PDA

View Full Version : Kenwood TS-440s - unwanted frequency digits displayed



N2HTL
05-26-2010, 07:38 PM
First the good news... my FT-857D arrived and is waiting for me to play with at home... while I'm stuck at work!

In the meantime, my ever faithful TS-440 has developed an annoying issue over the years that I feel should be resolved rather than forgotten about now that I have a second rig. While I don't normally "key-in" frequencies on the number pad, the tuning of the 440s can be very slow and cumbersome especially without a fingerhole in the tuning knob. Tuning down a band like 10 meters can take several hours... thus my need to directly key in a frequency. :D

My problem is that every time I hit the number "3" button, the display fills in 3 or 4 "3s" rather than just one immediately after I press the button. I'm wondering if the circuit pad the button sits on is dirty or if there's another issue at hand. It doesn't do this all of the time... but more often than not. Now that I think of it, the "7" button does it as well but not as frequent.

Any fix for this?

Thanks for all replies.

Aaron

WE6C
05-26-2010, 09:06 PM
I had a police scanner that did the same thing. I cleaned under the keypad and that cured it. Maybe this will work for you. Bob

K6JEA
05-26-2010, 10:15 PM
Aaron,

If you get on the Yahoo Groups ts440 group and do a search on sticky keypad there are quite a few posts on this issue. Sounds like you need a bit of patience and luck to pull it off. Here is a link to one reply...

http://groups.yahoo.com/group/TS-440/message/4184

Good luck,
Jim

MW0UZO
05-27-2010, 10:29 AM
First the good news... my FT-857D arrived and is waiting for me to play with at home... while I'm stuck at work!

In the meantime, my ever faithful TS-440 has developed an annoying issue over the years that I feel should be resolved rather than forgotten about now that I have a second rig. While I don't normally "key-in" frequencies on the number pad, the tuning of the 440s can be very slow and cumbersome especially without a fingerhole in the tuning knob. Tuning down a band like 10 meters can take several hours... thus my need to directly key in a frequency. :D

My problem is that every time I hit the number "3" button, the display fills in 3 or 4 "3s" rather than just one immediately after I press the button. I'm wondering if the circuit pad the button sits on is dirty or if there's another issue at hand. It doesn't do this all of the time... but more often than not. Now that I think of it, the "7" button does it as well but not as frequent.

Any fix for this?

Thanks for all replies.

Aaron

Yes I have a fix for this, I have done this myself on a totally wrecked keypad, with excellent results.

You will have to dismantle the front of the radio so you can get at the keypad units. Take off all the knobs, the tuning knob, the screws behind it and the screws fixing the front to the chassis of the radio. You might have to take off the fixing nut for the mic socket too. Take off the plastic front.

The keypad units are fixed to the chassis front and the wires and plugs are accessible so they can be removed.

When you get the keypad units off, you will discover you can dismantle them. Do this with a clear desk and remember how it goes together or make notes.

You will see small metal disks inside that form the switch for each button. These have to be removed. From memory I think there is an adhesive piece of plastic holding them in, this needs to be carefully peeled off and put to one side.

The disks will now be removable. Clean the PCB and switch contacts thoroughly with switch cleaner. Get some metal polish, e.g. Brasso. You will discover that the underside of the metal disks is all tarnished, this is the reason for the annoying switch bounce.

Clean the underside of the switches with Brasso and paper towels or tissue until the tarnished metal has all gone. Then rinse the disk in switch cleaner and dry. Do this for all the disks.

Reassemble carefully and it will all be fixed. I fixed my keypad a few years ago and the bounce has not returned.

Dan 2w0uzo

MW0UZO
05-27-2010, 10:33 AM
An extra note is that you will know the disk is properly cleaned because it will be nice and shiny. The link posted above just uses switch cleaner, which does not remove the stubborn layer of tarnish which causes the bounce. Using Brasso will guarantee the bounce to be gone.

