The Kenwood TR2400
a late seventies vintage solid state  Handheld transceiver for the 2 Meter Amatuer Radio Service

This page contains the schematic and a copy of the USER manual. The user manual is provided for completeness only, it does not contain much usefull information. For the  service manual, see below. Its only taken me thirty years to get my hands on this manual!  The user manual did contain a serviceable schematic which was an extract from the official service manual.








The display has advanced "lcd cancer" but otherwise, despite the dings on the case, the unit still works after 30 years. 




I purchased mine in 1979 second hand complete with manual. (Thankyou Mr Bek, VK3BEK) I noticed other older Kenwoods' very fine Ham Radio products now appearing on various Boat Anchor Radio manual sites.  It has performed flawlessly for me for nearly thirty years. Only the LCD display has now got "LCD cancer" and half of it is now a nice tastefull shade of black on black background. It only shows the frequency in use and now I sort of have to guess what its chanel setting is.  The keyboard still works fine, so its still possible to punch in your desired chanel.  It only puts out one watt, but that was prettty much the state of the art then.  It was nicely made with a sturdy die cast chassis.

The only operational issue with this unit is that noise gets into the VCO PLL circuit on transmit and imparts a bit of noise. My associates refer to this unit as the "burble-phone".  I have tried to address this issue but have been thwarted by the very compact construction that makes troubleshooting challenging.


The only modification that I may yet undertake is to replace the lcd lightbulb. The little light bulb draws allmost as much current as the reciever, and will quickly exhaust the batteries. I shall yet replace it with a white led.

The microphone insert in mine is showing signs of age, the audio is not very good now.

It is still possible to pick up one of these fine units at hamfests, and if you do it could be a bargain, unless the previous owner has permitted the Nicad batteries to leak corrosive gunge into it.

The detachable battery pack contains 8 size AA nicads,  NiMh batteries would make for a superior substitute.

Here is the schematic mosiac. The tarball contains the user manual and the schematic sections for you to print and paste into one sheet. You will have to guess the function of most of the ICs for yourself.
Kenwood TR2400 schematic
click me to get the user manual tarball


This service manual for this set was kindly given to me by WB5WSV  .  Regretably I did not scan this, its is not very clear, it came originally from another European ham site, when I can dig up the original URL again I will provide the proper attribution and link. Refer to my schematic, it is clearer.

I have taken this scan and retouched the images with the GIMP.  They are now very readable and printable,except for the schematics  which are beyond redemption.  This was an interesting exercise in using something the more rarely used
image processing functions in the GIMP.   The BLUR tool can used (sparingly!!) to restore readability to a badly scanned lineart image.  The use of the  DODGE and BURN tool in "burn" mode after a BLUR  can restore readablilty of things like labels in areas that were stippled or crosshatched in the original and a lineart mode scan rendered  the image unreadable.
Use the DODGE and BURN tool in "burn" mode  to remove unwanted grey speckle from a browned/stained document or blueprint .  Use the CURVE tool in the COLOR TOOLS to construct a custom  gamma curve  to restore lost contrast.

Used the pdfimages tool  from the Poppler package  to extract  images from a PDF document.
tr2400-000.pbmtr2400-001.pbmtr2400-002.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmtr2400-003.pbmtr2400-003.pbm
tr2400-003.pbmthese images are only jpg thumbnails. click on the images to download the .pbm
(portable bit map )  image. This is the one to print from something like the GIMP.
Your windoze box probably cannot handle pbm formats, but there are many freeware image conversion tools that can.







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mod record  added email sig Thu Dec 10 17:58:19 EST 2009; Thu Jul 15 19:07:21 EST 2010 added service manual...be be added attribution for manual
added reworked , retouched images taken from the original PDF.  Notes on use of the GIMP