KENWOOD TM241 PROBLEM

All:

I own a Kenwood TM241A 2M Mobile Transceiver which is used in a base configuration (not mobile) and I have a problem.

About a week ago I looked up at the radio and saw that it had a blank display and that the Dim Light was turned on and lit red. Up to this point it had been working properly with no problems at all except that every now and then the display would brighten and then dim at random intervals - I thought at the time that the display lights were getting weak.

I tried the re-sets that are listed in the manual and can only assume that they worked but the radio is still showing a blank screen and the Dim light continues to glow red - even turning the radio off and than back on has no effect on the radio. I even tried pressing all of the buttons in different combination's with no luck

The only button that functions is the DR/DT button and when it is pushed it gives me a series of 6 tones which I assume to be some sort of error code. A perusal of both the Operator Manual and the Service Manual has no mention of this at all and a comprehensive search of the internet revealed no mention of error codes at all for Kenwood Amateur Equipment.

Has anybody else experienced the same symptoms in a TM-241A and if so what was found to be the cause and how was it fixed.

Any help would be greatly appreciated

73 es Best Regards

Ian, VE3MUD
Mallorytown, ON

 

Ian -

Kenwood TM-241A/E Service Manual
http://www.repeater-builder.com/kenwood/pdfs/tm-241a-svc-man.pdf

M1HOG has a nice write-up with a photo on his web site -- as well as links for the Service Manual.
http://www.m1hog.com/projects/kenwood-tm-241e-repairs/kenwood-tm-241e-repairs.html

From your description (and age of this radio), the lithium battery may be failing (CR2032 with solder tabs). Kenwood Parts, DigiKey and retail Batteries Plus stores should have a suitable replacement.

The display problem is often noted -- M1HOG covers that.
Caig's Pro-Gold contact cleaner helps!

eHam.net product reviews -- many note display issue.
http://www.eham.net/reviews/detail/654?page=3

Preventative maintenance
http://www.seangri-la.com/cgi-bin/moin.cgi/Kenwood_TM-241_PA_Module_Repair

w9gb

Now back to North by Northwest .. one of Hitchcock's best!

 

TM-241 replacement lithium battery.

Just go get a CR-2032 from a drugstore. Using tape, or a piece of heatsrink that will fit, pressure fit 2 tabs of light sheet brass or something like that to the battery. Solder in and march on!

Replacement batteries are such a damned ripoff.

73 Doug

 

Another TM-241 problem.

While you have the rig open, take the mounting screws off the power amp module in the rear. gently take a small screwdriver and pry it away just a mm or 2 from the heatsink. If there is no white conductive grease between the two, go get some and put some in. I have seen DOZENS of TM-241's fail because of this issue.

Most of the time if your 241 isn't failing it either is a newer model from after the problem was caught, or had the output module already replaced at one time and the repairman saw the idiotic thing the Kenwood assemblers did and used some grease, like any person of the non-brainless plastic mannequin species would do in the first place.

Just rubs my asterisk the wrong way to even think about that issue!

73 Doug

 

Drugstores have the highest mark up for batteries!

Go to Batteries Plus retail store and they will spot weld the correct solder tabs for free (last time I went). Easy replacement.

I am often asked -- WHY did the Big 3 use solder tabs on lithium cells?
EASY ANSWER. Majority of these radios .. are Mobile Radios and lithium coin cells in the battery holders (e.g. Keystone and others) in the 1980s/1990s could "pop" the coin cell out with the correct "G" shock to radio.
Technology has now changed (again) that the need for external batteries to hold configuration or channel memories is not needed.

w9gb