Saturday, 22 March 2014

Chinese Conundrum

I've been buying IS1790 playback chips from AliExpress. These are about 1/3rd the price of the 'official' chips from DigiKey. Lately though I have been experiencing failures of around 50% of the chips that have been delivered.

The supplied chips are obviously copies, and when they work they work 100% of the original. However, the only way to check if they function or not is to solder a 28 pin SOIC down and hope for the best. A bit inconvenient if it proves faulty.

So to allow me to check the chips before sticking them down I came up with this:



It's a Tagbits UMT board wired into a 28 pin SOIC ZIF (Zero Insertion Force) socket. This lets me plug in a chip and test it without requiring me to solder it to a PCB.

3 comments:

Steve payne said...

Hi
Had same problem ordered 30 x ISD1790 DIP and only 6 work 3 with background noise. So where to get them is now an expensive problem.I am also interested in miles tag equipment

Tony said...

I take pot luck with the super cheap deals on AliExpress, and when I have to buy from DigiKey

Tony said...

I take pot luck with the super cheap deals on AliExpress, and when I have to buy from DigiKey