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Rotten USB to RS232 adaptors.

So, opened it anyways, tools used also in the picture: ftp://panteltje.com/pub/opening_potted_usb_to_rs232_img_1011.jpg and the backside. ftp://panteltje.com/pub/opening_potted_usb_to_rs232_other_side_img_1018.jpg

You can see in the second picture that a small electrolytic cap has remained in the plastic... See how badly it was soldered, and a solder drop shorting to the ground plane. Some more stuff came lose, and in the first pic you can see some small resistors missing. Still 3 chips in this thing, why would they solder a 000 resistor(?) on top of the crystal?

Reply to
Jan Panteltje
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ned in the plastic...

lane.

sistors missing.

I think it's a little unfair to expect all parts to remain attached as you pry off the plastic. Kinda like driving a bulldozer through the house and then complaining that some of the ground wires broke in the wiring.

op of the crystal?

Do I see that right, the top of the crystal's metal can has a 000 (zerohm jumper I guess) resistor on the can itself? That's just weird. Filling a hole?

Tim.

Reply to
Tim Shoppa

On a sunny day (Mon, 30 Mar 2009 07:10:41 -0700 (PDT)) it happened Tim Shoppa wrote in :

Yes, true, and I was no longer going for 'get it out in one piece', as I have ordered new ones (hopefully better ones). It took a lot of force and a screwdriver to break the plastic lose. I could not see the PCB edge through the plastic, so went in from the side until I _heard_ hitting the PCB, then went back a bit.

Yes, could be, but there is a gap between the crystal and the resistor, it is not flat against it. Maybe a production number? To recognise the type of board or crystal?

Reply to
Jan Panteltje

On a sunny day (Mon, 30 Mar 2009 07:10:41 -0700 (PDT)) it happened Tim Shoppa wrote in :

Look at the soldering of C8, top left: ftp://panteltje.com/pub/usb_to_rs232_bad_soldering_img_1014.jpg

I think this could have caused the original problem, intermittent RF on the output..... It is just touching, but not really soldered to the SMD cap at all.

Reply to
Jan Panteltje

Perhaps it's the cheapest thermal insulator they could think of? E.g., perhaps the metal can conducted enough heat away from the plastic during holding that it tended to cause more air bubbles or somesuch in the casing?

Reply to
Joel Koltner

Shoppa

the output.....

Just my guess, but that looks like a production change to physically smaller device that was not properly accomodated by changes to the pick and place file. .

Reply to
JosephKK

..

ned in the plastic...

lane.

sistors missing.

op of the crystal?

As of the last few years, any of the converters I've bought have been good. In the dark ages, the Keyspan devices were all I would buy since they were the most compatible. I got some cheap arse Airlink 101 from Fry's that drives all my legacy devices, even under X64. It uses the Prolific chipset.

Reply to
miso

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