Recent content by Alegend

You should be able to get a decent measurement and visuals even from a cheap-o-scope. Make sure you are using a 1:10 probe and that it is calibrated, calibrate using a clean square wave source or your scope's "probe comp" output if it has one. When connecting the probe's ground to your...

The power supply rail should be checked for sanity but has nothing to do with these spikes, as they are transient spikes generated somewhere in the working machine, and not introduced to the machine by the supply. You mentioned "spikier signals" on the faulty machine in general, so the issue is...

Digital ICs draw excessive current when switching, not when sitting at a sepecific logic level 1 or 0. The static fan-out load is a factor for the current draw of an output pin, but the switching is what really draws all the current. The shift register inputs, as you captured in the first photo...

Sorry about the link, here's the correct one: https://microvax2.org/wp/2023/05/03/microvax-i-vax-vms-4-7-successful-bootstrap/ There is a microvax2.exe file attached, built from one of the recent distributions. -Alon.

If you are familiar with simh you can use it to generate a standalone backup kit from within an emulated VMS system, on emulated RX33 floppies, you end up with three RX33 files (1.2MB each) that you then copy to the Gotek. Works fine on my generic Gotek. Procedure is here: Bootstrap guide -Alon.

Yes you must install a pull-up resistor for both the ready and write protect pins, so your drive is recognized and writeable. Any value 10K-100K should work. -Alon.

I had no problems using floppy images created by OpenSIMH. No conversions necessary, OpenSIMH is your friend for going most of the way towards a sucessful bootstrap. 1. Google "Installing MicroVMS V4.6 on SIMH" and follow the instructions. 2. Follow [my/any] instructions for creating a...

Take a look here: https://microvax2.org/wp/2023/05/03/microvax-i-vax-vms-4-7-successful-bootstrap/ I have achieved what you're trying to do but on a MicroVAX I. It should be pretty much identical on a MicroVAX II. -Alon.

Sure, each metal roller has a ~5mm circle in the middle. That's the spindle and that's where the oil should go. A tiny amount is enough. No need to disassemble anything. -Alon.

Not sure at all about how the TZ30 odometer is built, but the metal spool driving the odometer opto sensor could be faulty, oil may have dried up and it makes it difficult to rotate. Half a drop of sweing machine oil on its axle should help. Odometer sensor itself could also be faulty but that...

If it's anything like a LK402, then my post here may be of help: https://microvax2.org/wp/2017/05/24/lk402-aa-keyboard-fix/ Good Luck -Alon.

Not sure about that one, but I have three CDC disk packs that will. They are sitting on a shelf gathering dust so you can have them for a bargain 20000$ each , buy two get the third for free:ROFLMAO:

I prefer boards that are known working, I have two dead ones and don't need more. Untested will be considered also, bear in mind they are not very valuable to me at this point. Lots of QBUS boards for trade. Alon.

Yes, you need licenses. Going the legal way will most likely mean you will pay more on your licenses than on your 3100-40. It is not cheap running unsupported obsolete software packages on an unsupported obsolete OS installed on an obsolete barely-working dumpster-salvaged piece of hardware...

Not free, but with free evaluation versions and good enough for text editing: ZOC terminal IBM Pcomm -Alon.