I just wanted to start this off by saying thanks for all the help over the years from this website and happy new year and merry Christmas. Well with the dak it receives fine, mod meter is moving I can see signal on my sdr. No audio no rf power? Tubes tested good, saw a few caps looks iffy and replaced those... after playing with the radio and looking thing over I notice the sc1306 gets hot after you key the mic the? Just wonder if there any ideas or just pull the driver and test? This radio is way before my time and I don’t have the money for Cb tricks donations any help would be great.. thanks again for everything
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Need help with dak 9 no rf power
- Thread starter Justwantdahifiaudio
- Start date
This seems to work http://www.cbtricks.com/radios/dak/mark_ix/index.htm
Ok well leads me to this next question is a 2166 suitable for 1306? Should work from what I’ve read online. Thanks for the link cbtricks is tricky seems to work on day and next month is down..
I used a 2166 to replace a 1306 in 2 recent Cobra restorations. Works fine no problem. If I remember correctly, the 2166 has a little higher current rating (1a more I think?) than the 1306.
73
David
Well I appreciate everyone’s time tonight, after dinner I did pull the transistor and tested OK, Starting to think possibly the relay is staying key up after the first key up because the rx isn’t as strong.. I’m gonna play with it tonight and see what else I can come up with
Pulled relay cover cleaned relay and now have rx so don’t think the relay is the issue. But the driver is still getting hot when keyed up....
When the 2SC1306 was discontinued the 2SC2166 was what took its place in all the CB radios Uniden made during the 80s and 90s. Later production also used type 2SC2078.
A transistor that's getting too hot should at least get tested to see if it's damaged. The resistors connected to the transistor's base terminal should also get checked closely. They tend to get clobbered when a driver/final transistor fails.
73
A transistor that's getting too hot should at least get tested to see if it's damaged. The resistors connected to the transistor's base terminal should also get checked closely. They tend to get clobbered when a driver/final transistor fails.
73
Check voltage at the collector leg of Q305, which should be the C1306 (or C2166 if you replaced it), then check the base leg of that same transistor. If the voltages match, or are somewhat close to each other, you're getting too much voltage at the base, which will heat up the transistor. If this is the case, C314 has failed short or is leaky, so replace C314, which is a 100pF capacitor. That should fix the issue.
Another way you can check to see if C314 has failed is to lift the base leg of the transistor off the board (or de-solder it). If the transistor cools off, that indicates a shorted or leaking capacitor at C314.
Do these checks and let us know how you get on.
~Cheers~
Another way you can check to see if C314 has failed is to lift the base leg of the transistor off the board (or de-solder it). If the transistor cools off, that indicates a shorted or leaking capacitor at C314.
Do these checks and let us know how you get on.
~Cheers~
Top of the morning, the transistor is a through hole so kinda hard to lift a leg, so went to the next step and tested c314 all is good. I did key the mic with the cap removed signal looks the same on sdr but transistor is not hot
If the transistor is not hot with C314 removed, then I would suspect C314 has gotten leaky. Did you replace C314 with another capacitor? Did you check voltages at the base and the collector of Q305 to see if they were the same or somewhat close in value?
~Cheers~
~Cheers~
Yes I did replaced c314 with new part, forgot about the voltages, on rx c0, b15.3, e0 on tx base voltage goes up to 19.6 and 0 base and collector
Do you have another radio on hand to listen on the channel where the DAK is transmitting?
For that matter, are you sure the DAK is receiving on the channel frequency that's selected?
If the PLL has lost its lock on the receive frequency, you'll still hear channel noise, but on a random frequency. If you're sure it's receiving on the channel that's selected, it's time to see if you can hear a weak signal leaking out of the DAK into another radio on the same channel.
And if it's NOT receiving on the correct channel, you'll have to get the radio's PLL to lock onto the correct channel first. The radio has a lockout circuit that will shut down the transmitter any time the PLL loses its grip on the legal channel frequency.
And if you CAN hear a weak carrier from the DAK on another radio, that provides a starting point to pin down the fault.
73
For that matter, are you sure the DAK is receiving on the channel frequency that's selected?
If the PLL has lost its lock on the receive frequency, you'll still hear channel noise, but on a random frequency. If you're sure it's receiving on the channel that's selected, it's time to see if you can hear a weak signal leaking out of the DAK into another radio on the same channel.
And if it's NOT receiving on the correct channel, you'll have to get the radio's PLL to lock onto the correct channel first. The radio has a lockout circuit that will shut down the transmitter any time the PLL loses its grip on the legal channel frequency.
And if you CAN hear a weak carrier from the DAK on another radio, that provides a starting point to pin down the fault.
73