New 2023 PRODUCT ANNOUNCEMENT
Its Here!! PA Upgrade kit shipping
Its Here!! PA Upgrade kit shipping
Its Here!! PA Upgrade kit shipping
The PA Board is finished and shipping. If you were on the pre-order list, you will recieve your new PA very soon. If not, you can order the PA online now! Click on the image above to order. See the videos at http://www.k6iok.com/videos
NEW BNC to TMP Cables
Its Here!! PA Upgrade kit shipping
Its Here!! PA Upgrade kit shipping
As you likely know, it is impossible to find the cable connectors used for most RF connections in the TS Series radios along with other series as well. We now have a TMP Female TMP to a BNC connector so you can connect your RF signals to your test equipment!
TS-940 Supply Upgrade - FAQ
How much current does a TS-940 need?
In extensive testing using the TS0940 upgrade board, the radio requires 28V @ 14A, 21V @ 1.5A, 9V@ 250ma, and 5V at under 1A. The 28V supply is used exclusively for the final output stage. The switching power supply should be able to supply 28V @ about 15A peak.
Can I use an external power supply for the TS-940?
Yes! - Using just our supply upgrade board and a single buck converter for 21V, you can use your external 28V supply to run your TS-940. The board will be available as a kit and assembled so you can use your own 28V external power supply to run the radio.
Why are these internal power supplies such a problem?
The original TS-940 uses a linear power supply that outputs 28V, 21V, 10V, and 5V. The power transformer and bridge output combination starts with almost 40 volts which feeds all of the other circuits to drop the various voltages accordingly. When you start with 40 volts and drop it to 28V at 14A, things are going to get hot. The TS-940 can easily run 150 degrees when in receive mode. And when you transmit, it will get hotter. These excessive temps cause component failures. A shorted power supply pass transistor can easily destroy all of the boards in the radio. This supply upgrade normally runs at room temperature and can prevent a future catastrophic failure.
What we have learned about the TS-940
The Kenwood TS-940 is the best HF radio ever made!
The receiver is amazing, and the transmitter puts out more power than your average transceiver these days. It our testing, we can hear signals as low as .05 microvolts! I have never seen a radio that can perform that well. The design is amazing based on the age of the radio. But new technologies allow us to replace the power supply with a much more efficient option. The new Quint Phoenix switching power supplies have very little noise and an expected life of 500,000 hours. There are other power supplies and other brands that will work just fine as well. But the Quint supply fits perfectly within the case and leaves plenty of room to install an interface board to wrap the project up easily.
There are a few common issues with the TS-940
Common issues include:
1. A complete power supply failure which can damage the entire radio.
2. A shorted output transistor in the original power supply puts up to
40V through the entire radio and can render it useless.
3. Low output power is common and much of the time caused by
an RF output driver transistor that is no longer available.
4. A faulty attenuator resistor commonly shows up when the receiver hears better when the attenuation control is in the -10db or -20db range instead of the 0db selection.
5. The display produces dots instead of the normal frequency displayed numbers.
6. When you turn on the radio, the only thing that
happens is the LCD backlight comes on.
7. The radio is completely dead... We love this problem.
Might just have a dead power supply!
8. There are some modifications that can be made to enhance the receiver
9. The soldering technology back then was pretty bad and many of the problems today can be associated with cold solder joints.
Can these common problems be solved?
Most of these problems can be resolved by a technician with the proper tools, test equipment, and of course the knowledge. There might be hams in your area that have the ability to make these repairs as well. 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.