fidelity mid blocking or 10kc shift PLEASE

Discussions on CB Radio Modifications
Post Reply
beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

fidelity mid blocking or 10kc shift PLEASE

Post by beerbarrel » Monday 30th Jun 2008, 6:42

Hi guys iam after some how to do info on mid blocking the fidelity 2000 i have just brought i have the lc7132 if thats right, just how to do it, then put it in the car. any help i would be greatfull
Or any other little mods that is recomended for it,

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

134board

Post by warhorse » Thursday 3rd Jul 2008, 14:22

The mod you seek is on scotts main Cybernet UK 27/81 Mods Page
If you use a switching transistor to match the mids from the uk use a value of 100 pico(101) if its below this
On mids not a major problem if you follow transistor q20 use the middle track so you get as near as 26965-405, on uk should be on the money. The main,yell clear green coils be aware low pass fltrs, prob need tuning after the mod low pwr can be a pain or make V-pwr on the lo pwr switch use a 1k-5k 5k out of a dnt maybe,,,10k prob to high lin vr front panel wire into low pwr settingsof high lo pwr switch, 1 to o.volts leave other to the lo pwr setting-find the lo power pin at back of 134 board follow up to high lo power switch,, leave rv5 the preset in place place a 100/150 ohm res over r119. make sure the cb is reinlined before converting tx/rx if you here a rasping sound on tx you may need to alter the vco or,ct1 on tx but not to much as you may need to go 1-40 on both bands to get full lock after tuning the vco all vco voltages from a stock reinlinement go out the window but usually no higher than 5volts? If you get no mids after the mod and double checked all work. Lift pin 19 on lc7132 place a small capacitor-say1nano,to a higher pico value ceramic. between both pins or solder to the vacant hole if not a lc7136pll. If the 1-40 read out reads 80 =short on the 1-8 to ch selector. Theres lots of mods been done to these radios if they were that good there be hardly any? Mods u could try 1 ch below uk u use an inductor in uh it gives you 27 59mhz good in the day, v power but uHwatt instead ,crystall filter, auto sq, get a 11meg crystal gives you 11 chans on the high band 1 or2 A’channels of coarse 3 7 11 15 19 on mids being channel 41,mod place a v-cap to 1 pin of 10.240 use freq counter to tune for best freq on all bands.or use a seprate 10.240 to do the same.if your really insane turn the cb into a jammer’’audio jammer that is..

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

excuse the double postings

Post by warhorse » Thursday 3rd Jul 2008, 14:52

scott excuse the two post's,again i only click once but done again unsure why computer, grems. fluff in the digimous?

beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

Post by beerbarrel » Sunday 6th Jul 2008, 8:29

Thanks for the info mate got the lc in just got to wire the switch up and then give it a whirl after the retune much appreciated and would like to add that this is one of the best sites i have been on in a long time ,and the fact that someone is always able to help the most novice of modders out like me thankyou =D>

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

134jpeg

Post by warhorse » Friday 11th Jul 2008, 15:37

this method works ok.
Attachments
btone134.jpg.JPG
(531.74 KiB) Downloaded 326 times

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

134jpg

Post by warhorse » Friday 11th Jul 2008, 16:05

Hope the jpg helps a mod done 2months prior xcuse the cloth shot not very pc..not my table not my cloth.. basic cop' prefboard 20pin ic skt etc. use new/old resistors legs for the linkings. 2k2 res heatshrink 2sc945 npn or equiv. all other info this site or open channel.

beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

Post by beerbarrel » Sunday 13th Jul 2008, 19:19

Thanks warhorse for all your help i got all the info from open channel with its useful pictures the only problem i have is i have wired up the switch one side to switch between uk and mid but they is 2 other wires on it that make it more or less bang on freq and cant tell where these go from the pics or diagram thats on it, could you shed any light on this or any more useful pics thanks shaun :?

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

beerbarrel134

Post by warhorse » Monday 14th Jul 2008, 12:10

Think the mod thats explained is a simple 2 wire job 1 to earth the other to the cap via the switch. Played with lc71 mod in the 80’s for a simple way on the mids it works very well the uniden mod is much the same but tc9106/sm512? are quite hard to get in the uk. there are other 7130/1 mods but they are like a lot of hex inverted radios where the frequencys are way off spec to the example below.

U can tune both radio frequency(134board etc) so both are 60hz on the freq counter as long as both bands are 60hz you can get away with the audio being as sweet as a nut. But on example a pres lincoln being narrow banded can pick up on the mids being off spec by as much as 60hz= 2740560. in most cases its ok.

beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

Post by beerbarrel » Tuesday 15th Jul 2008, 5:40

Ok thanks for that i will give it a miss then and thanks again

warhorse
Frequent Keyer
Frequent Keyer
Posts: 94
Joined: Sunday 23rd Apr 2006, 1:15
Location: uk

beerbarrel,re cap switch

Post by warhorse » Tuesday 15th Jul 2008, 13:40

HI dont lose faith the mod isnt voodoo instead of the basic 2wire job get a wire and place 1Wire to the circuit trace pin 1 of ic1=TA7205 if you look closely there are flowsolder over holes on this trace locate with soldering iron desolder, the solder, the trace is 13.2v. feed the wire through the loom
to the switch the other wire from the switch goes to a 2k2 resistor/red/red/red/gold. or value inbetween these values brown/black/orange/gold,10k(you have to use a resistor because the volts will zap the transistor) then to a npn transistor say 2sc945 the resistor goes to the Base junction the collector to earth and the emitter to the cap of q20 centre trace,etc? looking from the left of the transistor flat side from the front= emitter-collector-base. easy yeah''. when you flick the switch to the base current makes the transistor conduct the emitter-collector(depends on how you loook at it) to earth but unlike the cap its only on when the base has volts so its a switching transistor.
Attachments
RotelRVC240.jpg
main ptbm134aox board.
(564.57 KiB) Downloaded 268 times

beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

Post by beerbarrel » Wednesday 16th Jul 2008, 6:25

Thanks mate i sort of grasp it and will give it a go, i want learn unless i try it i suppose thats my moto anyway,

beerbarrel
Dead Key
Dead Key
Posts: 27
Joined: Monday 23rd Jun 2008, 4:40
Location: burton on trent

Post by beerbarrel » Tuesday 29th Jul 2008, 3:32

Thanks warhorse all in and working great had to do the vco lost the bottom 20 channels will try the a channel mod next if you could shed some light on it thanks sorry i know iam a pain just intrested

Post Reply

Return to “CB Radio Modifications”