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cobra 25LTD, pc 901ab, hong kong,

the radio lites up
.
when i key up the radio , the meter swings backwards.

when i key up the radio, it switches from green to red.

transmits only at 1 watt also has no audio at all.

has no receive, it has movement on the meter.

pa not working. i would appreciate if someone can give me a hand with this radio. thank you,, galaxy

shorted audio chip

Thank you Remblingman for your help with this radio.. I changed the audio chip, the radio has good receive and good audio. it has low output power, please help me with that. galaxy

when you say low output power,,,do you mean low dead key carrier,,or low modulation swing,,or both..

both

sounds like your just running on your driver...final is probably burnt out.check your final.quickest way too check it.is to unsolder the collector of the final.then if there is a difference in wattage reading.its o.k..but if when you lift the collector of final,the wattage reading is the same,you know that it is blown.

i put new finals and driver in the radio,,when i cut d -9 . its dead keying 4.5 swings to 14 . should i change the pre- driver , would that help me do more wattage or do a pwer mod to it, thank you for help,,, galaxy

i wouldnt change pre driver that wont give you any measureable wattage difference...if you wont more swing,,install a swing kit...youll need a 220 uf capacitor,and a 100 ohm resistor...remove jumper jp-6 and install capacitor in those holes where jp-6 was..make sure that the negative leg of the capacitor is facing towards the final..then install 100 ohm resistor across the same connections on the solder side of the p.c.b..dont jumper out the anti-spiking diode....because needs to be left in circuit..to protect radio against stray rf feedback.........

thank you ramlbing man,, my radio is dead keying 5 watts swings to 18. with super loud audio.. i put in 35volt 470uf super swing kit in... would you know what cap is for the amc circuit modifications. i have the pc 901 ab board. (its not the same as the pc 417.) galaxy

ok,,,to start with,,if swing kit is installed right,you shouldnt have a 5 watt dead key..it should be like 1 to 2 watts max..and then swing from there about 15-18 depending upon meter..every meter shows different readings..but you need to get that dead key down.for the swing kit to be working properly..so lets start over with that then ill give you the full fleg mod...desolder jp-6 and remove this jumper..clean out holes so you can install your 220-470 uf 25-35 volt capacitor..remember capacitor must be installed with negative leg facing the final...then flip over radio,and solder your 100 ohm 1 watt resistor across the same two points,,your capacitor soldered too..if everything is making good connections and done right,you should see about a 1-2 watt dead key..no 5...heres the rest of the modification..replace stock final with a 2sc1969,,replace driver final with a 2sc1957..locate r108,and jumper this out on solder side of board.change out r43 to a 4.7 ohm,,remove c149,,locate c46 and parallel with a 100-150 pf disc cap..do this on solderside of board..locate c42 and parallel with a 33-68 pf disc cap..locate c62 and parallel with a 68-100 pf disc cap..change out r76 to a 1k ohm resistor..readjust l-10 for max..swing..just DO NOT jumper out the anti spiking diode,,this is in circuit for a reason,to prevent stray rf feedback..doing this only gives you a watt or two extra,,and it is not worth it..may cause more problems later...

I DID THAT TO THE RADIO... THANK YOU I JUST NEED TO KNOW THE AMC CIRCUIT attack time modification galaxy

to desensitive the amc circuit..change r76 to a 1k ohm resistor,,,change r43 to a 2.7 ohm resistor,,change r108 to a .47 ohm resistor...r76 is located near the mic socket.....this will make the mic gain very sensitive but it will also pick lots of background noise up,,especially if you running it as a mobile...or already using a power mic on it....your probably going to have to use a noise cancelling mic if you run as a mobile..if running it as a base,,you can probably get by using a regular stock mic,,or power mic..