Home » VintageKustom.com » Repairing Kustom Amps » kustom k100-1??! fuse specifications...
icon5.gif  kustom k100-1??! fuse specifications... [message #9292] Fri, 07 March 2008 18:09 Go to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Confused a friend of mine has been getting me to do volunteer repair work for a church here in oregon, they happen to have a few very old amps and pa systems that're in need of repair!!!,... i've gotten the specs for most from local electronic pals around town, but no one seems to have the specs on exactly what fuse is soldered into the BUSS fuse block in a kustom k100-1 serial#57325 bass amp, it was evidently removed for reasons unknown to the church people(& me!!!)... any clues from anyone on the fuse used(no pun intended)??!... or where to get the info from, i've read all the repair hints from 2006-2007 and all the components are functioning, just no fuse!!!...

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9293 is a reply to message #9292] Sat, 08 March 2008 17:02 Go to previous messageGo to next message
LesS is currently offline  LesS
Messages: 477
Registered: December 2002
Senior Member
Hi,
The K100-1 uses a 3 amp fuse.
-Les S

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9294 is a reply to message #9293] Sat, 08 March 2008 18:43 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Very Happy thanks alot!!!... been wonderin' whether i'd have to experiment w/ that in a slo-blo form or fast-blo,... i suppose fast'll give me component protection,... let you know what happens!!!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9295 is a reply to message #9293] Sat, 08 March 2008 18:44 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Very Happy thanks alot!!!... been wonderin' whether i'd have to experiment w/ that in a slo-blo form or fast-blo,... i suppose fast'll give me component protection,... let you know what happens!!!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9296 is a reply to message #9293] Sat, 08 March 2008 18:44 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Very Happy thanks alot!!!... been wonderin' whether i'd have to experiment w/ that in a slo-blo form or fast-blo,... i suppose fast'll give me component protection,... let you know what happens!!!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9297 is a reply to message #9293] Sat, 08 March 2008 18:45 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Very Happy thanks alot!!!... been wonderin' whether i'd have to experiment w/ that in a slo-blo form or fast-blo,... i suppose fast'll give me component protection,... let you know what happens!!!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9298 is a reply to message #9293] Sat, 08 March 2008 18:45 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Very Happy thanks alot!!!... been wonderin' whether i'd have to experiment w/ that in a slo-blo form or fast-blo,... i suppose fast'll give me component protection,... let you know what happens!!!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9299 is a reply to message #9293] Sat, 08 March 2008 18:49 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
my double clicking's a bit much!!!... sorry for the repeats alot of FUD's error messages showed up & i didn't get the cancel until i retried about 3-4Xs,... i'm better now... ...

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9302 is a reply to message #9292] Mon, 10 March 2008 08:57 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
It would be a fast blow fuse.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9305 is a reply to message #9302] Wed, 12 March 2008 16:22 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
a bit back ~2007's messages on this subject said that a slo-blo might be a possibility?!?... well, i've lost 2 3A fast-blo fuses so far... so now i'll just trouble shoot the components to see what's the cause??!... the 2 power capacitors both showed 40 volts before discharging, so they seem to meet the specs brought up on this site... i'll check on some of the other suggested problems: the rectifier, power transistors,... this being a serial #53000's K100-1, i notice a thermistor and also a small transistor-like component heatsinked between the 2 power transistors(all in the same heatsink w/ the thermistor)... the thermistor's hooked up to the 117VAC line(hot side)& transformer... could that be a problem in the fuse blowing??!, by the way, i do have access to an occilloscope for troubleshooting, will do if necessary...

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

icon10.gif  Re: kustom k100-1??! fuse specifications... [message #9306 is a reply to message #9305] Wed, 12 March 2008 16:32 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
now i've looked @ the original K100-1 repair sites & found a message on that one should never power up the K100-1's w/out a load on the output(a speaker cab),... is this true??!... i'd powered up w/ all the pots @ '0' and no input signal,... expected no 'work' to be done so no current to flow, eh?!!... evidently not, that first spike blows the 3A fast-blos, liketty split!!!... so do i always need to hook up a speaker cabinet(4 ohm to 16 ohm load-Z impedance-)to the output!??...

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9307 is a reply to message #9306] Wed, 12 March 2008 18:06 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
drb:
Now you know why the fuse was missing in the first place!

You should be able to turn on the amp with no speaker load without any problems.

