#976

[@visitslovenija]

I have a TM-741 with a dead 2m output module virtually the same as this one. Never knew about the crack issues, so after finding your video, pulled out the module and, sure enough, found an open circuit track and an almost invisible crack. Fixed and now working again. So really happy to have seen your video. Thanks a lot.

[@IMSAIGuy]

Great!

[@aheriady]

Legendary, TM241A, kenwood during 1990's

[@karlfell3768]

A nice easy fix. I have found that resting the module on a hotplate oe even an upturned laundry iron helps a lot with the dissipation issue.

[@kevinmccool3719]

Did this myself on tm241a in the 90s. Also same issue in an alinco dr130. Great video. Both were good basic 50 watt max 2 meter radios.

[@Dennis-uc2gm]

Remember the old Tektronix ceramic component terminals ? They always required silver bearing solder so the bond between the metal and ceramic wouldn't be damaged. I'd get yelled at by the boss when I worked in a cal lab back in the late 70's when he'd catch me with just regular 60/40 lead in a 565 scope 🙂

[@falandoareal4578]

PARA ABRIR O MÓDULO, COLOQUEI O MESMO EM UM PEDAÇO PLANO DE MADEIRA, FIXEI ELE COM PARAFUSOS LATERAIS E COM UMA CHAVE DE FENDA, ENTRE A CARCAÇA DE PLÁSTICO DO MÓDULO E A MADEIRA, DO LADO ESQUERDO, GIREI A CHAVE NO SENTIDO HORÁRIO E FUI DESCOLANDO A PROTEÇÃO DE PLÁSTICO FÁCIL !!! SEM DORES DE CABEÇA 👊😀🤙😎💪😜

[@billpowell5931]

Nice repair and explanation. What a nice entry level radio. Thanks for sharing.

[@pyrokinetikrlz]

it would be nice to take a look at the Toshiba module and see how it works

[@dh8dl]

The cracks are not coming from vibration or being dropped, it's coming from a different temperature coefficient of the ceramic substrate and the solder/tracks in the module. This module is just a bad design, i had to fix several of them. You can even see the cracks grow when you put a hot soldering iron to the tracks without getting the whole module to a high temperature before soldering on a hot plate for example.

[@IMSAIGuy]

that makes sense

[@joseppuig925]

A while ago in an exotic blog web page I saw this same module being modified for commercial radio use (88-108MHz) with just cutting the original coils and soldering the calculated new ones.

[@teste1177]

12:01min TEM 1 TRILHA MENOR (FINA) QUE TAMBÉM PRECISAVA DE 1 REPARO (MANUTENÇÃO PREVENTIVA) , BEM NO SEGUNDO PINO DO MÓDULO, OK ??? E O TESTE FULL POWER OU HIGH POWER ???? FICOU DEVENDO LEGAL !!! THANKS 🤙😎

[@DAVIDGREGORYKERR]

What about using the case for a new transceiver that does everything in software using a Texas Instruments DSP processor.

[@diemaschinedieviereckigeei2941]

Nice video! It would have been interesting to have a closer walkthrough on how this module works and the components therein. It seems to be a Class A Preamplifier combined with a Class C Output stage, where power is supplied by pin 2 (preamp) and pin 4 (amp), input at pin 1 (missing wire) and output at pin 3 (broken trace), I guess?. Very beautiful L/C matching structures. The black component in the middle, labeled TI could be a tantalum capacitor. But why is the negative side marked? Or is it a diode? These green-gray components on the right should be capacitors and the SMD part on the bottom right is a ferrite bead? Surprisingly feeble for that high current. Is the insulator ceramic made from beryllium oxide? It might be relevant to note to the viewers, that this is toxic when ground to dust. Edit: Oh wait, I think Pin 3 is power-in for the output stage and Pin 4 is the output. Then the green-gray components and the L make a Pi-Filter and the component in the bottom right is a coupling capacitor. That makes a lot more sense.

[@jerrydaugherty3781]

Procedure works on motorola MHW-720 series modules as well

[@Shawn_WW5JD]

Great video!! I have one of these 241a’s and when you turn it on it starts beeping and it’s like all the buttons are being pushed, and it won’t stop, it started as a intermittent problem and now it’s anytime it’s powered on. Any suggestions on where to start looking. I removed all the foam stuff that holds the buttons in could that be what is causing the issue?

[@IMSAIGuy]

take the buttons off, clean the pcb and buttons with alcohol

[@rfburns5601]

I had an Alinco DR-119 very similar to this unit. My output module got zapped by lightning. I replaced it with $35 module from RF Parts sometime back in the 90s. It got zapped by lightning again, and now it sits on a shelf with other broke stuff I lost interest in. I think the new module I bought was potted, and had no removable cover. I figure it'll keep sitting there. Oh hell, I just found one on fleabay for $32. Oh damn, you might inspire me to repair mine!

[@jeffreywyke368]

Use heatsink compound!!! Thin layer across the entire surface are of the rea of the module!

[@rfburns5601]

@@jeffreywyke368 I did. My Alinco had copious amounts of silicone under it. I replaced with normal thickness of silicone.Mine got zapped by lightning twice. Never was used in mobile service. Was base station connected to simplex phone patch. After second blast of lightning output modules available then in early 2000s were about $70. I think the whole rig was $120 new. I did not feel like repairing it. but finding one on fleabay for $32 might make me reconsider. BTW do you know where I can find a full service manual for Icom IC-245 - not the euro version? I have user manual and schematics that don't quite match mine.

