On Mon, 1 Mar 2010, kernkampj wrote: > Recently I had a problem with a Mitrek radio, The RX channel element > would not reliably start oscillating on power-up. In my > experimenting, I discovered that the problem related to the power > supply I used. > > I had four power sources - two linear supplies, one switcher, and a > battery. One of the linears and the battery worked fine. The other > linear and the switcher created the non-start problem. > > I finally noticed that the radio has two internal power sources for > the channel element (9.5 Reg and 9.5 switched), and wondered if the > timing of the two sources could be the problem. So I slowed down the > 9.5 switched source, and that cured it. The channel element now > starts every time from any of the power supplies. > > For those interested, I added a 100uF cap from the base of Q1 (the > receiver 9.5V Switched supply) to ground. This slowed down the > voltage output of the 9.5 switched source.
You might have one or more electrolytic capacitors which have dried out. I think the last Mitrek rolled off the line before I was born, which is longer ago than I'd like to admit. -- Kris Kirby, KE4AHR Disinformation Analyst
