Kasino Fever Schematic

[ogeecheeman]

kasino fever amp issue

yes the 725 did the trick.pre board now operating fine.power amp output stage looks good too. thanks for the tip. now... here's the $64,000 question. what caused the IC 14228 to fail?

amp is back.different issue. input stage transistors Q1 & Q2 with 8vdc on all legs.???

[52 Bill]

now... here's the $64,000 question. what caused the IC 14228 to fail?

I really don't think that you can attribute the failure to any one reason. It could have been a manufacturing defect in the chip, it could have been a power line surge, a too large of a signal at the chip input, too much heat on one pin when it was soldered into the board, etc, etc.

Now if every one of these preamp boards came back to the factory, all with the same chip blown, then there could be a design issue. Random failures can be caused by too many things to be guessed at. If you had access to a semiconductor lab, you could open up the case and find out what parts of the chip failed on the wafer. Then maybe you would know for certain why it failed.

[ogeecheeman]

yes the 725 did the trick.pre board now operating fine.power amp output stage looks good too. thanks for the tip. now... here's the $64,000 question. what caused the IC 14228 to fail?

[g1]

SL14228 is a 4739 IC, no direct subs are available.
You could try what is suggested in the following link, if you need more info please start a new thread.

http://music-electronics-forum.com/t28734/#post253659

[ogeecheeman]

not to hi jack the thread but a quick question if I may...on PC5102 my signal dies right after pin 8 of IC I1B. nothing on the other side of c22 and r30 which ties to pin 133 c 26 and c28.I suspect a faulty IC1 as cap and resistor both pass the test. looks to be a SL14228. any ideas for a sub.thanks gentlemen.

[cmfmadison]

Thank you so much!

[52 Bill]

Is the chip numbered an 80848 a CA3080? Given the pin 5 input, and the R35/R36 attenuator at its input, not to mention its role in the tremolo circuit, I'm getting that sense. BUt I'd like some confirmation all the same.

Yes, I've used a standard CA3080 as a replacement for that part. The originals all seem to be metal cased TO-5 versions, but the standard 8 pin dips fit the boards and work perfectly as well.

[Mark Hammer]

Is the chip numbered an 80848 a CA3080? Given the pin 5 input, and the R35/R36 attenuator at its input, not to mention its role in the tremolo circuit, I'm getting that sense. BUt I'd like some confirmation all the same.

[52 Bill]

Here is the PC5102 schematic.

[Enzo]

Go for it. Right now I have to fire up my old computer and shift various cables to do scans.

[52 Bill]

Enzo, if you don't find it I can scan the one I have.

It's interesting, I haven't heard of this amp in thirty years, and last week one came in for repair. Now here's another one. Interesting design with a sort of biamp output for the horn.

[cmfmadison]

Thanks so much!

[Enzo]

Let me see if uploads are working today...

Got the PC5033 already scanned, I'll have to look in my files for the other.

[cmfmadison]

The board numbers are as follows : PC5033 AND PC5102

[Enzo]

Then your repairman will have to give us the board numbers. Kustom amp boards have type numbers on them, PC5033 or PC108 or whatever. We need those PC numbers, as that is how the circuits are identified. The "schematic" for an individual amp model is really just a wiring diagram for the connections between boards.

There is a lot that can be done without schematics. We can usually verify power supply is present and clean. And if we have power, we can usually determine which section has the problem.

"Stopped working" could mean anything. It would be helpful to know whether that means the whole thing is dead and dark, or if the sound no longer comes out the speaker, or if it still amplifies but sounds like crap.

And it helps to know if it was failing for a while or if it worked OK and then just stopped instantly.

ON an amp that age, all the small electrolytic caps in the signal path are suspect, and for the very small cost they represent, they probably ought to be changed, and that usually fixes half the old Kustom amps I see.