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

hey ramblin man i replaced all the caps on the dx-44 like you said and still i have no audio i can key up but not modulate and i can see on the meter when people talk what else could be causing no sound

hey tim,did you try what i told you on the post below.change the am dector diodes..look on the post below,(helllppppp ramblinman)

no sir i havent tryed that yet but should i change all of the diodes mentioned and on the 66 it was working great then all of a sudden it started cutting in and out again after turning it off and back on a few times it has quit for now and is there a way to turn the talkback down some on the 66 i have to run my mic gain about halfway to keep it from squealing thanks

should i replace the x-1 10.240 crystal if so where could i buy one i have a electronics store near me that sells resistors,caps,transistors,audiochips,etc,would they sell these crystals and should i replace all diodes listed on the link you gave me

hey tim,dont replace 10.240 mhz crystal,that wont get you anywhere.as far as the diodes go.its d-23 and d-24,they are your am audio detector diodes.also try lifting collector of tr-39,and see if recieve returns....try these two things,and let me know how goes.

ok i,ll replace those diodes and which leg is the collector on tr-39 do you mean unsolder the collector and lift it from the board

tr-39 is the cw audio kill switch,the collector is the center leg.unsolder it and lift it out,disconnecting it.your radio does have cw mode doesnt it,or no.

no sir it doesnt have cw mode i,ve took the 2 diodes out do you know the value or part number of them i was thinking of going to radioshack to see if they have any and is there a certain way they go in and should i buy a new transistor if you think radioshack might have one

the part # for d-23 and d-24 are 1n60p,they are your am audio detector diodes.also forget tr-39,being yours dont have cw mode,also have you checked around your volume control,for loose wires of maybe,something shorting there.

ok can you get these parts at radioshack and do they go in a certain way i havent checked the volume wires it seems to deadkey but not modulate

yes,they have to go in a certain way.the black strip side,is the cathode of the diode,you should see on the pcb,a mark that lets you know which way the cathode goes.first lets check the diodes.with your vom set to the x10 ohm position,with the red lead on the cathode and the black lead on the anode(unbanded end)it should you should read about 3/4 scale,with the black lead on cathode and the red lead on anode you should read about 1/4 scale.if on either side it reads dead short(full scale) the diode is shorted,it needs to be replaced.if on either side it reads open(0) it needs replacing.but if reads like above said.its o.k.it does not need to be replaced.if your gonna do much radio repair,you gonna need to learn how to check parts.you just cant start replacing things left and right.thatd get quite expensive.so check them and let me know wha you find.as for the substitue,ill look it up and get back to you.i would think a 1n914/1n4148 would work,if so you should be able to get them at the shack//

If it is a case of no audio in RX mode, then check TR15 and 16 you may find one is O/C. If this is not the case check to see if you can hear the squelch pop when you open and close it. It would be helpful if you could let us have the voltages at TR15 and 16 withe squelch open and closed. Let us know what you find.

Is it TX ok?

Rick.

the ohm meter i have is a cb instruments gmt-12a with settings of dc v 10-500.ac v 10-500,dc ma-0.5-250 and ohm x1k is this a good meter to test with

well with the red on the banded side and black on the other end it shows the meter almost all the way over and with leads reversed the needle just barely moves the only way i can check them is with the meter set to ohm x1k is this the right setting or do i need a different meter

i,m sorry rick and ramblin man i,m trying to learn where would tr15,and 16 be located at and what setting should my ohm meter be set on

the diodes are good,reinstall them and go with ricks suggestion next.ck tr 15 and tr16 for open conditions...

since the tr,s have 3 legs how would i go about checkin g them and where are they located..thanks

by the way on the audiochip i lost the little plactic cover that sits behind the chip so i made one out of plastic could this be a problem

got a stupid question but where is tr-39 there is a tr-3 something near the mike socket but there is a plug that goes into the board covering up the number..also where are tr-15 and 16

i just found tr-39 still looking for tr-15 and 16

sorry i forgot about not checking tr-39 now i need to find tr-15 and 16 and how do i check them and also the volume wires are on good and tight

ok,rick,ramblin man i,ve found tr-15 and 16 now how do i check them since they have 3 legs and do i need to take them out to check them sorry to bother you guys so much i just want to learn

Trying to follow your fault description is not easy. First, if you have changed the audio chip, have you checked that the PA works? Before you do any more make sure that the PA is working, you can do this by plugging it a ext speaker in to the PA socket and talking in to the mic, you should hear your self, if not check the audio chip as there is something wrong around the audio chip, check all solder connections and make sure the audio chip is in the right way round.

Question cause the fault in the first place.

Rick

no sir the pa is not working at all ...i can see the needle move when people talk i can deadkey but i get very little if any modulation checked volume wires they are good and tight squech is turned all the way down rf gain is wide open have tryed the internal speaker no sound have tryed a ext speaker that works on all my other radios but not this one put the factory brand audiochip in not a nte brand i,ve put audiochips in several other radios before and have never had any trouble till this radio..tell me what to check or replace and i,ll do it i made sure not to solder over any audiopins that shouldnt touch

Is the audio chip getting warm?
Can you give us the voltages from the pins1, 2, 4, 5, 6, 9, and 10 the audio chip?
Pin 1 is the one nearest to C195 and pin 10 is the one connect to C146.
Alternatively, just try replacing the audio chip.

Rick