Smeghead wrote:
snip

Also I don't recognise what you are calling Simple Green?
It's a biodegradable household cleaner that's relatively safe on most
things. It disolves the organic stuff that alcohol won't and vice versa.

I wonder
what the equivalent is in the UK and I have been reading the very good
posts on PCB cleaning / different sorts of flux issues etc, I need to
do it right and I guess the cleaning stage is vital not to use the
wrong stuff and make matters worse. I wonder if the cap values are
critical...with 100 or so to replace it sounds a bit of a nightmare to
keep track of which ones are which value...made worse by not having
pcb level part lists or schematics.
I guess you do the replacement one at a time..or are the values and
voltage ratings likely to be all similar?
There are only two values. I took the highest voltage and the highest
C combination and used that for everything. The caps were random leaded
surplus electrolytics. There's likely to be some board damage when you
do that many. Use a 0.1 1206 cap in each place. That takes care of high
frequency issues and gives mechancial stability for the leaded caps.
I did one without the smt and that seemed to work too.


The solder on the caps will be corroded. Do one end at a time to break
thru the corrosion gunk and get a shiny joint. Then use two soldering
irons with a slight twisting motion. When it get hot enough, the cap
will rotate and flip off the board. That makes the joint stresses
sheer and will less likely lift a pad.

Don't skimp on the cleaning. Clean it twice, then clean it again.
Use a toothbrush and scrub it good...

mike

--
Return address is VALID!