No more 3B1 power supplies at Halted Specialties

[Thad P Floryan]

trw at usna.MIL (tsmith <trw at usna>) in <363 at usna.MIL> writes:

"In article <26789 at cup.portal.com>, thad at cup.portal.com (Thad P Floryan) writes
:
"> As I and several others discovered today (Friday, 9-Feb-1990), Halted has NO
"> more 3B1 power supplies; they still have a quantity of 7300 power supplies.
"> 
"I'm a virtual newcomer to this machine (having just acquired 2) but what
"precisely is the difference??  I thought the 3b1 and the 7300 were the 
"same machine.
"
"bill gunshannon

The 3B1 supply is 245W with 5A at 12VDC, the 7300 supply is 195W with 3.5A
at 12VDC; both supply 20A at 5VDC.  The -12VDC comes in several variations
depending on revision level; doesn't seem to make any practical difference.

Other differences:
	1) 3B1 powers its hard drive directly from power supply; 7300 powers
	   its hard drive off the motherboard.
	2) different model of TEAC floppy drive (3B1 has spring-eject, and
	   seems quieter)
	3) 3B1 keyboard has a "writeable" strip above function keys
	4) 3B1 has "hump" at case center for full-height hard drive
	5) 3B1 has one fan, (most) 7300s have two fans

Thad Floryan [ thad at cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]