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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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Ashdown Peacemaker 20 , 2003
Loss of valve preamp due to o/c dropper between HT1 and HT2.
Not the slightest sign of any heating to this 1/3W , 10K resistor . Never seems right to me 1/3W resistors in valve anode supplies - the 4 ,per anode, 1/3W 100K and 220K droppers downstream of the HT2 supply also look perfect . Same body colour as all the other 1/3W and no schematic indication of being a thermal fuse resistor. So replace with higher wattage or not.? Replace with a higher wattage and a current fuse, somehow, in case an overload could have knocked out this R without leaving the slightest trace of heating on it or the , more likely, higher resistance ones. I intend milling holes inter-trace, again (previous owner of a Peacemaker 60 grateful for the cooler running), through the pcb around the o/p bottles. Like all these Peacemakers, serious overheating of the pcb material etc, and this dropper is an inch from an output valve. No actual pcb discolour under this dropper , that stops about 1/2 inch from the bottles so I have difficulty in assuming its a heating problem. Or milling vent holes and only 1/3w 10R, metal oxide resistor replacement? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#2
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Ashdown Peacemaker 20 , 2003
N_Cook wrote in message
... Loss of valve preamp due to o/c dropper between HT1 and HT2. Not the slightest sign of any heating to this 1/3W , 10K resistor . Never seems right to me 1/3W resistors in valve anode supplies - the 4 ,per anode, 1/3W 100K and 220K droppers downstream of the HT2 supply also look perfect . Same body colour as all the other 1/3W and no schematic indication of being a thermal fuse resistor. So replace with higher wattage or not.? Replace with a higher wattage and a current fuse, somehow, in case an overload could have knocked out this R without leaving the slightest trace of heating on it or the , more likely, higher resistance ones. I intend milling holes inter-trace, again (previous owner of a Peacemaker 60 grateful for the cooler running), through the pcb around the o/p bottles. Like all these Peacemakers, serious overheating of the pcb material etc, and this dropper is an inch from an output valve. No actual pcb discolour under this dropper , that stops about 1/2 inch from the bottles so I have difficulty in assuming its a heating problem. Or milling vent holes and only 1/3w 10R, metal oxide resistor replacement? -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ very odd, scraped along the 10K, now removed, and 2 breaks one at an end then another about 300R from the other end with no sign of discolouration on the oxide layer, or cracks |
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