does not tx at all am or ssb...............ramblingman

ramblingman

hello rooster,,i would sure go with the 2sc2166 for the driver if it was me..also i am not sure,but i think a 2sc2086 with sub for the 2sc2538..also the 2sc2314 might sub,only thing to remember youll have to install reversed because the bias is reversed..the 2sc2538 is b-c-e- while the 2sc2314 is e-...

ramblingman

sounds like it is probably tr-45 o/c,,from the voltage readings.tr-45 is the pre-driver.

ramblingman

hello out there..first of all,you have checked all the simple stuff first right..like the mode switch,it not got a loose wire.maybe its staying in ssb mode even when you switch to am.should be able to tell that though from your incoming rx audio.or a bad solder connection,these boards are well noted...

ramblingman

thought id leave a update on this radio..found the problem.bad solder connection in the vco area.....thanks for the help rick......ramblingman

ramblingman

hello all..i have a connex 3300 with the ept-360014b pc board.this is older unit with only single final output. the unit output power is good..dead keys about 2 watt and swing 20..but on rx and tx audio,i get a solid buzzin or hummin sound that overtakes the incoming rx audio..and on tx is the same....

ramblingman

when you key the radio does the on the air light up,and do you hear the light pop of the key or not..

ramblingman

hi there,,is the noise in both rx and tx audio..or just in the tx audio

ramblingman

hey there,,,if i were you if i could get one..id replace the 2sa1012 with a 2sb754 which is a 60 watt or a 2sb817 which is a 100 watt device..it will be more stable and run cooler too............................ramblingman

ramblingman

hello,,,is the anl/nb helping at all when switched on..id bet,if this radios been modded much,this switch has been disconnected.to hook up talkback/noise toy or something like this in the past..and your running with no noise reduction.in turn it is picking up interferance from pc or other electrical...

ramblingman

hey there,,,sounds like it is stuck in transmit mode..if so you have a shorted switching diode..............................ramblingman

ramblingman

hello,,is the fuse blown,and does it blown the fuse instantly when you power it up..you might have a rectifier diode shorted,on the power supply board..some have four diodes in series,and some radios just have one bridge rectifier..square black chip with four legs attached to power supply board.chec...

ramblingman

hi there,,the pc board used in the melanka is the same pc board used in the galaxy 33 hml mobile unit...ept-360014b,,so go to cb tricks,then go to galaxy,,then to 33 hml...it will be the same radio,just in a base radio case.i would be looking in the area of the regulator..2sb754,,or in some cases th...

ramblingman

hello guys,,how is everyone,fine i hope...i got an old regency cb701 base station 40 channel unit..i am having abit of trouble with..maybe someone has had similar trouble,or has a idea what could be causing the trouble..the radio recieves fine..and dead carrier is fine..but the modulation is real we...

ramblingman

hello there guys.i have noticed most if not all the time.when the audio chip shorts out.you will find a small pin hole burned out in the center of the audio chip.side of chip facing the inside of the radio..tell tell sign it is toast.....take care ramblingman

ramblingman

hello,,the white wire should be the audio wire,the red wire should be the transmit wire,the brown wire should be the recieve wire,the blue wire is you switch wire..for 5 pin common,should be as follows..pin 1 is the audio wire or white wire.pin 2 is the shield wire.pin 3 is the recieve wire or brown...

ramblingman

hello guys,,,i have a cobra 89 xlr,it is stuck in transmit mode..i am pretty sure it is the tx switching transistor.but i dont have a schematic on this one..does anyone know,what the switching transistor pc number is for this radio..any help is appreciated...thanks guys,and good day to ya from the d...

ramblingman

hello there,,welcome to the forum..i would say that on the first 25 youve described,the problem is probably a poor loose solder connection..find you a plastic scratching tool,power up the unit,and gently scratch around on the solder side of p.c. board,until you find the general area,,solder all sold...

ramblingman

hello guys,,i have a cobra 29 ltd,,i am having alittle trouble with..it had no receive audio,and no am modulation..did the p.a. jack test..it had no audio at first..so i changed the audio chip and the shunt capacitors..now on the pa test i have low audio,but still not right..now i also have low leve...

ramblingman

the driver is a 2sc 1957,,also you can use a 2sc 2314.

ramblingman

hi there,,,thats to much drain on driver,,must be something dead short before driver stage..id check the pre-driver.

ramblingman

hello,,for no tx audio,with good dead key.check c-18 for short

ramblingman

hello once again....have you noticed when you dead key,does the meter light dim??

