Drake power supplies were discussed at length at the Drake Forum at the Dayton Hamvention last weekend. There are those that feel "if it ain't broke, don't fix it." I think that your experience, Carlo, supports the guys on the other side of the fence who say that after 35 years of service, one should update the power supply components (at least the bias supply).
Sorry to hear of your bad experience.
73,
Eric KA8FAN
carlobianconi <[EMAIL PROTECTED]> wrote:
In the last days, I had an intresting experience, that could be useful for all Drake enthusiasts;Take a TR4C and put inside 3 brand new 6Jb6, then connect it to a supposed well working AC4 ( the AC4 has the bias supply defective, but you don't know this). Switch the radio on, and while you wait for warm up, answer to a 10 minutes phone call, or better have a drink of your choice in the kitchen. When you come back,you will discover that the TR4 is in tx, the final is drawing all the current possible ( of course without load connected and not tuned up) and your expensive triplett of new 6JB6 is good as target for shooting with a slingshot or an air rifle!Yes, if the negative bias fails, ( - 20 V instead of - 60 circa ) this is what happens if you are not present, and notice that the radio goes in TX instead of RX at power-on.A stupid 20 cent. capacitor can make a multidollar damage.I suppose this happens with T4 series too, so my suggestion is to change the diode and the caps on bias line as default in the AC4Good time to all readers!Carlo Bianconi IK4ISQ Italy
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