> That is absolutely the classic circuit. I assume the AC terminals of the
> bridge
> rectifier come from the mains input, possibly via fuse,switch,filter.
>
> To understand it, draw the bridge as 4 separate diodes. Now assume the triac
> is
> turned off (open-crcuit) and it's just a standard br
> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 30 August 2017 19:30
> To: r...@jarratt.me.uk
> Cc: 'General Discussion: On-Topic and Off-Topic Posts'
> ; 'Tapley, Mark'
> Subject: RE: PSU Input Rectifi
On Wed, 30 Aug 2017, Rob Jarratt wrote:
> > The purpose of the sleeve is mainly electrical insulation -- so that you
> don't
> > have a battery of large live components mounted next to each other posing
> a
> > risk of a short circuit if their surfaces accidentally touch.
> > In the past some ele
> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 30 August 2017 09:21
> To: r...@jarratt.me.uk
> Cc: 'General Discussion: On-Topic and Off-Topic Posts'
> ; 'Tapley, Mark'
> Subject: RE: PSU Input Rectifi
In my case the cap is epoxied to the board so I can’t rock it :(
From: drlegendre . [mailto:drlegen...@gmail.com]
Sent: 30 August 2017 07:24
To: r...@jarratt.me.uk; Rob Jarratt ; General
Discussion: On-Topic and Off-Topic Posts
Cc: dwight
Subject: Re: PSU Input Rectifier Question
snap
On Tue, 29 Aug 2017, Rob Jarratt wrote:
> I would just like to make doubly sure, before cutting into the outer body of
> the caps, am I likely to hit any gotchas? Just how wet are they inside, do I
> need to take any precautions with the electrolyte?
I suggest that you cut the sleeve only first
On 08/29/2017 11:24 PM, drlegendre . via cctalk wrote:
> snap-cap removal goes like this: heat up the joints and solder-suck
> them clean as possible. Then hold on to the cap body, and attempt to
> rock it back & forth has you re-heat one pin and then the other(s).
> Once all the pins are broke fre
tmail.com]
> Sent: 29 August 2017 22:25
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts
> Subject: Re: PSU Input Rectifier Question
>
>
>
> They would have electrolyte in them. It is mildly corrosive as it is mostly
> a borate s
x27;Maciej W. Rozycki'; 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: PSU Input Rectifier Question
> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 29 August 2017 01:06
> To: r...@jarratt.me.uk <mailto:r...@j
7;
Subject: RE: PSU Input Rectifier Question
> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 29 August 2017 01:06
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts
> Cc: 'Tapley, Mark'
&
> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 29 August 2017 01:06
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts
> Cc: 'Tapley, Mark'
> Subject: RE: PSU Input Rectifier Qu
On Tue, 29 Aug 2017, Rob Jarratt via cctalk wrote:
> Not really no. The base of the capacitors is actually touching the board, so
> I can't get under it to cut anything anyway, which is why I am thinking I
> would have to cut the tops off them. Even if I could cut one of the leads, I
> can't solde
> Rob, I assume there isn't room (front or back of the circuit board) to
just cut
> one of the leads, and wire in a replacement in parallel to the old one,
leaving
> the old one in place? That's not a good answer if the old one is leaking,
but if
> it's still intact, cutting one lead takes it out o
On Aug 28, 2017, at 5:12 PM, Rob Jarratt via cctalk
wrote:
>>
>>> If anyone has any good ideas for a "clean" way to remove them I am all ears.
>>
>> Fully unsoldering the leads and rocking back and forth usually does the job.
>>
>
> Indeed. That is my normal method. But in this case the epox
>
> > If anyone has any good ideas for a "clean" way to remove them I am all ears.
>
> Fully unsoldering the leads and rocking back and forth usually does the job.
>
Indeed. That is my normal method. But in this case the epoxy and the fact that
the base of the caps are in contact with the boar
x27;General Discussion: On-Topic and
Off-Topic Posts'"
Sent: Monday, August 28, 2017 2:30 PM
Subject: RE: PSU Input Rectifier Question
>
> I suspect those capacitors!
>
So do I, but I fear they are going to be really difficult to remove. They are
both epoxied in two places, in
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Tony Duell
> via cctalk
> Sent: 28 August 2017 19:35
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: PSU Input Rectifier Question
>
> On Mon, Aug 28, 2017
On Mon, Aug 28, 2017 at 7:30 PM, Rob Jarratt
wrote:
> So do I, but I fear they are going to be really difficult to remove. They are
> both epoxied
> in two places, in both cases one of the glue dabs is pretty inaccessible. I
> am minded
Are you sure it's epoxy? Every time I've had components g
>
> I suspect those capacitors!
>
So do I, but I fear they are going to be really difficult to remove. They are
both epoxied in two places, in both cases one of the glue dabs is pretty
inaccessible. I am minded to just cut the bodies of the caps off (ie above
their bases, cutting directly in
On Mon, Aug 28, 2017 at 5:52 PM, Rob Jarratt
wrote:
> I have posted some information along with a rough schematic here:
> https://rjarratt.wordpress.com/2017/08/28/decstation-5000-model-240-h7878-possible-fault-found/.
> Other information is in the previous post:
> https://robs-old-computers.com
> On Aug 28, 2017, at 12:52 PM, Rob Jarratt via cctalk
> wrote:
>
> ...
> Interesting that Tony mentions a Triac. There is indeed a triac. I am using
> 220/240V input (being in the UK), would it be expected to double the voltage
> in this case to 325V?
No, 325V DC is what you'd get out of a
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Tony Duell
> via cctalk
> Sent: 28 August 2017 15:52
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: PSU Input Rectifier Question
>
> On Mon, Aug 2
On Mon, Aug 28, 2017 at 12:49 PM, Rob Jarratt via cctalk
wrote:
> My recently acquired DECstation 5000/240 has had a PSU failure. After
> replacing a couple of small capacitors with high ESR, I have been doing some
> basic checks to see which stages are working. My first step has been to
> check t
> On Aug 28, 2017, at 7:49 AM, Rob Jarratt via cctalk
> wrote:
>
> My recently acquired DECstation 5000/240 has had a PSU failure. After
> replacing a couple of small capacitors with high ESR, I have been doing some
> basic checks to see which stages are working. My first step has been to
> che
My recently acquired DECstation 5000/240 has had a PSU failure. After
replacing a couple of small capacitors with high ESR, I have been doing some
basic checks to see which stages are working. My first step has been to
check the output of the input rectifier, which has two large capacitors to
smoot
25 matches
Mail list logo
