Hi everyone and thanks for letting me in!
I was looking for 2504/1404 and the 2519b shift registers, it seems that these chips are no longer aviable at a reasonable price, is there somewhere some working clones of these chips?If not, I was wondering if a reproduction of those with an ATtint85 (for the 1404) and an ATmega328p (for the 2519b) is possible. At a software level it should work without problem, there's enought ram to store the bits. The main concern I have is the speed, an ATtint85 and an ATmega328p can work without an external clock source at 8MHz, this can be enought to sample the bit input and recirculate? Does anyone here who knows atmel assembly knows if these chips are fast enought with an interrupt driven sampling?
Thanks,
Toms98
Hi Toms98,
the 2519 can be replaced by 6x4557 mounted on a small PCB.
Circuit design is by Natas, the SMD PCB design is mine.
You can find all the information (along with links to Natas's page) to build it here:
https://p-l4b.github.io/2519/
Enjoy! :-)
Claudio - P-LAB
I've built such replacements for the 2519b, it works great even though it closes the beautiful 7.5k resistor stage. You can get a good price for the HEF4557 if you buy a tube of 50 or more at once. If you need a ready made one, I have a couple of pieces just for that occasion.
https://www.ebay.com/itm/185243661692?mkevt=1&mkcid=16&mkrid=711-127632-2357-0
Many thanks!
I prefer to use new parts to ensure a long life to my build and save some money.
Did any of you knows about a replacement for the 2504/1404 shift registers (even if it's not a drop-in replacement)?
@mackintosh_nik I just bought one of yours :)
I haven't heard about replacing the 2504 with modern components, so far it comes down to finding cheaper 1404 and 2804.
P.S. thanks for the order, I will send tomorrow.
In post #4, Toms98 wrote:
"Did any of you knows about a replacement for the 2504/1404 shift registers (even if it's not a drop-in replacement) ?"
There are still some 10,000 of those 1404/2504/2804 ICs from various manufacturers listed by IC brokers around the world. The problem is that if you want to build one Apple-1 and need 7 of them, you have the situation where you would need to buy 500 (or more) to get a good price.
This is the situation. Even for me it's nasty (I make these famous Apple -1 IC kits). You have to waste a lot of time with greedy usurers who want moon prices, many of which are just pretenders who don't even have these parts in stock, but would buy them from third parties and add their "skim", and once you found the (few) real sources with real stock, unless you buy 500 or 1000 there is no deal to be had.
It's not that these parts would run out of stock. It's just greed and usury which takes the fun out of our hobby. I bought my last lot of 1K x 1 dynamic shift registers for $1.25 each. This is the real, OEM level, fair market price, if buying OEM quantities.
If you buy from usurers (and with "you" I mean not only Toms98 but the whole worldwide Apple-1 crowd) then you encourage them to further jack up their prices. This bit me with the character generators, the Signetics 2513N went from $7 each to $150...$200 each, and YOU did that to us all, by buying at usurious prices.
So, please don't buy from usurers. Just tell them to FOAD. Boycott them. Only if they sell none at their moon prices, the prices will normalize.
Comments invited !