fnjlh1@acad3.alaska.edu (HARRIS JAY L) (03/31/91)
While chasing some problem that caused intermittent lockup w/ black screen,
after trying heat and cool spray, and getting random bomb numbers, I finally
removed the ZRAM, removed the MMU, treated the little pins w/ Cramolin (neat
stuff), and reinserted. I tried to be carefull and worked on a static mat, tried
to account for the little interrupt insulation that the ZRAM uses on one pin,
but still ended up with .5M instead of the normal unenhanced 1M. I found this
very discouraging.
Is there a specific pin that addresses each bank of memory, and where,
as exactly as possible might it be on the mmu? Or should I bark up another
tree entirely? I also fiddled with the video shifter in the ZRAM removal if thart
could be implicated.
Thanks for any help. Stuck on my wife's 1M st... J Harriskclenden@silver.ucs.indiana.edu (Kevin Clendenien) (04/01/91)
In article <1991Mar30.204831.12866@ims.alaska.edu> fnjlh1@acad3.alaska.edu writes: > > > While chasing some problem that caused intermittent lockup w/ black screen, >after trying heat and cool spray, and getting random bomb numbers, I finally >removed the ZRAM, removed the MMU, treated the little pins w/ Cramolin (neat >stuff), and reinserted. I tried to be carefull and worked on a static mat, tried >to account for the little interrupt insulation that the ZRAM uses on one pin, >but still ended up with .5M instead of the normal unenhanced 1M. I found this >very discouraging. > Is there a specific pin that addresses each bank of memory, and where, >as exactly as possible might it be on the mmu? Or should I bark up another >tree entirely? I also fiddled with the video shifter in the ZRAM removal if thart >could be implicated. > Thanks for any help. Stuck on my wife's 1M st... J Harris Here are the trouble shooting instructions from my ZRAM board: MACHINE BOOTS FINE WITH NO EXTRA MEMORY: Visually check every RAM chip pin to make sure no pins are bent or out of the socket. This is very common. Other possibility is pingrid board is not making contact. Reseat pingrid board. If problem still persists make sure epoxy is still on the two pins of the pingrid board. If off, follow directions below. PULLING THE BOARDS OUT. AIRGAPS LEFT: If you pull out the pingrid board and try to boot up the ST, you will not be able to do so because of the two epoxied pins leaving air-gaps in the contacts. Inorder to fix this, pull out the MMU chip and take a pointed razor blade and pull the socket contact out towards the MMU. EPOXY FALLEN OFF: Follow above directions to pull out the MMU chip. Inspect the chip to make sure that all the MMU pins are straight and do not short on the bottom. Straighten with fingernails if needed. Now get some electrical or masking tape and cut a very thin piece and put it on the MMU socket contacts pin #8 and #18 where the epoxied sides of the pingrid board go in. According to the MMU pinout diagram the two epoxied pins, #8 and #18 are RAS0 and RAS1, respectively. I had the same problem with my machine only recognizing .5 MB of memory. My problem was that the epoxy had come off pin #8. If the instructions above do not help, try calling the company. They were very friendly, and helpful to me. ZRAM is made by: Zubair Interfaces, Inc. 5243B Paramount Blvd. Lakewood, CA 90712 (213) 408-6715 -- -------------------------------------------------------------------------- kclenden@silver.bacs.indiana.edu Kevin Clendenien BLAST BBS - (812) 332-0573 BLAST member "I want someone like you, only nicer."