Jump to content

Help Identifying Mystery LC PDS Video Card

Recommended Posts

  • 68020

I ordered an LC with what I assumed was a co-processor card from a birds eye photo.  However, once I got it, it appears to be a video card.  The only marking is on the main chip but Googling the sticker revealed nothing.  It is a DB-9 style monitor connector and has 4 hm53461zp-12 video memory chips.  Anyone see one of these before?  Is it a single page display card?


Link to post
Share on other sites
  • 68kMLA Supporter
24 minutes ago, maceffects said:

The strange thing is that the DB-9 connector is removable. 

I bet there was a Mac model with an LC PDS slot that needed a backplate and wiring harness to reach the backplane.   Maybe the Classic II or Color Classic.


The removable DB-9 connector would have allowed the connection of a harness and back plate.

Link to post
Share on other sites

Sounds like a plan.


Doubtful you'll need drivers as they should be in the Declaration ROM. I can only recall a single instance where drivers were required for basic function of a video card and don't recall for sure if that one was Slot Manager/DeclROM architecture. Drivers in DeclROM are required for any VidCard to be the primary display on boot after POST, else you'd never see the :huh: icon indicating successful hardware check. Happy Mac screen indicating boot drive located would only be seen at some point after extensions/drivers were loaded, the process of which would be on a blank screen. I've never seen that to be the case and I have or have had and played with a very large number of VidCards.


Frantic driver hunts to get a card that doesn't appear to work at all would in response to output/sync rate/display mismatch as I see it, not a lack of driver support. Drivers add features, not the basic functions necessary for any VidCard to support a Primary or Single Display.


That's how I see it of course, others may disagree.


Edited by Trash80toHP_Mini
Apparently I can no longer typel ;-/
Link to post
Share on other sites
  • 1 year later...

I think I found the Data Sheet for the Chip (ICD2042) on your Circuit Board, it's a Dual VGA Clock Generator. It supports IBM VGA, XGA and 8514 graphic applications. The Data Sheet I found is from Cypress.


You also have a Crystal Oscillator (silver can) on the Circuit Board which is used to help generate vertical and horizontal frequencies for the CRT Monitor.


The large square Chip is a Field Programmable Gate Array (FPGA). Graphic Card Companies would program this type of chip as a Graphics/Video Controller.


It looks like you have a total of 128K Bytes of Memory, which means the Video Card only has enough memory for a Monochrome Display (Black & White).


Radius made a (FPD) Full Page Display Video Card (640x864) like yours around 1991 for the Macintosh Classic. See attached Image with square Chip and four vertical Memory Chips.  


Radius also made a (FPD) Full Page Display Video Card  (640x864) for the Macintosh LC around 1991. I never found a picture for it.  


Is there any numbers or letters on the back of your Circuit Card?

Classic Front.jpg

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...