On Wed, Jul 1, 2015 at 7:13 PM, william degnan <billdeg...@gmail.com> wrote: > The Microvax 3100 model DV-31BT4-A - what "number" is that model? > Originally I thought it was a "30" but then I found that there are 3100-30 > nameplates, so I must be wrong. Was there just a plain vanilla Microvax > 3100? Now you have me thinking I need to check for a battery. I need to > track down the hardware ref but I am unsure other than open it to see for > myself.
I just went and took a look at one of my MicroVAX 3100 Model 20 boxes. The label on the back says Model DV-31BT1-A. No idea what the difference might be between that and a DV-31BT4-A. The badge on the front only says MicroVAX 3100 just like your picture here: http://www.vintagecomputer.net/browse_thread.cfm?id=604 When you power it on what does it say for the KA**-* CPU version? If it says KA41-A then it is a Model 20. A KA41-D would be a Model 20e. Or if you were to open it up and look at the part number on the CPU board: 54-18856-01 MicroVAX 3100 Model 10 / Model 20 KA41-AA (90ns) 54-18856-02 VAXserver 3100 Model 10 / Model 20 KA41-BA (90ns) 54-18856-04 MicroVAX 3100 Model 10e / Model 20e KA41-DA (60ns) 54-18856-05 VAXserver 3100 Model 10e / Model 20e KA41-EA (60ns) 70-28103-01 InfoServer 100 KA41-CA 54-18856-06 InfoServer 150 Reference: MicroVAX 3100 / VAXserver 3100 / InfoServer 100 SYSTEMS Illustrated Parts Breakdown EK-A0372-IP-003 A0372IP3.PDF