[@joeteejoetee]

I, for one, question if this entire design is lead-free soldered, because I'd be GREAT if you would reveal EVERY instance that you discover "Lead-Free" solder joint failures - because we are all suffering from the total failure of ROHS solder connections over time, and EARTH will suffer forever without using Lead based solders from now on and forever. Leaded solders have connected and created the entire of Earths Electronic mastery, and we need to preserve and protect past electronics excellence, and ALL of it's soldering DATA.

[@markusm.lambers8893]

Very good repair, have a similar problem with my standard C-5200D a few years ago. But we missed the maximum output-power the radio could deliver! You explained that you forget to adjust the current-limiting adjustment, on the power-supply, but we didn't see, how much the power out, was on the "high" level, of the radio! Could be as much as 50 Watts and more? Only a question, but it will be interested to know, how much the max. power is on this 'kitchen machine' made by Kenwood. (Hi Hi !) 73 de Markus ; db9pz

[@mikekokomomike]

I bought one at a hamfest maybe 20 years ago, and the seller told me he replaced the original module with a 25 watt one. I have an ADI AR-146Chinese clone with a good 50 watt module for a spare, the ADI display has always been intermittent and the modulation on it never right. The Kenwood still running on a lower power module just fine. Did Mitsubishi make the module for the ADI?

[@IMSAIGuy]

I don't know

[@WElektronik]

I like the device, the monochrome green screen. when can i have a tool like that..

[@iblesbosuok]

Congrats Similar to what I've done to M57737 of TM-201A

[@sethlavinder]

Happen to know anything about the scrambled display problem these get?

[@IMSAIGuy]

nope

[@lawrencethompson465]

Don’t take this as gospel but I vaguely recall this issue likely was caused by a bad ground connection with the display unit. It has been 20 years since I used this radio. Good little units.

[@jeffreywyke368]

SURE HOPE you DID NOT put that brick back in without HEAT SINK COMPOUND!!! I was a Kenwood Commercial Radio Tech for years, and ALMOST ALL of the radios hitting my bench had VERY LITTLE... or NO heat sink compound!!! WHY... WHY... WHY??!!! A failure for Kenwood assembly procedures... for sure! Loosen that one back up and put some goop (thin layer... all the surface area covered)... Or you will have it fail AGAIN... especially at high power! Thanks for the video, but the heat sink compound should have been included here.

[@kd4nc]

Comparing the video at 6:00 Min there’s no sign of white on the chassis when he removed the module, but at 16:00 Min there is an uneven white substance that looks like he applied heat sink compound.

[@IMSAIGuy]

@@kd4nc yup. I put it on.

[@8du]

Looks apparent to me that Compound grease was used 14:30

[@jeffreywyke368]

Hope so... but that should have been mentioned.

[@Fanan67]

For the other project radio Icom, if the Arduino is to slow to perform all the tasks, maybe an ESP32 can handle it.

[@grllchiquitita_1029]

Cara reset radio rig clarigo L90,yg muncul tulisan CODE...radio hanya diam..

[@JohnTarbox]

What de-soldering tool were you using? Looks like it does a good job.

[@IMSAIGuy]

Hakko FR-301

[@kd4nc]

It costs $303 on Amazon but IMO it’s worth every penny… Get some replacement tips and filters if you buy one.

[@IMSAIGuy]

@@kd4nc yes, get a bigger tip also. the tips come in several hole sizes.

[@TeslaTales59]

Nice repair.

[@jeffreywyke368]

Yes... except he left out the heatsink compound. VERY IMPORTANT!

[@flyingfox8072]

I have one SHINWA M17 900mhz personal communicator. Don't know how to operate, /use. Anyone out there who can help me?

[@jjoeygold]

Ask the user if it has been dropped to cause the crack I wonder?

[@dh8dl]

The cracks are not coming from vibration or being dropped, it's coming from a different temperature coefficient of the ceramic substrate and the solder/tracks in the module. This module is just a bad design, i had to fix several of them. You can even see the cracks grow when you put a hot soldering iron to the tracks without getting the whole module to a high temperature before soldering on a hot plate for example.

[@camilocosta4239]

tenho um deste muito bom!!! pena que a rx dele esta ruim , so tem rx de transmissão fortes!!! ( I have one of these very good!!! pity that his ex is bad, only has strong transmission rx!!! )

[@graham2803]

Good video! I have a TK-705 that is running into the same issue - milliwatt-level transmit power, receives perfectly fine. I haven't cracked open the RF module case yet and I originally suspected the APC circuit was bad, but now, even after consulting with QRZ forums, I'm starting to wonder if this is the issue. It uses the same type of module, only branded as Mitsubishi. Unscrewing it from the chassis revealed absolutely no thermal paste at all. Really scary!!! I'll have a look this weekend.

[@donaldasayers]

I thought it was going to be a stand mixer...

[@galileo_rs]

Way too much for a broken one ...

[@tangoalpha8381]

MUITO BOM AMIGO 🇧🇷👍

[@R2AUK]

👍

[@sayiycarotv5764]

VERY GOOd VIDEO

[@YO9DOC]

GOOD WORK NICE JOB 73 de yo9doc