30 Mar
2019
30 Mar
'19
1:26 p.m.
Hi Charles,
The H786 was standard for the 11/23, BA11-N. The H7861 was for the 11/23+,
BA11-S and had afrw more amps of +5 volts.
I would start by looking at the electronic caps.
I have a few extras here but am pretty busy for the next week or so.
Paul
On Sat, Mar 30, 2019 at 2:25 PM Charles via cctalk <cctalk at classiccmp.org>
wrote:
I have a PDP-11/23+ and the power supply (H786)
"last ran when parked" a
year or so ago. But there's no DC output at all today, and the fans are
running so there is AC power...
I also have the original H7861 that came with it, which had a blown
chopper
transistor. I couldn't find anything else bad, so I replaced the
transistor
and within a few seconds of running, it blew again. :(
So I need some help - I've never been good at fixing switching supplies,
not
to mention the high-side hazards.
The simplest solution would be just to replace it with a working unit.
Anyone got one to sell, hopefully cheap? :)
If not, can anyone fix one or both of mine?
thanks!
Charles