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cleaning pots? [message #20386] Sat, 29 March 2014 21:27 Go to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
Just acquired my 1st Kustom amp, which I am learning about as I unpack and fire it up.....A black K100C-8 with 4 speakers. Looks like new condition and sounds awesome with sustain that never ends. Probably was stored for 40 years. Some pots must not have been turned in decades. Tone was a little flat until I started turning the pots many times and the brilliant hi 's are coming alive the longer I play it. And bass too. There's not really much scratchiness turning the pots, but rather for a brief bit the tone changed the bass and treble tones to weaker, then stronger. After turning knobs several times tones seem mostly normal now. Turning the bass knob seems to slightly tax the amp's power and the blue light ever so slightly dims then brightens. But after turning the knobs many times they seem to have loosened the internal oxidation and are performing as they should for the most part.

What should I use to clean the pots? I use Radio Shack electronics spray cleaner to spray into my Fender pots. An old broadcast engineer says no; use Radio Shack electronics lubricant spray.

The reverb has a very short decay, but it's
loud, just not as long decay as Kustoms I hear on Youtube. When the amp arrived via FedEx, a 10" spring had fallen out of the amp into the box.
It 's not broken. Haven't opened the back yet. First things first
firing it up to evaluate condition. Loose spring sound like the short reverb decay issue?

What year of manufacture is serial # 46458?

I hear what the Kustom amp owners are raving about now. Wish I'd of found one years ago.

thanks.....

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Re: cleaning pots? [message #20387 is a reply to message #20386] Sat, 29 March 2014 22:01 Go to previous messageGo to next message
oren hudson is currently offline  oren hudson
Messages: 274
Registered: March 2008
Location: Gastonia, NC
Senior Member
The best stuff is Deoxit. Radio Shack works OK, but as advised, get the cleaner/lube combo.

Serial number puts manufacture between October through December 1969. Smile

Can't help you with the reverb/spring issue. Sad

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Re: cleaning pots? [message #20388 is a reply to message #20386] Sun, 30 March 2014 07:49 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
Hello and welcome to the Kustom sickness that as infected us here!
You very lucky that the reverb spring pan that came out of the amp did indeed come out and not remain in the amp to short something out whe you turned it on.
The bad news is that these reverb pans are covered with glued on cardbaord from the factory, so someone has already been in the amp tryin to fix it.
The problem of a broken off reverb spring can only be fixed by replacing the whole reverb pan with a new one.
The pilot lamp dimming is normal on Kustoms when a certain level of output power gets produced.
lubing the pots is easy on that model amp, the pots are mounted on the two preamp circuit boards in such a way the the slots are facing up.
Never turn the crap out of a pot to get it work, as that only wares the resistive carbon trace even more!
Why more pots do not come lubed when made is a crime.
Since the amp has been sitting unused for many years, the best thing you can do is to play thru it and or leave it on for 8 to 12 hours which will help the two main filters reform themselves.

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Re: cleaning pots? [message #20389 is a reply to message #20388] Sun, 30 March 2014 09:14 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
Thanks for the advice. The spring doesn't appear to be broken anywhere nor on the ends. You're right for sure about leaving it on. After a dozen hours the sound is coming alive noticably hour by hour. And it's actually pretty quiet with not much buzzing. Still has 2 prong cord. Washed the nauhahyde. Will apply armorall this afternoon. Thought getting the naugahyde treated was a priority.

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Re: cleaning pots? [message #20390 is a reply to message #20386] Sun, 30 March 2014 13:02 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
I'll second the DeoxIt recommendation, there is no better cleaner on the market. As for the stiff controls, they just need a little spray to soften the old grease that is inside the back of the pot. With age, the grease hardens and makes the wiper harder to turn. If you spray too much, the grease can actually get washed away, so just use a little to remove the basic layer of dirt and oxidation.

The reverb tank is a Type 4 tank, meaning 4 springs inside. It looks like there are only two long springs, but each of those is made up of two counter wound springs joined at the middle with a crimp connector. The two long springs are different lengths, creating a thicker reverb sound. If the longer spring is missing from the tank the reverb could sound shorter than normal.

If you open up the tank, you can look at the ends where the springs connect to the transducers. There are very thin wires that have a little black ferrite magnet bead attached to them that come out of the transducers. The springs hook onto the end of these wire. On older tanks the springs just hook on to the transducers. Later ones were glued with a drop of epoxy. If you are lucky, the spring will just hook back in and you will be on your way. If you are not so lucky, the transducer wire will be broken off and the little bead magnet will be stuck somewhere to the metal tank. If the wire is broken, there is no easy way to repair it and a replacement tank will be in your future.

[Updated on: Sun, 30 March 2014 13:04]

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Getting to the reverb pan [message #20395 is a reply to message #20390] Tue, 01 April 2014 07:58 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
Since I'm not a tech and this is my first Kustom amp, thought I'd ask for advice before trying a couple repairs and damaging something.....How do I get to the reverb pan in my K100C-8? Inside the speaker cab, and on the bottom of the plywood the amp head sits on, I see 4 screws that appear to go up into the amp head. Are these what needs removing to pull the amp head out?

