| Major Bass Combo Restoration Project [message #16600] |
Mon, 23 January 2012 20:01  |
trainwreck_joe
Messages: 10
Registered: January 2012
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Junior Member |
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Where to begin?
Just this past weekend I received the guts of a 1971 1-15 K-100 bass combo amp from an old friend of mine. Components are all there, along with the original front panel, and the open-top, metal "box"--but that's it. The cabinet and its speakers (not to mention the original castors!) are long, long gone.
Does anyone know if there's anybody out there who can build vintage Kustom cabinets from scratch to pretty much original specs? For that matter do any blueprints, specs, information or knowledge bases exist for how these cabinets were constructed?
By the way, the components are a complete mess--but it looks like everything is there. My old friend told me that the amp no longer works (I'm afraid to even plug it in in its current condition), but that it *could* just be a loose capacitor (wishful thinking on his part I'm sure).
I realize that I could probably just buy a vintage Kustom amp out on ebay for much less than the $$$ it will probably take to restore this amp, but I have a lot of personal history with it. It goes all the way back to my high school days, and I'm absolutely floored that--even in the current state it's in--it's come back into my life.
Thanks in advance for any information just to get me started.
--TWJ
ps: Will upload pics of what I have asap.
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| Re: Major Bass Combo Restoration Project [message #16601 is a reply to message #16600] |
Mon, 23 January 2012 21:18  |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Welcome to the place. We all have stories and feelings about pieces of gear that we had back in the day.
There are a few guys here that build their own cabinets and have sources for tuck and roll, maybe they can help you out. Another idea would be to look for another donor amp that can give it's cabinet and other parts.
I work on the electronics parts of these amps, so I will try and help you get the amp up and running if I can.
A couple of things that you can do are to find the numbers of the pc boards in the amp. That way we can try and get the schematics for you. Also, if you do post photos we can get a better idea as to what sort of condition it is in.
Again, welcome.
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| Re: Major Bass Combo Restoration Project [message #16602 is a reply to message #16600] |
Tue, 24 January 2012 12:55 |
trainwreck_joe
Messages: 10
Registered: January 2012
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Junior Member |
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Thanks, ChicagoBill.
Well, took my camera downstairs last night to take pics--batteries were dead and no others in the house. So new ones for the camera are on my to-do list for today.
But I did take a good look at all the components with a strong flashlight. Overall it looks pretty good. All the circuit boards look OK--just grimy and dirty--although who knows what components might have gone bad over the 30 years or so this was laying around in my friend's cellar.
So first I'd like to ask if blowing the loose debris out with compressed air would be ok. I can't see why not, but I'm not an expert. Beyond that, is there anything you can recommend as far as a component cleaner? Again, circuit boards are pretty grungy--everything is, but I don't want to end up gunking things up even more.
As far as damage, my friend was prescient enough to see a loose capacitor laying inside the head. He stuck it in a baggie and sent that off to me as well. I *looks* like it broke off at the power switch--that's really the only place where anything looks broken. Offhand, do you know if these amps tended to have a cap that went from the switch to a ground lug? The cap is completely hosed and will need to be replaced, but I don't see any number on it.
I'll upload pics of all this tonight. Also will get the numbers on the pc boards--great idea.
As far as a donor amp, would that be just watching Ebay or Craigslist--or are there other resources where something like that might be available?
Hey, thanks for the reply. I do appreciate it.
--TWJ
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| Re: Major Bass Combo Restoration Project [message #16603 is a reply to message #16600] |
Tue, 24 January 2012 16:53 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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In my experience, even the worst looking amps can be electronically fit. You really can't tell by just looking.
Yes, there is normally a cap that connects either side of the ac line to the chassis. This is a hum reducing grounding cap or is sometimes referred to as the "death cap". Some people remove this cap and change the ac cord to a three wire one.
As far as cleaning the internals, I use a shop vac with an old 2 inch wide paintbrush. I just carefully brush off the boards, etc. while holding the vacuum hose underneath to collect the gunk. When there is some serious stuff on the boards, I will sometimes use a spray bottle of distilled water and an old toothbrush. I don't recommend this unless you fully understand how to do this without getting other things wet and how to dry off and recondition the boards when you're done.
As for donor amps, eBay, CL and the guys here can be a possible source. Post an ad in the classified section and see if anyone responds.
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| Re: Major Bass Combo Restoration Project [message #16606 is a reply to message #16600] |
Fri, 27 January 2012 06:17 |
stevem
Messages: 4773
Registered: June 2004
Location: NY
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Senior Member |
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Hello and welcome also!
