Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > > > > -Original Message- > > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm > Tiffe > > Sent: 25 December 2015 13:15 > > To: General Discussion: On-Topic and Off-Topic Posts > >

Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > Good news! It looks like I have managed to get this working again. I > realised I had not checked the electrolytic capacitors on the main logic > board, ones situated far from the main power output boards. I found one > which had a higher ESR than two other identical ones,

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm Tiffe > Sent: 25 December 2015 13:15 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > This Capacitor was bad in my PSU

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent > Hilpert > Sent: 21 December 2015 22:33 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > SMD markings and packaging

RE: VAX 4000-500 PSU Overload?

Good news! It looks like I have managed to get this working again. I realised I had not checked the electrolytic capacitors on the main logic board, ones situated far from the main power output boards. I found one which had a higher ESR than two other identical ones, although the ESR was still

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: Robert Jarratt [mailto:robert.jarr...@ntlworld.com] > Sent: 20 December 2015 07:04 > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: RE: VAX 4000-500 PSU Overload? > > > > The problem is just how to physical

Re: VAX 4000-500 PSU Overload?

On 2015-Dec-21, at 3:10 AM, Robert Jarratt wrote: >> -Original Message- >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent >> Hilpert >> Sent: 21 December 2015 10:12 >> To: General Discussion: On-Topic and Off-Topic Posts >> Su

Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > > > > -Original Message- > > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul > > Koning > > Sent: 20 December 2015 22:32 > > To: General Discussion: On-Topic and Off-Topic Posts > &

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm Tiffe > Sent: 21 December 2015 08:51 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > Robert Jarratt wrote: > &g

Re: VAX 4000-500 PSU Overload?

On 2015-Dec-21, at 1:14 AM, Robert Jarratt wrote: >> -Original Message- >> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm > Tiffe >> Sent: 21 December 2015 08:51 >> To: General Discussion: On-Topic and Off-Topic Posts >> Subje

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent > Hilpert > Sent: 21 December 2015 10:12 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > The lighter-beige ones,

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul > Koning > Sent: 20 December 2015 22:32 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > > > On Dec 19, 20

Re: VAX 4000-500 PSU Overload?

> On Dec 19, 2015, at 4:05 PM, Robert Jarratt > wrote: > > ... > I can't tell if this is a Kelvin connected one or not, although I suspect it > probably is. You can see a picture with two here: http://1drv.ms/1micVN7. > These are from a second board in the PSU, but

Re: VAX 4000-500 PSU Overload?

On 12/19/2015 04:56 AM, Robert Jarratt wrote: Actually, I may have just narrowed it down a bit. I connected a 12V DC bulb to the -12 output, in parallel to a 15R resistor, and the PSU shuts down immediately. The 12V bulb has a 21W rating. If my calculations are correct, that means the bulb

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Robert > Jarratt > Sent: 19 December 2015 17:20 > To: 'General Discussion: On-Topic and Off-Topic Posts' > <cctalk@classiccmp.org> > Subject: RE: VAX 4000-500 PSU Overload?

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Robert > Jarratt > Sent: 19 December 2015 19:19 > To: 'General Discussion: On-Topic and Off-Topic Posts' > <cctalk@classiccmp.org> > Subject: RE: VAX 4000-500 PSU Overload?

Re: VAX 4000-500 PSU Overload?

>> Bulbs have a lower than normal resistance when cold [...] >> Three or four 15 ohm resistors in parallel would probably make a >> better load for the -12V line. > Unfortunately I don't have enough of these to hand, and the local > shop (Maplin) does not have enough in stock. :-( > But getting

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul > Koning > Sent: 19 December 2015 19:26 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > > Something to watch out

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Dave > Wade > Sent: 19 December 2015 18:32 > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: RE: VAX 4000-500 PSU Overload? > > > > > Seeing

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Dave > Wade > Sent: 19 December 2015 20:44 > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: RE: VAX 4000-500 PSU Overload? > > > > > I wond

Re: VAX 4000-500 PSU Overload?

>>> But getting something in series to measure load is going to be >>> really awkward, [...] >> As in, you don't have any such thing to put in series, or you don't >> see a good way to get it in series? [...] > I think the suggestion was to put an ammeter between the PSU and the > backplane.

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Mouse > Sent: 20 December 2015 01:46 > To: cctalk@classiccmp.org > Subject: Re: VAX 4000-500 PSU Overload? > > >>> But getting something in series to measure load is go

RE: VAX 4000-500 PSU Overload?

A bench test of the PSU with a small dummy load saw the PSU appear to work fine. It might help to load it more to see if it still operates correctly under load. The specs for the PSU are: 22 amperes at +12.1 Vdc 60 amperes at +5 Vdc 7 amperes at +3.4 Vdc 4 amperes at -12.1 Vdc Has anyone got

RE: VAX 4000-500 PSU Overload?

> > Actually, I may have just narrowed it down a bit. I connected a 12V DC bulb > to the -12 output, in parallel to a 15R resistor, and the PSU shuts down > immediately. The 12V bulb has a 21W rating. If my calculations are correct, > that means the bulb draws 1.75A. The 15R resistor would draw

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: Robert Jarratt [mailto:robert.jarr...@ntlworld.com] > Sent: 19 December 2015 09:56 > To: 'General Discussion: On-Topic and Off-Topic Posts' > Cc: 'cct...@classiccmp.org' > Subject: RE: VAX 4000-500 PSU Overload? > > A bench test of th

RE: VAX 4000-500 PSU Overload?