ramblingman

hi there,,,i guess you know there is alot more involved in this mod than just changing the driver and final..here is the mod,,so just reverse it to remove..remove l-40,so youll need to replace l-40,remove c-149,,so youll need to replace c-149..remove r-181,,so youll need to replace r-181..install ju...

ramblingman

hi guys,,,i just bought one of these old rigs a couple weeks ago..it was working pretty good to begin with.just wasnt doing much wattage..so i decided to tune it abit..so i found a manual on it,with the proper tuning locations,all was well until i got to t-10 tuning can.i which i broke the adjusting...

ramblingman

possibly shorted or open fet 1 and or fet 2..try lifting the collector of tr-13 and tr-11 and see if audio returns.

ramblingman

hello,and welcome to the forum......well first of all you should never jumper out anything..i know alot of these mods tell you to jump out anti spiking diode and resistor that regulates voltage to the driver final..but these are in the circuit for a reason.and jumpering these out your only asking fo...

ramblingman

hi,,,when you key up the mic,,,does the light in the meter go dim...also does your tx and rx switching lights work properly..red tx light when keyed,,green rx light when in receive mode..

ramblingman

q51 is the am modulator/regulator.it is the large three legged transistor bolted to the right rear rail of radio-with knobs facing you...q51 is a 2sb-754..check for your 8 volt source....also if you need a schematic they have it on cb tricks GO TO CBTRICKS.COM THEN CLICK ON RANGER/RCI RADIOS THEN CL...

ramblingman

hi there,,,sounds like the am regulator has gone bye bye...

ramblingman

hello,,welcome to the forum....when you say you have tx,,does that mean you have a dead key carrier,and no tx audio...or both tx carrier,and tx audio..just no rx audio?????

ramblingman

hello;.does your s meter indicate received signal..like on a know busy channel say 19....also if you have a external speaker,plug it into the pa jack in back of radio,,put radio in pa mode,and see if you get any audio through the speaker.this will let you know if your audio chip is shot...but it sou...

ramblingman

hello,,,welcome to the forum.....aint trying to be a smart *ss,,,but you do have your anl/nb switch on right.....if not,,youll always have some noise in the receive,,especially in day-time,,skip is bad right now,you know.....

ramblingman

you can get them from rf parts out of cali...but only bad thing about that you have to have a minimum 25.00 order....do you have any old parts radios laying around..if so just take one out of it....if you cant find any anywheres else,,let me know,,and give me your address and i will mail you one.......

ramblingman

hello there,,and welcome to the forum..tr-32 is the amc shunt,,,and tr-53 is the amc amp,,,they are both 2sc-945p transistors....depending on which transistor was pulled...some remove tr-32,,and some remove tr-53...i is better not to remove either one...but if i was gonna remove one,,take out tr-53....

ramblingman

hi there,,,i was checking the schematic,,and i had another thought...l22,,l22 is off trace of pin 8 of ic-10..i have had radios before,i which,the tuning cans as l22 were not completly,through the p.c.b.at factory and over time,,it loses its ground,as very little solder is holding...try heating l22,...

ramblingman

nte-153 or ecg-153 are suitable subs..but i have seen the 2sa-1012 put back where a 2sa-473 was...so i think it will work with no problems..

ramblingman

hi guys,,,yes i did the erf-2030 final mod. on my 148 gtl,it was a older model...and i tell you i got very poor results..it was doing better with the stock final..as far as swing wattage..i dont know,,maybe youll have better luck...

ramblingman

to desensitive the amc circuit..change r76 to a 1k ohm resistor,,,change r43 to a 2.7 ohm resistor,,change r108 to a .47 ohm resistor...r76 is located near the mic socket.....this will make the mic gain very sensitive but it will also pick lots of background noise up,,especially if you running it as...

ramblingman

hi,,,,i could be something as simple as the mode switch..ive had them before cut out,because of a dirty mode switch..spray with contact cleaner and flip in back and forth a few times,and that might be all it takes..

ramblingman

ok,,,to start with,,if swing kit is installed right,you shouldnt have a 5 watt dead key..it should be like 1 to 2 watts max..and then swing from there about 15-18 depending upon meter..every meter shows different readings..but you need to get that dead key down.for the swing kit to be working proper...

ramblingman

yes,,the cobra 148 gtl comes factory with a 2sc-1969 final,,and a 2sc-2166 driver...have you tried the npc mod on it yet???????

The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Search found 331 matches

wishing everyone merry xmas

connex 3300-bad hum on rx and tx audio

regency cb701--weak modulation/talkback through speaker

cobra 89 xlr-need some info..

help with a cobra 29 ltd-no audio

old tube type -robyn t240d-no tx