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Need Swing Mod for Galaxy DX66V

Wire Weasel

Wire Weasel

Senior Moment
Dec 13, 2008
3,112
780
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Hey gang,

Another friend just scored a 66V for $25 bucks. Highway robbery it is. Lucky duck. I've removed the the talkback for him so he can use the echo.

We followed the tune up procedure as outlined at cbtricks adjusting in order, L 43,44,42,40,33 with a 1khz tone. And then the low & high power VR's.

Max power is only about 3 watts swinging to 7. Surely this radio will do more than this. Any suggestions for more power?

Also looking for the swing mod for this one. Could not find one with google. Also can't really see the Board # without removing the front end off the radio. Is there a simple "add a diode to the end of a resistor" swing mod for this 66V similar to the R246 mod on the DX 959 & similar and/or the R238 mod on the DX99V ?

Thanks for any help guys!

WW
 

Hi Funky...don't know. Used radio and have no idea what previous owner may have done to it. Modulation is clean and clear but it's not that Galaxy blasting loud audio like it should be. Was there an early model that didn't have mosfets? I didn't think to look when I was there but I'll have him get the numbers off the finals.

These radios will definitely do more power. Another local has one and with the V turned up it will do 10 swing to 28.

There is some other step you have to do on the low and medium power Galaxys to get that that big chunk of power out of them besides tuning the L40-44 cans and the barrel can back by the back of the radio....there's something else you have to do and I haven't come across it yet.

Have the the same situation with the DX 959 I got a couple of weeks ago. Followed the tune up procedure exactly as stated at cbtricks and only seeing around 15 swing on it but I know these radios will do closer to 30 watts every time. I'm missing something.


Added later: Called the guy up and got the finals. Left final is 1266 and right is 1969. NOT mosfets right? Think this is an early model - or can you get close to 30 watts pep with these finals - did this radio come with mosfets and they were changed out with the cb regular finals or what?
 
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If it is a single-final 2SC1969; then it is limited to the output potential of that device. No more than 20 watts PEP. No more than 16 watts PEP if using a Dosy meter for setting it up. My 99V is a dual-final 1969 that I set to do no mare than 32 watts PEP; dead key no more than 8 watts.

The 2166/TR44 and 1969/TR43 are the right parts for this radio that I can see from the schematic and the parts list.

I think that eBay is LOADED with guys selling single-final and dual-final conversion MOSFET kits for that model. Cost is around $35-40. Power output using the ERF-2030's should be no more than 45 watts PEP to let them breathe a little.

Did you check the driver and final bias current settings yet? I would do that first. Then I would do the transmit tune-up for the cans.

The TopGun Compressor and/or Modulator might be a consideration if he wants a loud talking radio. Usually, tuning the TX cans pleases most people. I didn't put the TG stuff in my 99V because it did well enough without it after tuning. If nothing else, the TG compressor would be a nice mod - IMO...
 
Thanks Robb

My friend is watching the thread too and may join in.

Have you come across a swing mod for this radio?
 
No, I haven't - sorry.

The swing mod works at the output end of the radio. The compressor mod somewhat emulates the same effect by doing it at the front end of the radio at the mic preamp chip - if I recall the directions correctly. The TG compressor uses a diode and a capacitor - if I'm not mistaken - and will also bring the average output up considerably and sound very nice - IMO. Which is basically the same thing that a swing mod does...

I would get a single ERF-2030 kit for ~$25 and see 25 watts PEP out of the radio's tail.
 
Wire Weasel said:
Hi Funky...don't know. Used radio and have no idea what previous owner may have done to it. Modulation is clean and clear but it's not that Galaxy blasting loud audio like it should be. Was there an early model that didn't have mosfets? I didn't think to look when I was there but I'll have him get the numbers off the finals.

These radios will definitely do more power. Another local has one and with the V turned up it will do 10 swing to 28.

There is some other step you have to do on the low and medium power Galaxys to get that that big chunk of power out of them besides tuning the L40-44 cans and the barrel can back by the back of the radio....there's something else you have to do and I haven't come across it yet.

Have the the same situation with the DX 959 I got a couple of weeks ago. Followed the tune up procedure exactly as stated at cbtricks and only seeing around 15 swing on it but I know these radios will do closer to 30 watts every time. I'm missing something.


Added later: Called the guy up and got the finals. Left final is 1266 and right is 1969. NOT mosfets right? Think this is an early model - or can you get close to 30 watts pep with these finals - did this radio come with mosfets and they were changed out with the cb regular finals or what?
Click to expand...

the 2sc2166 is the driver transistor,the 2sc1969 is the final,they should both be proper mitsubishi for best results.Mosfets may bring more power but the bi polars will be much cleaner seeing as they were designed as 27 mhz devices.

radio should do 4w avg carrier,you might get a touch more but risk harmonics,but keeping it lower will make it last longer,has 2sb754 so should give good strong AM modulation at 4w.

seeing as both these transistors are now discontinued i wouldn't recommend bootng the shit out of them as they can be hard to locate and pricey,not to mention the world is flooded with fakes,especially the 2sc1969.

transistors are original for that early production model,it should be an ept360014b main board,same as superstar 3900 and countless other radios.

as far as i know mosfets were introduced on later ept360014c board although some late 14b's may be mosfet.

Carrier high power is VR13,low power is VR16.AMC for AM modulation is VR14 and FM deviation is VR5.

swing mod could destroy final,pricey repair and totally unnecessary.
 
Hey....my friend stuck with it and he got it goin' ! He's a decent tinkerer and has some good meters. What was off was the VCO Buffer adjustments contained in the PLL alignment procedure. Now on max power can d-k 7W and swing to 25 and is loud.

So he got the VCO / L18 set to specs then aligned the RF points again and that's it !

I'm going to check the same thing on my DX 959 and see if I don't get more out of it.

Thanks for all the tips guys !
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Dx66v

PA output mod, I switched out my Uniden pc78 for the 66v and dropped a lot of volume to my pa. I use it on the trail and need it loud again. is there a mod for that?
 

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