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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

They do not all drift.
This is more often than not, due to a bad setup from day one.
The cure is to have it setup by someone who knows what they are doing.

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,

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

rick what you reckon

Hi matey.

This might and I say MIGHT be of some use to you...

November Tech Tip on the Month: RCI-2980: In some units, you may notice that the frequency will drift when the unit gets warm. This is caused by the "KIA6410S" IC's installed in place of "TA7310P" for IC8 and IC10. To correct this drifting problem, perform the following modifications: a.) Replace C165 with a 270pF ceramic disk capacitor. b.) Replace C190 with a 47pF ceramic disk capacitor. c.) Add a 100pF ceramic disk capacitor between pin 1 of IC9 and GND.

Forget the model number BUT look at the chip to see which one is in your radio.

Or , check the xtal 10.2417 ?

Hey its a start ! I hope Rick has some input to this.

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

Hello again.

Go to this website and click on ranger / or superstar etc and follow the cuircut layout.
The name may be different but youll find that many radios are identical inside.


http://www.cbtricks.com/radios/index.htm

Goodluck , youll get there in the end. Cheers mate.

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.

Hi ya bloke.

Im not sure about any other forums , this is quite good. Perhaps Rick is on holidays.
Mate c190 , yes it is the one near the bum end of the radio BUT you must understand c190 in the Ranger chassis does not mean it is the same in your case.
You've got to do some snooping around as to what c190 is "called" in your radio.
Look ,for a start I would replace ALL the electrolitics around that chip AND it does not hurt to replace the ceramics.
OR , get yourself a can of freeze spray and gently freeze each part in that area.
BUT as I have said you have to find out what c190 is in your particular radio.

http://malzev.tripod.com/cb-funk/index.htm

I think the capacitors that are being referred to would be C120 and C75 on the EPT3600 chassis.

I would try changing C120 to 270pf and C75 to 56pf (use NP0 caps), then performing a re-alignment of the 14 MHz oscillator in accordance with the service manual.

To be honest I don't think that tinkering with these capacitor values will do much to improve the frequency stability of the radio, a better approach might be to remove the KIA6410S (IC10) and replace it with a genuine Toshiba TA7310.

Regards,

Brian.

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.ph ... ic&p=23700
View topic - Galaxy Pluto :: Transmission1 :: Radio Resources for PMR 446, Scanning, Broadcast, Amateur and CB Radio

thx angus

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 wrote: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,

is this just the simple replacement job?