Jan 13 2018

Repairing 23cm transceivers from Japan

Last week I’ve received a shipment with several 23cm capable transceivers from Japan. One was the Kenwood TM-541 and two others were Kenwood TM-833’s. The 833’s are quite unknown since there are only brought to the Japanese market. basically it’s the more familiar dual-band 733 but now with the bands 70cm/23cm.

The first 833s (10 Watts) received was a plain transceiver (no cable, clamp or microphone) and was in excellent condition.  Clean and keen! It even had the LED display modification.
The second 833 had issues. The transceiver worked on both 70cm as well on 23cm, but the receiver on 23cm was quite deaf. I was missing about 20 dB of signal. Since I’ve bought two it was easy to compare. The pre-amp fet died. The next problem was to find out what fet was used, but one email to repairmen Leo was answered within minutes helping me out. I’ve ordered a new one in the UK for 6 euros and hope to receive it within a week or so.
The TM-541 looked dead when testing. The rotary encoder is borked. When hooked up on calibrated and reference synct testing equipment at the radio club we found out that the frequency was 22 kHz off. Trimming the VCO solved this issue in minutes. Now I have to find an hour of time to carefully remove the display which helds the rotary encoder to clean and lubricate it.

The 'UN' FET, which is a 3SK274. Thanks, Leo from radioamateurshop.nl.

The ‘UN’ FET, which is a 3SK274. Thanks, Leo from radioamateurshop.nl.

Importing transceivers from Japan:

  • Japan has 435.000 licensed ham radio operators. It’s a big second hand market! Japanese transceivers even have a function to find a free channel in urban area’s like Tokio. To find free space, Japanese operators go up in frequency. So there are many UHF-radios vor 70cm and 23cm.
  • Japan has S-version transceivers for Phone class licensees. These have limited power. For instance the IC-7300S. The amplifier module differs from the normal version. There is no software modification to upgrade to a full transceiver.
  • Most transceiver displays use modified LEDs instead of small bulbs to light things up. This may look weard, but occurs that the liquid crystals in the display dry out.
  • Keep in mind, repeater shifts are 5 MHz on 70cm and 20 MHz on 23cm. Only if the rig supports ‘odd frequency memory’, they are usable in the EU; For the TM-833, use the TM-733 manual since this one is quite well available online. The 833 manual is only available in Japanese.
  • The default frequency steps in Japan (and the US) are 20 kHz, while in Europe it’s common to use 12,5 KHz stepping. Unless your transceiver is 25+ years old, it should support 12,5 Kc steps.
  • Not all transceivers come with microphone or cable. Be sure to double-check the photos and the (Google translated) description in the text.
  • Shipping from Japan will cost you about 30 euro and will take a week. Keep in mind that packages will be inspected by customs. PostNL will charge 17 euro for this ‘service’. If the value is more then 22 euro – and this includes shipping – VAT should be paid (+21%). If the value is over 150 euro, import tax should be paid on top of the PostNL and VAT fee. The amount depends on the category. Best is to label your packages as ‘computer parts’ by the sender. This has a 0% rating and there is a 95% change that if customs checks your package and sees a connector, they’ll assume its true.
  • A good place to buy is the Yahoo affiliated Buyee.jp. Select Auction and search for ‘1200 MHz’. It works just like eBay. But, when winning an action, choose the ‘Standard plan‘ for shipping from the seller towards the BuyEE facility. This will cost less than 10 euro in total. This parts differs from eBay since packages will be send to the BuyEE depot first.
  • When the package arrived at the BuyEE facility, they will store it up to 30 days for free. You can choose how to send it towards Europe. By boat is the cheapest solution but will take a minimum of 60 days. It’s also possible to consolidate several packages into one and there are options to use extra packaging since Post treats your package like a football.

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