The board, being double sided, has solder connections on both component and foil sides. As a part of the services we plan to provide, we will be posting not only these issues but also will be providing links to other sites that address these issues with some clarity. I ended up changing the other three semiconductors on this heat sync as well, shown on the left. But, in the middle of the night, excited with this amazing discovery, I kept on thinking if this error was the only one. When I got the 28. The store is online now and we are accepting new orders.
The soldering technology back then was pretty bad and many of the problems today can be associated with cold solder joints. Luckily, one of the audio nuts from 14. When the socket is removed, it is very important to insure that each pin is completely solder free. D3 then shorts out rather then regulating correctly, causing Q1 to burn opened. The original problem was the board and a not too knowledgeable repair person.
Take your time and ensure the 28. Then it starts all over again on the next word. All solder joints should shine nicely and not have a crystalline or opaque appearance. If you want to know more or withdraw your consent to all or some of the cookies, please refer to the. The heat sink is room temperature even running the rigs all day! You're the first to show how to upgrade the 940's power supply. These excessive temps cause component failures.
. Time required for this modification is 1 hour or less. A shorted output transistor in the original power supply puts up to 40V through the entire radio and can render it useless. The power supply upgrade went very smoothly thanks to your terrific kit, instructions and videos. The display produces dots instead of the normal frequency displayed numbers. It gives me direction when we have made something not quite as easy as it should be.
The purpose of zener diode D3 is voltage limiting via bias current bypass. Almost two decades waiting to be corrected! When the 940 is up and running again, I will upgrade the 930 as well. The time constant is now changed. As a final note, many have found the solder joints to be less then adequate on this particular Kenwood radio, with a high number of cold solder joints. I left this jumper on as I have no interest in remote control of the radio and want the supply to maintain stable voltages if this plug is ever removed.
With this measurement we would have an idea about the sensitivity losses due to the two errors. There are other power supplies and other brands that will work just fine as well. If the display fails press the reset switch. Once again, Thanks for your time and Let's resurrect some radios! The balanced modulator modification detailed above did improve my sound in my opinion anyway ;- but it still lacked sibilance! Great job on the upgrades for these radios. This mod was recommended by a ham online to shield Q6 from transients during power up and power down.
Q1 is not heat synced either. From the 455K filter the audio is applied to the 8830 filter. For my application I was able to apply audio from the unused right output of my MicroVerb4 to the mic jack on front of rig. I will continue to share your thoughts to give others the courage to give it all a try! This required a very tiny drill bit. Do not pry up on the socket. Having to pry up on the socket means that it is not completely desoldered and will cause the circuit foils to tear.
I use a 22Mfd capacitor in the audio + to provide proper coupling. This Radio has high density packed components with little extra space anywhere. Please see the details of this change below! Socket 5 pin 1 to pin 3 was solder jumpered on the board to activate the 5 volt supply with plug 5 removed, shown above in blue. When I started the installation, I could not believe what the resistors in my fan looked like!! Most of these problems can be resolved by a technician with the proper tools, test equipment, and of course the knowledge. Clock memory cleared on each power down, then gave strange responses on each power up. You can check out our site at to see what we have so far to offer! If the demand is If you would like to see a diagram that we do not offer, please contact me using the Send a Message link below. Swing the mount toward the right side of the transceiver and allow it to rest on the Digital B unit shield.
Two errors that I found, both also showed in the Service Manual, Revised Edition. It would be interesting to measure these gains before the correction. See the heat sync photo above. To get a bit wider bandwidth around 3. Plastic tie straps, or even simple electrical tape works very nicely. Put the front up but leave the covers off. The modifications below will dramatically improve the response and flatness of the receiver.