Re: Thank you! P1
¿ªÔÆÌåÓýNicole,I'd never call someone clueless for being genuinely interested and asking questions. The wires themselves are of more than adequate size for what they're carrying, only ~2A max on startup, 1.7-1.8A continuous, so they aren't the problem. That's why soldering them directly to the board ensures that it'll never happen again. But the wires, like the connector pins, are far too small for the holes in the board, so they really should be bent down against the foil traces before soldering. Attached are a couple photos from a unit I just started working on, after being inspired by the conversation here.? Note how much gap there is around the middle four P1 pins that haven't been reworked yet.? These should be a slight friction fit, binding a bit when inserted, but they're just swimmin' in them thar holes.? Makes one wonder if Engineering knew about this at the time, because if they did, they shouldn't have let it go to production. Related question: Does anyone know if Kurzweil did board assembly in-house, or did they farm it out to a subcontractor? Pin 1 (right side) has the wrap-and-solder fix, and pin 6 (left side) is only wrapped, so far. There's a short "tail" of wire intentionally left to solder to the foil trace, for added stability. You can see that pin 2 had gotten so hot that it burned the board, and on the top side of the board, the plastic on both parts of the connector was slightly melted and charred. While desoldering the pin from the board, part of the trace disappeared, because there's so little of it around the oversized hole.? I stopped at this point in the repair, partly to take pics, and partly because I'm still debating whether or not to delete the connector on this one, due to the condition of the foil trace at pin 2.? More of the saga later, if anyone's interested. Regards, Brian On 12/19/20 11:59 AM, Nicole Massey
wrote:
I have only a cursory experience with electronics hardware, so feel free to tell me I'm clueless. Would it be possible to hardwire the connection using thicker wire to remove any wiggle room from the connections? I seem to remember that would lower resistance, but would that matter? Sent from my HAL 9000 in transit to Jupiter -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of LarryS Sent: Saturday, December 19, 2020 7:00 AM To: [email protected] Subject: Re: [K1000-K1200] Thank you! P1 I think this is what I¡¯m going to do. Just solder the leads straight on. My units are from 25-30 years ago. And NOW I¡¯m getting ready to repair a couple. Of course, the temptation is to ¡°restore¡± it because ¡°someday I might want that to plug-in¡±. After all ¡°if it was good enough for the factory¡±, but, like you said, it was for the exigencies of assembly, not end-user advantages. But I can¡¯t think of an overriding reason to have a disconnect there. And I can think of several reasons to have hard-soldered leads ¨C a proven technique of reliability for many years. L. I've had severe cases where heat from the pins has melted the connector. When that happens, I completely remove P1 and solder the transformer leads directly to the board. This also eliminates the original problem, but requires a bit more work than the fix above. The connector was for ease of assembly in the factory, anyway, so there's nothing lost by removing it. Hope this helps someone! Regards, Brian |