8 Feb
2016
8 Feb
'16
6:51 a.m.
> -----Original Message-----
> From: cctech [mailto:cctech-bounces at classiccmp.org] On Behalf Of Jos
> Dreesen
> Sent: 07 February 2016 17:55
> To: classiccmp at classiccmp.org
> Subject: The PDP11/04 has landed..
>
> Yesterday I picked up the PDP11/04 that Jay mentioned a few days ago.
> Less than 15 miles from home !
On Sun, Feb 7, 2016 at 1:24 PM, Robert Jarratt <robert.jarratt at ntlworld.com>
wrote:
I have one of these on my restoration list. I know the
PSU does not work,
and that others have tried to fix it before me, who probably know PSUs
much
better than I do. It has core memory so I really would like to get his one
fixed. I have never seen a PSU for it come available in the UK or Europe,
so it looks like it won't be an easy job. :-(
Regards
Rob
-----Oorspronkelijk bericht-----
From: Pete Lancashire
Sent: Monday, February 08, 2016 2:20 PM
To: General Discussion: On-Topic Posts
Cc: classiccmp at classiccmp.org ; jdr_use at bluewin.ch
Subject: Re: The PDP11/04 has landed..
Until one can restore the original power supply, it is pretty easy to
substitute a modern supply, good quality used commercial grade switchers
with remote sensing can but put on a rack shelf. But if you take that
route, be very very careful of Chinese supplies.
------
Jos,
great catch! And so close to home ... you're very lucky ;-)
Rob,
the PSU of the 11/04 has a big transformer in the primary. Secondary
is just 24-30 VAC. The "bricks" are not overwhelming complicated.
They all have the 24 VAC as input which is rectified by a bridge and
followed by a big capacitor. There is also a fuse. A first check would
be these 3 components. Then the uA723 (or LM723) regulator ...
Only the +15V (or is it the -15V?) needs the - (or +) 15V besides
the 24VAC input.
Pete,
although you could use a "modern power supply", nothing beats
the original stuff. Also you need some some components to
generate the AC LO and DC LO signals. The 11/04 needs them.
- Henk