Date
1 - 10 of 10
Tm-V708A no audio/beep
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I got this radio as a broken, panelless radio. Got a tm-d700 panel, I can do each and every function, radio has tx and rx. But no speaker audio whatsoever. No beep from keypresses and no squelch action. Same happens on the tm-d700. Of course, I have reset the panel on the menu and the radio on the reset button many times. I diagnosed the problem on the panel CPU. For every command in the panel, there is a serial message sent by the panel. When you change volume/squelch there is also a message genersted by the panel. I traced the variable voltage generated by the volume/squelch pots up to the panel cpu pins, and there is no message sent in the serial bus. Since I can access every otjer funcion besides volume/squelch, I assume the panel CPU has clock, etc. Working. The problem seems to be isolated on the A/D part of the CPU. I cant see this problem as anything but the panel cpu. Since this is an expensive replacement, I ask for help from the elmers, maybe I forgot to check something... Thanks and 73 de PU2SEX Alexandre Enviado do meu Tele-Movel |
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Sorry, I completely forgot I had already described my problem here... Enviado do meu Tele-Movel Em seg, 21 de nov de 2022 05:00, Alexandre Souza via groups.io <alexandre.tabajara=gmail.com@groups.io> escreveu:
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Alexandre, have you opened the radio body and made sure the radio's speaker is plugged in (and functional)? Or have you tried an external speaker?
I'm trying to follow your explanation but it sounds like two separate problems. I'm not familiar with the TM-708 so that doesn't help either. Joshua |
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Oh, sure...Thanks for asking
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Em 21/11/2022 11:22, Joshua KJ7LVZ escreveu: Alexandre, have you opened the radio body and made sure the radio's speaker is plugged in (and functional)? Or have you tried an external speaker? --
---8<---Corte Aqui---8<--- http://www.tabalabs.com.br - Main site http://tabajara-labs.blogspot.com - My blog http://www.tabalabs.com.br/esquemateca - High-Quality Schematics FREELY avaiable |
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R. Patrick Ryan
I have a TM-D700A model and offer that the CPU appears to be muting audio and beep tones due to a menu function, AND/OR a menu setting selecting SPEAKERS internal/external-SP1 and/or SP2 Refer to link pages: http://rockdalecountyares.org/attachments/Kenwood_TMD700OwnerManual.pdf KEY BEEP ON/ OFF Page 69 CHANGING BEEP VOLUME Page 69 S-METER SQUELCH, Page 68 SPEAKER MUTE Page 72 CHANGING SPEAKER CONFIGURATIONS Page 72 Hope this helps 73 de Pat R. Patrick Ryan ARS: KC6VVT, ASEC/IL, OES/IL, Grid: EN51lf, email: kc6vvt@... Facebook for ham related: http://www.facebook.com/KC6VVT/info
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R. Patrick Ryan
Alexandre Additional added links Note the audio switching is done in the cross point switch IC702 that is controlled by the CPU See information in Service Manuals http://www.radiomanual.info/schemi/KENW_VU/TM-D700A_E_serv.pdf https://www.manualslib.com/manual/764293/Kenwood-Tm-V708a.html?page=7#manual 73 de Pat R. Patrick Ryan ARS: KC6VVT, ASEC/IL, OES/IL, Grid: EN51lf, email: kc6vvt@... Facebook for ham related: http://www.facebook.com/KC6VVT/info
On Sun, Nov 27, 2022 at 3:39 AM Alexandre Souza <alexandre.tabajara@...> wrote: Oh, sure...Thanks for asking |
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Well, fixed it =)
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In the end, it was a very simple problem, but I wasn't able to pinpoint it corectly. I'm not the brighest apple, you know.. The radio turns on/off the amplifier and the internal fan using Q912, a 2SB1386. 13.8V comes from F901, passes thru Q912 and goes to the fan (thru F900), IC806 which is the audio power amplifier (LA4446), buffer amplifier (NJM2904V, IC805), AF Amplifier (IC802, TA75S01F) and line 37 which goes to other parts of the circuit. Since I had no audio, I came from the loudspeaker to the switch matrix to see where the signal stopped. There was NO 13,8V on the audio amplifier. Replacing Q912, when any loud sound was played by the radio (like the keyboard beep) current comsumption goes to heaven and my power supply limitted at 5A turned the radio off. Changing the LA4446 and Q912, restored the audio Since my front panel CPU is still broken, I used AQ 0,10 on the serial port (remember, I modified it to a TM-D700) to raise the volume, and audio played flawlessly =) Now, gotta buy another front panel CPU or an entire CPU board. Or, if any of you has a broken front panel or working CPU willing to sell =) Thanks and 73 de PU2SEX Alexandre Em 27/11/2022 16:59, R. Patrick Ryan escreveu: Alexandre --