N0SYA
05-27-2010, 12:20 PM
Hi
Applying something like deoxit to the contacts may help keep this issue from arising in the future.

N2HTL
05-27-2010, 01:19 PM
Thanks for all the information, guys. I'll give that a try this weekend... that is... if I can pull myself away from the new 857D long enough. What an amazingly cool radio!

K8JD
05-28-2010, 03:00 AM
I have a used TS440s for my main rig for about ten years now and never bothered with the keypad until I did the mod to get on 60M.
When I tried to progrem the memory for the 60M "channels" I found this repeating digit problem and it took hours of re-entering the frequencies over and over until I finally got them entered. I suppose if I ever found another reason to mess with that keypad I could take the front off and get into the keypad with some contact cleaner but it hardly seems worth all that effort !
One way I found to speed up the tuning rate is to switch to AM mode while you are going from one end to the other and switch back to the proper mode (CW for me) when you arrive at the frequency you want..

K6DDX
05-28-2010, 05:29 AM
I have had the same problem and offer an easy solution that has worked for me. Last night I had it happen, mostly when I hit 8 it gave me a series of 8s. So I punched 8 about 50-60 times. Problem solved. I did it for the other digits as well and now all is normal, saving me from an involved job. Ya gotta use it once in a while, I guess.

MW0UZO
05-28-2010, 08:13 AM
I have had the same problem and offer an easy solution that has worked for me. Last night I had it happen, mostly when I hit 8 it gave me a series of 8s. So I punched 8 about 50-60 times. Problem solved. I did it for the other digits as well and now all is normal, saving me from an involved job. Ya gotta use it once in a while, I guess.

This does work, however if the problem has got quite bad, it comes back after a short period of not being used.

MW0UZO
05-28-2010, 08:17 AM
I have a used TS440s for my main rig for about ten years now and never bothered with the keypad until I did the mod to get on 60M.
When I tried to progrem the memory for the 60M "channels" I found this repeating digit problem and it took hours of re-entering the frequencies over and over until I finally got them entered. I suppose if I ever found another reason to mess with that keypad I could take the front off and get into the keypad with some contact cleaner but it hardly seems worth all that effort !
One way I found to speed up the tuning rate is to switch to AM mode while you are going from one end to the other and switch back to the proper mode (CW for me) when you arrive at the frequency you want..

It takes an long afternoon to do the job carefully, and its worth it if you can't enter a frequency reliably. As mentioned, contact cleaner on its own will not fix the keypad.

N0SYA
05-28-2010, 01:34 PM
Hi
You might also use some contact cleaner via a qtip or similar on every connector and mini-coax you can reach, after disconnecting them, of course.

WA4ILH
05-28-2010, 02:22 PM
... One way I found to speed up the tuning rate is to switch to AM mode while you are going from one end to the other and switch back to the proper mode (CW for me) when you arrive at the frequency you want..

Good suggestion from JD,... I use this method myself on my aging 440. Actually, I believe that if you switch to the FM mode, the tuning rate may even be faster than AM mode.
Tom WA4ILH

K8JD
05-28-2010, 04:36 PM
It takes an long afternoon to do the job carefully, and its worth it if you can't enter a frequency reliably. As mentioned, contact cleaner on its own will not fix the keypad.

I already had the front off to do a couple of function mods and it took a lot longer to get it back together than I expected.
Don't need to go through that aggrivation again just for a keypad that I may not ever use again :(
Yes, cleaning may not do it. I have replaced a lot of button pads on commercial portable and mobile radios and I doubt if Kenwood can supply model specific replacement parts for 20 year old Ham rigs.

K6JEA
05-29-2010, 12:05 AM
One way I found to speed up the tuning rate is to switch to AM mode while you are going from one end to the other and switch back to the proper mode (CW for me) when you arrive at the frequency you want..

Thanks for that tip. Hadn't heard it before.

Jim

ad: elecraft