Kachina 505DSP Transceiver    The origional software controlled radio

Users Resource Website



This section is our self-help area -- certain common symptoms of a problem often comes up, so here's some documentation about known problems and their cures.

It is possible that Kachina Communications Inc. may have changed things between first production and the final unit, so any description on these pages applies to the experience of the individual author with his own transceiver. Your own transceiver may differ slightly.



John, KA9CAR, has come up with a small modification for using an electret type microphone which may be of interest to you. It is found in this document mic_mod.pdf

PLL Tuning Cap

From Pedro, ON7WP, we have a neat modification to help with the 75.039 MHz circuit PLL drifting out of lock. With a small amount of work and one capacitor, it should cure the problem in most cases. WARNING: the very thin blue wires are actually coax cable interconnecting modules -- be careful not to break or pinch these cables! His nice writeup is at pll_mod.html

The Johanson 5201 or 5202 capacitor used has the followed reported availability:

Newark in One (their stock #17F154) for $11.92
Newark in One (their stock #17F155) for $11.91
Arizona Components Company, ???.
Surplus Sales (Lincoln, NE), ???

Also reported to work is the JFD glass piston 0-20 pf, about 3/4" long from Dan's small parts $2.50

[See hint about the large electrolytic capacitors in section below about the PLL]

For some 2003 correspondence from Kachina Tech Dan Kimball regarding alignment of module PC301, have a look at these JPEG copies:
page 1 and
page 2.
(Note: you may wish to download these images to your computer and then view them using one of various jpg file browsers if the page is not readable using your normal web browser. Each page is around 3/4 MB in size.)

PSK31 (and other soundcard) Interfacing

This is not really a "mod", but more a "How To". Here's one way of doing it by John, KA9CAR snd_card.pdf

From AE5K: I used a small kit sold by Buxcom for interfacing the sound card and PTT control and the Kachina 505DSP. I had problems with the PTT control and finally fixed it by addition of two resistors and a MOSFET. An optoisolator chip, the 4N37 was used in the original circuit to pull the PTT line from the Kachina low. Unfortunately, in my case it did not pull it low enough (still around 1.6 vdc) to turn on the transmitter. Since 12vdc is available at the accessory connector, I added the 2N7000 to do a good job of bringing the PTT line low. Anyone duplicating this might consider adding ferrite beads and/or bypass caps, not shown in the diagram below in case of RF problems:

Any More Mods?


Here is a PDF document (4 pages) from W3FRG detailing the cables and connections for the 505-DSP: cabling.pdf


One of the problems often asked about on the discussion list (reflector) is about apparent low power output from the 505DSP. In this section are some hints of what to look for. It is urged that you do all power testing using a dummy load able to handle the full (100 watts) power expected from the 505DSP as this eliminates factors such as VSWR and is good (legal) amateur radio practice.

There are two things to check for at the start of troubleshooting:
(1) Measure the voltage you are supplying to the transceiver under load (use CW mode, key down). If this voltage sags very much from the expected 13 vdc or so, that will affect output.
(2) Make sure it is not "cockpit" error in not having the controls set properly. In CW mode, run the power control slider to the right (maximum power), *AND* the mic gain slider to the right (maximum gain). The use of the mic gain slider is not intuitive, so don't be embarrassed if this is your problem!

Jeff Woods, W0ODS, gives this information:

After performing the above checks (and still in CW mode with both sliders to right):

a) Does the power meter in the control software show an accurate power reading? If not, what does it indicate and what is the actual power output?

b) Same conditions - switch the meter to view the ALC level. What is the reading (if any) on the meter?

An inaccurate internal power meter reading indicates that the problem is in the radio's directional coupler circuitry or the ADC associated with it. However, if no ALC indication can be seen per (b), then the PA is not getting enough drive power from the exciter or the cabling from the exciter to the PA is faulty. The exciter was designed with plenty of headroom, so the problem should be obvious once you know where to look.

(Thanks Jeff!)

Further suggestions: please discuss this on the reflector and we'll try to incorporate them here.


Precautions - ESD

During module handling, proper ESD procedures should be observed. If you don't know what this means, FIND OUT FIRST!

Precautions - the thin Blue Coax

We cannot emphasize enough the importance of being extremely careful in removing and reinstalling the cover watching out for the very small blue coax cables running between modules. See section on Repair Hints below for further instructions.

Module Removal

Starting with the plug in module nearest the front cover, module location is:
1 - PC401
2 - PC301
3 - PC201
4 - PC101

Modules may be unplugged from the "motherboard", but observe our warnings about the thin blue coax cables and other warnings, in addition to handling and reinstalling gently so as to not bend connector pins.

