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On Wed, 16 Feb 2005 08:23:34 -0500, Vinnie S.
wrote: On Wed, 16 Feb 2005 08:08:36 -0500, Dave Hall wrote: On Tue, 15 Feb 2005 13:36:32 -0600, "Chad Wahls" wrote: Did you see any bottom mounted caps connected to the final transistor? If not then you might have to mount a piece of grounded shield plate over the final or experiment with bypass caps until you kill the oscillation. But try setting the bias first. If I remember right, the bias for the final should be set at somewhere in the 30 - 40 mA range. I'll check the manual and give you the exact value. Dave "Sandbagger" I kinda figured oscillation also. Bad bias can cause it. Make sure that's correct. See if any one had hinkeyed around in there, Check serial numbers, did these not use 2 different finals at different times? When changing finals did they change drive components? Unfortunately I do not have a schematic here to look around. Did anyone do any "coil spreading"? I checked the factory service manual last night. They recommend setting both the driver and final bias to 50 mA. That seems a bit high, as the driver stages in many other radios are set around 40 mA. My 2510 is set to factory specs and I've never added any "mods" to it, and it doesn't oscillate. Dave "Sandbagger" I need a DMM that measures current. any recommendations on one that is good, without breaking the bank? The Flukes run abour $150 on ebay. I didn't want to spend that much. For current settings, I use a simple 15 year old Radio Shack VOM. It's analog, but it's not that critical, and they (At least they used to be) cheap, and available. I also have a Textronix DMM that does current, but it's not as portable. Dave "Sandbagger" |
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