As the fuse blows on power up, with no load, I would suggest checking the filter caps for either a short or low ESR.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9308 is a reply to message #9292] Thu, 13 March 2008 06:22 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
I would start by trouble shooting it like this.
First disconnect the red and green wires that come off the 2500 mfd filter caps and go to the driver board, replace the fuse, turn the amp on, and if the fuse holds then the rectifier bridge is ok.

Next reconnect the two wires to the filters and slde off the connectors from each output transistor making note of what color wire was facing the rear of the amp. with this done repower the amp and if the fuse holds, then one or both of the output transistors is shot.
If the fuse still blows then one or both of the driver transistors in the square heat sinked case( if they are original) is bad, and so is one or both of the output transistors.
Most times when a output transistor goes, it takes the 5 watt emitter resistor next to each driver with it, so it will read open.
The Item you wondered about in the clip in between the two output transistors is a thermal diode that keeps check on the bias of the output transistors in realtion to heat.
These rarly go bad, but they should be held tight in their clip, and their should be some thermal compound grease on it for good heat conductivity.
I find it helps and saves time in a troubled amp like this to clip in a circuit breaker untill I get the shorting problem resolved.

Report message to a moderator

icon6.gif  Re: kustom k100-1??! fuse specifications... [message #9311 is a reply to message #9308] Thu, 13 March 2008 18:30 Go to previous messageGo to next message
drbambam is currently offline  drbambam
Messages: 12
Registered: March 2008
Location: portland, or
Junior Member
Cool it shows the rectifier to be the culprit as of now,... now to see ??? the hell was meant by 25W to 35W radioshack bridge rectifier replacements,... rectifiers're only rated by voltage & amperage, ouch!!!... so i'm assuming(hoping not to make a fool of myself)that what was meant was: 25A to 35A bridge rectifiers(again assuming the voltage to be ~50V to 100V!!!), this voltage from the 40 to 43 Vdc charge of the filter power caps!!!... so the radio shack here in no po, or only has 1A to 25A, 200V to 50V range bridge rectifiers... the 100V to 200V are all between 1A to 6A, whereas the 50V is 25A... so am i right about the 50V, 25A bridge for a replacement??!

reggaeallonebassforfundancemusicpoetryonelove!!!

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9314 is a reply to message #9292] Fri, 14 March 2008 06:20 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
You need more than a 50 volt rating to have a high enough inverse voltage rating on the bridge.A 200 Volt Bridge at even 4 amps is good, or you can get four 1N4007 diodes and a four post terminal strip and make a new bridge recto set up.
The quiter set up noise wise will be to make up a new bridge using Hexfred/fast recovery type diodes and place a .01 at 200 volts or better ceraimic cap across each diode,adding these caps can even be done with a bridge recto.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9316 is a reply to message #9314] Fri, 14 March 2008 12:39 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
Steve: The 1N4007 diodes do not have enough current capacity for this application. They're fine for a tube amp, but not for the Kustoms.

I've used 200 volt/25 amp bridges as a generic replacement for all Kustom amps, other than Frankenstein heads. The only real problem is that the push-on terminals that are on the wiring harness will not fit the new rectifiers and must be removed or replaced.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9318 is a reply to message #9292] Fri, 14 March 2008 12:48 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
I could have sworn I used them once on k100? thats 2 amps of current that they can handle on each leg of transfromers secondary for 4 amps total, No?

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9321 is a reply to message #9318] Mon, 17 March 2008 12:20 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
The 1N4000 series diodes are rated at 1 amp.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9322 is a reply to message #9292] Mon, 17 March 2008 12:57 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
Right, but their are two on each leg for the bridge feed.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9325 is a reply to message #9322] Mon, 17 March 2008 17:15 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
Yes, each diode conducts on half of the cycle and can only supply 1 amp each.

Report message to a moderator

Re: kustom k100-1??! fuse specifications... [message #9342 is a reply to message #9325] Fri, 21 March 2008 12:02 Go to previous message
C4ster
Messages: 686
Registered: June 2001
Location: Mukwonago, WI (Milwaukee...
Senior Member
One other thing about the bridge rectifier. The caps hold at 40. Because of the bridge arrangement, the total reverse voltage is across 2 diodes in series, so a 50 volt bridge is more than sufficient to withstand the voltage in a Kustom. The current supplied to the output transistors is in excess of 5 amps at 100 watts into 4 ohms. A K100 would be 2.7 amps into 8 ohms.

Report message to a moderator

Previous Topic: Tuck "N" Roll
Next Topic: quick k-150 question
Goto Forum:
  

[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Mon Apr #d 09:20:50 EDT 2024
.:: Contact :: Home ::.

Powered by: FUDforum 3.0.9.