Re: plus4 power supply

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Wed, 19 Sep 2012 21:40:25 +0200 Message-ID: <505A1FA9.8080602@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 09/19/2012 09:25 PM, Hegedűs István wrote:
> Hi,
> I have done a major repair service on my plus4 power supply. Replaced
> the electrolyte and tantal capacitors, the diodes. Now it supplies 5.6v
> while before it supplied 5.4v. Is it dangerous for the plus4? What
> should be the voltage level of a normal power supply? (Note that I have
> only a multimeter and no scope so might be measurement difference).

It shouldn't go above 5.2V. You should do a complete rework of the power 
supply remove the existing regulator, get a switching regulator, for 
example

  http://www.ebay.de/itm/290572036224

This one is adjustable, so adjust to 5.2V _before_ connecting the Plus/4.

As a sideeffekt, the PSU will run much cooler.

If you feel _really_ adventurous, you can put a complete switching power 
supply that runs on 230V and supplies 5V 2A into the empty part of the 
Plus/4 PSU. The transformer will then only be used for 9V AC.
But since one has to work on 230V AC, this is only for people who know 
exactly what they're doing.

  Gerrit

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