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

I have a RCI 2950DX problem is only has 1-4 watts power on AM? FM has 2-8 watts SSB has 20 watts. Any ideas AM regulator or what could it be? Thanks.

Has it always been this way or has it just suddenly changed ?

The radio has two VR adjustments inside it, for the minimum and maximum power levels (to adjust what range the front panel control allows), off hand I can't remember the pot numbers, I seem to remember that they may even be marked as "lo" and "hi" or "min" and "max"

I bought it this way not knowing it was like it is. I can adjust the vr pots for FM and go as high as 10 watts but when on AM they only go as high as 4 watts max? The vr pots are for both am/fm.

What is your peak power on AM?

A common fault, 9 times out of 10 it’s the two finals have gone low gain, but before you change them check the voltage at TP8 in AM/ FM, and SSB.

Adjust VR15 AM/FM APC for 5.60 volts at TP8
Adjust VR19 SSB APC for 12.40 volts at TP8

With the above settings, you should get 10 watts on AM/FM and 25 watts on SBB.

If the power is still low I would changes the finals and the driver.

Rick wrote: With the above settings, you should get 10 watts on AM/FM and 25 watts on SBB.

If the power is still low I would changes the finals and the driver.

I get 10 watts FM and 20+ on SSB but AM only 4 watts max no forward swing? That still means finals still could be bad? Maybe something else wrong with it besides finals? Thanks.

So what voltage do you have at TP8 in AM? and can you the voltage with VR15.

The radio may have some crude AM swing mod, check the components for any non stock parts.

Rick wrote:So what voltage do you have at TP8 in AM? and can you the voltage with VR15.

The radio may have some crude AM swing mod, check the components for any non stock parts.

I get 0 voltage on tp8 on tp7 I get 3.90v w/mirror board out. vr15 does nothing.

All voltages to be taken with the mirror board in place and Power control fully CW.
What voltages do you have around Q65 in AM and FM
The base voltage of Q65 should change if you adjust VR15 adjust, and there fore change the collector voltage, if not check Q65.

I get the voltage you say I should on TP8 and does adjust w/vr15. OK on Q65 I get 13.1-7-6.5 readings. Thanks.

So its working ok now then?

Rick wrote:So its working ok now then?

No am has no swing only keys 5 watts max? Actually talking into mic has a backward swing? FM keys 8 set where it is. Think it may have a bad final working on 1 not both? I will have to try to find 2 new finals to put in it? Thanks for your help.

I have a problem with my 2950dx that is similar to this. When I first turn the radio on it has a deadkey of about 10 watts on high. You can say one word into the mic and the power drops down to 2 watts on high. At this point I turn on my low drive linear and get really good audio reports but the radio itself is only keying 2 swing to about 7. On sideband it swings to about 7 on hi. If I don't talk for about a half hour and key up again I will have that initial 10 watt key then it drops down again. Should I go through the same testing procedure Rick recomended to this guy?

Try doing the test in this thred.

Last night I checked the voltages Rick posted and I figured the finals were bad. I couldn't find any sc2312's but did have (2) sc1969's. A local told me they could be interchanged so I installed them and now everything looks good. I guess I'm good to go as long as sc1969's and sc2312's are interchangeable.