Precautions - mixing modules

Richy, N2ZD, advises: "Be careful swapping modules in the 505. The later modules have an "A" revision. As an example, a "non-A" revision tuner will not work in an "A" revision radio. The "non-A" has one connector and the "A" has two. The PC-401 module also has a similar revision, in that the early version (1.x, 2.X, 3.X firmware) will not support a 4.x upgrade even on a PCMCIA card upgrade. There are late 505's with MARS capable PROMS right on the PC-401 and others have the card upgrade and "non-A" boards with a retrofitted PC-401 card. The cards must be matched to the rig by closely following the revisions. Not all 505's are the same!"

Common Troubles

Serial Link

Loss of serial (RS232) communication between your PC's control program and the Kachina 505DSP can be caused by several things. Most likely there is a bad or incorrect connection of the serial cable or an attempt to use the wrong COM port. Another would be the zapping or other failure of the RS232 interface chips, either in your PC's serial port, or in the 505DSP itself. The chip in the Kachina is located in module PC401 (the long one next to the front plate of the radio) and is shown as a MAX207 in the schematic -- or on my board it is actually a HIN237CB (same as MAX237CWG). It appears at this time if this chip needs replacement, the TI MAX207CDWR or MAX207IDWR might be the best bet -- they have 15 KV ESD protection. Some simple signal tracing with a scope should determine where the problem is in case of actual signal failure. But make sure you have good cables and are using the correct COM port first! Use of one of those in-line LED indicators for RS232 will certainly help in the troubleshooting.

PLL Out of Range - Periodic Chirp

See the modication (PLL Tuning Cap) above for a nice writeup and solution to this common problem. Symptoms are inability of the radio to calibrate to WWV (or other frequency standard) and/or a periodic narrow sweeping "drift" of the radio. This drift has been described as a periodic "chirp" -- from every few seconds up to possibly a minute. You can hear it listening to a SSB or digital signal whereby periodically the frequency will jump slightly and then quickly drift back to the correct one.

One more tip from Harro, VK5HK:
The PC 401 board has a construction fault. A voltage regulator supplying the PLL and others has two 470 uF Elko's just sitting above it's heatsink. Those capacitors go therefore dry after the years. And the PLL goes berserk. It happened to all my three Kachina's. I replaced both with top quality 105 degree types, no Chinese el-cheepo's !

Battery Replacement

Although this has been a problem with a few 505DSP's, it will no doubt become a major problem in the next few years -- the original battery on the PC401 module will reach the end of its life. If the battery is disconnected or its voltage drops too low, the data in the RAM internal to the MC68HC16 microprocessor will be lost.

Early production used BR2325-1HG, about the size of a U.S. quarter, 23 mm diameter.


The C and D versions used BR1225-1HC, about the size of a U.S. dime, 12.5 mm diameter.


THERE ARE SEVERAL OF OUR GROUP WHO ARE ACTIVELY WORKING ON A GOOD SOLUTION TO THIS PROBLEM. Update: May 31, 2007: Please read KUN001 and KUN002 for the latest information. (KUN="Kachina User Note") as found on the Kachina_User_Notes page. Update: October 1, 2007: It appears quite possible in the future we'll have a firmware update available that would allow elimination of the battery. Stay tuned to our Kachina Discussion List or Announcement List!

Continuous Transmit

We need info on this one. Please discuss on list or email webmaster.

Continuous Tone on Receive

Apparently some condition in the KC505.EXE control program (the one you run on your PC to control the Kachina 505DSP) may cause the transceiver to produce a continuous "sidetone" during receive. If this happens to you, try putting the transceiver in CW mode and during receive depress and release the space bar on your keyboard. If this cures it, congratulations! If not, you might try re-installing the kc505.exe software. Note that you can have more than one install of kc505.exe as long as each are in their own folder/directory.

If you have had this problem and the "cure" above worked for you, it would be helpful to mention it on the Kachina discussion list (reflector) so we might know how prevalent this problem is. If anyone can figure out what conditions get one into this unwanted situation, speak up!

Thanks Harry-K6HS, Paul-AA4ZZ, Lasse-SM5GLC.

Power Connector

It's a Molex 0003091042. Here's a link to the Molex page:
and then plug in the part number, 0003091042, in the "search" box. Note that you'll also need to buy the four terminals for it; they're listed on the same page, P/N 42478.

At time of this writing, both Digi-Key and Mouser stock it. Digi-Key WM1333-ND and Mouser 538-03-09-1042. But neither appear to have the terminals with number listed above. Alternate terminals are shown on the Molex data sheet.

Thanks Jeff-W0ODS

Using Windows XP (and Vista?)

Users switching from Win98 to XP often find they cannot access the serial port for Kachina 505DSP control. All you have to do is to "right click" the mouse on the desktop icon, and there should be a menu that pops up, select "NT" mode, and it ought to take right off.

