Home » VintageKustom.com » Repairing Kustom Amps » I'm finally having my K200 tuned up :-D
I'm finally having my K200 tuned up :-D [message #4993] Mon, 25 October 2004 16:32 Go to next message
voided3 is currently offline  voided3
Messages: 200
Registered: July 2004
Senior Member
Hello. Some of you may remember my post a while back ("K200 thump") about my K200-A5 PA head. I finally saved enough cash and worked up enough pride to bring it in to my local music store and have it tuned up. I figured that since it's about 35 years old, it couldn't hurt; i think the power caps on it were starting to go, and I depend on this amp, so I figured why not. I should have back within a week and i'll keep you guys posted if you're interested. Thanks!
Re: I'm finally having my K200 tuned up :-D [message #5009 is a reply to message #4993] Fri, 29 October 2004 16:54 Go to previous messageGo to next message
voided3 is currently offline  voided3
Messages: 200
Registered: July 2004
Senior Member
Hello. I just got a call today about the status of my amp; i'll get it back this week. The repairman said he cleaned it out completely (and it needed it dearly; everything was covered in cig ash and cobwebs), and he said one of the input jacks was faulty (i'm guessing channel 4; it always buzzed), so he replaced it and cleaned the rest. He said it's sounding really good and that with the old amps, you should make sure to keep using them to keep the caps charged up; not a problem haha (but the salesman I bought it from said it sat in someone's studio rarely used for the last 20 years, so what the repairman said makes sense). Now all I have to do is wait for it to return to the music store from the repair place and let 'er rip!
Re: I'm finally having my K200 tuned up :-D [message #5012 is a reply to message #5009] Sat, 30 October 2004 21:33 Go to previous messageGo to next message
voided3 is currently offline  voided3
Messages: 200
Registered: July 2004
Senior Member
Hello. I got it back today! I was right, he replaced the channel four input and cleaned everything and checked the caps; he said they were low so he ran the amp for about 12 hours and they were completely charged when he was done (any comments on this method?). It works great and is ready for many more years of uber loud fun. Thanks!
Re: I'm finally having my K200 tuned up :-D [message #5248 is a reply to message #5012] Sat, 01 January 2005 14:25 Go to previous messageGo to next message
Smoke1
Messages: 107
Registered: September 2003
Location: Southern Maryland Solomon...
Senior Member
Confused Hey V3, If you were to replace these caps what would be the part number and do you know where to buy them and how many?
Rolling Eyes


Smoke1 Plays Kustom Amps & Old Tube Amps Loud in S. Maryland
Re: I'm finally having my K200 tuned up :-D [message #5249 is a reply to message #5248] Sat, 01 January 2005 14:40 Go to previous messageGo to next message
shadow is currently offline  shadow
Messages: 21
Registered: October 2004
Junior Member
smoke .i think i saw a post one time that gave some specs on caps to upgrade your kustom .you might try a search on replement caps.......shadow
Re: I'm finally having my K200 tuned up :-D [message #5264 is a reply to message #5248] Mon, 03 January 2005 09:19 Go to previous messageGo to next message
Smoke1
Messages: 107
Registered: September 2003
Location: Southern Maryland Solomon...
Senior Member
Very Happy OBTW I Found the K200B Capacitor PN on an old post Mouser 539CGS50V25000. Phone: 800-346-6873

Smoke1 Plays Kustom Amps & Old Tube Amps Loud in S. Maryland
Re: I'm finally having my K200 tuned up :-D [message #5267 is a reply to message #4993] Mon, 03 January 2005 16:21 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4288
Registered: June 2004
Location: NY
Senior Member
That is the part number for a 2500 MFD cap, the K200s use a 4500MFD 50volt cap.These are electrolytic type caps, meaning wet like a car battery.When they make these caps, inbetween the aluminum foil they use for the plates they put a electrolite compound, then they run a small voltage and current thru the cap for anywhere from minutes to many many hours. The current passing thru the electrolite produces a aluminum oxide film on one side of the foil. this is the dielectric or insulation from one layer of foil to the other. the thickness needed of this insulation depends on how much voltage the cap will be rated at, and in turn how long the forming process takes.So they are growing the insulation inside the cap. Now heres the problem, as they age, heat and non-use makes the electrolite dry up, once that starts the cap can not keep up its dielectric and the stuff will start to crystalize. What repair techs can do some times if they are not to dry, is reform the caps, just like when they first make them.This repair will work for a while depending on how much voltage the powersupply hits the cap with, compared to how many volts the cap is rated at, and once again like some people have heard how offten the amp gets used. Use is better for cap life.But be ware once what ever amount of electrolite goes crystline inside the cap, that hard stuff can never be reverse, and even worst once crystline it becomes a conductor of electicity just the oposite of what it needs. It may not conduct enough current to blow the amps fuse( but at some point it will) but the amp will start to get a 120 cycle A/C hum out of the speakers and it will go into distortion and sound ugly at a lower and lower volume level.You can replace the caps with a larger MFD value for more clean head room and tighter bass control, but from what I have found, any thing more than 15000 MFD on each side of the powersupply is a waste and a big expence if you go for new caps in the same size 3 inch size cans. Back when this amps where made they wanted to use the best caps, and they did, these are called computer grade caps. now a days caps have come a long way, you can get 3 times the MDF value in a cap all most 2/3s smaller then what came in the amp. This smaller type will need smaller mounting clamps, but what I do is just silicone glue them in, or tie strap them to the original filters if still good and then add some glue. Do not be tempted to use shoe goo glue or a tube type contack cement, you will regret it later. The silicone is plenty strong!
Re: I'm finally having my K200 tuned up :-D [message #5283 is a reply to message #5267] Tue, 04 January 2005 14:09 Go to previous messageGo to next message
Smoke1
Messages: 107
Registered: September 2003
Location: Southern Maryland Solomon...
Senior Member
Thanks,

So putting in 2 each Mouser PN 539CGS50V15000 page 465 will work just fine? Confused It's a -12 bucks difference for 2 instead of the 25000's? Roger on using silicone. I know about sealants. Cool


Smoke1 Plays Kustom Amps & Old Tube Amps Loud in S. Maryland
Re: I'm finally having my K200 tuned up :-D [message #5294 is a reply to message #4993] Wed, 05 January 2005 08:52 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4288
Registered: June 2004
Location: NY
Senior Member
Yes, they will work fine, but you should consider also replacing the bridge rectifier( the thing that looks like a small flying sauser with 4 wires on it) with a 16 to 30 amp type. The higher MFD values pull alot more current thru the bridge at turn on, and I have seen the stock ones pop. The good thing is the higher values bring the voltage up slower so the simiconductors after the filters have a longer life.
Re: I'm finally having my K200 tuned up :-D [message #5297 is a reply to message #4993] Wed, 05 January 2005 12:52 Go to previous message
stevem is currently offline  stevem
Messages: 4288
Registered: June 2004
Location: NY
Senior Member
Just for everyones info there is a easy way to tell if these caps are going bad. Look on the top of them and you will see a little round red dot, sometimes they are green, other times there is no color just a small circle out line about the size of the head of a pensil. In anycase if these start to swell out like a reverse bell button, then the cap is going bad, even some of the other type axial caps have these vent ports.
Previous Topic: k250 Nasty Hum/Part ID.
Next Topic: Reverb Hum
Goto Forum:
  


Current Time: Wed Aug #d 12:47:26 EDT 2020
.:: Contact :: Home ::.

Powered by: FUDforum 3.0.9.