22 Oct
2015
22 Oct
'15
8:10 p.m.
Hello,
My Vaxstation 4000-60 seems to be dead, probably due to a PSU problem (it does not power
on). Does anyone know about options to find a replacement or to diagnose/fix it? (I just
noticed it is dead, I have not even dissassembled it yet).
Jordi Guillaumes Pons
jguillaumes at me.com
HECnet: BITXOV::JGUILLAUMES
22 Oct
22 Oct
9:30 p.m.
Change capacitors? perhaps? Had it been switched off for how long?
? Origineel bericht ?
Van: Jordi Guillaumes i Pons
Verzonden: donderdag 22 oktober 2015 20:10
Aan: HECnet Mailing List
Beantwoorden: hecnet at Update.UU.SE
Onderwerp: [HECnet] Vaxstation 4000-60 dead...
Hello,
My Vaxstation 4000-60 seems to be dead, probably due to a PSU problem (it does not power
on). Does anyone know about options to find a replacement or to diagnose/fix it? (I just
noticed it is dead, I have not even dissassembled it yet).
Jordi Guillaumes Pons
jguillaumes at me.com
HECnet: BITXOV::JGUILLAUMES
9:45 p.m.
One issue I had was a dry solder joint on one of the transformer connections to the PSU
circuit board - given the weight of the transformer this is definitely worth checking.
The switch for VAXstation 4000/60 & 4000/90 PSUs (they are the same physical unit
although they have different part codes IIRC) is a 'soft switch' so power is
applied to the input stage of the power supply as soon as the cable is plugged in. I'm
not sure whether that is significant although part of me thinks that this is more likely
to cause a breakdown of the high frequency mains filtering capacitors if the machine has
been left plugged in, even if switched off.
Just my 2? worth...
Sent from my iPad
On 22 Oct 2015, at 20:31, Jordi Guillaumes i Pons
<jg at jordi.guillaumes.name> wrote:
El 22 oct 2015, a les 21:30, Hans Vlems
<hvlems at zonnet.nl> va escriure:
Change capacitors? perhaps? Had it been switched off for how long?
Months
10:02 p.m.
My experience with mains filtering capacitors is on the MicroVAX II, which is
somewhat older, but in that case a failure of one of these capacitors causes
smoke and smell, but doesn't stop the PSU working. I don't know if a more modern
PSU would stop working if one of these capacitors failed, but I think you would
know that it had failed.
Regards
Rob
On 22 October 2015 at 20:45 Mark Wickens <mark at wickensonline.co.uk> wrote:
One issue I had was a dry solder joint on one of the transformer
connections to the PSU circuit board - given the weight of the transformer
this is definitely worth checking.
The switch for VAXstation 4000/60 & 4000/90 PSUs (they are the same
physical unit although they have different part codes IIRC) is a 'soft switch'
so power is applied to the input stage of the power supply as soon as the
cable is plugged in. I'm not sure whether that is significant although part of
me thinks that this is more likely to cause a breakdown of the high frequency
mains filtering capacitors if the machine has been left plugged in, even if
switched off.
Just my 2? worth...
Sent from my iPad
On 22 Oct 2015, at 20:31, Jordi Guillaumes i
Pons
<jg at jordi.guillaumes.name> wrote:
El 22 oct 2015, a les 21:30, Hans Vlems
<hvlems at zonnet.nl> va escriure:
Change capacitors? perhaps? Had it been switched off for how long?
Months
9:44 p.m.
First thing is going to be to get the PSU out of the machine and connected to a
dummy load. Then check whether the PSU is outputting anything, check each
voltage as it might be only one of the outputs that is not working. It might not
even be the PSU that is the problem, but if fans are not running then I suppose
the PSU is the main suspect. You could check all this without disconnecting it
from the machine, depending on whether you are worried it might damage the
machine further if you try to switch it on. It really could be anything at this
point though, perhaps just a fuse, bad electrolytic capacitors, a blown chopper
transistor or goodness knows what else. You have to go through a process of
elimination....
Regards
Rob
On 22 October 2015 at 20:30 Hans Vlems <hvlems at zonnet.nl> wrote:
Change capacitors? perhaps? Had it been switched off for how long?
Origineel bericht
Van: Jordi Guillaumes i Pons
Verzonden: donderdag 22 oktober 2015 20:10
Aan: HECnet Mailing List
Beantwoorden: hecnet at Update.UU.SE
Onderwerp: [HECnet] Vaxstation 4000-60 dead...
Hello,
My Vaxstation 4000-60 seems to be dead, probably due to a PSU problem (it
does not power on). Does anyone know about options to find a replacement or to
diagnose/fix it? (I just noticed it is dead, I have not even dissassembled it
yet).
Jordi Guillaumes Pons
jguillaumes at me.com
HECnet: BITXOV::JGUILLAUMES
3321
days inactive
3321
days old
5 comments
4 participants
participants (4)
-
hvlems＠zonnet.nl -
jg＠jordi.guillaumes.name -
mark＠wickensonline.co.uk -
robert.jarratt＠ntlworld.com