Yamaha CA-1000

RustinFord

New Member
OK so, I recently acquired a Yamaha CA-1000. I'm brand new to working on electronics and I am wondering how I would go about fixing it.

I replaced all the fuses and then when I powered it on. The red circled fuse blew. To me it does not look like an important fuse because it connects directly to the AC Outlets on the back. You can see what I'm talking about in the photo. The receiver does make 1 click noise when I attempt to power it on.

CA1000
http://www.toocuteforpublic.com/CA-1000-Inside.jpg
Main Circuit Board 1
http://www.toocuteforpublic.com/Main-Circuit-Board1.jpg
Main Circuit Board 2
http://www.toocuteforpublic.com/Main-Circuit-Board2.jpg

I'm not sure about how to go about trouble shooting this device. Any help would be greatly appreciated.
 
It is a very important fuse, like a main fuse..Its in series with the panel fuse on the rear panel.It should be a 5A pigtail.

Remove the bottom cover and inspect the power supply board--more fuses..

Suspect either bad capacitors ,diodes in the power supply or it could be something in one of the amplifier assemblies.

The fact that your blowing the pigtail tells me the rear panel fuse is possibly the wrong size fuse.It should be a 5A as well.
 

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Do you know how to read a schematic ? Do you have a multimeter ? At this point its not necessary to install and blow anymore fuses nor apply any power.Need to locate the shorted circuit.
 
Does the click happen after a short time like 3 secs - 5 secs after power on?
If yes I think this is supposed to happen - its the relay. ( I have this click on the CA600 after 5 secs)
 
No, the click was pretty much immediate after the power on. At this point when I power it on. Nothing happens at all. I spent some time today looking at the schematic and touching things with the multimeter. But really I have no idea what I'm looking for. I don't know whats a good reading or a bad reading. I'm utterly confused. Any suggestions anyone?
 
No, the click was pretty much immediate after the power on. At this point when I power it on. Nothing happens at all. I spent some time today looking at the schematic and touching things with the multimeter. But really I have no idea what I'm looking for. I don't know whats a good reading or a bad reading. I'm utterly confused. Any suggestions anyone?

For resistors you can check to see if they are in spec by reading their resistance with a multimeter, and checking that against the color bands. There are various calculators online (http://www.samengstrom.com/nxl/3660/4_band_resistor_color_code_page.en.html), or you can get a chart to calculate the values yourself. You can often tell visually what resistors might be out of spec. Darkened or blackened resistors with discoloration on the circuit board is a sign they got hot. Check any showing those signs. If you see any spots on the circuit board with severe discoloration or blackening with toasted looking components you are probably looking at a problem.

Also, the fusistors in old Yamahas tend to drift values over time. The 3 on the power board that have the bluish/white tint to them labeled 40399 on the board are all fusistors (and were all well out of spec on my CA-1000). Also, the two white ones labeled 20422 on either side of the cluster of 4 black capacitors are also fusistors. Check them.

Another way to check resistor (or any component) values is to look them up in the schematic. There will be a circuit board view, and a schematic view in the service manual. If you really can't figure a component out you can find what it is numbered as in the circuit board view by comparing between the actual board and what's on paper. The actual circuit board is labeled the same way as the circuit board view in the service manual, but the actual circuit board is often missing labels or is unreadable. After you know what the component is labeled as (e.g. R432) find that corresponding label in the schematic, and it will give you the value, component type, etc (e.g. 4.7 kOhm 1/2w resistor).

I'll leave this show with the real techs now. ;)
 
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Maybe you want to find some webpages about basic electronics: Ohm's Law, resistance, capacitance, inductance, diodes, and what (bipolar junction) transistors are and what they do... ? Like this:

http://www.makingthings.com/teleo/products/documentation/teleo_user_guide/electronics.html

I have a degree in computer engineering (which included EE classes), I know the theories, and I can read schematics somewhat, but am lost in deciphering basic building block circuits so even for me it is fairly hard to fix electronics, though doable.

I think getting at least the basic knowledge of electronics down pat will put it closer within reach.

There are some super sharp folks on here who can help you out, of course.

At this point you must find the source of the blowing fuses before powering the unit up again (unless one of the gurus tells you otherwise) or you might damage it further.

Michael
 
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