RetroBrew Computers Forum: General Discussion » Looking for a source for DM9368N

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Looking for a source for DM9368N [message #10460]

Thu, 19 October 2023 19:57

smbaker
Messages: 49
Registered: January 2017

Member

I'm looking for a decent source for DM9368N. This is a 7-segment display driver, notably used in Sergey's micro-atx backplane.

I chose to use 10 of the damn things in a recent project, only to find out that the 5 I had in stock (from some China eBay seller back in 2017) were all exhibiting random problems. I bought another 15 "tested" ICs (from some China aliexpress seller) this month, only to find every single one of them is bad, with exactly the same problem. So now I'm down to the one potentially reliable source I have, a US eBay seller that sells them for almost $6 each. Which I ordered and I'm keeping my fingers crossed.

Given that these are used in other retro projects, such as the micro-ATX backplane, I was hoping someone here might have a source. Otherwise I better redesign my project lest someone unfortunate soul decides to build one and runs into the same problem. I can buy TIL311 for less than I can get these DM9368 for, and that's saying something... Sad

Scott

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Re: Looking for a source for DM9368N [message #10461 is a reply to message #10460]

Fri, 20 October 2023 06:14

plasmo
Messages: 916
Registered: March 2017
Location: New Mexico, USA

Senior Member

Have you looked at utsource.net? They do have DM9368N for about $3.50/ea used. It is still too expensive for my taste. CPLD are cheaper than that and can do lots more.
Bill

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Re: Looking for a source for DM9368N [message #10462 is a reply to message #10461]

Sat, 21 October 2023 00:17

smbaker
Messages: 49
Registered: January 2017

Member

Yeah, I ordered some from utsource for $1.63 only to get an email in the middle of the night that their supplier didn't have them, asking me to cough up the difference between $1.63 and $3.50. This is better than what the US eBay seller has them for, but it's still very expensive. I went ahead and ordered a few to try. I have better confidence in utsource that I do in random aliexpress sellers. We'll see.

As for the project itself, I did a respin of my board to use TIL311. They're cheaper and use much less board space than DM9368 + display. That way when I publish the design, there will at least be a viable option for people to pursue.

The CPLD you mention, do you have one that can do current limited outputs? That's an advantage of the DM9368. I don't have the board space to add 70 resistors (or the equivalent dip-resistor packs). I'm also trying to keep the thing reasonably period-accurate.

Scott

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Re: Looking for a source for DM9368N [message #10463 is a reply to message #10462]

Sat, 21 October 2023 06:24

plasmo
Messages: 916
Registered: March 2017
Location: New Mexico, USA

Senior Member

For multiple 7-segment displays, I would use CPLD to multiplex the drive signals so only one display is on for a short time before moving to next display. Current limiting resistors are still needed, but only 7 resistors since they only need to limit the current of the one display being driven. CPLD is products of 1990's so not period-accurate to 1970-1980's.
Bill

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Re: Looking for a source for DM9368N [message #10528 is a reply to message #10460]

Tue, 05 December 2023 11:11

mikesmith
Messages: 80
Registered: March 2018

Member

I recall NS having a 4-digit LED segment display / panel meter with a Microwire interface in-period, but can't find any in the usual places these days...

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