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IBM EGA Card Memory Expansion Boards
- Thread starter ab0tj
- Start date
Has anyone found a reasonable price on the (24) 4416 memory chips needed for this board ?
I've always wondered if it would be possible to modify the card slightly to use
fewer and cheaper memory chips (ex one bank of 256K chips)
I think it depends on how the memory is configured on the card, just seen as
192K or does the card access each bank separately.
I've always wondered if it would be possible to modify the card slightly to use
fewer and cheaper memory chips (ex one bank of 256K chips)
I think it depends on how the memory is configured on the card, just seen as
192K or does the card access each bank separately.
modem7
Veteran Member
There is a compatibility table at the bottom of [here].
You could win eBay auction 392596996728 really cheaply. 400 pieces of M5M4416P-15. Current bid: US $3.99. Put aside 24 plus some spares, then use the remainder as Christmas tree decorations (although, probably more appropriate as b-tree decorations).
eBay item 174023679712 (buy-it-now) is for 40 pieces of MB81416. That corresponds to about 50 US cents (plus postage) for each chip, and includes enough spares to last you until the death of the planet due of climate change.
maxtherabbit
Veteran Member
I would very much like to build one of these, are you willing to release the design files?
SunSpotter
Experienced Member
I'd be very interested as well. Also curious how much it cost to have this printed, and what the cost of components were?
IBM EGA 8-bit ISA Card with Memory Expansion Module 6480099 1501530XM
https://www.ebay.com/itm/283787270426?nordt=true
The Memory Expansion Card seems to be early type than IBM original EGA card.
I didn't bid it because I've already have IBM original EGA card (P/N:6278173XM).
https://www.ebay.com/itm/283787270426?nordt=true
The Memory Expansion Card seems to be early type than IBM original EGA card.
I didn't bid it because I've already have IBM original EGA card (P/N:6278173XM).
maxtherabbit
Veteran Member
I already have an IBM EGA, paying $200+ on eBay is unacceptable
ab0tj
Experienced Member
I don't mind sharing the design files for this. You can download KiCad and Gerber files here
I'd recommend using the longest pin header you can find for the connector. The most expensive part of the build is the memory itself. I found a decent deal on UTSource, but some patience watching eBay auctions might work as well. The rest of the parts (sockets, capacitors, etc) total less than $20 from Mouser.
I do also have some spare PCBs due to the minimum order quantity from the board house. Maybe $5 plus shipping? I really just need to open an Etsy shop or something these days :D
I'd recommend using the longest pin header you can find for the connector. The most expensive part of the build is the memory itself. I found a decent deal on UTSource, but some patience watching eBay auctions might work as well. The rest of the parts (sockets, capacitors, etc) total less than $20 from Mouser.
I do also have some spare PCBs due to the minimum order quantity from the board house. Maybe $5 plus shipping? I really just need to open an Etsy shop or something these days :D
maxtherabbit
Veteran Member
In preparation for this, I pulled out my IBM EGA and stuck it in my 5150. It works, but checkit is showing memory errors between 0A0000h and 0A001Eh. There appear to only be 8 memory ICs on the EGA, but I don't recognize the part numbers. Also do not know which one would correspond to this range. I've attached a photo. Any thoughts?
gslick
Veteran Member
inmos databook 1986
www.bitsavers.org/components/inmos/Inmos_Data_Book_1986.pdf
Page 2-15 (Page 82 of the PDF)
IMS2620 High Performance 16Kx4 Dynamic RAM
DESCRIPTION
The IMS2620 16K x 4 bit dynamic RAM is fabricated
with INMOS' advanced Double Poly N-MOS technology
and utilizes advanced circuit techniqes to achieve high
performance, low power and wide operating margins.
Multiplexed addressing and common data I/O allow the
IMS2620 to be packaged in an 18-pin, 300-mil wide
plastic DIP with JEDEC standard Pinout.
maxtherabbit
Veteran Member
I'll be damned! So there is no problem at all, good thing I didn't break out the desoldering gun yet.
maxtherabbit
Veteran Member
Excellent, thanks. Good to know they are JEDEC standard 16kx4 DRAMs in case I ever do have an issue with one
maxtherabbit
Veteran Member
Yeah I already tagged that eBay listing for 40x MB81416s that you linked earlier in the thread. I'll have plenty of spares after building the expansion card :D
maxtherabbit
Veteran Member
I ended up ordering this pin header for the project
https://www.digikey.com/product-detail/en/TSW-132-14-T-D/SAM1058-32-ND/
According to my measurements, it should be almost perfect and better yet it's a stock item at digikey
https://www.digikey.com/product-detail/en/TSW-132-14-T-D/SAM1058-32-ND/
According to my measurements, it should be almost perfect and better yet it's a stock item at digikey
ab0tj
Experienced Member
maxtherabbit
Veteran Member
I can now confirm this header fits perfectly in real life. Mouser also stocks it, ignore their incorrect description and just trust the part number.