Using the rci-2950dx on cw question

[dc2rf]

Has anyone on the forum used the RCI-2950DX in the cw mode? I realize that the radio has that mode thrown in as an afterthought, but I am using it on cw.

On the positive side, I notice that there was an attempt by the designers to narrow the bandpass of the receiver in that mode. You can hear the difference in the rcv audio when you switch from lsb to cw.

The negative for me is that besides the normal sidetone you hear when keying, you also hear an annoying "thump" from the speaker with every keydown/keyup. It's really aggravating to listen to this during a QSO. I understand that the radio is listed as being "semi-break-in" for the cw mode.

Has anyone using this radio for cw noticed this? Anyone care to suggest a fix to eliminate the thumping so only the sidetone can be heard?

p.s. Please, no "why don't you get a real ham radio for cw" comments. Thanks

 

[Mudfoot]

I've made a bunch of CW contacts on my 29XX rigs. Great fun. Sorry, I have not experienced your speaker issue.

 

[dc2rf]

Hmmm. I get a distinct "thump" in the spkr. with every keydown, besides the sidetone.

Guess I'll have to bring out the test equipment. I'm thinking that maybe DC is passing through the speaker along with the audio tone.

Just my first guess.

Thanks for passing along your observation with your radios.

 

[CTStallion]

Hmmmm, could actually be the speaker itself; the material may not be as taught as possible, thereby causing a "thump" as you say.

Have you tried either:

A. - An external speaker

or

B. - A set of headphones plugged into the external speaker jack

.... just to see if you still hear the 'thump'?

 

[dc2rf]

Good advice to try another speaker. I haven't, but since the thumping is still there when no external speaker is used (using the internal speaker) I figure it's not a speaker issue.

I may try inserting, in series, a capacitor (say 2uf) with the external speaker. That would block any dc component that maybe passing through the voice coil.

That would test my "dc" theory.

 

[dc2rf]

Uhh oohh. The plot thickens.

I had an "accident" with the radio awhile back. I had the radio open and was checking some voltages with a meter. The meter probes slipped, and when I put it back together, I found the radio would not key up in transmit again.

Oh crap.

I had to troubleshoot and find the problem, order the part online, wait a week for arrival, then replace a keying transistor. I replaced the transistor, the radio keyed, and I considered that I fixed the radio myself a "win". It was an expensive mistake, both in my time and material (but it would have cost more if I sent the radio in for repair).

Ok... long story short.

Perhaps my "win" wasn't a total and complete victory. Now that I think about it, that thumping in the speaker when operating cw may be a symptom of another component that was ruined along with the keying transistor. Come to think of it, even when I key the radio with the microphone to talk, there is a "thud" sound from the speaker the instant I key the radio.

I'm postulating that the speaker is not properly muting when the radio switches into the transmit mode.

Btw, the transistor that was ruined was Q49 on the parts list. I would wager that I need to find another bad component that was also ruined when Q49 drew that heavy current because of the short.

great...

It was hard enough to find the bad transistor. It had no physical signs of "distress". It was pure troubleshooting logic to find it.