Re: Adding Additional VRAM to Cirrus 1MB SVGA

Background: http://ohlandl.ipv7.net/video/1MB_Short_SVGA.html

2MB Short SVGA

Without the help of Jolt, I asked about pumping up the 1MB SVGA-

  Pin 141 is right abouve the trace that goes to R27.

>Please point out the second pair of solder pads for additional memory on t=
he short 1MB.

Peter writes:=20
As far as I have traced the connections on the short Cirrus as well as on t=
he Reply Mod. 80 board you could solder another pair of 424260 (or 4C1627 f=
rom Micron) 1:1 over the existing chips - minus the pins 14 on the new ones=
.. These are the RAS pins, which have to be connected via a 22 Ohms resistor=
 to pin 141 on the CL5428 chip. It is marked OE* in the datasheet - but a f=
ootnote says it is RAS1 on 5426/28/29 chips for the 2MB RAM configurations.=

Question: Was this successful?  Are there more detailed plans?  Does the AD=
F need to be modified as well? =20

Happy holidays,
12/18/2016 4:47:27 AM
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Dim memories suggest not under NT4. Never did the mod, so I don't have 
first hand experience.

12/18/2016 2:02:59 PM

Originally equipped in 5521-YSB/YWB. Not available as an OBI. This 
adapter is Flicker Free. Ready to upgrade to 2MB ( but you need 
soldering work ).

Just solder SOJ DRAM chips at the solder pads.
Each pin # 14 of solder pads for additional VRAMs  are already connected 
to pin # 141 of CL5428 through 100 ohms resistor which is marked "R26".

Value printed atop of the resistor is "101".   Reply Video Board  uses 
33 ohms resistor for this connection.
12/18/2016 2:05:18 PM
On 12/18/2016 08:05, Louis Ohland wrote:
> http://sandy.blue.coocan.jp/Video/svga.html#CL5428%20SVGA

  Win9x builtin driver can detect 2MB and provide 1024x768 16bit mode
(if the system property is correct ).
  NT4 can detect only 1MB of VRAM even if additional 1MB have been 
12/18/2016 2:07:04 PM