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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Why is it that no matter how many old schematics and manuals you've got
stuffed in your filing cabinets, you've never got the one you actually need ? Anybody help me out with the schematics for this old beast ? Only need the bit around the STK4142 output hybrid. Theres an obscure problem with it taking about three minutes to unmute. I can see a voltage that creeps up slowly on one of the pins, and I can see a pair of resistors that I thik it comes via. Trouble is that area is so inaccessible for getting components out to check the values of, so it would be helpful to just see what value these resistors are supposed to be, as I think the 'upper' one has probably gone high (there's what I think is probably a delay cap at the junction). In case anyone's got the diagram, but not in pdf or can't be bothered to scan it, the resistors in question are R20 and R21. TIA Arfa |
#2
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Arfa Daily wrote in message
... Why is it that no matter how many old schematics and manuals you've got stuffed in your filing cabinets, you've never got the one you actually need ? Anybody help me out with the schematics for this old beast ? Only need the bit around the STK4142 output hybrid. Theres an obscure problem with it taking about three minutes to unmute. I can see a voltage that creeps up slowly on one of the pins, and I can see a pair of resistors that I thik it comes via. Trouble is that area is so inaccessible for getting components out to check the values of, so it would be helpful to just see what value these resistors are supposed to be, as I think the 'upper' one has probably gone high (there's what I think is probably a delay cap at the junction). In case anyone's got the diagram, but not in pdf or can't be bothered to scan it, the resistors in question are R20 and R21. TIA Arfa AX M430 uses STK4142-2 R20 from gnd to pin 1, 56K R21 from grounded 47uf to pin 2, 330R -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#3
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![]() "N_Cook" wrote in message ... Arfa Daily wrote in message ... Why is it that no matter how many old schematics and manuals you've got stuffed in your filing cabinets, you've never got the one you actually need ? Anybody help me out with the schematics for this old beast ? Only need the bit around the STK4142 output hybrid. Theres an obscure problem with it taking about three minutes to unmute. I can see a voltage that creeps up slowly on one of the pins, and I can see a pair of resistors that I thik it comes via. Trouble is that area is so inaccessible for getting components out to check the values of, so it would be helpful to just see what value these resistors are supposed to be, as I think the 'upper' one has probably gone high (there's what I think is probably a delay cap at the junction). In case anyone's got the diagram, but not in pdf or can't be bothered to scan it, the resistors in question are R20 and R21. TIA Arfa AX M430 uses STK4142-2 R20 from gnd to pin 1, 56K R21 from grounded 47uf to pin 2, 330R -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Thanks, but not quite the same. On the '400, R20 and R21 are associated with the ripple filtering between pins 9 (supply -ve) and 8 (base of internal transistor) Arfa |
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