| Repair and Restoration of K250-1 & 1-18-B [message #24136] |
Mon, 09 November 2015 03:01  |
tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
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Junior Member |
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I just acquired a gold sparkled K250-1 amp and 1-18-B cabinet.
Problems
1. The vinyl is discolored and has darkened over the years. The unexposed areas seem much lighter. I do not think it was ever one of the silver versions however.
2. The vinyl has some minor nicks, cuts, and scrapes, mainly on the back cover of the cab.
3. The upper and lower grills are completely missing.
4. On pre-amps 1 and 2 sound like an overdrive pedal is engaged at volumes that would be the equivalent of a 3 or 4 on the volume knobs.
5. The SELECTONE knob on pre-amp 1 does not seem to have any discernible change in the tone that I can really hear.
6. The treble pull knob on pre-amp 1 does not seem to have any effect as well.
7. On pre-amp 1 there is a rattle that sounds like possible cone damage on the speaker but could also be from faulty electronics in the amp...unsure. It is prominent when I play an A on the E string or the open A string itself. It is difficult to tell if it is the horn or the electronics. Upon inspection, the cone looks surprisingly good for something that is 43 years old.
8. There seems to be a slight hum and hiss coming off the the amp. The kind of hiss/hum that you would hear on something that is turned WAY up. This hum and hiss gets ridiculous when the instrument is not connected.
9. The screws on both amp and head for all covers, handles and plates have some minor rust.
The Good
1. The amp is loud...INCREDIBLY LOUD and has some major thump and drive when connected to either pre-amp.
2. Pre-amp 2 sounds incredibly clean and all the knobs/controls seem to be working fairly well.
3. The cabinet appears to be fairly structurally sound and there is no rattle to it.
4. The transformer in the head has a small bit of rust on outer casing but the electronics in the head look amazingly well with no visible issues with the components.
When I got it this week, the amp and and cabinet were filthy and covered in many years of cigarette smoke residue. I have done what I could to clean it up. I have also repainted the black wood inside the cabinet and that looks fairly good now. It stills slightly smells like an ash tray but it smells much better now.
What I need now from the hive mind here is either information or to be directed to...
1. Build or replace the grills.
2. Repair the vinyl damage.
3. Troubleshoot and repair possible issues that seem to be plaguing pre-amp 1. I am quite handy with a soldering iron. I used to repair arcade games and pinball machines.
4. Find the correct screws for all parts.
Christopher "Tofur" Duvall
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| Re: Repair and Restoration of K250-1 & 1-18-B [message #24139 is a reply to message #24136] |
Mon, 09 November 2015 13:19  |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Welcome to the place. That is one great amp. Well it is if you're young enough to carry it around.
There is a lot of collected information here, so you should be able to get info on all of your questions. To make it simpler on yourself and on us, I will suggest starting specific threads for each part of your restoration. That way we will not be mixing electronic repairs with the cabinet repairs, etc.
The first thought for the electronics restoration would be to open the chassis up and clean all of the pots, jacks and Molex connectors with some DeoxIt.
The Molex connectors are a common source of problems with these amps, so in addition to cleaning them, you might also want to check to see that they are firmly soldered in place.
Good luck and congrats with the new member of your family.
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