[ICOM] IC-765 question

[Jack]

Is there a replacement/substitute for IC1 ?

On 4/25/2015 11:31 AM, Gary Fiber wrote:
> Look here http://www.ab4oj.com/icom/ps35/main.html
>
> Grab the PS-35 user manual  PDF. IC1 and R5 used to be problematic in those
> supplies too. R5 might have changed value, it is a current limiting
> resistor. IC1 would not fire off all the time as I remember. If you look
> through this manual and see the voltage change on the PCB layout, that is my
> hand writing hahaha. Funny to me to see my hand writing all over the net.
>
> Others here are more familiar with this supply than I am anymore, left Icom
> in 2001 so daily tech support is history.  When I was there 80 telephone
> support calls a day on all of their products combined was normal. My ear was
> tired at the days end ;)
>
> Gary K8IZ
>
>
>
>
> -----Original Message-----
> From: Icom [mailto:icom-bounces at mailman.qth.net] On Behalf Of Marc & Tricia
> Niebergall
> Sent: Saturday, April 25, 2015 7:48 AM
> To: ICOM Reflector
> Subject: Re: [ICOM] IC-765 question
>
> Gary and Rich,
>
> Thank you both for your input.  The fuse is cleanly soldered and power
> output is normal. At this point while I have the board out, I plan to change
> all the electrolytics as they are around 25 years old.  The freeze idea
> sounds like another good troubleshooting technique and will give it a try.
> The rig works marvelously; the only exception being this rather long pause
> on first start-up.  Sometimes the pause is rather short, a 1/2 second or so.
> Other times it may be as long as 2-3 seconds.  While 2-3 seconds doesn't
> sound like a long time, it seems like an eternity when it happens.
> I'm sure I will eventually find the cause.
>
> Marc
>
> On Fri, Apr 24, 2015 at 4:42 PM, Gary Fiber <gfiber at comcast.net> wrote:
>
>> Marc,
>>
>> If you are lifting the main board in the power supply, look at the
>> bottom for a flat bar about 1/4 inch wide by about 1.5 inches long.
>> That is a current shunt resistor. Check the solder joints at each end
>> closely for cracks. If they are cracked, de-solder that resistor clean
>> up the solder and reinstall it using some flux and  fresh solder. DO
>> NOY flow solder past the holes in each end of the bar as doing so will
>> change it's resistance. What happens is if there are cracks in the
>> solder the 765 will work fine up to about 50 watts but will not output
>> any more power when it is increased as the resistor would heat up a
>> bit, the solder cracks would open and develop a high resistance
>> connection. This was a fairly common fault in that and the other Icom
>> supplies of this type like the ones in the IC-761 and IC-751 series. I
>> wished I remembered other power supply issues but there were not that
>> many with those switchers. One good thing though the DC plug coming
>> from the internal supply that plugs into the 765 is the very same
>> wiring as an external DC power cord for Icom HF equipment, verify
>> this,  I remember the techs running those radios on the bench using a
>> PS-30 bench supply many times when I worked at Icom America.
>>
>> Gary K8IZ
>>
>>
>>
>> -----Original Message-----
>> From: Icom [mailto:icom-bounces at mailman.qth.net] On Behalf Of Marc &
>> Tricia Niebergall
>> Sent: Thursday, April 23, 2015 9:08 AM
>> To: ICOM Reflector
>> Subject: Re: [ICOM] IC-765 question
>>
>> Rich,
>> Thanks for another great idea.
>>
>> Marc
>> On Apr 23, 2015 9:01 AM, "Rich Dailey" <redailey1 at gmail.com> wrote:
>>
>>> In lieu of a meter, you might try the following: Let the rig run for
>>> several hours, or a day, and see if the power cycles on and off
>>> without the delay. If it is normal, lightly freeze spray areas of
>>> the power supply while cycling power until the delay reoccurs. Then
>>> localize the spraying to individual caps, until you find the
>>> culprit(s). Sometimes requires heating the area back up with a blow
>> dryer.
>>> Use to be the 'poor-man's' troubleshooting procedure, but not so
>>> much today, considering the prices I'm seeing for freeze spray -hi.
>>>
>>> Rich, N8UX
>>>
>>> On Wed, Apr 22, 2015 at 2:08 PM, Marc & Tricia Niebergall <
>>> mtniebs at gmail.com
>>>> wrote:
>>>> When pushing the AC on switch there is sometimes a pause of a
>>>> couple seconds before the rig powers up.  Other times it comes on
>>>> almost instantly.  This usually occurs on the first application of the
> day.
>>> Don't
>>>> know if it is a relay or an electrolytic capacitor taking time to
>>>> charge
>>> or
>>>> what.  I changed two 33uf electrolytics in the power supply that
>>>> were swollen, but no change.  Any suggestions are welcome.
>>>>
>>>> Thanks,
>>>> Marc-k7wxk
>>>> ----
>>>> 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/ To support QSL/QTH.net:
>>>> http://www.qsl.net/donate.html
>>>>
>>> ----
>>> 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/ To support QSL/QTH.net:
>>> http://www.qsl.net/donate.html
>>>
>> ----
>> 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/ To
>> support QSL/QTH.net: http://www.qsl.net/donate.html
>>
>> ----
>> 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/ To support QSL/QTH.net:
>> http://www.qsl.net/donate.html
>>
> ----
> 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/ To
> support QSL/QTH.net: http://www.qsl.net/donate.html
>
> ----
> 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/
> To support QSL/QTH.net: http://www.qsl.net/donate.html
>


-- 
Jack Hartley K4WSB / VP2MSB #1 DXCC Honor Roll QCWA OOTC "Celebrating 
over 1/2 century in Ham Radio"