Home » VintageKustom.com » Replacement Part Suggestions » Repair and Restoration of K250-1 & 1-18-B (I am looking to repair and restore the K250-1 & 1-18-B amp and cab as much as I can)
Repair and Restoration of K250-1 & 1-18-B [message #24136] Mon, 09 November 2015 03:01 Go to next message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

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
Re: Repair and Restoration of K250-1 & 1-18-B [message #24137 is a reply to message #24136] Mon, 09 November 2015 03:09 Go to previous messageGo to next message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

Here is a link to the image of the amp...

imgur.com/x3XSXKs


Christopher "Tofur" Duvall
Re: Repair and Restoration of K250-1 & 1-18-B [message #24138 is a reply to message #24137] Mon, 09 November 2015 11:09 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
Messages: 767
Registered: June 2014
Senior Member
As to repairing the vinyl, if the rips are small you can buy a repair kit to fix that. Walmart carries a kit in automotive made by 3M that works fairly well. As to matching the color, Pleat has suggested getting finger nail polish at one of the dollars stores. That does work pretty well and will probably be your closest match. To clean the vinyl and remove as much of the oxidation as possible, I use a good automotive wax. Works very well.....use a tooth brush to get in between the tucks. A good buffing afterwards really makes it shine.

If you've got large rips and pieces missing, your only option is to have it recovered.

As to hardware and grille.....Pleat probably can help you there or Bart.

Stevem or Chicagobill are our electronics experts.......they will be able to get you back up to speed.

The fun begins.
Re: Repair and Restoration of K250-1 & 1-18-B [message #24139 is a reply to message #24136] Mon, 09 November 2015 13:19 Go to previous messageGo to next message
chicagobill
Messages: 1995
Registered: April 2003
Senior Member
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.
Re: Repair and Restoration of K250-1 & 1-18-B [message #24140 is a reply to message #24136] Mon, 09 November 2015 14:16 Go to previous messageGo to next message
Kustom_Bart is currently offline  Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN
Senior Member
I sent you a message about how to repair the small areas.
Re: Repair and Restoration of K250-1 & 1-18-B [message #24141 is a reply to message #24140] Mon, 09 November 2015 15:58 Go to previous messageGo to next message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

Thanks to all. I will be going through the site to get more info but you guys have given me a launching point.

Christopher "Tofur" Duvall
Re: Repair and Restoration of K250-1 & 1-18-B [message #24142 is a reply to message #24141] Mon, 09 November 2015 23:06 Go to previous messageGo to next message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

I just finished cracking open the head and went through and checked all the solder joints, cleaned the boards, the pots, the molex plugs and anything I could my hands on inside the head. Got all back together and fired it up. Looks like my sound issues have gone away. Sounds AMAZING!

Christopher "Tofur" Duvall
Re: Repair and Restoration of K250-1 & 1-18-B [message #24143 is a reply to message #24136] Tue, 10 November 2015 06:13 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4571
Registered: June 2004
Location: NY
Senior Member
Welcome to the place here!
Glad to hear as I sure you are that it was a simple fix.
Do you use any Bass guitars that have active pickups ?
Re: Repair and Restoration of K250-1 & 1-18-B [message #24144 is a reply to message #24142] Tue, 10 November 2015 13:24 Go to previous messageGo to next message
chicagobill
Messages: 1995
Registered: April 2003
Senior Member
tofur wrote on Mon, 09 November 2015 22:06
Sounds AMAZING!

I think he's hooked.
Re: Repair and Restoration of K250-1 & 1-18-B [message #24145 is a reply to message #24136] Tue, 10 November 2015 13:35 Go to previous messageGo to next message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

Yep...I am. Shakes the whole house too. This thing needs to be cut loose on stage somewhere. I just need to get better.

Christopher "Tofur" Duvall
Re: Repair and Restoration of K250-1 & 1-18-B [message #24146 is a reply to message #24136] Tue, 10 November 2015 13:36 Go to previous message
tofur is currently offline  tofur
Messages: 6
Registered: November 2015
Location: Denver, CO
Junior Member

Nothing with active pickups...yet. I need to work on my skills first before I branch out on anymore equipment.

Christopher "Tofur" Duvall
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