[hpsdr] Hot ADC

[Andreas Troschka]

On Tuesday 13 January 2009 19:53:40 Kjell Karlsen wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> I do not have a thermometer to measure the temp of the ADC but it felt  
> very hot, much more than I liked. I glued a small Heatsink on top of the  
> chip and it helped a bit. 

That doesn't solve the problem. Temperature *must* be lowered by correct thermal contact on the lower pad.
Everithing else is pure illusion.

> When I had a look at the  aeria on the bottom of   
> the board directly under the chip, I discowered that the solder may not  
> have melted properly when the board was produced. 
> There was no sign of   
> solder up in the holes below the ADC. 

This is a very serious production quality issue. Every board having such problems should be turned back to the sender without waiting a minute.
Who is responsible for the quality check at customer side? TAPR?
He (it) has to manage the problem now and not assuming we have to sit on the brocken egg!
Yes, somebody of us may be able to repair this problem at his own risk but the majority shouldn't wait to have their ADCs/boards cooked cause poor production quality.
Don't be fooled by the fact that at the moment the board works correctly. IC's transistors give up their souls randomly, and sooner or later (maybe in 12 days or months) you will start having strange troubles with the board.
 
> I resoldered the aeria and now the   
> bottom of the card is warmer than before. Unfortunately I can not confirm  
> this by measurements, but my feeling is that the chip is colder now.
> 
> Can someone do a tempereture measure before and after resoldering and  
> report back?
> 
> Kjell
> 

The best thing we can do is to contact the distribution manager and localize the exact lot of boards (any id numbers on the boards?).
This isn't usually a problem connected with one or two boards but with an entire lot.
Go on with pictures of the lower side corresponding to the adc and FPGA!

Don't e.g. "do not" try to resolder the components by yourself if you are not pro with this task. Home made solutions can't be the same as professional rework.

This my 50cents.

Regards

vy 73s de IK2WQI, Andreas Troschka
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