DX959 dual 1969 upgrad mod?

[skybolt58]

This probably has been pisted already but has anyone done this mod and have it work??

HIGH POWER MOD (30-35watts)
This will work for most EPT-069610Z Boards.

Install the parts listed below:

1. Q47 One additional 2sc1969 final with isolation hardware.
2. A heat sink should be bolted to the rear of the chassis after the conversion.
3.D91-1n4148 diode.
4. C209-390pf 5% 50mv mica capacitor.
5. C212-104uf 5% 50mv ceramic capacitor.
6. R242-22 ohm 1/8 watt 5% carbon film resistor
7. R243-150ohm 1/2 watt 5% carbon film resistor
8. L34-22uh conformal coated choke
9. Q47-2SC1969 Transistor
10. VR11-100 variable potentiometer.

And also maybe this mod and have it work or maybe do both?

RF Output Increase Modification

This modification will allow the DX959 & DX949 to exhibit the RF output and swing of the Galaxy DX-series 10-meter radios. The board was always capable of this type of output; it was simply choked off by the design engineers in order to meet FCC 11-meter specifications.

The first thing you need to do is turn up VR14 which is the AM high power variable. If you?ve already done the modulation improvements, you should be able to dead key about 8-10 watts and swing around 15 watts. 18 watts is probably the best you?ll get (using a peak-reading Bird wattmeter). Now, perform the following modifications:

Remove C218 (3pf) and discard.
Change C216 (470pf) to a 1000pf (100V mylar-type)
Remove C210 (470pf) and discard.
Remove C199 (560pf) and reinstall it in the C210 spot.
Adjust your dead key to around 5 watts. I was able to achieve average peak swing readings of around 35 watts. Depending on the audio input (voice or whistle), I was able to whistle myself to readings of over 40 watts peak! There was a slight decrease in modulation and it seemed as though I was really pushing it. I found that I was able to regain the modulation level by lowering the dead key (using the RF Power control on the radio face) to around 2.5 watts. This netted peak swing readings of just around 28 watts! More than enough given the fact that the modulation was over 95% and crystal clear! This is just about the same performance that I got from my Galaxy DX66V after performing the 1N4001 diode heavy swing modification. Like I alluded to earlier, this new radio has "the stuff." You just have to work slightly harder to get at it.

I did the first one and it don't work, I also installed a jumper in J91,

 

[9C1Driver]

I think that might be an old mod. The 1969 final has been discontinued and the real deal finals are right at 30 bucks. Most shops do a mosfet final mod and there is a dual mosfet mod. Give this guy a call. Site Disclaimer - Custom CB radios

 

[AudioShockwav]

In the long run you are better off with a small amp. It is a lot of work for a small power gain...or if you send it out by the time you ship and pay for it you can get a bigger increase for your dollar with a external amp.

73
Jeff

 

[psycho]

In the long run you are better off with a small amp. It is a lot of work for a small power gain...or if you send it out by the time you ship and pay for it you can get a bigger increase for your dollar with a external amp.

73
Jeff

Couldn't have said it better myself. Dual final radios look great on a wattmeter but thet don't drive amps worth a damn.

 

[skybolt58]

Thats the problem, I have a 1000 watt tube amp and the stock dx959 and tr696f do not have enough power to drive it!

My Point> thank you, now please answer what I asked

 

[RatsoW8]

Thats the problem, I have a 1000 watt tube amp and the stock dx959 and tr696f do not have enough power to drive it!

My Point> thank you, now please answer what I asked

Audio already gave you the best answer.

 

[skybolt58]

then I will need a power supply , I wanted to do the final upgrade so the get the full advantage of the amp, A smal linear will fry the amp As per the tech who rebuilt it! I just need 10 watt dead key and at least 25 watts swing, the 959 and 696f only gets a 18 watt tops swing,

 

[gamegetter]

could the kl 40 mobile amp be used here with a low drive out of the 959?

 

[AudioShockwav]

What tube amp are you driving?

73
Jeff

 

[RatsoW8]

What tube amp are you driving?

73
Jeff

My prediction is a Phantom or similar sweep tube amp. Hence the low drive and probably crazy non-linear output..

 

[skybolt58]

I have a SCP amp 5 tube. (one 6lx6 driving 4 6lx6) the one who rebuilt it said it will put out 1000 watts, He was driving it with a 55v. He is the one who sugested the 2 final? but he is in FLA now relaxing for the winter, I am up here in CNY colse to Canada. in no where land. sort of close to Fort Drum.

 

[ExitThirteen]

A 6LX6 tube has a plate dissipation of 33W, which is the driver tube in that SCP amplifier. It is not recommended that your input power exceed the maximum plate dissipation of the driver tube, as you'll do one or more of 3 things to it. 1) dramatically shorten tube life, 2) cause an arc inside the tube, destroying it, and 3) pop the junction on the cathode of the tube, also destroying it. It will also make for very nasty, splattery audio. That SCP amp is designed for low drive, about 18-20W input. And 6LX6/6LF6 tubes aren't cheap to replace.

Audioshockwav hit it, for what it's worth, you'd probably be better off running a small external box for the power upgrade, but my recommendation would be to have a reputable tech disconnect the driver tube in the SCP amp and run just the 4 finals, you can then run approximately 100W into the finals with no trouble.

Just my .02 worth, and I'm not trying to be a jerk, just educating you on what could happen.

~Cheers~

 

[9C1Driver]

Thats the problem, I have a 1000 watt tube amp and the stock dx959 and tr696f do not have enough power to drive it!

My Point> thank you, now please answer what I asked

I already told you who to call. Why do you think his shops name is "Custom CB Radio".