K250-1 repair questions [message #15201] |
Tue, 01 February 2011 21:46 |
ramrod250
Messages: 32 Registered: January 2011 Location: Germantown, Wisconsin
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I recently bought a K250-1 head on eBay, and the previous owner stated that channel 1 didn't work, and channel 2 did, but was noisy. The price was right, so I got it, thinking it might be useful for parts. (S/N 80117)
Lo and behold, when it arrived, a rare reversal of Murphy's Law occurred: it all worked fine! Strange, but then I could hear something rattling inside. I opened the case tonight, and found this:
The jack came loose from the lower-right corner (out of frame, viewed from the rear). The serrated washer was loose inside, and the nut was gone.
Note that only one wire is soldered; looks like there was another wire soldered to the other terminal at one point, but it has been desoldered, with no clue as to where the hookup should be.
What's this for, and should I reactivate it?
It was also interesting that the schematics were pasted inside the lid, with some 2/74 dating.
Was there some service or rework done to this amp? From what I gather about the S/N, it was made in early 1972, not 1974.
There's also a blue polarity switch. Which position is correct?
Thanks to all for their help. I've learned a lot in my short time here, and have a long ways to go. But the members here have really been helpful, and I appreciate it.
Jim
Jim Haught
Creedence + Kustom: a great combination.
[Updated on: Tue, 01 February 2011 22:44] Report message to a moderator
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Re: K250-1 repair questions [message #15202 is a reply to message #15201] |
Wed, 02 February 2011 09:04 |
pleat
Messages: 1454 Registered: June 2004 Location: Belding, Mi
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Jim, great to hear the amp works without any issues. That's always a plus when you think your going to have to some repairs. The jack appears to be the Power module output jack that should be mounted in the hole lower right side looking at the back of the amp. It is used to feed the power module speaker cabinet. I don't have any idea why the 2-2-74 date is marked on the schematic.
The polarity switch, is used to remove any shock hazzard if you touched other equipment such as a Mic and got shocked. Switch the polarity switch to reduce shock hazzard.
pleat
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