| k0jdd | Posted: 7 Apr 2025, 08:47 PM |
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 Member Posts: 5 Joined: 6-April 25 |
This post will document the sources where I was able to find the necessary parts to build the clock. YMMV. A couple of parts were particularly hard to find at an affordable price and I had to resort to Amazon.com - MAX7219CNG LED Display Driver -- This part is no longer manufactured and the Maxim direct replacement part, the MAX7219CNG+, lists for over $17/ea at the US supply houses! Fortunately there many sellers for the MAX7219CNG on Amazon.com. I suspect these are NOT Maxim manufactured and that they are Chinese clones. But they can be had for about US$2 each. - 10016AS 7 Segment 1" Display -- I bought these on Amazon as well for about US$1 each with a two week delivery time. The closest match I could find in the US was SA10-21SURKWA made by Kingbright. But at US$3.22 ea for a quantity of 20 I can afford to wait for shipment. (I sure hope the dimensions are correct...) - GPS Module -- I found the XIITA ATGM336H on Amazon. Many sellers. - USB-A to 5.5mm x 2.1mm DC power cable - Found it on Amazon. I was able to get the other parts direct from Digi-Key. Here is the parts list: Desc // Digi-Key Part Number ATTINY4313 // ATTINY4313-PU-ND 20 Pin DIP socket // 1175-2553-ND Active GPS Antenna // 553-GPSMOD1315-ND Power Jack // CP-002A-ND 3mm Red LED // 67-1110-ND 2N5401 PNP // 2N5401YBUOS-ND LDR/PHOTORESISTOR // 1528-2141-ND Not listed: capacitors and resistors PC Board - From PCBway There is a referral link in the SHOP page for the clock that let you direct order the PCBs. (Min qty 5) I repeat the link here: https://www.pcbway.com/project/shareproject/mitxela_Precision_Clock_Mk_II_cf4850bc.html ------------- |
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| mit | Posted: 10 Apr 2025, 10:53 AM |
 yeah whatever Admin Posts: 588 Joined: 4-May 16 |
Thanks for sharing. Aliexpress is a good source of parts especially if you want to buy more of them, I generally would order a few hundred 7-segment displays at a time. Ebay has lots of sellers too. The thing to watch out for is to go for common cathode, they are often listed as "1 inch 10-pin CC". The part number often doesn't get you many results, but the "A" means common cathode, and common anode digits are labelled as "B". The last letter is sometimes "H" instead of "S", I'm not sure what that means. The Maxim chips are difficult to get at a sensible price, as you may have seen I once had a shipment of clone parts that was entirely dead on arrival. My technique for the last few years was to buy lots of them from different sellers, and test every single one in a ZIF socket before sending them out. ------------- |
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| k0jdd | Posted: 10 Apr 2025, 02:04 PM |
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Member Posts: 5 Joined: 6-April 25 |
I did read about your issues with duff parts. I have decided to spend an extra USD $1 per clock and add 24pin dip sockets for the MAX7219s's so that they are easy to swap out if necessary. Of course if I do that all the chips will be just fine. :) Cheers ------------- |
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