crogers1@umn-d-ub.D.UMN.EDU (Clyde Rogers) (12/23/87)
I just finished installing a Dove MacSnap 548s memory upgrade on my 512KE.
The computer boots up just as it should, and recognizes that it now has two
megabytes of memory. But not all is right with the world. My Mac now has
some sort of interference mucking about on its screen. A horizontal distortion
moves down its screen, and I can hear a sort of irregular ticking from either
the power supply or the monitor.
Any guesses as to what's wrong? Any idea what the ticking sound could be? Any
idea where the insidious interference could be coming from?
One or two more facts about my Mac, should you need them:
1. It is an original 128K Mac, upgraded to 512K using my
trusty soldering iron and a copy of Dr. Dobbs Journal.
2. It received new ROM chips and an 800K drive this past summer.
3. It has never needed any repair work whatsoever.
Any replies would be appreciated ASAP. I'll be monitoring my mail and the net
over the holidays, so your reply can't come too early.
******************************************************************************
Clyde Rogers crogers1@ub.D.UMN.EDU (this SHOULD work...)
University of MN, Duluth
******************************************************************************pswisnov@phoenix.Princeton.EDU (Peter S. Wisnovsky) (12/24/87)
I installed a similiar upgrade to my 512e. After experiencing some problems, I called Dove: they were very helpful, and said that most problems relating to memory failing (Note: get the 2 megabyte memory test from your nearest mac archive) related to a mismatch in the timings of the chips (I believe if the chips on your motherboard are 200ns one must solder in a 47Ohm resistor parallel to r10 (I had to do this) but since I am going from memory don't trust me on it) or that the voltage on the power supply was off (it should be between 4.90 and 4.92 volts: I also had to change this.) The upgrade has been fine since then. -- Peter Wisnovsky pswisnov@phoenix.princeton.edu BitNet: pswisnov@pucc Please use mail: this news feed is VERY unreliable.