Anyone that reads this blog on a regular basis will know of my fondness for older items that were designed well and built to last, but there are some things that have actually improved over the years. In some cases these items are much better thanks to modern materials and computer aided design. Some things that immediately come to mind are automobile tires and batteries. The last battery I replaced in my old Nissan lasted more than 7 years and was not an expensive high-line battery. Quite amazing I think. When I first started driving back in the 1970's it was considered good to get 3 years out of even an expensive battery. Today's tires also perform better, stop shorter, are less likely to hydroplane, return better fuel mileage and last much longer. When I was a teen' it was considered good to get 40000 miles out of a set of tires. Today even the cheapest tires will easily last that long while outperforming even the best tires of the '70s. More expensive tires often last up to 80000 miles or more if properly maintained.
And while many of the older electronic devices were well designed and manufactured with care, some of the components available to designers today are nothing short of phenomenal. Capacitors have always been a weak part of many designs and electrolytics in particular are prone to failure or loss of capacitance as they age. The MCS 3275 receiver I have been repairing is no exception. I will be replacing all the electrolytics in that device while I have it on the bench. The power amplifier voltage supply is filtered by a pair of Rubicon 10000uF 63 volt caps. A good quality part when it was made and probably one of the more expensive passive devices in the set. One of the challenges faced when sourcing a replacement is finding a part that is physically large enough to fit in the original mount without having too much capacitance. The replacements I chose are Panasonic CE THA of 15000uf at 63 volts. The new part is considerably shorter than the original, but the critical mounting dimension is the diameter, so this one will fit without modification. The capacitance is higher than original, but still close enough that it won't require any circuit modifications. It should actually perform better.
Oh, I almost forgot. The power amplifier repair on the 3275 was successful. Good clean audio from both channels and no smoke.
1 day ago