drifting when i am talking....

[KD2GOE]

ok I was talking to some people on USB and I was getting a report back that I was drifting when I was talking. I every time I would start off talking it was fine then as I would go on jaw jacking it would drift out.. is there a quick part swap to fix this..? like the AM reg?
I just got this radio back from the shop and it is all tuned up.. :glare:



This is happing on my RCI-2990 I am starting to think of just selling this thing if it is giving me all this trouble...

 

[TonyV225]

What is happening is and you talk for awhile or at a longer transmit it warms up and when parts heat up the value can change.Ife never had a 2950 chassis radio do this but know they can which is why I do not cut or open the clarifiers anymore and just center the the transmit frequency so I dont have to worry about this issue.

Also you will notice that when you first turn a radio like this on that they may drift a bit until they warm up which is why I make it a habbit to turn them radios on and let them sit a stabilize if I know Im going to be using them.

I do it with my HF rigs and amplifiers aswell even though they dont drift like that but even the rigs I have with the TCXO Stabilizing Crystals in them get turned on to sit for a bit before use.

 

[2RT307]

Hi mkube, glad to see you got the 2990 fixed. Did you replace the finals? Also, are you running the fan kit on this rig? I hear it is highly recommended.

73,
RT307

 

[KD2GOE]

What is happening is and you talk for awhile or at a longer transmit it warms up and when parts heat up the value can change.Ife never had a 2950 chassis radio do this but know they can which is why I do not cut or open the clarifiers anymore and just center the the transmit frequency so I dont have to worry about this issue.

Also you will notice that when you first turn a radio like this on that they may drift a bit until they warm up which is why I make it a habbit to turn them radios on and let them sit a stabilize if I know Im going to be using them.

I do it with my HF rigs and amplifiers aswell even though they dont drift like that but even the rigs I have with the TCXO Stabilizing Crystals in them get turned on to sit for a bit before use.

yeah I understand this was after it was on for 2 hours..
and after I am done talking it is fine then when I start up it drift out..

I have a small fan I was thinking of putting a fan inside the radio to move air around do you think that will help???

 

[KD2GOE]

Hi mkube, glad to see you got the 2990 fixed. Did you replace the finals? Also, are you running the fan kit on this rig? I hear it is highly recommended.

73,
RT307

HI I guess you can call it fixed. The finals are the stock 2SC2990 and I tested it on a 3ed antenna and it works fine on that one... so I need a new antenna.. I got bit by the BAD A99

 

[Robb]

It could be caused by unstable voltage in the PLL circuit or a crystal that has gone or is going south. But by no means is that a definitive diagnosis, just a knee-jerk response to this kind of issue.

Strange that the tech that worked on your radio failed to notice this problem when he aligned it after he repaired it. That kind of problem is usually quite easy to detect at that point.

In addition, ambient room temperature can make a huge difference too. Best to operate from a warm room. If the room is cold and you begin to talk, parts heat up and change their value and it will drift. If you didn't have the clarifier unlocked, than this condition will only serve to make these problems worse. Any radio will be affected by temperature, some more than others.

 

[KD2GOE]

It could be caused by unstable voltage in the PLL circuit or a crystal that has gone or is going south. But by no means is that a definitive diagnosis, just a knee-jerk response to this kind of issue.

Strange that the tech that worked on your radio failed to notice this problem when he aligned it after he repaired it. That kind of problem is usually quite easy to detect at that point.

In addition, ambient room temperature can make a huge difference too. Best to operate from a warm room. If the room is cold and you begin to talk, parts heat up and change their value and it will drift. If you didn't have the clarifier unlocked, than this condition will only serve to make these problems worse. Any radio will be affected by temperature, some more than others.

ok ill have a look at the voltages to see if there stable.. and I have a crystal that some one in the passed soldered a wires to it from the ground strap but on the crystal so I can suspect that crystal I think.. it was last that night ill just know USB is doing it so ill see if LSB is drifting as well that may help to pin point it so I can take this back to the tech....

man I need to sell this car so I can get tools to do this my self. had 2 people look last week...

 

[Robb]

If you go changing out these parts in the PLL willy-nilly, it will then throw the radio out of alignment - I can assure you.

Think I would concentrate on operating in a room with a warm environment and see if that doesn't do the trick - first.

 

[KD2GOE]

ok it is more or less confirmed I am only drifting on USB just spent the last 2 hr talking to my friends.
I use LSB more then USB but there is a few people on USB 40

so I guess just running LSB is a quick fix for now.. I can call "RADIO SHOP SUPPLY" they have the parts..

so transmitting on USB is on the blink what can I look for?

guy had 4 wires soldered on I removed them but the 1. ill remove that one tonight it runs to an add on beep board.

 

[9C1Driver]

If you like the radio and will be keeping it I would send it off to a tech that knows his way around the RCI radio's. The 2950/70/90/95 radio's are complex and a good tech can trouble shoot specific problems.

The first step with yours would be a complete factory alignment, here is a link for the process. If you don't have the proper equipment then it's time to send it off. You can start at page 20 of the service manual. An alignment should solve all your problems unless a part has failed, then what ever part it is will need changed.

Ranger RCI-2995DX

 

[KD2GOE]

If you go changing out parts willy-nilly, it will then throw the radio out of alignment - I can assure you.

Think I would concentrate on operating in a room with a warm environment and see if that doesn't do the trick - first.

I assure you I will not be swopping parts out willy-nilly. but I am trying to make the most educated guess to why it is doing this.

When I sell my car I may just suck it up and send it out to a service place that deals with this type of radio if all else fails...

 

[KD2GOE]

If you like the radio and will be keeping it I would send it off to a tech that knows his way around the RCI radio's. The 2950/70/90/95 radio's are complex and a good tech can trouble shoot specific problems.

The first step with yours would be a complete factory alignment, here is a link for the process. If you don't have the proper equipment then it's time to send it off. You can start at page 20 of the service manual. An alignment should solve all your problems unless a part has failed, then what ever part it is will need changed.

Ranger RCI-2995DX

Thanks but that's not the right radio I have a RCI-2990 it is an older ver and I do have a link to the right radio.

I am not going to adjust any thing in this radio because I don't want to shop that worked on it, say I messed it up.. I may just take it back and explain what it is doing..

when I took it in the first time I told them to do the alignment and look it over for any faults...

 

[Robb]

The radio uses the same crystal in USB as it does in LSB; so that is not the problem.

Someone may have added ground wires to the crystal, that is in no way an indicator of its failure.

If I were to test anything at all, I would put a voltmeter on the VCO voltage and monitor it and see if it remains stable.

 

[KD2GOE]

The radio uses the same crystal in USB as it does in LSB; so that is not the problem.

Someone may have added ground wires to the crystal, that is in no way an indicator of its failure.

If I were to test anything at all, I would put a voltmeter on the VCO voltage and monitor it and see if it remains stable.

ok but that adjustment can next to it is the TX for USB and the plastic inside is melted a little bit.
Would you say it is worth a shot for $4 part? I can order it and have it on hand if the shop wants to through it in.

 

[Robb]

I would say that if it were of any consequence to the guy that aligned your radio, he would have already replaced it before he aligned it. Replacing it now will in no way change your radios drift problem one way or the other, other than throwing the radio out of alignment once again because it will then need to be re-adjusted.