[ICOM] IC756PRO3 no tranmit and receive audio

[Phil Krichbaum]

PROIII and PROII are very prone to ESD problems and even blowing dust 
has wiped them out.  It takes out some FETs in the ant tuner and then 
next to zero power out. I had a PROII destroyed by lightening with no 
antenna connected, power off but Icom PS was connected to rig and off 
but plugged into AC mains.(PS is still in use 5 years later and needed 
no repairs).  Lightening came in  DC cord from PS, and CIV jack from 
computer that was off, CW jack on the back from the same computer. All 
damage seemed to come in via Neutral side of AC mains. Also lost phone 
answering machine, TV set, water well control relay and wireless router. 
Since then I had the power company install a  "Meter Treater" at the 
meters for about $70 each and no further problems. I understand this 
device costs the power company considerably more than the $70 they 
charge and is basically three big mother MOVs. Meter treater is probably 
a good investment. I'm in CO and we are number 2 state for lightening 
strikes, 2nd to FL. I had 5 close strikes in 2 minutes recently (2 
seconds from flash to boom) and one tree was set on fire and my neighbor 
put that out. I lost the well relay as the only other damage for the 
third time in 7 years. My well is 1/4 mile from the house so long power 
run to the pump.
    Phil N0KE

bonddaleena at aol.com wrote:
> I had a similar problem last year. The AC line took a direct lightning hit which fried a LOT of stuff in the house and radio room. The PRO had no antennas connected but somehow the spike took out some chokes at the acc connector. Few other diodes were toast as well. Receiver worked perfect, but no xmit.....
>
> ron
> N4UE
>
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> -----Original Message-----
> From: Stephen Budensiek <kzerosd at gmail.com>
> To: ICOM Reflector <icom at mailman.qth.net>
> Sent: Tue, Jul 30, 2013 4:08 pm
> Subject: Re: [ICOM] IC756PRO3 no tranmit and receive audio
>
>
> George,
>    I had a similar problem about a year ago with a IC-756Pro.   Do you have
> the CI-V connected to the computer?  Did you loose that also?  I had Q652
> fried, Q3772 was burnt, some chokes were burnt open around the back acc
> plug where I interfaced to the RTTY DSP audio in and out in the computer,
> IC311 and IC331 in the audio mute circuit was blown.   It had come in the
> demod line on the acc socket, and gotten several IC's.  Got it repaired,
> but it was a little crazy for abit.
>
> 73's de Stephen, K0SD
>
>
> On Sun, Jul 28, 2013 at 11:55 PM, George Szymanski <du1gm at dxhams.net> wrote:
>
>   
>> Has any one ever come across this problem?
>> I had a nearby lightning strike which caused a power surge complete
>> with sparking sounds from one ac outlet! The computer was connected to
>> the rig via the mic socket for digital modes at the time. The computer
>> motherboard went south and the rig does not transmit in any audio mode
>> but does transmit in CW. There is also no receive audio at all from
>> speaker or headphone. The display is fine, as if nothing happened, and
>> I can "see" signals as usual so the rest of the rig is fine.
>>
>> I'm guessing the problem may be in the 8V supply as that comes through
>> the mic socket and, perhaps the 8V regulator is dead. I don't know if
>> this supply is common to both transmit and receive audio.
>> Before I do any work I was wondering if anyone in the group had heard
>> of this problem before, can confirm my suspicion or can point me in
>> the correct direction if my guess is not correct. I can't really
>> follow the schematics as my eyes are too tired for all those lines!
>> I have a very old 756PRO with no display which I can use for spares.
>> I already checked the 8V regulator (on the PA board) on that rig and
>> it's ok to use.
>>
>> Thanks in advance
>>
>> George, DU1GM
>>
>> ----
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>>     
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
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>
>  
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
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