comments from Picaxe thread as pointed out by PaulRB:
Note that: - the end pins are "half pins" - shown as "full-pins" on the Maxim datasheet - the two moulding marks on the top - the lack of a dimple by pin one - underneath perhaps - two moulding marks with two alphanumerics in each and no extra printing? - end to end 1.171 inches - the vertical bar on the top somewhat inboard and full width
I've used MAX7219s from Tayda and while their appearance fits that of the fakes, they seem to work fine for me.
But recently I bought one of those 8-digit LED display modules on eBay, it had an SOIC MAX7219 on the back of the board. The thing worked, but drew about 300mA. The MAX7219 ran very hot to the touch. The LEDs themselves were OK, I removed them and it hardly changed the current usage. I breadboarded a similar circuit (with the Tayda part) and it uses less than one-tenth of the current.
Don't know if it was the MAX7219 itself or something else wrong with the board, but I demanded my money back. At first the guy wanted to give me a partial refund, saying "as our item is very low price ,it may be not as good as other ones that is more espensive for this case ,can we partial refund to ease you ?"
Of course his web page said nothing about the product being "not as good" so I got pretty direct with him and he did give me a full refund.
Once every few years I have to buy something on eBay just to remind myself why I shouldn't.
I have used about twenty of these cheapies in Marco's Parola boards and various other scrolling LED projects and they work perfectly. No excessive heat but now that Jack has mentioned the potential for high current consumption I will have a look at that but I think it's all good. Sometimes when I have run my eight board Bigger Parola boards from the USB port only because I forgot to plug in an external power supply it still ran OK.
As Jack said, you have to buy now and then from Ebay to realize that it's mostly junk...
(for example: cut the cheap chinese breadboard jumper wires and see what's inside, or rather... what's NOT inside...)
I also bought 10 Maxim 7219 chips but out of frustration I finally purchased some real ones.
For my DCF77 radio clock project, I used 8 Maxim chips in a daisy chain for the Common Cathode Displays and 1 Maxim for the Common Anode one.
But I noticed that at random, some displays showed strange characters. Also some LED's lit up very dim when they should be off.
I'm curious to see what happens when I use genuine Maxims when they arrive...
front panel text needs to be corrected but it's still a work in progress.
The cheapest I've found real Maxim 7219's is actually through Sparkfun. Granted, I'm going off their word in correspondence that they are buying direct from Maxim, but I trust their word more than eBay.