- Update on the massive Crown ... - 1 Update
- Right to repair article in WSJ - 1 Update
| "Arfa Daily" <arfa.daily@ntlworld.com>: Sep 13 02:43AM +0100 "Phil Allison" <pallison49@gmail.com> wrote in message news:83211fc5-b019-4a52-a02f-f22f9f5726a0@googlegroups.com... > Roland Cube 60; 12ohms (160VA) .1A > .... Phil I used to do all sorts of stuff like that to make life easier for the future, but somehow, I just don't seem to have the motivation any more. I guess it's just part and parcel of getting older. I seem to really lack enthusiasm the last couple of years. Every now and then I get one that provides some satisfaction. Like the Studio Due Shark 250 moving head last week. It was really slow to do its power on reset. It found the pan endstop microswitch ok, then reversed direction as it should, to index the opposite end of the pan range. But it moved REALLY slowly doing this. And instead of stopping just short of the mechanical end point, it ran into it, leaving the pan stepper motor clunk-clunk-clunking. And there the reset process stopped for ever. I opened it up and took a look at the output from the pan position encoder. It's made up of a slotted wheel running in two slotted optos side by side, presumably to generate Gray code or some such to determine which direction it's going. The output from both optos was poor, never getting close to zero. I thought it was unlikely that both of them would be faulty, so I took my air line, and blasted out the gaps, and the slots in the encoder wheel. When retried, reset proceeded at normal speed, and fully completed. When I checked the output from the optos again, this time it was a full zero to 5 volts. A good example of what a problem 'dust in the works' can be. That fix gave me a good degree of satisfaction, but the week went downhill from there ... :-\ Arfa |
| Jon Elson <elson@pico-systems.com>: Sep 12 04:37PM -0500 whit3rd wrote: > where a socketed fuse could only be replaced by swapping the power > supply. Other times, subassemblies left out cables or brackets or > shields Well, in many cases, a fuse is to prevent fire, AFTER a major component has failed in a switching supply. Usually, more than one component is popped in that case, so it is unlikely the average joe would have any luck repairing it. And, you REALLY don't want to tempt people who might try to put in a bigger fuse! Why the fuse was socketed, I don't know. But, my experience with switching supplies is that the fuse REALLY RARELY blows due to surge fatigue, it is usually after major failure. Jon |
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