Re: Profile gotchas

[Michael J. Mahon <mjmahon@aol.com>]

Peter Ibbotson <pibbotson@gmail.com> wrote:
> On Wednesday, 8 May 2013 19:47:51 UTC+1, Michael J. Mahon  wrote:
>> Peter Ibbotson <pibbotson@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. 

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