| Author |
Message |
    
Snapperhead
Intermediate Member
Username: Snapperhead
Post Number: 195
Registered: 2-2002
| | Posted on Sunday, March 06, 2005 - 10:16 am: | 
|
Hey guys, I've read a few older post's here on different ways to beef up the 148gtl....Mine is an older one, Can't make out which model....The metal tag on back of chassis is gone,,,,It's another Ebay hacker......First thing I noticed was R131 was cut, as well as TR24 (Limiter).....I was having problems on SSB with garble, and audio running to HOT.......I soldered back R131 and left TR-24 clipped......I need to get one, to replace...I believe its 2sc945,.........I read some post's a while back saying something about replacing C-18 with a 25v 1000uF cap.....What does this do.....Also, is there anything else I can replace to beef up the TX department..........Thanks all |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 262
Registered: 9-2004
| | Posted on Monday, March 07, 2005 - 1:41 am: |
|
snapperhead, this radio is the same chassis as the grant xl, the 2000gtl, and the uniden madison.
do a search in this forum on each of these radios.
you will find lots of different mod info to choose from. i just made a post listing three different modulation mods for the 2000gtl.
most likely, TR24 is a 2sc945.
as radios get older, the caps begin to dry out on the inside. replacing them will bring back good audio quality, freq. stability, etc.
sometimes replacing a capacitor with one of a larger value (capacity), will provide you with more headroom. like having more current on demand when you need it. in the audio section of your radio this can give your modulation more "punch" by having more current on demand for your quick voice peaks.
that radio you have is one of the best ever made in my opinion. i just bought one on ebay this week. if i were you, i would have a complete alignment done before you start any mods. that way you know youre starting at zero.
matt |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 118
Registered: 2-2005
| | Posted on Monday, March 07, 2005 - 9:56 am: |
|
Replacing capcitors in an audio circuit with different values will change the audio characteristics of that circuit. Many times that means the frequencies that will or won't pass change. It doesn't provide more punch like using a larger capacitor in the power section will.
As long as you change the capacitor with the same capacitance value, it should be fine. Using a cap of higher voltage won't change the characteristics. |
Snapperhead
Intermediate Member
Username: Snapperhead
Post Number: 196
Registered: 2-2002
| | Posted on Monday, March 07, 2005 - 7:59 pm: |
|
Very Interesting guys, thanks for the reply. I've checked all kinds of different mods on the internet. Most of them are all the same info with Adjusting variables and clipping limitors and what not.....I have all the paperwork on that stuff, but I was just wondering if anybody here on the this forum had some tricks other than the basic adjustments. A while back I found a web page for the RCI Ranger 2950 (Old Style not the DX model)....It was called the RCI Bible.....Awesome mods to the TX chain....I replaced transistors, caps and what not and All I can say as it was a Big Improvement on the Audio Quality as well as keeping things cool........I was hopeing some of ya's could maybe tell me a few tricks on this oldie but goodie.......To get the big Punchy audio, with Topnotch quality and Not splatterin' all over the band..........Any input from you techs or just plain SSB radio nuts would be appreciated.......73's |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 265
Registered: 9-2004
| | Posted on Monday, March 07, 2005 - 10:41 pm: |
|
racer x, thanks for the clarification. one more CB misconception gone from my memory banks.
snapperhead, here is one more mod i found for the 2000gtl. i have not tried it so i dont know what the results will be.
here is is just for posterity.
this mod is for radios with no other mods done.
find D54, pull it out and solder it back in backwards. now pull R194 and replace with a 1N60 diode, cathode to ground.
thats it! i found this one on the yahoo 2000gtl group.
if you try this one let me know the results.
matt |
Snapperhead
Intermediate Member
Username: Snapperhead
Post Number: 197
Registered: 2-2002
| | Posted on Tuesday, March 08, 2005 - 7:55 pm: |
|
Hey there Kid vicous. Thanks.....I've never heard of that one.....What does this mod do?.......Thanks for your input.......Any others would be much appreciated.....73's |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 274
Registered: 9-2004
| | Posted on Tuesday, March 08, 2005 - 9:24 pm: |
|
i have no idea what this mod does. maybe racer x or one of the guys more "in the know" can tell us what happens when you turn a diode around. my only guess is that since a diode is meant to conduct at a certain voltage, that turning it around will turn it on when it should be off, and vice versa. again, i dont know.
matt |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 128
Registered: 2-2005
| | Posted on Wednesday, March 09, 2005 - 7:40 am: |
|
One of the few Sams manuals I don't have is the one for the Cobra 2000, so I don't know what those components do.
