Actually, the factory fix was a "bucking transformer", a whole second power transformer installed out of phase in series with the primary power transformer so that the voltages were subtractive. There is a factory ECN on this topic. But the bridge regulator solution was common among the user base (I myself have used it) as a lot simpler and cheaper, and almost as effective. ------------------------------ Message: 3 Date: Sat, 28 Feb 2009 11:07:56 -0600 From: Jim Battle <frustum at pacbell.net> Subject: Re: S-100 power supply voltage ranges To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <49A96F6C.6060602 at pacbell.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Chuck Guzis wrote: The Sol-20 had an app note about this problem. Apparently they shipped them for a while with transformers that were out of spec with the end result that the unregulated power ran high. The recommended fix was to take a power bridge, mount it to the case, and wire it in series with the positive voltage run in order to get a ~1.4V drop.