| Author |
Message |
    
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 103
Registered: 9-2004
| | Posted on Friday, November 17, 2006 - 3:06 pm: | 
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This is a repost of a question I asked earlier.I have a TRC 485 which I moded the clarifier but I only get about 3 1/2 kc swing.I got this mod from an internet site.I was wondering if anyone has any info on this mod so that it will get better swing so I can swing to the zero,s IE 27.110 etc?So far I havent been able to locate the varic diode to try a choke in series to see if that will give me the swing that I want.So anyone please anyone know what diode is the varic so I can try this.
Tnx Bob CEF451/PC451/CVC104 |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2278
Registered: 9-2004
| | Posted on Saturday, November 18, 2006 - 11:23 pm: |
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D102 is your varactor diode.
do not confuse the term varactor with variac, which is a device for controlling the voltage from a wall socket to a device.
a varactor is a capacitor that varies its value with different voltage inputs.
i would try adding 3uH to the banded end, then try 5.6uH. after that, i suspect things will get weird.
as always,i have not tried this so do it at your own peril.
D102 IS the varactor, but what effect adding inductance to it will have; i cannot say.
use a ground strap for your wrist.
good luck,
matt |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 104
Registered: 9-2004
| | Posted on Sunday, November 19, 2006 - 7:36 am: |
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Tnx Kid, well I guess that I used the wrong abbrevation for varactor lol. will give it a try later tnx.
Bob CEF451\PC451\CVC104 |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 105
Registered: 9-2004
| | Posted on Sunday, November 19, 2006 - 8:02 am: |
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Kid I cant seem to locate D102 on the board most of them on the main pc board are labled D1,D2 D3 etc there are some chip diodes behind the display board that are labled D201 D202 etc.I dont have access to a schematic to further check this out.The # on the PC board is JPMXX0213 and the # on the display board is JPFXX0134.To bad there isnt more correct info out there on this radio because when its moded it will cover from 25.165 to 29.xxx the mod is tricky but will try that later.
Bob CEF451\PC451\CVC104 |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2286
Registered: 9-2004
| | Posted on Sunday, November 19, 2006 - 11:16 pm: |
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here is a link to the schematic.
just CLICK on it!
good luck,
matt
http://vo1mds00.tripod.com/sitebuildercontent/sitebuilderfiles/ss485-c.pdf |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 106
Registered: 9-2004
| | Posted on Monday, November 20, 2006 - 1:24 pm: |
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Tnx for the info Kid but this looks like a different schematic cause not much of the the stuff looks the same this radio has the sy 201 chip installed and the one shown on the schematic is an sy 202, I have located d 1 but its not your typical varactor as a matter of fact it looks like a dectector diode there are 2 of them near what looks like the ist if amp, that schematic must be for a different style radio.This one is the realistic TRC 485 not the dragon 485 or the albretch 485ss.The only diodes that look like varactor diodes are located near the front of the board and are D27, D28 D29 just in front of the tuning coils for usb lsb and am.I cant even find a parts list anywhere for it ??
Tnx Bob CEF451 |
Tecnicoloco
Intermediate Member
Username: Tecnicoloco
Post Number: 101
Registered: 4-2003
| | Posted on Monday, November 20, 2006 - 9:02 pm: |
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Hi Just follow this link for more info on your radio.
http://support.radioshack.com/support_electronics/26574.htm
Regards
Tecnicoloco
CEF-117
Sonora,Mexico. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2290
Registered: 9-2004
| | Posted on Monday, November 20, 2006 - 10:52 pm: |
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this is the only schem. i could find.
the link is labled the TRC485 and the schem says albrecht ss485.
usually this means that the insides are the same, and there is just another brand name on the outside.
this is VERY common in the CB world.
do not go by what the diodes "look" like.
parts do not necessarily look the same as they used to.
lets make sure the schem. is right first.
on the schematic that i have D102 is DEFINITELY a varactor diode.
it is right next to crystal X101 which is a 4.5mhz crystal, and also right next to T101 which is a tuning coil.
does your radio look like this?
will you tell me exactly what you did to mod the clarifier?
i will look for more schems.
matt |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 107
Registered: 9-2004
| | Posted on Tuesday, November 21, 2006 - 9:21 am: |
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Hi Matt, well the saga continues, that schematic must be for a similar radio but what I found was that D102 is D 47 on my radio it is located near the 4.5 mhz crystal and in series with one leg of the crystal, also the diode is not your normal configuration it is square almost like a chip diode but with only 2 legs, it has one leg going to ground and the other side must be the anode side .
Tnx Bob CEF451\PC451\CVC104 |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2293
Registered: 9-2004
| | Posted on Tuesday, November 21, 2006 - 2:11 pm: |
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the cathode is the banded end on old style diodes, and it will probably be the end that is connected to one leg of the crystal.
the anode side is probably the one going to ground.
also, the varactor is in parallel with the crystal, not in series. series would be if you lifted one of the crystal's legs off the board, soldered one end of the diode to it, and soldered the other end of the diode to the PC board hole where the crystal's leg used to go.
i have never seen the insides of one of these so i have no idea how delicate it is in there.
so be very careful if you do this.
i would try the inductor in series with the anode side of the varactor, the ground side.
it does sound like D47 is the one you want.
good luck,
matt |