A product called PB Blaster (white spray can) which can be had from most auto part stores is light years faster than WD-40 as long as its not dried sugar from soda, or sum from spilled beer that is binding the nuts on.
On some plexi front amps like yours I have had to center punch the hold down nuts on oppsite sides and use a very small hobby type number drill to make two holes and then colapse and snap the nut off the pot.
If you need to go this route get at least 4 drill bits and drill real slow as when the bits bite through the back side of the nut they tend to snap unless you power the drill chuck by hand for better control.
Keep us informed on your progress.
[Updated on: Fri, 27 January 2012 06:19] Report message to a moderator |
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| Re: Major Bass Combo Restoration Project [message #16614 is a reply to message #16611] |
Sat, 28 January 2012 07:11 |
pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi
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Senior Member |
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It looks like the the power switch may be wired incorrectly, which may be the reason the orange cap was removed, it's hard to see from the photo. The white wire from the power cord goes directly to the lower right tab of the switch. If wired correctly the black wire from the power cord goes to the fuse holder and the other end of the fuse goes to the top right tab of the switch. The two center tabs of the switch are black wires that go to the transformer section. The orange cap goes from the chassis ground to the top center lug of the switch. Wiring a new three prong ground AC cable, the black and white wires of the power cord goes to the same lugs as the old two wire AC cord, and the green ground wire of the new cable goes to the ground tab of the chassis, and the orange cap can be removed. Your photo shows that the fuse may have been bypassed, (best I can tell from the photo) Does the amp power up, or is it DOA? If you can post a better photo and explain what the amp is or is not doing, will help a lot in giving some answers.
pleat
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| Re: Major Bass Combo Restoration Project [message #16617 is a reply to message #16614] |
Sat, 28 January 2012 11:20 |
cassent5150
Messages: 341
Registered: August 2009
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Senior Member |
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For all general purposes I would leave the cap off the power switch and make sure theres no wires coming from the switch that go to ground or chassis. Make sure the fuse is good, not more than like 3 amp rating and that it is in the black wire of the power cord. If you have a multi meter to test voltages, set it to DC voltage and with nothing plugged in at the inputs as well as speaker output, clip the meters black wire to the - green wire at the top of the 2 big power filter caps and clip the red meter lead to the red wire on top of the caps and power it up. What does it read? Also test the speaker output jack for DC voltage.
Steve C
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| Re: Major Bass Combo Restoration Project [message #16618 is a reply to message #16600] |
Sat, 28 January 2012 21:55 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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The cap is broken, throw it out. It can't be fixed.
Yes, the photos are pretty bad, but they get the message across. I've seen worse as far as the dirt is concerned. It needs to be cleaned up. The connectors to the power transistors and the thermal cutoff switch all need to be serviced and cleaned.
As SteveC stated, you should check the basic amp functions. Please check the power switch wiring before you do anything else. If there are mistakes in the power switch wiring, it can cause you physical harm.
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| Re: Major Bass Combo Restoration Project [message #16679 is a reply to message #16600] |
Fri, 10 February 2012 13:56 |
trainwreck_joe
Messages: 10
Registered: January 2012
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Junior Member |
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Sorry for not responding in a while. I came down with a major case of flu (real h1n1 type junk) and was flat on my back for over a week.
Anyway, thanks to all for all the info. I've decided, however, to take the amp to be repaired professionally--by an older, local guy I know and trust (used to work for Dumble). Looking over the amp he said it shouldn't be hard or too costly to fix at all. Well, we'll see...
When I get it back, though, I'm still going to need to either get or build a cabinet. I'd actually prefer to build one, so if anybody can help me out with dimensions and materials Kustom originally used I'd very much appreciate it.
I'll definitely post a progress report when the amp comes back from the shop.
Again, thanks much.
--TWJ
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| Re: Major Bass Combo Restoration Project [message #21016 is a reply to message #16600] |
Sat, 26 July 2014 11:31 |
mlzippy
Messages: 1
Registered: July 2014
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Junior Member |
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I have an old Kustom K100-C6 amplifier that I have completely torn down and am refurbishing. I love the old amps because they are much easier to work on; no microprocessors or chips. Some of the things that I found so far are that some of the tantalum capacitors are shorted in the preamp boards. I also don't like the fact that the old setup does not have a ground. So, I am installing a grounded plug cable. I have gone to the extreme of even documenting the hole pattern of the front panel and the chassis on CAD. What can I say? I was bored one night and needed the drawing practice. I am an electronics technician by trade with over 40 years of experience if you have any questions. Thanks again for your post. I am glad that I am not the only one that appreciates the older stuff.
Zippy
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