Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Profile gotchas

130 views
Skip to first unread message

Peter Ibbotson

unread,
May 8, 2013, 6:01:56 AM5/8/13
to
I've just moved into a new house, so now it's time to setup the retro computer museum now I have space for stuff that's been in storage.

I have an 5Mb profile drive that I'd like to fire up, I seem to remember that if the power supply has bad caps this tends to also take out the analog board.

So is there a recommended order for bringing Profiles back into use after storage? i.e. should I disconnect the PSU portion of the profile, put some load on and try powering up the PSU?

Thoughts? I do have a scope,good quality soldering iron, multi meter and a fancy measuring thing for capacitors/inductors etc so replacing the capacitors is an option.

Peter

Michael J. Mahon

unread,
May 8, 2013, 2:47:51 PM5/8/13
to
Peter Ibbotson <pibb...@gmail.com> wrote:
> I've just moved into a new house, so now it's time to setup the retro
> computer museum now I have space for stuff that's been in storage.
>
> I have an 5Mb profile drive that I'd like to fire up, I seem to remember
> that if the power supply has bad caps this tends to also take out the analog board.
>
> So is there a recommended order for bringing Profiles back into use after
> storage? i.e. should I disconnect the PSU portion of the profile, put
> some load on and try powering up the PSU?

This is an excellent procedure, since the power supply is the most likely
location for electrical issues.

My next concern, given a working power supply, would be the lubricant(s) in
the drive itself. Warming up the drive (both metaphorically and physically
;) may help if that's a problem.

Good luck!

> Thoughts? I do have a scope,good quality soldering iron, multi meter and
> a fancy measuring thing for capacitors/inductors etc so replacing the
> capacitors is an option.
>
> Peter


--
-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon

Peter Ibbotson

unread,
May 9, 2013, 3:53:39 PM5/9/13
to
On Wednesday, 8 May 2013 19:47:51 UTC+1, Michael J. Mahon wrote:
> Peter Ibbotson <pibb...@gmail.com> wrote:
> > I've just moved into a new house, so now it's time to setup the retro
> > computer museum now I have space for stuff that's been in storage.
> >
> > I have an 5Mb profile drive that I'd like to fire up, I seem to remember
> > that if the power supply has bad caps this tends to also take out the analog board.
> >
> > So is there a recommended order for bringing Profiles back into use after
> > storage? i.e. should I disconnect the PSU portion of the profile, put
> > some load on and try powering up the PSU?
>
> This is an excellent procedure, since the power supply is the most likely
> location for electrical issues.

Sadly it all went horribly wrong... Smoke from the PSU I'll investigate properly at the weekend.

Peter

Michael J. Mahon

unread,
May 9, 2013, 6:43:23 PM5/9/13
to
If the smoke is from the large electrolytics or diodes near the mains
connection, then either one was bad and took out the other. Both the cap(s)
and the diodes should be replaced.

I'd the switching driver is shorted, it could take out the diodes or (hope
not) the primary of the toroid transformer.

Hopefully it's just the mains side supply and no more. Those large filter
caps tend to lose their voltage rating (forming) with time, and could have
caused big overcurrent when turned on.

Peter Ibbotson

unread,
May 10, 2013, 4:58:05 AM5/10/13
to
On Thursday, 9 May 2013 23:43:23 UTC+1, Michael J. Mahon wrote:
> Peter Ibbotson <pibb...@gmail.com> wrote:
>
> > On Wednesday, 8 May 2013 19:47:51 UTC+1, Michael J. Mahon wrote:
>
> >> Peter Ibbotson <pibb...@gmail.com> wrote:
> >>> I've just moved into a new house, so now it's time to setup the retro
> >>> computer museum now I have space for stuff that's been in storage.
> >>>
> >>> I have an 5Mb profile drive that I'd like to fire up, I seem to remember
> >>> that if the power supply has bad caps this tends to also take out the analog board.
> >>>
> >>> So is there a recommended order for bringing Profiles back into use after
> >>> storage? i.e. should I disconnect the PSU portion of the profile, put
> >>> some load on and try powering up the PSU?
> >>
> >> This is an excellent procedure, since the power supply is the most likely
> >> location for electrical issues.
> >
> > Sadly it all went horribly wrong... Smoke from the PSU I'll investigate
> > properly at the weekend.
> >
> > Peter
>
> If the smoke is from the large electrolytics or diodes near the mains
> connection, then either one was bad and took out the other. Both the cap(s)
> and the diodes should be replaced.
>
> I'd the switching driver is shorted, it could take out the diodes or (hope
> not) the primary of the toroid transformer.
>
> Hopefully it's just the mains side supply and no more. Those large filter
> caps tend to lose their voltage rating (forming) with time, and could have
> caused big overcurrent when turned on.
>

On the plus side VintageMicros have spare power supplies so if it's not repairable I may jury rig something from bench PSUs and then order if the rest of it works.

I have a euro plus that needs a new PSU, a couple of //e and a //c that I've still got to check out. So I'm just hoping that the Profile was my "bad luck" PSU.

Peter

Peter

Steven Hirsch

unread,
May 10, 2013, 7:26:16 AM5/10/13
to
On 05/09/2013 03:53 PM, Peter Ibbotson wrote:

> Sadly it all went horribly wrong... Smoke from the PSU I'll investigate
> properly at the weekend.

If the smell was extremely acrid, it's the "X2" capacitor used for power line
bypass. Not a big deal to replace, but phew what a stink they make.

osgeld

unread,
May 10, 2013, 9:23:42 AM5/10/13
to
kind of like burning corn chips

Steven Hirsch

unread,
May 10, 2013, 5:56:11 PM5/10/13
to
If you grew the corn in mustard gas, maybe :-). I had to open the windows and
air out my office with two fans for several hours in the middle of a January
day in Vermont...

Polymorph

unread,
May 14, 2013, 4:07:43 AM5/14/13
to
On Saturday, May 11, 2013 7:56:11 AM UTC+10, Steven Hirsch wrote:
> If you grew the corn in mustard gas, maybe :-). I had to open the windows and
>
> air out my office with two fans for several hours in the middle of a January
>
> day in Vermont...

I can attest to that! When I first pulled my //e out of mothballs back in 2007 (after about 15 years) I got the complete mustard gas experience too. Anticipating the worst, I had fired the //e up outside, and the rancid smell still managed to permeate the house and stay there for the next two days. :-)

Cheers,
Mike
http://apple2.sytes.net/
0 new messages