The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

angusuk

ok if it works when you press it together just put 2 or 3 tiewraps round it and pack as needed that will probly work for years to come,and you will save some pennys,

angusuk

hi all,
the problem was the eprom and the pll02a was blown ,replaced both and
the radio is now working fine again.

cheers angus

angusuk

hi scott,
can you help i cant seem to send private message.
thanx

angusuk

dave scott,
i removed the uk eprom board and reconnected the pll02a as it should be
now it wont work on any channel, i checked the ncode to the pll02a from the channel selector and it is 255 on channel 1 as it should be,
so i guess the eprom is ok???
any ideas ,wished i had a spare pll02a

also i ...

angusuk

hi dave,but if thers no change in ncode to pllo2a when switching uk in from the eprom doesent that point to broke eprom,

angusuk

hi dave thanx for helping,
the eprom is a 2732 ,
the board i a PTBM059COX

also the 7805 is ok i allready tried another one
and the 5volts to pin 24 is fine

angusuk

im pritty sure the eprom has gone titsup,
i checked the volts on pins 15 to 7 from the eprom to the pll02a one at a time while turning the eprom uk switch on and off and it dident make any change,shouldent the eprom send a differant n code when the uk40 is
switched in.

angusuk

hiya scott,
testing with uk40 switch off so rig should work as standard on low mid high bands,.

readings for channel switch pin side to eprom are as follows
low band channel 1=319
mid band channel 1=319
high band channel 1=319

that is
15=+5
14=+5
13=+5
12=+5
11=+5
10=+5
09=0v
08=0v
07=+5

readings ...

angusuk

hi scott thanx for helping,
well to be honest this is another radio, ham international multimode 2,
pll02a,with spectrum eprom fitted giving normal low/mid/and high,
then with eprom ading uk 40 and an extra low band,it was working fine till i moved it to another room,then the channels went tits up ...

angusuk

scott is it possible to desolder the eprom and reprogram it,i think i have a programmer some where,

thanx angus

angusuk

hi scott,i have found on the coil L134 from q133 to power rail.
it reads 13v all 3 legs in rx

but in tx

collector of q133 6.5v_______ left leg of coil L134 right leg ________9v

|
|
|
bottom leg of L134 to power rail 13v

angusuk

hi scott and thanx for helping.
i did what you said and now q132 is reading spot on,but still only o,watts output.

and q133 still reading
rx collector 13v
tx collector 6.5v.

thx angus

angusuk

checked these 2 again

q132
rx collector 13v
tx collector 7.9v and going higher and higher the longer the mic key

q133
rx collector 13v
tx collector 6.5v and going lower and lower the longer the mic key.

angusuk

hi scott,yes ther is 13.8v in rx and yes the track has been blown before and repaired.so its something else close i think

angusuk

hi rick and thankyou for your input,
i think what probly happend was when i first got the radio ther was about 1 watt coming (i think this was cos the final was blew)i then stupidly used the radio for about 1 hour localy without replacing the final on 1 watt then all of a sudden it droped to 0 watts ...

angusuk

hi all,
i took some tranny volt tests on
q124-all ok in tx and rx
q134 rx ok /tx c=ok e=2.33 b=3.01
q132 rx ok /tx e=ok b=ok c=7.9 and going higher and higher the longer the key not stable
q133 rx ok /tx e=ok b=ok c=6.5 and going lower and lower the longer the key not stable.
what you thing guys ...

angusuk

thanx rick your help is very much appreiciated,im only an amature with cbs and only no some basic stuff,
i do like to try and fix things if i can,with a little help on the forum from you top boys and by looking at the forums, you seem to be very good at what you do.and i dont mean to affend,just ...

angusuk

hi,i also have a 2950dx and have also noticed it gets quite hot
after being used for a short time,so me to would be interested to find out why,and the solution.also i have been using mine with power knob set at minimum around 8 watts.

angusuk

rick i checked the old c1969 and it was broke,so i fitted a new one with your
instructions with the cap and resister,but thers only about .2 of a watt coming out.i havent checked the driver or final bias ma yet.
do you think c2166 could be gone to.modulation is coming out fine tho.

thanx angus

angusuk

yes scott i probly will invest in a mrf455 or maybe a mrf477,when i no the radio works ok but for now 4 watts will be fine. what pot tuning do you advise,??driver bios or is there an high power pot.

thanx a

angusuk

hi scott,i looked at getting a mrf455 but they are more than i want to spend,so i have allready orderd a new 2sc1969,i will be happy with say around 8 watts fm and 12watts ssb,so would be gratefull if someone could tell me what will need adjusting,so it doesent blow the new c1969.

thanx a

angusuk

hi rick thanx for speedy reply,
i have noticed with another radio in the same room on the same channel i can ear the lincoln ok modulation and low signal so does this mean the driver is ok,and lol i spelt bios instead of bias hehe i guess its my age,

angusuk

hi all,
here i have a president lincoln pb-111ae,it came to me with only 1 watt coming out ,i suspected blown final i noticed the mrf477 has been replaced with a 2sc1969 ,
anyhow decided to try it out localy ,1 watt was fine every one local could ear me then all of a sudden the watts out went to ...

