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kasino 400 doesnt turn on [message #21020]

Mon, 28 July 2014 12:01

TCPMeta
Messages: 4
Registered: July 2014
Location: Jacksonville

Junior Member

A friend of mine gave me his old Kasino 400 that has a built in u200 amp. He bought it back in the 70's and for the past 10 years it has been sitting in a storage room at his house. I brought it home and plugged it in and the amp doesn't power on.

I tried trouble shooting it with my multi-meter and it seems something is grounding out. like the capacitors and transformer are grounding out. I am starting to think it's the little black disk like thing where the transformer, capacitors and the positive side of the power light connect together.

any ideas on where to start?

[Updated on: Mon, 28 July 2014 12:10]

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Re: kasino 400 doesnt turn on [message #21021 is a reply to message #21020]

Mon, 28 July 2014 12:30

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

Welcome to the place. By "doesn't turn on" do you mean the amp will not power up (no lights or sound) or do you mean there is power, but just no sound?

The black disk thing is the bridge rectifier. It changes the ac voltage coming from the power transformer to a dc voltage that the amp circuits can use. They can go bad, but when they do, they usually blow the fuse.

Tell us exactly what symptoms your amp has and we will try and guide you to a cure.

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Re: kasino 400 doesnt turn on [message #21022 is a reply to message #21020]

Mon, 28 July 2014 13:40

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

If you find that the fuse is blown then unscrew the red and green wire on the two main filters that go to the amp boards, not the red and green that go back to the bridge rectifier.
Next replace the fuse with one of half the needed amperage an turn on the amp.
If the smaller fuse holds than the basic power supply is hood and with a meter set for dc volts you will read over 40' volts positive across the red and black on the main filters and then over 40 volts negative across the green and black wires.
Please report back to us on your findings!

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Re: kasino 400 doesnt turn on [message #21023 is a reply to message #21020]

Mon, 28 July 2014 14:59

TCPMeta
Messages: 4
Registered: July 2014
Location: Jacksonville

Junior Member

I fixed it.

By not turning on as in the power head does not power on.
The power lamp is burnt out as well.

The bridge rectifier was one of the issues so I googled a for a local place that had one and found a old electronics repair shop and bought a new one. The amp still didn't power on so I went into looking at the power supply again. Come to find out the power cable has a couple of breaks in it and the power toggle switch was on its way out. To move the switch you really had to press on it. I found a extra toggle switch in my box of parts. For replacing the power cable I bought a cheap 6ft orange extension cable from harbor freight and hardwired it when I installed the new toggle switch. It finally powers on now and works fine but the volume potentiometer goes in and out so you have to play with it to get the desired volume. Looks like i'll have to special order the poteniometer.

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Re: kasino 400 doesnt turn on [message #21024 is a reply to message #21020]

Mon, 28 July 2014 16:00

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

Just get some Deoxit brand F5, it's a cleaner and lube which should fix it up if you can get at the terminal side of the pot.
If not what I do is remove that circuit board and on the bottom side under the pot drill a small enough hole to get the spray tube thru.
Just make sure there are no resistors or caps in the way on the top side,also if need be you can drill thru a circuit trace and just solder on a wire jumper when you are done.

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Re: kasino 400 doesnt turn on [message #21025 is a reply to message #21020]

Tue, 29 July 2014 01:34

TCPMeta
Messages: 4
Registered: July 2014
Location: Jacksonville

Junior Member

I really wouldn't want to drill into a 40 year old circuit board, granted its a one sided board but the thought of drilling it creeps me out. I rather de-solder it lube/clean it.

Another note since the first four knobs are missing I was thinking to replace all of them with these.

sparkfun.com/products/10002

or

sparkfun.com/products/10001

Just use the trusty dremel and some JB weld on the back side of the knobs to make them fit correctly. Unless I can find something better, so far I like these since they kinda match the OEM color scheme.

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Re: kasino 400 doesnt turn on [message #21026 is a reply to message #21020]

Tue, 29 July 2014 06:31

stevem
Messages: 4775
Registered: June 2004
Location: NY

Senior Member

It doesn`t matter if the fiberglass circuit board is 140 years old and is a great time saver!
I been doing repairs for near 40 years and if you have ever had to unsolder more than four mini pots of the type that have a two or more steel support frame you would quickly see that drilling holes can save the owner near an hour in labor time, not to mention saving the circuit board from the plealing trace issue that can take place
It sounds like a bit of a project with the knobs to keep them centered?
Glad the amps playin again for ya!

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Re: kasino 400 doesnt turn on [message #21027 is a reply to message #21020]

Tue, 29 July 2014 12:20

chicagobill
Messages: 2006
Registered: April 2003

Senior Member

I don't like the idea of drilling the boards either, not that I can think of a time that I needed to drill one to get access to the pot opening. If you remove the board from the amp, you should be able to get some cleaner in there from some angle.

I find that with a little bit of plastic tubing, I can get to the open side of most any pot. StewMac also sells a plastic thread on sleeve that will allow for the DeoxIt to get into the pot from the shaft side. This is great for things like the Fender reissue blackface amps where the pots are all buried under the pc board. Removing all of the controls just to clean one pot is a real time waster.

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