> Bulbs have a lower than normal resistance when cold so it is possible that you > may be drawing more than 4A from the -12V line at the instant that you apply > power. > > Bulbs are great for supplying a minimum load for a power supply that won't > regulate without it but they are not so great

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Maciej W. > Rozycki > Sent: 17 December 2015 16:18 > To: cctalk@classiccmp.org > Cc: cct...@classiccmp.org > Subject: RE: VAX 4000-500 PSU Overload? > > NB th

RE: VAX 4000-500 PSU Overload?

On Sun, 13 Dec 2015, Robert Jarratt wrote: > > No leaking ChemiCon SXF-series capacitors inside? They seem to suffer > > from some kind of design or manufacturing defect and consequently the > > electrolyte gets through the seal eventually even in parts never used. A > > number of DEC PSUs

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm Tiffe > Sent: 16 December 2015 17:27 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > Robert Jarratt wrote: > > .

Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > > Tonight I replaced the leaking capacitors on the +12V/-12V board, and also > > replaced the two similar ones that looked and measured fine. I put the PSU > > back together, put in a couple of less important boards and drives, and > the > > machine now seems to power on

Re: VAX 4000-500 PSU Overload?

On Tue, Dec 15, 2015 at 12:38 PM, Robert Jarratt wrote: > > Tonight I replaced the leaking capacitors on the +12V/-12V board, and also > replaced the two similar ones that looked and measured fine. I put the PSU > back together, put in a couple of less important

RE: VAX 4000-500 PSU Overload?

> Tonight I replaced the leaking capacitors on the +12V/-12V board, and also > replaced the two similar ones that looked and measured fine. I put the PSU > back together, put in a couple of less important boards and drives, and the > machine now seems to power on OK. I measured the ripple using

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Glen Slick > Sent: 14 December 2015 01:36 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > I took a look at the DSSI &am

Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > > > > -Original Message- > > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Glen Slick > > Sent: 14 December 2015 01:36 > > To: General Discussion: On-Topic and Off-Topic Posts > > Subject: Re: VAX 4000-500

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Maciej W. > Rozycki > Sent: 11 December 2015 01:48 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > No leaking ChemiC

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Holm Tiffe > Sent: 11 December 2015 07:42 > To: General Discussion: On-Topic and Off-Topic Posts > Subject: Re: VAX 4000-500 PSU Overload? > > There is a big rectangular Cap

Re: VAX 4000-500 PSU Overload?

On Thu, Dec 10, 2015 at 11:42 PM, Holm Tiffe wrote: > > Another thing is that small PCB on the DSSI storage Backplane, the Caps > there where dead too. I thing it is the termination Power regulator and in > my case the bad caps "simulated" a bad disk, I could'nt initialize

RE: VAX 4000-500 PSU Overload?

On Fri, 11 Dec 2015, Robert Jarratt wrote: > Well, I have the exception that proves the rule. My H7864 PSU (from an > rtVAX 1000, same PSU as MicroVAX II) had a switching transistor and > resistor fail, no cap failures Well, I did admit I was exagerrating. :) -- Richard Loken VE6BSV,

Re: VAX 4000-500 PSU Overload?

> From: Jon Elson > You should be able to safely power the machine with only a couple > boards at a time to find which one is bad. For debugging power supplies, a 'load module' (a card with only a bunch of resistors on it) is invaluable. No trying to figure out where/how to connect a

Re: VAX 4000-500 PSU Overload?

On Thu, 10 Dec 2015, Jon Elson wrote: > On 12/10/2015 04:30 PM, Robert Jarratt wrote: >> My VAX4000-500 will no longer power up, with the PSU starting up and then ... > Most likely there is a failed capacitor somewhere. Look ... My doctor once said to me that all problems in the head involve

RE: VAX 4000-500 PSU Overload?

> -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Richard > Loken > Sent: 11 December 2015 16:45 > To: General Discussion: On-Topic and Off-Topic Posts > Cc: gene...@classiccmp.org > Subject: Re: VAX 4000-500 PSU Overload? > &

Re: VAX 4000-500 PSU Overload?

On Thu, Dec 10, 2015 at 2:30 PM, Robert Jarratt wrote: > My VAX4000-500 will no longer power up, with the PSU starting up and then > immediately shutting down. I suspect a possible short somewhere. I have > measured the resistance of the load presented to the PSU by

Re: VAX 4000-500 PSU Overload?

> > My VAX4000-500 will no longer power up, with the PSU starting up and then > immediately shutting down. I suspect a possible short somewhere. I have > measured the resistance of the load presented to the PSU by connecting > probes to the backplane sockets used to power the machine. The odd one

Re: VAX 4000-500 PSU Overload?

On 12/10/2015 04:30 PM, Robert Jarratt wrote: My VAX4000-500 will no longer power up, with the PSU starting up and then immediately shutting down. I suspect a possible short somewhere. I have measured the resistance of the load presented to the PSU by connecting probes to the backplane sockets

Re: VAX 4000-500 PSU Overload?

On Thu, 10 Dec 2015, Robert Jarratt wrote: > My VAX4000-500 will no longer power up, with the PSU starting up and then > immediately shutting down. I suspect a possible short somewhere. I have > measured the resistance of the load presented to the PSU by connecting > probes to the backplane

Re: VAX 4000-500 PSU Overload?

Robert Jarratt wrote: > My VAX4000-500 will no longer power up, with the PSU starting up and then > immediately shutting down. I suspect a possible short somewhere. I have > measured the resistance of the load presented to the PSU by connecting > probes to the backplane sockets used to power the