angusuk

hi scott,
sorry for taking long time to reply had some family buissniss,
the only markings i can make out on a dirty white sticker on the eeprom is OB2??,

angusuk

howdy all,
here we have a cobra 148gtl dx missing 6 channels from 28245 to 28305
super hi channel 35 to 40 .
its ok to channell 34 ,28245 then from 35 to 40 frequency stays at 28245.
the rig has a 6 position band switch fitted, and a uk40 eprom that is on position 6,position 5 is super hi,

thanx ...

angusuk

its ok ,i have sorted it now

angusuk

hi all,
just got hold of a superstar 3900 as new untouched only working on 40 channels so would appreciate if some one could give me info how to open all the channels and connect the 10kc shift up.

regards angus

angusuk

hmm i did this mod today on a ss3900 but doesent seem to do much to me.
btw for superstar 3900 its tr17 d1 d2 d23 d24 that need changing.

angusuk

hi m8,
did u try it if so what did u think to the results.
regards angus

angusuk

hi all,
i tried changing the 2 caps and also changed the xtal 10.240 but did not make any differance,i also noticed ic10 chip does not seem to have part no on it looks blank.
any more ideas guys

angusuk

hi brian,thanx for the help
that seems a good idea can i just change the ic10 as in desolder KIA6410S then replace with Toshiba TA7310,

maybe you could all take a look here and let me no what you reckon

http://www.transmission1.co.uk/index.php?name=PNphpBB2&file=viewtopic&p=23700
View topic ...

angusuk

hi ray, i found c190 its at the back right hand corner under the power lead plug,but i cant see that having anything to do with frequency drift.
ray is there anymore forums i could try ,dont seem to get much help
on this one.

angusuk

hi Uncle Ray,thanx for your input,
it does have the KIA6410S installed in ic10,but i cant seem to find C165 or
C190,need some better glasses,any idea where they are located.
thanx angus

angusuk

rick what you reckon

angusuk

hi rick,could do with some help if possible ,im aged 48 been working with generators for a few years,i have an heart condition,so just got into cbs for an hobby to keep me buissy,

thanx angus

angusuk

rick i forgot to mention it does have a fm varable power nob on the back,
and looking inside its had the pot removed and the 2 wires added to the nob.
so should i remove the nob and fit a new pot and set to 5watts.to be on the safe side.

angusuk

hi rick,
i have alighned the pll according to the service manual but it still keeps drifting the longer its on
the more it drifs.have you got any tips on what to try,

angusuk

seems to run very hot after using for about 1 hour,is this normal,casing gets hot,does have a large added heatsink on the back.

thanx angus

angusuk

hi all,
ss 3900 frequency drift,i have been informed they all do it,but does any one have a solution or fix or any idea what causes it.

thanx angus

angusuk

hi,
there is not any wax removed ,there is one coil that is spread open but i never did this,i have now turned the power down with vr203 to 4watts.

regards angus

angusuk

yes if you read the other post you will see the power went up after removing somekind of swing mod and yes it went upto 10 watts checked on 2 differant watt meters.

and btw it was over 10 watts on some channels

angusuk

comeback all is forgiven

angusuk

hi rick,i have give up on the cobra uk 25 think yourright the mcu is cream crackerd.

but on the cobra uk 29 with the channell mod,i removed the top cover no speaker and it has had somekind of mod.do u no what it is ,there is a 5488 tranny a 103 cap 2 resistors 1 diod 1 piece of wire with 1 more ...

angusuk

hi all,
im looking for cobra uk 29 ltd st tuning and alignment help.
cant find anything on the net.

have found vr203 is power out but fully open its only kicking out 3 watts
the radio does have a c1969 fitted.

thanks in advance for any input

regards angus

angusuk

ok rick i will check those.
also rick i have the cobra uk 29 ltd st that works fine so yesterday i did the channel unlock mod but its only working on some bands it wont lock/key on some seems like the vco needs adjusting,what do you recomend,which is the vco ther is 2 cans coverd in wax is it the 1 ...

angusuk

yes rick radio is fitted with LC72322N MCU/CPU,
which is the vco test component,?

just noticed when it transmits after switching pa on and off it is not receiving
but it does transmit .so to get it to tx i have to switch pa on and off and to get it to rx i have to switch ch19 on and off.

readings ...

angusuk

hi rick,can you give me a bit more info im a learner with cbs,what no is the vco in this radio and what volts ??.

and any chance if you have the alighnment info for the cobra uk 40 rick,

angusuk

hi all,i will try to describe what the fault is.
switch the radio on receives fine on all uk 40 channels,but will not transmit,now if i switch to pa and back it transmits and receives fine on the channel your on ,but then will not change channell.
now if i switch the channell 19 swich on and of the ...

angusuk

hi rick,thanx for the link but i cant find any on there ??? maybe they stoped selling them.

angusuk

im looking for place to buy an echo board kit to fit in a mobile cb
seems hard to find any one who stocks them in uk.

thanx in advance

The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

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