---8<---Corte Aqui---8<--- http://www.tabalabs.com.br - Main site http://tabajara-labs.blogspot.com - My blog http://www.tabalabs.com.br/esquemateca - High-Quality Schematics FREELY avaiable |
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Oh my...Kenwood, why make my life so complicated :\
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Ok, fixed the (now) TM-D700. Everything works, but the audio/squelch pots. This fault is already traced to a faulty CPU on panel and can be fixed by some $100 in USA with a new panel board from pacparts. Being a third-world-guy, that is a lot of money, so lets look for a cheaper solution. Using the PC connected to radio I can use the AG command to control the volume and the SQ command to control the squelch. Already tried, everything works. So, I can find an easy solution. I though. Got an Atmega8 (no arduino for you, guys), a MAX232, wrote some 40-50 lines of code, added 4 pots and created a small device that sends the correct AG and SQ commands thru the serial port to command the radio. Easy enough, eh? Of course, life is NEVER easy when you're talking kenwood. The serial port of the radio requires honoring of the CTS/RTS signals, and in a VERY strange way I have never saw. If I turn off the cts/rts wires from the serial port from the PC, it does not work either. So I have to honor CTS/RTS The question is: I have programmed it in all ways I know. I'm not a strange to serial port, and there is NO way I could make it work yesterday. I spent some 5 hours trying to make this circuit/code work, and nothing, simply NOTHING can make it work. Radio is perfectly controlled from the PC, but my circuit does exactely nothing. I'll eventually make it work. But man, what a troublesome process. Kenwood, thanks for the fishes! :\ Better a radio with an "external volume/squelch control" than no radio =) " 73 de PU2SEX Alexandre Em 29/11/2022 06:36, Alexandre Souza via groups.io escreveu: Well, fixed it =) --
---8<---Corte Aqui---8<--- http://www.tabalabs.com.br - Main site http://tabajara-labs.blogspot.com - My blog http://www.tabalabs.com.br/esquemateca - High-Quality Schematics FREELY avaiable |
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Jess Haas
Connect the CTS and RTS lines from the radio and it should work fine. That way whenever the radio serial port asks if the line is clear the asking signal will itself be saying yes it is. The basically just disables hardware flow control which isn't really needed anyway. I do this to use cheap bluetooth serial dongles and have never had a problem. -Jess K5LLI On Thu, Dec 1, 2022, 1:19 PM Alexandre Souza <alexandre.tabajara@...> wrote: Oh my...Kenwood, why make my life so complicated :\ |
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Update: It worked. Nothing like a good night of sleep to find bugs in code =)
Em 01/12/2022 09:35, Jess Haas escreveu: Connect the CTS and RTS lines from the radio and it should work fine. That way whenever the radio serial port asks if the line is clear the asking signal will itself be saying yes it is. The basically just disables hardware flow control which isn't really needed anyway. I do this to use cheap bluetooth serial dongles and have never had a problem.Jess, I think you haven't understood the question I'm not willing to use a PC to control the radio. My radio has a broken panel, it does not send volume/squelch information to the radio thru the panel cable. I created a device with 2 pair of pots that connects to the serial port of the radio, and works as the volume/squelch controls of the panel Video in: https://www.youtube.com/watch?v=j7rt1NIK3ts Unfortunately, I have no access to a working panel, so I could decode the serial comm between the panel and the radio, and I would do a cleaner fix - I would insert a microcontroller inside the panel to read the pots and send the commands thru the serial link of the panel as it normally is. That is what I can do at this moment. And it works. Now I have a great dual band radio I can use on my car \o/ Hope this info someday will be useful to anyone 73 de PU2SEX Alexandre -- ---8<---Corte Aqui---8<--- http://www.tabalabs.com.br - Main site http://tabajara-labs.blogspot.com - My blog http://www.tabalabs.com.br/esquemateca - High-Quality Schematics FREELY avaiable |
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