Hi Michael, Luckily it?s not the I-Cache that?s gone fut as the SROM test programs are shoved into I-Cache for the CPU to start up and initiate the test cycles. Testing of the B-Cache integrity is done from code moved into I-Cache. You should be able to run with B-Cache disabled for quite a while but it will be slower. Someone please correct me if I?m wrong (?). I?m not sure if the 800 5/500 is a 2.2volt system or 3.x or 5.x, but the 2.2?s cache is pretty susceptible to voltage drop-outs. I?ve had some problems a couple of years ago with my ES40. I recapped a VRU and some board caps and it magically worked again. It may be an option once you do source another part to resurrect the misbehaving one? Regards, Al From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Michael Holmes Sent: Monday, 2 October 2017 3:11 PM To: hecnet at Update.UU.SE; dectec at detech.info Subject: [HECnet] Alphaserver 800 5/500 CPU Module B-cache error Before I go looking on Ebay, I thought I'd ask here first. My Alphaserver 800 5/500 wasn't responding when I came back from a business trip. And when I rebooted it, I heard the 1-2-4 beep codes and no screen. Found out it means "Backup cache error. Replace the CPU daughter board" And I found out in the manual that "The system can be operated with the B-cache disabled until a replacement CPU daughter board is available." After re-seating the CPU board and the memory it still got the error beeps and changed the J1 jumper and it booted up fine. Does anyone know the impact of running with the B-cache disabled? The text in the system manual said the jumper setting "Allows the system to run despite bad B-cache until a replacement CPU board is available." How long can the system be run in this mode? just curious so I know how much time I have to watch for a reasonable price 5/500 CPU module to show up on ebay (since there aren't many VAX/Alpha geeks in DC on craigslist). Thanks in advance Mike Disclaimer The information in this e-mail is confidential and may contain content that is subject to copyright and/or is commercial-in-confidence and is intended only for the use of the above named addressee. If you are not the intended recipient, you are hereby notified that dissemination, copying or use of the information is strictly prohibited. If you have received this e-mail in error, please telephone Fujitsu Australia Limited on 02 9776 4555 or by reply e-mail to the sender and delete the document and all copies thereof. Whereas Fujitsu Australia Limited would not knowingly transmit a virus within an email communication, it is the receiver?s responsibility to scan all communication and any files attached for computer viruses and other defects. Fujitsu Australia Limited does not accept liability for any loss or damage (whether direct, indirect, consequential or economic) however caused, and whether by negligence or otherwise, which may result directly or indirectly from this communication or any files attached. If you do not wish to receive commercial and/or marketing email messages from Fujitsu Australia Limited, please email unsubscribe at au.fujitsu.com.