Okey guys, so either one of those two will do the job, if only amount is the difference, thanks.
I just got my oscilloscope up and running...
Of course i can just order the rectifier, but it could be fun to check it at first with my oscilloscope, if it's good enough to do the job..

How do i measure the main power rails with it?

 

Is there a link to the manual for your oscope so we can have an idea of what you are working with?

 

Is there a link to the manual for your oscope so we can have an idea of what you are working with?

On page 3 it says «How to use»
This is the only manual i can find

http://akizukidenshi.com/download/ds/sainsmar/UserManual_138ss.pdf

 

To measure power supply ripple with your DSO138 scope, set:

SW1 - AC
SW2 - 1V
SW3 - x1

SW4 - Running

Press SW7 until the desired feature is selected which will be hilighted. Use SW5/SW6 to change highlighted setting.

Set time sweep to 5mS
AUTO

(if you set to NORM, press SW7 until arrow on right edge of screen changes from purple to blue. Then use SW5/SW6 to move arrow UP/DOWN while watching the trigger voltage setting at the top right of the screen).

Show us a photo if you can.

You can HOLD the scan by pressing SW4.

 

@Marius83 It's good to know what your equipment can do. We know you can only view up to 40V peak to peak, so we won't ask you to measure some signals as most from stage 3xx to the output audio can exceed 60 V peak-to-peak. Now if you manage to get a x10 probe, then those measurements could be safely made.

 

@Marius83 It's good to know what your equipment can do. We know you can only view up to 40V peak to peak, so we won't ask you to measure some signals as most from stage 3xx to the output audio can exceed 60 V peak-to-peak. Now if you manage to get a x10 probe, then those measurements could be safely made.

Okey.
Will these be the correct ones?
Only problem is it takes three weeks for them to show up..

https://www.ebay.com/itm/P6100-2pcs...697257&hash=item466de5d468:g:ot0AAOSwonBZ5gIC

 

I just noticed you were in Norway. Yes, that style would work.

 

I just noticed you were in Norway. Yes, that style would work.

Yes I am located in Norway.
What about it?

The shipping takes so much time just because all these items from China are included some free shipping...
But i just found the same item with another shipping option, i might get it a lot quicker !

 

Nothing wrong with Norway. I am ignorant with respect to the supply chain over there.

 

To measure power supply ripple with your DSO138 scope, set:

SW1 - AC
SW2 - 1V
SW3 - x1

SW4 - Running

Press SW7 until the desired feature is selected which will be hilighted. Use SW5/SW6 to change highlighted setting.

Set time sweep to 5mS
AUTO

(if you set to NORM, press SW7 until arrow on right edge of screen changes from purple to blue. Then use SW5/SW6 to move arrow UP/DOWN while watching the trigger voltage setting at the top right of the screen).

Show us a photo if you can.

You can HOLD the scan by pressing SW4.

Set up the way you said on the picture.
I have ordered an x10 probe like JoeJester suggested, when it arrive we can measure i guess

 

Have you tried using the DSO138 to take any measurements as yet?

Connect the BNC cable with the alligator clips to the input BNC jack.
Touch the RED alligator clip with your fingers. You should be able to pick up 50Hz line frequency.

Play with the SEL control (SW7). This allows you to cycle through the following options:

HORIZONTAL POSITION
VERTICAL POSITION
TIME/DIV
MODE - Single / Normal / Auto
TRIGGER SLOPE
TRIGGER LEVEL

Use the UP/DOWN buttons to alter the selected option




In order to get a periodic waveform to stay stationery on the screen, adjust either VERT POSITION or TRIGGER LEVEL such that the TRIGGER LEVEL is positioned between the minimum and maximum portions of the trace.

The green "Triggered" LED at the bottom of the board should be flashing when the scope is being triggered.

 

Your DSO138 shown in the photograph is displaying a +0.5V offset when no signal is present.

To correct this:

Set CPL (SW1) to GND
Press SEL (SW7) until the VERTICAL POSITION arrow is highlighted.
Press and hold [OK] HOLD/RUN (SW5) for 2 seconds. This will shift the trace down.
Adjust the VERTICAL POSITION to bring the arrow back to the centre line.

 

Thank you MrChips for the guide to use my oscilloscope, i have scrolled through options and have got more familiar with it.

I have corrected what you said, and here's a picture what it picks up when i hold the RED alligator clip with my finger.

 

Nice.

Now, as an exercise, see if you can calculate the line frequency from the information of the scope.

 

Okey i'll try
I guess since it set to 5ms, one grid division would be 5ms, a complete cycle of the signal is 4 divisions, so if i convert 20ms it would be 50hz

I just don't understand how it picks up 50 hz from my finger...?
I did google it.. -so i am actually an antenna, amplifying the frequenzy of my electricity in the house... in this case my garage.. hehe.

 

Okey i'll try
I guess since it set to 5ms, one grid division would be 5ms, a complete cycle of the signal is 4 divisions, so if i convert 20ms it would be 50hz

I just don't understand how it picks up 50 hz from my finger...?
I did google it.. -so i am actually an antenna, amplifying the frequenzy of my electricity in the house... in this case my garage.. hehe.

Your body is a good receiving antenna. Think about how you can "perceive" 1 mA of current, and 100 mA can kill you. You have body resistance. You can measure it. And if you wet your fingers and remeasure, the resistance will be lower.

 

So i',m still waiting for my x10 probe.....

But i bought this tester to make transistor testing a little bit easier.... didn't cost much.. hehe.

 

We are going to wait until you get the x10 probe.
We would like you to look at the ripple from the power supply.

 

If you want to play with that tester, go right ahead. Check a good one that you know is good and a bad one you know is bad. Might as well become familiar with your test equipment as you don't apply power to that amplifier.

After your comfortable testing out of the circuit, do a couple in circuit test ... again, with no power applied to the amplifier.

Just keep copious notes in case you have any questions.

I see it also is an ESR tester. You can test your electrolytics with that.

The LCR function is inductors, capacitors, and resistors.

Take some time and become familiar while you are waiting.

 

My x10 probe finally arrived