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

this is my first post hope i do it rite. i have a superstar 3900 plus.it was working fine when i went to bed. when i got up and turn it on today it wont key up . theres no key up on am or ssb. receive on the radio is fine.any ide where to start on this radio to fix the problem. thanks for any help---unit

First you may want to check the mic cable. Start with the lil things first.

marveylus22 wrote:First you may want to check the mic cable. Start with the lil things first.

ok i checked the mike on another radio and it work fine. i did notice while i had the radio opened up looking arround the radio key up for just a second and then nothing again. have tryed many working mikes on this radio and still nothing. what next. just to update this alittle i installed a new c2166 driver and still the same no key up on am or ssb . one thing i did notice is that if you hook an exsternal spaker in the pa jack and switch the radio to cw there is no audio comeing out just a small hum. where do i go from here .thanks for any help---unit. ps where can i locate the keying transistor on this radio. i think its d-77. i guess no one has any info on this radio thanks---unit.

unit551961 wrote:

marveylus22 wrote:First you may want to check the mic cable. Start with the lil things first.

ok i checked the mike on another radio and it work fine. i did notice while i had the radio opened up looking arround the radio key up for just a second and then nothing again. have tryed many working mikes on this radio and still nothing. what next. just to update this alittle i installed a new c2166 driver and still the same no key up on am or ssb . one thing i did notice is that if you hook an exsternal spaker in the pa jack and switch the radio to cw there is no audio comeing out just a small hum. where do i go from here .thanks for any help---unit. ps where can i locate the keying transistor on this radio. i think its d-77. i guess no one has any info on this radio thanks---unit.

its hard to belive know one knows anything about this radio or how to fix it.

Is the RX/TX led change colour when you key-up?

What is the voltage at the collector pass regulator TR51 in the TX mode on AM; this is the transistor, which is bolted to the chassis near the rear right corner

if you got it to key up briefly will wiggling around on pc board..you have a poor solder connection....with unit powered up.key it up and bump on the foil side of pc board with the but end of a plastic handle screwdriver..if you see it key on your meter..then find you a plastic scratch tool..i use a old broken plastic tuning stix..just dont use nothing metal..lightly scratch and bump around until you get tx back..isolate the problem area..and resolder

Rick wrote:Is the RX/TX led change colour when you key-up?

What is the voltage at the collector pass regulator TR51 in the TX mode on AM; this is the transistor, which is bolted to the chassis near the rear right corner

could u give me the right voltage readind for tr51 . and also do u know what number the keying diode that is near the mike socket. a freind said it mite be bad. thanks for the help youre giveing me.---unit

ramblingman wrote:if you got it to key up briefly will wiggling around on pc board..you have a poor solder connection....with unit powered up.key it up and bump on the foil side of pc board with the but end of a plastic handle screwdriver..if you see it key on your meter..then find you a plastic scratch tool..i use a old broken plastic tuning stix..just dont use nothing metal..lightly scratch and bump around until you get tx back..isolate the problem area..and resolder

i only saw it key up once and never again . i have done what u said with no go. still the same .just to be on the safe side i bought 2 more finals and a driver .installed them and still no am or ssb power.i can lay another radio beside it and when i key the mike i can see the needle on the other try to move but thats it. iam almost ready to get out the big hammer,lol thanks for helping me---unit.

I will try one more time.

Is the RX/TX led change colour when you key-up?

What is the voltage at the collector pass regulator TR51 in the TX mode on AM; this is the transistor, which is bolted to the chassis near the rear right corner. and what is the voltage at the collector of TR38. It will not help you asking what the voltages should be, we need to know what you have.

Rick wrote:I will try one more time.

Is the RX/TX led change colour when you key-up?

What is the voltage at the collector pass regulator TR51 in the TX mode on AM; this is the transistor, which is bolted to the chassis near the rear right corner. and what is the voltage at the collector of TR38. It will not help you asking what the voltages should be, we need to know what you have.

yes it will chang colors when i key the mike.

unit551961 wrote:

Rick wrote:I will try one more time.

Is the RX/TX led change colour when you key-up?

What is the voltage at the collector pass regulator TR51 in the TX mode on AM; this is the transistor, which is bolted to the chassis near the rear right corner. and what is the voltage at the collector of TR38. It will not help you asking what the voltages should be, we need to know what you have.

yes it will chang colors when i key the mike.

dont give up on me iam trying lol---unit.

What is the point in putting the quote from the last message in to your message. this is pointless.

The guys which is trying to help you ask you some questions if you cannot answer them. You cannot expect to help you and maybe it is best to take the rig to someone who can repair for you.

James.

well to start with i didnt no i was to use the post reply. but yes the tx light changs color when you key the mike. i was told by a good freind of jp when i joind this site that i would meet some rude people.but hey have a nice day unit.

I do not think that James is being rude, I think he is pointing that you did not answer the question put to you.

I did ask you what is the voltage a the collector of TR51 on AM in TX mode and what is the voltage at the collector of TR38 in TX.

If you can not answer the questions then it would be best to get the radio to some one which can fix it for you.

sorry for the remark james .i guess i was haveing a bad day.i got the radio up and running. it was a bad tr51 it had 13v first pin and the other 2 where dead. i replace the tr51 b754 with a new 1 and problem fix. once again sorry for the remark.have a nice day unit.