Also, how do I get the pilot light bulb out to replace it? Does it come out from inside the amp head or does the glass light cover unscrew from the front?
I've read here an 1829 bulb is the replacement, or an 1819 Radio Shack will work, but won't be as bright .

Thanks for all the advice.

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Re: Getting to the reverb pan [message #20399 is a reply to message #20395] Tue, 01 April 2014 12:13 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
Yes, remove the 4 screws and the chassis should slide out the back of the cabinet.

The pilot lamp holder is similar to a vintage Fender one, except the jewel lens is blue. The lens portion should unscrew and the bulb will be visible. It is a bayonet type socket, so press in on the bulb and twist it to the left and it should pop right out. If you have problems gripping the bulb, a small piece of rubber tubing or heat shrink slipped over the bulb will help make the removal easier.

The only problem could be when the lens is screwed in too tightly, the entire threaded mounting section sometimes comes loose. If this happens the internal hold down nut will need to be tightened up from the inside of the chassis.

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Re: Getting to the reverb pan [message #20400 is a reply to message #20399] Tue, 01 April 2014 12:35 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
thanks

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Re: Getting to the reverb pan [message #20405 is a reply to message #20395] Tue, 01 April 2014 16:49 Go to previous messageGo to next message
pleat is currently offline  pleat
Messages: 1452
Registered: June 2004
Location: Belding, Mi
Senior Member
The reverb pan needs to be in the amp. Tanks come with different grounding, impedances on input and output, grounded input or grounded output, and also part of the part number of the tank signifiys which way the tank is to mount. Springs up, Springs down, sideways mounting, etc. Mounting the tank to the bottom of the amp cabinet, will put your tank in a upside down position. Is there a reason you want to move the tank?
pleat

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Re: Getting to the reverb pan [message #20406 is a reply to message #20405] Tue, 01 April 2014 18:56 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
I'm not wanting to relocate the reverb pan. What I was inquiring about is how to get the amp head out to get to the reverb pan so I can try to figure out how to fix the reverb. The reverb is working, but it's a very short decay, not like rich fuller long decay Kustom sound. I just bought the amp and had it shipped 2000 miles. When I unpacked it a spring fell out of the box. I am assuming it fell out of the amp. But I don't see how it may of come out of the head, so someone may have laid it in the speaker compartment. The spring that fell out is actually 2 springs that are connected. I don't see any damage to the connecting ends of the springs. But someone has been in the amp as the padding material is loosened away from it 's staples. Is the padding asbestos?... This is my first Kustom. I never even saw one in person. But I like the tone so well I am going to get rid of my Fender amps..... thanks everyone for your advice.

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Re: Getting to the reverb pan [message #20407 is a reply to message #20406] Tue, 01 April 2014 19:11 Go to previous messageGo to next message
pleat is currently offline  pleat
Messages: 1452
Registered: June 2004
Location: Belding, Mi
Senior Member
Opp's mis read what you were trying to figure out. As ChicagoBill suggested, once you get to the reverb pan, there should be some black foam covering. On each end of the pan, there should be a little hook that the spring you found will hook to. These little hooks are fragile, so go slow to re connect the spring at each end. If you find a hook missing then it's time for a new reverb tank. You can see how the spring hooks by looking at the spring that is still in the tank.

I'd suggest you do any repairs with the amp unplugged from the wall.
On the covering material, the material is Nagahide (not sure of the correct spelling) and the foam behind the covering is a standard foam.

One modification most collectors do, is to replace the AC power cord with a Grounded three wire AC cord. Follow the AC cable to the fuse and power switch and solder the new AC cord just as the original, then fasten the green ground wire to the chassis.
pleat

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Re: Getting to the reverb pan [message #20408 is a reply to message #20407] Tue, 01 April 2014 19:18 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
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Sorry, I 'm referring to the padding inside the speaker cabinet stapled to the plywood sides, top, and bottom. Or it might be called insulation, I'm not sure. It is black and like as adbestos...

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Re: Getting to the reverb pan [message #20409 is a reply to message #20408] Tue, 01 April 2014 19:31 Go to previous messageGo to next message
pleat is currently offline  pleat
Messages: 1452
Registered: June 2004
Location: Belding, Mi
Senior Member
It's acoustic Fiberglass.
pleat

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Re: Getting to the reverb pan [message #20410 is a reply to message #20409] Tue, 01 April 2014 19:40 Go to previous messageGo to next message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
thank you.

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Re: cleaning pots? [message #20411 is a reply to message #20386] Wed, 02 April 2014 06:30 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
If as Bill posted you need to go in the amp to hold the pilot lamp holder to get the jewel off, then make sure that the amp has been off for a few minutes as right next to the pilot lamp holder is a 5 watt resistor that gets very very hot and it will give you a bad burn!

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Re: cleaning pots? [message #20413 is a reply to message #20411] Wed, 02 April 2014 09:29 Go to previous message
vintagefan is currently offline  vintagefan
Messages: 166
Registered: March 2014
Location: Dallas
Senior Member
I appreciate everyone 's help.... will update as I slowly make progress.

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