[Elecraft] General SMD Soldering Question

[Wyn Hughes]

Thanks, Don:

I have a larger iron and will try that approach first. I could also have 
tried to source other caps but instinctively went first for something 
similar to what was there before.

Again, greatly appraciate your advice,

73
Wyn, VR2AX
----- Original Message ----- 
From: "Don Wilhelm" <w3fpr at earthlink.net>
To: "Wyn Hughes" <vr2ax at attglobal.net>; <elecraft at mailman.qth.net>
Sent: Thursday, July 27, 2006 11:29 PM
Subject: RE: [Elecraft] General SMD Soldering Question


> Wyn,
>
> If you have the hot air gun or oven and solder paste and know how to use 
> it,
> by all means go that route, but if not, then just use the Hakko - you will
> be soldering two widely spaced tabs on the capacitors rather than finely
> spaced leads like are encountered on SMD ICs.  Yes, the Kester 44 will 
> work
> just fine if the diameter is small enough to properly control the amount 
> of
> solder applied.
>
> If the copper area is large, crank the heat on the Hakko a bit higher or 
> use
> a larger iron.
>
> Since you have a 15 to 20 mm gap on the PC board, why not use capacitors
> with leads rather than the SMD variety (unless you already have the SMD 
> caps
> in hand).  The extension tabs that you add will likely have just as much
> inductance as the capacitor leads.  Of course, if this amp is for use at
> VHF/UHF, then  any extra inductance may matter, but likely not for HF.
>
> 73,
> Don W3FPR
>
>
>> -----Original Message-----
>>
>> This is distantly related to the mainstream of Q&A on this net.I
>> intend to use my new K2 to drive a Icom IC-2KL amplifier. Please
>> imagine for now, there is an intermediate amp between the K2 and the 2KL.
>>
>> One of the twin PA boards on the 2KL ( a backup, I have 2 of
>> them) is unfortunately, smoked. My immediate task is to solder a
>> pair of 1KV Syfer  ceramic SMD 0.1 mfd caps between two troubled
>> pcb tabs in the PA output coupliing stage, where the previous
>> incumbents were vaporized, by previous owner. I think he/she ran
>> it into a low R/high C load on 80 or 160.
>>
>> This is a heavy solder job at least as heavy as the KPA100
>> (judging from the manual). I think I may need to solder extension
>> tabs to the caps, which are about 5mm wide, to bridge a 10-15mm
>> gap between the tabs on the PA board. Of course, I need to clean
>> up all the carbon residu on the PA board and tidy up the tabs first.
>>
>> How does one go about this task? Is a solder iron loke a Hakko
>> 936 the best tool or should I use a hot air SMD soldering unit or
>> even an oven? Should I use solder paste or ordinary 63/37 Kester
>> 44? What temps shuld one use? I normally run the Kester 44 at
>> 750F, as per the recommendation on their website.
>>
>> Comments  much welcomed.
>>
>> Wyn, VR2AX
>>
>>
>