[Kenwood] Kenwood TS-850

[Mike - wz5q@juno.com]

Howdy Y'all,
    The repair is to change out R2 and R3 which are 22 ohm chip 
resistors to 14 or 16 ohm resistors. I have repaired many boards this 
way and have never had a recurrence of the problem. This repair can be 
referenced on http://mods.dk/
    If your careful and have a good soldering iron (and a good eye) you 
can repair the unit while it is still attached to the RF motherboard.
    Another thing to check is the choke L605 on the RF Unit X44-3120-00 
(this is the board the DC-DC Unit mounts to) for an intermittent open. 
This choke supplys 14V DC to the DC-DC Unit. I have had this cause the 
same exact ALC problems due to the choke opening up and closing once the 
rig gets warm.
Take Care,

Mike
WZ5Q
from Deep Down in the Dark Dismall Swamps of the Calcasieu
http://www.wz5q.net



GALE STEWARD wrote:
> I agree and can almost guarantee that the problem is the DC-DC converter board. I've replaced two here and it is a pretty easy job provided that you are comfortable working on these radios. 
>
> This is a common failure with the 850 (and maybe other model Kenwood radios?). Has anyone ever done any troubleshooting of these boards to determine which component(s) are the cause of the failures? It's a fairly simple circuit.
>
> There must be lots of DC-DC converter boards sitting around waiting to be repaired! I know I have a few.
>
> 73, Stew K3ND (have 2 X TS-850S)
>
>
>
> --- On Thu, 10/14/10, Dick Wilborg, W1ZC <dwilborg at surfglobal.net> wrote:
>
>   
>> From: Dick Wilborg, W1ZC <dwilborg at surfglobal.net>
>> Subject: Re: [Kenwood] Kenwood ts-850
>> To: "LouisCableJr11" <louiscablejr11 at comcast.net>, kenwood at mailman.qth.net
>> Date: Thursday, October 14, 2010, 6:59 PM
>> Sure sounds like the dc to dc
>> converter board failing. Common history of problems. It
>> controls the ALC stability. Still available at Kenwood
>> Parts.
>> 73s, Dick, W1ZC 
>>
>> -----Original Message-----
>> From: kenwood-bounces at mailman.qth.net
>> [mailto:kenwood-bounces at mailman.qth.net]On
>> Behalf Of LouisCableJr11
>> Sent: Tuesday, September 14, 2010 9:38 AM
>> To: kenwood at mailman.qth.net
>> Subject: [Kenwood] Kenwood ts-850
>>
>>
>>
>>
>>
>> Hello to all, 
>>
>>        Has anyone ever had this
>> trouble? The Transmit power wavers 20 to 30 watts at full
>> power or any power setting it also wavers  . This
>> happen is CW or ssb with a tone , so you can see it happen.
>> All antennas are low SWR , so I have ruled that out. Ts 850
>> is used and looks used. I think someone was in there. It
>> transmits out of band, I like that  now I have 60
>> meters. Thank you for any help , W1DIG w1dig at arrl.net
>> ______________________________________________________________
>>
>>     
>
>
>       
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