Category Archives: Retro-Computing

Repair Progress on the H7826 Power Supply

I have been working on the H7826 power supply that came in the TURBOchannel Extender of my DECstation 5000/240. Normally, after a visual inspection, I will just apply power to see if a PSU works. This one, though, was not … Continue reading

Posted in Retro-Computing | Tagged | Leave a comment

Imaging RD51 From a DEC Rainbow 100 Model B

I recently acquired a DEC Rainbow 100 Model B, with a working RD51 disk. The disk is running MS-DOS 2.11. I want to preserve the contents of the disk before it fails. A while back I acquired the MFM Emulator board designed … Continue reading

Posted in Retro-Computing | Tagged | Leave a comment

Corroded H7826 Power Supply

Now that I have got the DECstation 5000/240 working again it is time to move on to the TURBOchannel Extender that came with it. This is in a terrible state, with lots of corrosion all over the place. The worst … Continue reading

Posted in Retro-Computing | Tagged | 1 Comment

Booting VAXen From The Network

Sometimes it is very useful to be able to boot a VAX from the network. The two most common scenarios are Your machine is diskless. As time goes on this is going to be more and more common as SCSI … Continue reading

Posted in Retro-Computing | Tagged | Leave a comment

DECstation 5000/240 Running Ultrix

Having recently fixed the DECstation 5000/240 PSU, I wanted to see that the machine actually runs properly and can run an operating system. I had previously had another DECstation 5000/240, which I had swapped for something else, but I had kept the … Continue reading

Posted in Retro-Computing | Tagged | Leave a comment

DECstation 5000 Model 240 PSU Fixed

I have finally fixed the H7878 PSU from my DECstation 5000 Model 240. When I last posted about it, the PSU was not working very well, it was unable to sustain any load. Following that post I asked for suggestions … Continue reading

Posted in Retro-Computing | Tagged | Leave a comment

DECstation 5000 Model 240 PSU Failing Under Moderate Load

The H7878 PSU in my recently acquired DECstation 5000 Model 240 had a shaky start and then stopped working altogether. I found a problem with the input rectifier smoothing capacitors, at least one of them anyway. It was a real job to … Continue reading

Posted in Retro-Computing | Leave a comment