Years ago, I had realized that 800ma of 15V was not enough for all the MOTM modules in one Dot Com walnut cabinet (26U). At that time I upgraded one cabinet to a Power-One HBB15-1.5-A to get 1.5A per rail of plus and minus fifteen volts.
And I solved the need for +5V in a few modules, by installing a Power-One HTAA-16W-A triple voltage supply with +5V into the two top cabinets, together with the existing HAA15-0.8-A.
The cabinet pictured above shows the old dual supply setup. I used this for many years and it worked OK. But when it came time for recapping supplies, I decided to get rid of the +5V in these cabinets and upgrade to using one 1.5A supply. Power-One has been superceded by Condor, with the equivalent model being the MBB15-1.5A.
The Power-One, on the left above, has been recapped and reused. On the right is a brand new Condor 1.5A supply. The most obvious difference is the fuses on the secondary side of the transformer on the Condor. While the Power-One specifies a 1A power line fuse for use on the primary side with 120VAC, the Condor specifies 1.25A. But I left the 1A fuse in. One of the downsides of having two power supplies in one cabinet, was that they shared an AC line fuse. Not so good, as each supply specified a 0.8A fuse. The new, single-supply arrangement is much better, fuse-wise.
Pictured above is one cabinet with the new Condor supply. Below is the other cabinet, with the Veeblefetzers installed. I kept the MOTM distribution boards with 6-pin headers, because they can connect to a 4-pin cable, if one is careful to align it properly.
What about the modules needing +5V?
Five modules were using +5V. Two of them were Veeblefetzers, which were built with a jumper enabling external OR internal +5V. That was easy. And I removed the +5V wire from the Veeblefetzer power cables, which have the six-pin MTA header used by Synthesis Technology for power distribution that includes five volts.
Two of the other modules that used +5V were Modcan B. They had been modified to use external +5V, for which there was a provision on the power header. For those two, I added onboard regulators, which have a location, but weren’t installed. A 43 ohm, 2 watt resistor was also needed for these.
The fifth module was a MOTM-730 VC clock divider. Sorry to see it go, but it sold quickly.
