H744 +5 supply - easy to fix? - test-drb@ccmp.vtda.org

3 Mar 2004

Just my 2c.
I repaired 2 H744's up till now.
They are indeed an easy piece to work on.
One had a defective rectifier bridge (the 1 x 1 inch square
block with 4 terminals) and the other was more peculiar:
one big electrolitic capacitor (AFAICR it is connected
directly to the PCB, fixed with screws) made a short circuit
between the housing of the capacitor and a trace on the
board. The plastic insulation of the capacitor some how was
that bad to allow the short circuit ...!

  success with your repairs,
- Henk, PA8PDP

...
  -----Original Message-----
 From: Brad Parker [mailto:brad@heeltoe.com]
 Sent: woensdag 3 maart 2004 22:39
 To: General Discussion: On-Topic and Off-Topic Posts
 Subject: H744 +5 supply - easy to fix?

 I finally got my TS11 racked this morning and after a good cleaning
 found that it has no +5v.  (I must say, I love DEC manuals...)

 Looks like the H744 supply is not working.  Anyone know about these?
 Are they easy to fix?  Should I just pull it, find a schematic and
 start probing?

 (anyone have one they want to part with? :-)

 thanks!

 -brad 