Watts Up: Packaging to the End

Now that we have a working system, it’s time to package the new PSU so that it fits inside the SPARCstation-10. Given that the SS10 is a very slimline, cramped chassis, this took some ingenuity. I knew it would even before I started and had picked the PSU/components/mounting-location/etc cleverly to make internal mounting possible. But there’s a huige difference between theoretical “oh yes, that will fit in there” and the actual practicalities of allowing for screw-width, the mounting rubber grommets that the SS10 requires for drive bays, and so on and so on.

Craggy Island
In spite of not living on Craggy Island, it took four weeks to source a Dremmel-like mini hand-grinder/cutter/low-speed-drill tool. Hardware stores, ironmongers, friends and acquaintances all came up dry. *Eventually*, only yesterday (with RetroChallenge time running out), I found the last one in town in a petrol station, and snapped it up. Good job, too, because it would have been impossible to finish the prject without it.

Boxy Horror Picture Show
Two days, a complete weekend (apart from a break to play hockey) of measuring, marking, drilling, grinding, cutting, bolting, screwing, unscrewing, rescrewing… I’m exhausted, but got there in the end…

First up was fitting a fan (and the necessary cutouts and plastic bolts in each half of the plastic box enclosure obtained in Episode One)20150201_12044820150201_120521Oh yeah, and drilling the vent-holes. The fan blows “inwards”, from where the AC terminals will be to where the DC output harness and the vent-holes are – mandated by TDK NV1 application notes and handbook.

20150201_04240220150201_04242120150201_042444You will notice that the PSU is “raised” off the floor of the box by plastics bolts and a couple a “spacer” plastic nuts – necessary because the few surface-mount components on the underside of the PCB get slightly warm, so there needs to be at least some airgap there.

Final adjustment to the old APS-39 PSU chassis was a cutout to be able to route the incoming main cable so that it wasn’t in the way of the other cables:20150201_042527

Next up was a cutout in the main cross-bar of the SPARCstation-10 lid (originally intended to reduce RFI/EMI emissions from 1990-vintage disk-drives from effecting adjacent memory-modules, and vice versa, but not a problem these days, I won;’t be running a Seagate upside-down 10-platter 1st-generation thermonuclear Barracuda disk drive ever again!).

And here is the completed adapted new PSU all wired up:20150201_195913

Finally, and this took several hours of sweat and tears, was to mount and install this monstrosity in the chassis, using the SPARCstation-10 drive-mounting grommets, which have to be very accurately positioned so that it will just slot into place. But after a lot of fiddling, measuring, drilling and screwing, I got it into shape to just slide in (and more to the point, just slide out again if needed)…20150201_225747.

And the main trick is to hide the cables underneath the diskette drive, just about the only “unused” space in the SPARCstation-10 chassis. The end result is pretty neat and tidy:20150201_225849

Yes, you *can* relieve yourself of having to limp along with the original APS-39 PSU in a SPARCstation-10, but it’s virtually impossible squishing anything else in there, especially something that can provide 5.1VDC @21A, unless it is a naked TDK Lambda NV1-350-TT or NV1-350-TT-N and some clever home-brew plastics (the pre-boxed versions of the NV1 are too long).

Finally, never assume that ATX crimpable female blanks and a standard AWG-18 ratchet-crimp-tool will go perfectly together. They won’t. You’ll usually need to pre-cut the tangs on the blanks so that they’ll crimp properly with the tool you have. And in spite of all the advice *not* to pre-solder the wires before crimping, you will probably have to pre-solder when doing two-into-one crimps.

It’s done and works, but it will be a long time before I talk myself into doing this again! I’m off for a well-deserved kip now…. zzzzzZZZZZZZZZZZ


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