modified Franken'ed zero
Quote:
Originally Posted by Pricklely Peete  A stainless steel dental pic is good for the stubborn solder. Heat the solder up that is left over while carefully pushing the pic through the hole. The stubborn solder will be pushed out of the hole and won't stick to the stainless steel pic. You need to be careful when heating the board to do this and must not use excessive force to clean out the hole or overheat it enough to burn the pad/board. It's a fine line between enough heat and too much, enough force and too much.
A good method for removing the old diodes is to cut the legs as close to the top holes as you can get them. That way when you remove the solder from the underside the likely hood of not getting the hole clean in one go is lessened considerably. You can also lightly grip the one side with some tweezers and heat up the solder to remove the cut leg that way without causing any damage to the pcb.
Another good method for stubborn solder is to reflow some fresh solder into that hole and try again with the tool you use to vacuum the solder out with (manual pump, wicking material, or desoldering iron ).
Have a look at You Tube for videos showing the various methods you can employ for tricky parts and stubborn solder removal.
Good luck.
Peete.
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Good luck.
Peete.
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Thks for your detail advice, Peete!
Have to admit that it's really challenge for me to desolder on lead-free PCB.
Most of my experience has been limited to tin/lead solder of work.
The challenge mostly lies with the correct temp control. Been running the iron at 350- 410degC range (662degF-770degF) The lead-free solder cured in a much faster time, thus require prolong heating in some cases, thus increase the risk of heat damage and delamination.
A dental pic is a good idea, I've used a pointed compass tip to 'force out' the stubborn solder but it's still hard to prevent 'autosealing' of the hole from spent solder. Most of the time, the board will be standing on it edge, with iron on one hand, sucker on the other, i find that it speeds up things.
Diode removal is quite straightforward, using the pencil tip iron to heat-and-pry the whole row of legs on one side, and use a plier n iron on the next sets of legs, no cutting necessary.
Incidentally, I have checked out videos on desoldering techinique, but cant find any useful info.
I've no luck using the wick, despite 'pre-treating ' it by sanding, cleaning with IPA blah x3 , the darn wick just refuse to 'siphon-all-up'.
Update:
After spending near close to 10 hours of intense struggling with the mod, finally, i've manage to complete the mod- but scoring literally 'zero' in finesse and esthetic department. Most of the caps are standing way too high and in a messy manner to facitate soldering on the top pad.
After clearing up the messy flux and solder dust covered board with lots a toothbrush and IPA, i carefully position and fix everything in place, making a final inspection before power on, and when i whisper a silent prayer.....and press the 'ON' button.......in eager anticipation of the 'Moment'.... voila... The ultra bright blue and Red LED brighten up the whole room ! It works.... electrically, no magic sparks, no holy smoke!!!
On hearing check,
can= senn Px200
DAC= fraken'ed Zero( with original OPA), optical-USB to my beaten-up PC.
track= FIM Audiophile Reference IV -'Alexander Warenburg - Deer Hunter' ,FIM Audiophile Reference IV
- Esther Ofarim - La Vezina Catina (vocal)
No humming or any noise.The entire performance is very musical and fluid.It's a brand new way of listening to the same track but in a very different way- very emotional, lyrical flow of musical expression. Very detail... I can distinctly hear some friction sound from strokes of the bow against the violin strings, which i can't hear previously.Vocals sound very clear, sharp and real. The Dynamics is very good as well, with very good bass response with good seperation. I'm very
satisfied with all these- even before any burn-in !!!
Some minor changes i've made- UF diode replaced with UF4004 ( 50ns), 4x 47uF coupling caps changed to cerafine( am i right to say that the orginal silmic is supposed to be better than cerafine? hmmm)
. In addition to the russian greenies, i have another box caps installed before hand( cap-box-pio). wanted to post some pic, but might put some people off with the messiness.
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, because headphones which i bought from someone from this forum, didnt arrived yet. 
