Dear Everyone
I have an anomaly with a spare reference board on my IRD245 dynamic balancer. The board itself was one a was given a replacement for twenty odd years ago and I de-populated it thinking one day I would have a go at trying to repair it. That day has arrived but I am no expert in digital electronics or indeed any electronics I'm simply trying to learn more to a certain extent by repairing parts of these IRD units as various bits fail. I've dealt with power supply problems, vacuum fluorescent display problems, switch interface problems and even a microprocessor board problem and acquired various bits of test gear along the way to help with diagnosis and also calibrating these units etc. So far those repairs, albeit usually a trial, have proved successful in the end but what seems a really minor problem left with this reference board is defeating me because my knowledge is still in its infancy. Anyway I've attached photos of the schematic, faulty board, a perfectly working board and the overall unit they belong to. The problem is that the reference speed readout is giving exactly half the speed input. To someone like myself who doesn't fully grasp what is going on on the board it seems like a minor problem but I cannot locate a solution. Beyond the speed anomaly everything works just fine. The amplitude and angle aspects are all good it simply reads half the input speed. Any ideas anyone?? The last photo is of my re-populated board. I suspect people will note all the chips are on sockets but I did go for good quality ones on the basis that most of the chips are obsolete and sockets would allow easy changing out of chips in the event of a problem. Just by way of info this board was my first problem case with the very first unit I acquired. It only registered vibration at zero degrees and 270 degrees hence made the balancer useless. Bit if a shock twenty years ago when I'd blown all my funds on it but a really helpful guy in Houston, James Dreymala, helped me out with a replacement, a kindness I'll never forget!
I have an anomaly with a spare reference board on my IRD245 dynamic balancer. The board itself was one a was given a replacement for twenty odd years ago and I de-populated it thinking one day I would have a go at trying to repair it. That day has arrived but I am no expert in digital electronics or indeed any electronics I'm simply trying to learn more to a certain extent by repairing parts of these IRD units as various bits fail. I've dealt with power supply problems, vacuum fluorescent display problems, switch interface problems and even a microprocessor board problem and acquired various bits of test gear along the way to help with diagnosis and also calibrating these units etc. So far those repairs, albeit usually a trial, have proved successful in the end but what seems a really minor problem left with this reference board is defeating me because my knowledge is still in its infancy. Anyway I've attached photos of the schematic, faulty board, a perfectly working board and the overall unit they belong to. The problem is that the reference speed readout is giving exactly half the speed input. To someone like myself who doesn't fully grasp what is going on on the board it seems like a minor problem but I cannot locate a solution. Beyond the speed anomaly everything works just fine. The amplitude and angle aspects are all good it simply reads half the input speed. Any ideas anyone?? The last photo is of my re-populated board. I suspect people will note all the chips are on sockets but I did go for good quality ones on the basis that most of the chips are obsolete and sockets would allow easy changing out of chips in the event of a problem. Just by way of info this board was my first problem case with the very first unit I acquired. It only registered vibration at zero degrees and 270 degrees hence made the balancer useless. Bit if a shock twenty years ago when I'd blown all my funds on it but a really helpful guy in Houston, James Dreymala, helped me out with a replacement, a kindness I'll never forget!