Just a guess - because a particular type of diode is specified, if D54 and R194 are near each other and in the audio circuit it may be an attempt to create a clipping action in the audio circuit. |
Sg569
Intermediate Member
Username: Sg569
Post Number: 104
Registered: 12-2004
| | Posted on Wednesday, March 09, 2005 - 12:16 pm: |
|
Snapperhead,
What have you done so far??? |
Snapperhead
Intermediate Member
Username: Snapperhead
Post Number: 198
Registered: 2-2002
| | Posted on Wednesday, March 09, 2005 - 8:09 pm: |
|
Well, When I received radio from a seller on Ebay it was pretty hacked up.....It had TR-24 removed (Of Course).It was 1kc off freq on all modes.......and It had a garble sound on SSB that I found that who ever hacked it up cut R131.....So we soldered her back.....I'm looking for a 2sc945 to put the limiter back in.....It had 1 toggle switch in wich seem to kick it to 27.605Mhz and up.....All I've done is try to tune it with the backyard tech way....LOL....I fired up my Kenwood TS-930s. I tried to tune LSB, USB and AM cans to close as possible to sounding normal on my Kenwood RX......I've noticed that on USB........can is all the way turned in and it's still off freq.....I did manage to Unlock clarifier thanks to some help here on the forum...I also put extra toggle switch to get the rest of the Extras.......Bottom line is, I need a real tech with Signal generators, Scopes, proper freq counter and what not to tune it the right way.....What do I expect, I payed 20 bucks for here.......lol. I've tried to Email a few techs that I've found on the internet, but haven't got any responce.....So, I'll just put here aside and wait for a good tech, if I can find one.........That's about it Sg569............73's |
Sg569
Intermediate Member
Username: Sg569
Post Number: 105
Registered: 12-2004
| | Posted on Thursday, March 10, 2005 - 5:09 pm: |
|
oh ok, you do need a tech. I didn't know it was a basket case, sorry to hear that, but your right; for $20-. I'll keep my ears open for a good tech. |
Snapperhead
Intermediate Member
Username: Snapperhead
Post Number: 199
Registered: 2-2002
| | Posted on Thursday, March 10, 2005 - 9:16 pm: |
|
She will talk ok now, but I just need to send her in someday.....I also have a Virgin Cobra 148gtl(Made in the Philippines) that I want a complete overhaul with all the goodies done......I know your not supposed to solicite techs other than here, on the Copper Forum...... but I'm having a hard time trying to find a good one.......... I've Emailed a few that I've found but I guess they are just too busy these days......Still haven't got a response. We'll just have to wait and see...........73's |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 279
Registered: 9-2004
| | Posted on Thursday, March 10, 2005 - 10:15 pm: |
|
snapperhead, send me an email. i might be able to help.
matt |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 280
Registered: 9-2004
| | Posted on Thursday, March 10, 2005 - 10:21 pm: |
|
racer x, i looked at my 148gtl last nite, and R194 is right next to D54, which looks like a germanium diode. not sure what it is though.
does this help you determine what this mod is doing?
matt |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 141
Registered: 2-2005
| | Posted on Friday, March 11, 2005 - 6:08 pm: |
|
Nope. I'd have to see the schematic to understand what it's function is. |
Mrgoody
Junior Member
Username: Mrgoody
Post Number: 14
Registered: 1-2005
| | Posted on Sunday, March 20, 2005 - 6:55 pm: |
|
Hey guy's:I have a slight problem here with a setup of mine I have the 148gtl a kl-200p and a wilson 1000 ant.and I'm thinking about adding a amplified ecoh mic to the system what would be you guy's advice on this. |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 292
Registered: 9-2004
| | Posted on Monday, March 21, 2005 - 1:20 am: |
|
mrgoody, i dont know that i have any advice for you persay, but i do have an opinion. (go figure!)
i think you have a great setup there. i think echo is useful if used with discretion. (only a little bit.) i dont know of any mobile echo power mic on the market today that is worth the money. (just me opinion). i like the D104M6B for a handheld mic.
other than that, make sure the deadkey on your 148 is turned down to about 2 watts, and that the SWR coming out of the amp is below 1.5 on all channels, and you should be good!
matt |
