Recently I got this card. I noticed that it has empty solder points for DRAMs and decided to upgrade it to fulfill memories. I soldered 8x dip20 sockets and 8x 100nF capacitors.
After put 8x MB81C4256A-70 - unfortunately the screen is glitching.
Probably 74F04 circuit and PAL/GAL is also needed (left side of card)? Finding 04 will be easy but worse case is cloning GAL... Any advice?
Cloning a GAL is not easy. They get protected usually and are not "readable" like an EPROM. Check this: https://www.edaboard.com/showthread.php?22087 … PAL-GAL-reading
I know but I am not sure if GAL is required. Perfectly to find photo of the same card but with already 2MB
I don't think the GAL is needed. I have one Tseng card that also didn't have the sockets soldered and I decided to add them, populated them and also got garbage image. I imagine the cards had a design flaw which is why the sockets weren't populated in the first place but I haven't explored it yet, but I don't really see any other reason.
T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜
There are also many unpopulated jumper pads and R7, R8, R11, and R15, which are maybe used to configure the card's amount or RAM?
With W32i a common issue is too low speed of drams (in 2MB mode). Here is a standard chip so 70ns should be good.
I will make some tests (populate only Bank1 etc) and maybe will discover something interesting.
Can you take a pic of yours card?
About jumpers - I will check with multimeter where traces are going..
I assume this is a 32bit card with 2-bank interleaving organisation and those chips are 256Kx4 devices. Thus I think address buses, the data bus and most of control strobes in those empty sockets are shared with already populated chips. Only 8 CAS strobes will be unique per a pair of chips (one strobe per byte) with dedicated wiring to the ET4000 chip to support the interleaving thing.
Et4000/W32 could also have a much less common 2MB end even 4 MB non-interleaved configuration with slightly different wiring of the address bus, but that shouldn't the case for your card.
One thing to consider is that the upgrade chips should be identical to already installed chips (same manufacturer, speed and even revision). That's because due to nature of interleaving, memory cycle compatibility is much more critical than if the upgrade would form a separate bank like on normal cards. If you can't get the same chips, you should replace even originals to have the fully matching set or face issues.
I put 16x NPN 45ns and initially looks good (I have to run some benchmarks). I had similiar annoying issues with W32i ISA when fullfiling to 2MB
mt777 wrote on 2020-04-05, 09:54:I put 16x NPN 45ns and initially looks good (I have to run some benchmarks). I had similiar annoying issues with W32i ISA when fullfiling to 2MB
I am curious:
Is it faster with 2MB? I thought that W32i and W32p do interleaving. But this is a W32 only.
Faster - I don't think so, only higher resolution in W95 will be possible.
And yes - it is only W32 but in 2MB mode - also problematic like w32i
