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Message |
    
Kid_vicious
Junior Member
Username: Kid_vicious
Post Number: 34
Registered: 9-2004
| | Posted on Tuesday, October 26, 2004 - 11:07 pm: | 
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hey techs and screwdriver experts!
i have a mirage 2950 that is modified for 26-32mhz, and tuned up by copper, but otherwise its untouched. i do not want to experiment with this radio so i have taken a lot of time to find the best upgrades for it. i would like to know your opinions on the following mods.
Q18-2SC1674 to a 2SC2999. this looks pretty good to me.
Q51-2SB754 to a 2SB688, or 2SB817, or ECG37. which one is the best replacement?
Q53-? to a 2SA473, or ECG153, or 2SA1012-0. which one is best?
D34&35-1N60's to ECG583, or SK9975, or NTE583. which is best?
D1&2- i read somewhere to change these out but i cant rember the replacement #'s.
R194-10K to 4.7K
R178-4.7K to 3K
R281-4.7K to 10K, are these to increase wattage out? if so i'm not going to do them. (what difference does 2 extra watts make anyway.) if they're required for the transistor changes, then i'll do them.
there is a modulation increase mod. done by adding a 1N914 diode connected to a 50 ohm resistor across two points near Q51. i plan on using my silver eagle mic. on this radio (I like the sound) and want to know if this mod will improve audio quality or just create distortion and harmonics.
i also read to replace all the plastic insulators with mica ones? how much does this help heat dissipation?
there are also some capacitor changes-C270,261, &262 to 1000pf. i dont think i'll be doing this either as it seems to be for those who want to see their needle move more. i am, however, open to suggestions.
so what do you guys think? i just want a clean loud radio that operates efficiently.
also i would like to know which of these mods require re-tuning as i dont have a scope or a signal generator.
thanks in advance.
matt. |
Kid_vicious
Junior Member
Username: Kid_vicious
Post Number: 35
Registered: 9-2004
| | Posted on Wednesday, October 27, 2004 - 10:19 pm: |
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i hope that someone will lend their expertice to this as i'm sure that whoever does a search for 2950 mods will find this thread very informative. |
Tech808
Moderator
Username: Tech808
Post Number: 3955
Registered: 8-2002
| | Posted on Thursday, October 28, 2004 - 10:07 am: |
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Kid vicious,
Unless you have access to or own some Good Test Equipment and your Radio is working good I would NOT suggest doing any of the mods mentioned above.
Without the Proper Test Equipment and/or Experience you can get that radio so far out of whack it could become useless.
RADIO GLODEN RULE #1
IF IT's NOT BROKE DON'T MESS WITH IT!
Just my nickels worth.
Lon
Tech808 |
Bruce
Senior Member
Username: Bruce
Post Number: 1718
Registered: 9-2003
| | Posted on Thursday, October 28, 2004 - 11:59 am: |
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Works ..... Q18-2SC1674 to a 2SC2999. This is receive RF stage change also used in lincoln and grant LT.
Diode changing I have a supply of the diodes and having tried shanging them in several radios realy found little change.
"D34&35-1N60's to ECG583, or SK9975, or NTE583. which is best? "
Q51 should be a power regularor the replacement does run cooler.
As Lon said if you dont have the equiptment dont mess with that radio. |
Highlander
Advanced Member
Username: Highlander
Post Number: 652
Registered: 12-2001
| | Posted on Thursday, October 28, 2004 - 3:35 pm: |
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I would just throw a channel guard in it, and get a good tune-up/alignment done on it. I see no reason to dink with the transmitter in those things, a good quality mic and having the modulation set properly, they do really well, AM/SSB. The receiver is already plenty sensitive, but the bleedover on SSB when the 11 meter band is hopping is pretty horrendous on the old 2950. A Channel Guard will do more for that radio than any other mod I can think of. |
Kid_vicious
Junior Member
Username: Kid_vicious
Post Number: 37
Registered: 9-2004
| | Posted on Saturday, October 30, 2004 - 10:23 pm: |
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sorry i havent replied guys; i've been traveling.
i plan on getting a channel guard for the radio.
i was kind of hoping that someone would give me the information i need and let me make my own decision as to whether or not to do the mods.
has anyone done these parts replacements? which part did you use?
I have been doing this since i was 12, i became a ham at age 14, and have been repairing friends radios ever since. i do not consider myself a tech., but i do know how to use an oscilloscope, (used to work in a TV repair shop,)
and i am planning on getting one anyway.
i feel that i have the skills required to perform the mods. i just dont think that the directions i've found are detailed enough.
so, is the reason you guys are hesitant that anytime you replace a semiconductor, that there are other component changes involved?
if so, wouldnt you be telling me that the mods i listed are no good?
so i ask again. has anyone (besides bruce. thanks man.) done these mods to their 2950?
what was your expeience?
i realize that i stated in my original post that i dont want to experiment with this radio. May i please restate this. i only want to do mods to this radio that others "in the know" have done and liked.
thank you all for replying.
matt. |
Inspector
Member
Username: Inspector
Post Number: 99
Registered: 12-2001
| | Posted on Sunday, October 31, 2004 - 2:29 am: |
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I would just get a good tune-up and perhaps the negative-peak compression (NPC) mod ONLY if it is done correctly. I have done all the other mods, mostly on my own equipment and they work, to one degree or another, but are not necessary unless you are REALY picky.0 If your Mirage 2950 is one of the older models, you can trick it into going WAY out of band, much like the key-pad trick for the RCI-2950DX... |
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