17 Jan
2003
17 Jan
'03
6:30 p.m.
On 2003.01.17 20:35 Tony Duell wrote:
The DEC 'bricks' -- the H744, etc, regulators
-- used in the 10.5"
PDP11/34 box are relatively friendly to work on. They are swtichers,
but they start from a 30V AC input (from a large mains transformer --
an isolating transformer).
The owner showed me already a big transformer (should
be around 200..400
VA) from the PSU. He also said that the PSU is modular and one of the
modules is broken. An other reason why I an expecting a /34.
So they're not as dangerous to work on as most
SMPSUs.
Well, I have a isolating transformer...
And they're fairly simple electronically.
Hmm. I have no clue about SMPSUs. Good reason to learn more about them.
Especially as there is a SGI Personal Iris 4D35 with broken PSU waiting
for repair also. Fortunately I know a electronics designer who has
designed several SMPSUs. So I am able to get some help.
On the other hand, the PDP11/44 supply is painful.
Heared about that.
smoothing capacitors -- the later are coke-can sized
(!).
I have a 78 mF (mili, not micro) capacitor from a Printronix chain
printer. It is about 1' tall and 5" in diameter...
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/