Em 12/3/2010 16:09, Marechiare escreveu:
>>> Majority expressed in what?
>>>       =

>> Total number of electronic products manufactured to date
>> (many now residing in land-fills or entering recycle centers).
>> Have a look at most electronic products manufactured for
>> consumers say: from 1965 to perhaps a couple of years ago.
>>     =

> My statement was about certain company which sells development tools,
> not consumer electronics. Besides, let's take a typical family:
> mobiles, mp3 players, computer cards and peripherals (HDD, DVD,
> printers, scanners, PSUs etc, etc) modern TVs, digital cameras and
> even battery chargers - many dozens PCBs - about all are double or
> more sided PCBs. Single sided, I can suggest from the top of my head,
> are only some single chip remote controls and some very cheap PSUs.
> How am I expected to come to the conclusion that single sided PCBs are
> majority?
>   =



I owned two DVD players that went dead. Both because the disk spin motor
was brushed and the brushes worn out.

Both had a large single side board with the much smaller decoder board
(this one fiberglass with four layers and a lot of fine pitch SMDs) and
the optical pick-up attached to it.

Both equipment had through-hole component with straight pins and some
SMDs also, soldered to the main board.

The main board hosted the power supply, output connectors,  keypad
circuit and the VFD display circuit, among other circuits.


Regards,

Isaac


>> Most of those products were manufactured with single-sided
>> boards with through-hole components.  I'm talking about:
>> TV sets (CRT-based), VCR's, radios, portable electronic
>> devices such as walkman units, cassette players, radios,
>> etc. I've been inside of many of those units - I used to spend
>> a LOT of time fixing broken electronics items for friends and
>> family back when I had the time and interest.
>>     =

> Yes, I did repairing 494 chip based computer PSUs and CRT-based TV
> sets and monitors among other devices. It was not quite rare that
> reheating some certain solder joints on that single sided PCBs did the
> job.
>   =



Me too, but is was due to the very poor soldering quality from the
manufacturers.
Most cracked solder joints I observed were on boards that the solder was
no more than an aluminum foil thick, not a good solder cone.


Regards,

Isaac

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