hi guys,
i recently picked one of these up at a garage sale for 2 dollars, but i havent even turned it on yet.
the audio chip is the KIA 7217 AP.
as for why your radio doesnt work, i always start out doing a full alignment on a radio. that way, you can see how far you get in the alignment before things start not looking right and you will know which area of the radio to begin looking at.
unsolder the final and driver leads from the board and do the diode test with your voltmeter to determine if they are good or not.
here is a link to the cbtricks site. there you will find the schems that you need.
Cobra 19 Plus
you will also find the factory service manual here. in it you will find all the voltages for the PLL so you can check if its working properly.
read through the whole manual, you will learn alot about this radio.
as for the supertune; dont worry about which diode they are talking about because you dont want to mess with that anyway.
they are referring to the anti-spiking diode whose job is to keep large voltage spikes from damaging the windings of the audio transformer.
even if you did jumper it, you would only gain about 1 watt, if that.
not worth the possible damage to the audio transformer, which will be hard to find a replacement for.
the resistor they are referring to is R311, which is a 3.3K ohm resistor.
jumpering this will increase the deadkey. this may be what you are looking for by replacing the final with the 1969, but if you plan to run an amplifier after the radio, you might not want the higher deadkey.
i would try just replacing the final with the 1969 and then just re-align the transmitter. see what that gets you before you move on to other mods.
if you find that R311 does indeed change your deadkey, you can choose how much deadkey you want by playing with the value of that resistor.
check to see if D502 is cut or removed. this is your AMC diode, and its better if you leave it in and just adjust RV501 for max modulation.
if D502 is gone, just replace it with a 1N4148/ 1N914 type silicon diode. (very common)
looks like lots of fun can be had with this little beauty!
on mine im going to experiment with an NPC mod and some schottky diode mods for the receiver.
good luck with yours,
LC