(This was originally a Twitter thread from May 7, 2019.)
May 7, 2019
New addition: Datavue 25 portable lunchbox PC. Keyboard stows on front, two 3.5 floppy drives, 13 pounds.
The screen pivots upward out of the case, presumably for a better view. I don’t know yet, it won’t power up. The power supply goes into the battery compartment.
Fuse was blown inside the power supply. I replaced it and it blew again. Nothing looks visibly bad to me. Some slight discoloration (old flux?). Bad cap(s) perhaps.
May 8, 2019
A tip from @UpLateGeek suggested the bridge rectifier as a starting point. I metered it in circuit and two adjacent pins are shorted in both directions so it may have failed. I have this spare BA20 but can’t find what the marking mean (E5A vs C3G). Thoughts?
May 9, 2019
Swapped in the new BA20 bridge rectifier. (One side was bad in the old one.) On the advice of @anachrocomputer I also checked the two switching transistors. All pins are shorted together. NTE379 looks to be a replacement for C3159.
May 13, 2019
Parts are in for the DataVue 25 power supply. These NTE379 will be stand-ins for the C3159 switching transistors.
Carefully bent the legs, added extra heat sink compound, and screwed them down. Put it all back together and tested. Voltages at 13.3V which I think is OK without a load. But will it power the DataVue 25 portable?
It works! Look at that screen! I don’t think I’ve seen yellow on red of this gas plasma display. Apparently this machine has a built in RAM disk function. Is that common on early DOS machines?
It also includes a resident dumb serial terminal in ROM. A key press brings it up instantly anywhere. That’s going to be really handy to have.
May 15, 2019
The DataVue 25 supported an external floppy drive as a “backpack” add on. Presumably it connected to this 34 pin connector. I assume this supplied power too? No pinout in the manual. It would be great to connect a Gotek floppy emulator here.Any guesses?
Do you have a DataVue 25 or similar lunchbox PC? Let me know in the comments!