M7891-DC 2a fuse on +12?

From: Brad Parker <brad_at_heeltoe.com>
Date: Thu Feb 5 08:25:01 2004

I had a spare moment yesterday so I decided to try and troubleshoot my
bad M7891-DC (128kw) in an 11/34a.

Looks like I have no +12v. The 12v regulator seems to be working as I
have 12v up the 2A fuse. But nothing after that.

I'm assuming the fuse has blown. Easy to replace, but I also suspect it
blew for a reason. (and replacing it might just yield another blown fuse
:-)

Anyone seen this before? Do they sometimes blow due to transients?

I'm tempted to apply 12v after the fuse with a bench supply that has a
current regulator and see what it draws. It's been a while since I
worked with "plain old DRAMs" but I assume the 12v is for them (Vdd).

-brad
Received on Thu Feb 05 2004 - 08:25:01 GMT