Thanks Harry-K6HS, Gil-WA5YKK, Allan-AB8AA and others

Using Windows 7

My Windows XP computer was recently upgraded to Windows 7. I was a bit worried that the Kachina software might not work as I think I recall people saying they could not get the Kachina running on Windows 7.

I set up my W7 32 bit version computer to run my Kachina yesterday. The install program does not work. The Kachina program was written for W3.1, and as such does not install anything into windows, it simply uncompreses the files and creates the Icons and program group for you. Those functions would not work in my W7 environment.

Here is how I did it manually:

1) Create a "Kachina" directory any place that is convienent to you. I put mine in Libraries as that is an area I regularly copy for back up purposes.

2) Get UNCOMPRESSED versions of the KC505.EXE file, and the "mars" version. I renamed them KC505HAM.EXE and KC505OPEN.EXE. Fortunatley I had made copies of the complete Kachina directory on my old pc so everything I needed was available.

3) Copy these files into the Kachina directory, along with configuration files if you have memories you want to tranfer.

4) Open the directory, and drag the two files to the desk top, and "create shortcut", don't move or copy the files.

5) The first time you execute the program, it may want to know the port number for the radio. It will want to know what operating system you have, I told it "NT". It may come up in "demonstration mode" in which the software on the PC seems to work, but the radio does nothing. Turn the demonstration mode off in the "Special", "Station settings" menu.

Unrelated to the W7 operations, is how I have run the "all band" software since it became available. I usually use the Ham version of the software since it keeps the bands straight for me and except for the Autotuner everything works on any frequency. If I need to use the auto tuner on 60 meters I switch to the "open" program. If both versions are both in the same directory the two versions of the program will share all configuration choices. When using the open program, then switching back to the Ham version, some of the "band stack" data will be wrong.

KA9CAR - John Dewey

Lightning and a Good Ground

Not too long after I put my 505DSP into service at a new QTH in Arkansas, we had one of our terrible thunderstorms. I had dutifully driven about 4 long ground rods the best I could into our rocky soil and connected them using varying lengths of heavy copper wire to a common point in the shack and thus to my Kachina 505DSP. I was also networking (LAN) the computer connected to the 505DSP to several other computers upstairs using coax. The antenna was completely disconnected and feedline away from the Kachina during the storm.

A nearby lightning strike took out the ethernet boards in all computers as well as zapping the serial RS232 ports on both the 505DSP and my PC connected to it.

I learned the hard way -- the NEC requirement that ALL grounds need to be connected together! The good RF grounds to my shack and Kachina was one end of the circuit, with the AC house wiring to the various computers the other end, and there must have been quite a potential difference between them during the close strike. It could have been worse. It's about 9 years later now, and not any problem -- the thunderstorms still come and go here! (Just ask my dog!)

--Don AE5K

Repair Hints: That thin blue coax

The connector is an OSSM type and the coax, AKA 0.085", is RG-174, RG-316, Etc. These connectors are readily available (not cheap) as well as the coax.

There are two blue coax cables that are connected in the second module from the front, which is module PC301, over a shield plate and PC201, to the terminating module PC101. To remove either PC301 or the PC101 modules, "Great Care" should be exercised in order to prevent breaking either of these fragile coax cables from their connectors or solder joints.

NOTE: These are NOT grounding wires, but mini coax, e.g. RG-174 type, 0.085" dia.

First, the 2 x 8 inch cover plate over the back modules must be removed to allow access to modules PC301 and PC101 which contain the small blue coax cables termination points. This cover plate is just a friction fit so just pop it up and off. With this cover plate removed, access to the terminating ends of the two blue coax cables can be seen and that any excess may be gently lifted free from between the modules where they are tucked away during use.

NOTE: Do not attempt to disconnect either of the coax cables from either end at this time.

One of the cables has a ground clip soldered to the coax braid. The ground clip can be slipped off the separating plate between modules. With these two coax cables now free, but still connected at both ends, which now allows the safe removal of the module(s) without destroying the cables, gently lift the PC301 module from its mating connector on the 505 mother board. Fold over and lay the removed PC301 module on the remaining modules at the rear of the main chassis with the finger covers on top, so that access can me made to remove these covers.

Removal of the fourth module, or PC101, where the blue coax cables are terminated can be removed in like fashion using great care as above. With both PC modules removed, they can now be relocated to a safe work place where adjustments or modifications can be performed safely.

NOTE: Remember, that during module handling, proper ESD procedures should be observed.

The coax cables are each connected via a type "OSSM" connector on the PC301 module, but at the opposite end, the center conductor and shield are soldered directly at the PC101 module.

Reverse the above removal procedure for replacing the module(s).