KUSTOM K100-5 PA Amp Question

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Janitor Tzap
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Re: KUSTOM K100-5 PA Amp Question

Post by Janitor Tzap »

Easy now......
Take a step back from it, and get something too drink.


I looked at the KUSTOM Site that CeaSaR Linked too; http://www.vintagekustom.com/

In the "Technical Schematic's Area", it shows 4 other models that use the PC900 board.

Models:
K100C-6
K100C-7
K100C-8
Kasino Club


The K100-5 Model uses the PC900, PC803, and PC105 boards.

Does the board have markings on it stating it's a PC900?


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

i replied earlier, but i see now that it somehow did not post..

anyway they board is a PC900
but the transistor lay out ( transistor diagram ) does not seem to match the schematic
or am i crazy ? ( too tired ? )
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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

ok,, i think i got it figured out..
it appears that the page (transistor diagram) is mislabeled Q903 is actually Q906
and Q906 is (not identified, it is in between Q902 and Q907) actually Q903
so now i have a better grasp on the schematic now..

so next issue will be to find 1% resistors (95.3 ohms 1/2W)
and 5% (510 ohm 1/2W)
without having to special order..
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Re: KUSTOM K100-5 PA Amp Question

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dacflyer wrote:so next issue will be to find 1% resistors (95.3 ohms 1/2W)
and 5% (510 ohm 1/2W)
without having to special order..
If you still have some old scrap boards in your junk pile,
the 510 ohm 5% 1/2watt you might be able too find from one of them.

But that 95.3 ohm 1% 1/2watt will more than likely need to be ordered. :(

Also, are these Carbon Resistors, or are there some that are wire Wound Cement, or Ceramic Resistors?

The well made musician quality PA/Guitar Amplifiers of that era, will use the Cement, or Ceramic Resistors.
Because they were much more stable when put under high current loads.


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

the only stone resistors are the 2 emitter resistors 1ohm @ 5W.
i think the amp failed because of the diode lead broke on the Bias circuit.
it is supposed to be a metal diode that sat in a clip on the heat sink.
but it was replaced with a glass diode.. i'll have to figure out what i could use to mount to the heat sink. ( for temperature or bias compensation ? )

i'll most likely replace the bad resistors with flame proof resistors, and they will be elevated off the board, not flat to the board..
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Re: KUSTOM K100-5 PA Amp Question

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dacflyer wrote:the only stone resistors are the 2 emitter resistors 1ohm @ 5W.
i think the amp failed because of the diode lead broke on the Bias circuit.
it is supposed to be a metal diode that sat in a clip on the heat sink.
but it was replaced with a glass diode.. i'll have to figure out what i could use to mount to the heat sink. ( for temperature or bias compensation ? )
The FD111 Diode Crosses to a NTE519.
Yeah, the metal case of the FD111 Diode probably acted as a heat sink, and RF shield. :/
dacflyer wrote:I'll most likely replace the bad resistors with flame proof resistors, and they will be elevated off the board, not flat to the board..
Hehe...
Ceramic stand off's would work nicely for that.
Image


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

1N3754 is what the schematic shows.. i found some on ebay...but not cheap... unless i order from china..
could get 20 of them for 1/2 the price of 1...lol
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Re: KUSTOM K100-5 PA Amp Question

Post by Janitor Tzap »

There is one 1N3754 and is equivalent to the NTE116; (R-Si, 600 PRV, 1.0 Amp).{CR902} *
*{Diode is mounted in a clipped on chassis}

Two 1N3193 which is also equivalent to the NTE116; (R-Si, 600 PRV, 1.0 Amp).{CR900 - CR901}

Then there are Two FD111 Diodes that cross to the NTE519.{CR903 - CR904}

Edit:
Okay, the diode is CR902.
Unless there is some other marking on the diode, the cross I'm coming up with is NTE116. :/


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

the other diodes test ok, it is just the diode that clips onto the heat sink i need to find.. i founf a pair of them on ebay last night. $12.00 ( crazy priced, but i needed them. )
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Re: KUSTOM K100-5 PA Amp Question

Post by Janitor Tzap »

This is what I found.
Image
They are Rectifier Tubes, in a steel can, with radial leads. :???:
Is that what this is?

The picture you posted shows two Diodes with axial leads.

This is a 1N3754 that is on E-bay as well. :???:
Image

Also.....
You may want too read this: http://www.vintagekustom.com/FUDforum/p ... 47bc02561c
Here it says a NTE5801 is the Diode that replaces the 1N3754. :?
{Okay, now I'm confused.}
The Cross Numbers I got, came from my old NTE Cross Ref Book{Circa 1998}.
Went to the Online NTE Cross Reference and it comes up with NTE5801.

Argh!
This is giving me a headache! :mad:

I guess the only way too be sure what is the right replacement is to find the original spec's on the original diodes.
Then compare them to the spec's of the NTE5801 and NTE116.


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

naww... the one i tried to post looks like the 1st pic,, the metal can with leads
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Re: KUSTOM K100-5 PA Amp Question

Post by Janitor Tzap »

Sorry for the late reply.

Was trying to dig up the original spec's of those RCA 1N3754's.
So I could compare them too the replacement Diodes that I found.

Unfortunately I could not find any real info. :???: :/

That link I posted ( http://www.vintagekustom.com/FUDforum/p ... 47bc02561c ) has a person working on a KUSTOM AMP,
subbing in the NTE 5801 for the 1N3754 and having it work.

I'd give that a shot first, before plunking down the $12 a Diode for the original's.
{Unless the guy is one of those who wants it as original as possible.} :roll:


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

ya. your a day late..lol
i ordered the originals last week already..should be here this week.
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Re: KUSTOM K100-5 PA Amp Question

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dacflyer wrote:ya. your a day late..lol
i ordered the originals last week already..should be here this week.
Okay,

Well, as long as he is fine with it, that's all that matters. :smile:


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Re: KUSTOM K100-5 PA Amp Question

Post by dacflyer »

trying to get it as best to original as possible..
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