Recent content by antiquekid3

"Drawbacks of CVTs are their larger size, audible humming sound, and the high heat generation caused by saturation." https://en.wikipedia.org/wiki/Voltage_regulator#Constant-voltage_transformer

Unless I missed it, what are your voltage rails measuring?

FIDIA made CNC machines, so that would be my bet.

If one had access to a vacuum oven, I would think that would work very well and would allow for reduced temperature if you pulled enough vacuum, yes? Long enough bake time should help reduce air circulation requirements since the pressure is so low. Any idea if this has been tried?

I like the reed switch panel other than the fact that the switch can turn continuously, 360° and more. Just a funny quirk of it.

The one with reed switches is the earlier one. I think I have one of each. The front panel graphics do differ between the two to get the angles correct, as Doug brought up.

Are there corresponding polarity markings on the PCB that I'm missing as well?

Yes. A big difference is that there are no markings for polarity on the ones pictured. In my experience, those surface mount caps pictured are either good or very obviously bad. And a shorted tantalum will make itself known as soon as it catches fire and explodes off the board—at least in my...

Out of curiosity, how did you determine the caps need to be replaced?

Al beat me to it. Looks like the regulator board was used in the TU60 as well if I'm understanding it correctly. http://bitsavers.org/pdf/dec/unibus/DH11_EngrDrws_Jul76.pdf

You are most welcome! :)

Since it's only a DTXA rather than a DTCA DTXA, it will XOR the GO bit with 1, which was presumably set already, thus clearing it and only it. Without looking at it further, I'm not sure why they don't just clear all of register A if they want to stop it and return.

If you get SerialDisk running on your system, you can watch all of the transactions taking place in real time on the server side. I don't have a running system in front of me to show that at the moment, unfortunately.

Yeah, that's the one!

You may want to confirm that the 74LS family is acceptable for replacing all of the dead 74 family chips you find. My recollection is that there are some cases where only a plain 7474, for instance, will work. Factors include switching speed and the actual internal circuit of the flip-flop, in...