Author Topic: Repair Analog Oscilloscope BM 566 A  (Read 3805 times)

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Offline teslapand

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Repair Analog Oscilloscope BM 566 A
« on: March 01, 2016, 10:33:57 am »
Hello Friends,

I have two oscilloscopes, one of them is  Analog Oscilloscope BM 566 A and another is  Analog Oscilloscope BM 556.
The two oscilloscopes are broken and I want to repair them.
I have downloaded the service manual from internet, but in the diagram is missing values for check points indicated in circuit diagram.I mean that values wright in circle marked as "U...".

Can somebody to help me for this values?!?!

Sorry may poor english.

Thank You,
 

Offline Anks

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #1 on: March 01, 2016, 11:04:11 am »
Are there any signs of life or are they completely dead?
 

Offline teslapand

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #2 on: March 01, 2016, 11:14:19 am »
No, it isn't totally dead.

The two traces do not apear, and the voltages power supply are no good(for BM566A).

The"+12V" and "-12V" are "+11.4V" and "-3.55V" for BM 566A.I think there are broken some tantalium condensator.
The two traces  apear, and the voltages power supply are no good(for BM556).

The"+12V" and "-12V" are "+12.1V" and "-11.5V" for BM 566.I think there are broken some tantalium condensator, too.

But I want to measure the voltage in check point indicated in diagram for reason to find exactly where is the problem.
There are many tantalium condensators and the acces to measure them is difficult.

 

Offline tautech

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #3 on: March 01, 2016, 11:28:12 am »
Please provide a link to the manual. We all need to be on the same page.  ;)
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Offline teslapand

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Offline teslapand

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Offline frantisek

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #7 on: February 10, 2017, 10:25:06 am »
Tantalum C!
 

Offline Armadillo

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #8 on: February 10, 2017, 02:02:18 pm »
The two traces do not apear, and the voltages power supply are no good(for BM566A).

The"+12V" and "-12V" are "+11.4V" and "-3.55V" for BM 566A.I think there are broken some tantalium condensator.
There are many tantalium condensators and the acces to measure them is difficult.

IO3 the MMA741 is responsible to pull down and regulate the -12v rail...

Firstly, confirm the collector of E24 is at least -15v with respect to Ground;
Then measure pin 6, if it is at Zero voltage with respect to GROUND?
if it is, then the problem is the transistor E71 or E24 or both, otherwise replace MMA741.

Measure across R81/R82, what is the voltage?

Adjust R70 to attain +12Vdc, the negative -12v should tracks the positive voltage.
 

Offline cnqhdszq

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #9 on: February 25, 2017, 06:09:10 am »
I have not seen the two machine before.it is beautiful . but the screen is to small .
 

Offline tautech

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #10 on: February 25, 2017, 08:16:10 am »
I have not seen the two machine before.it is beautiful . but the screen is to small .
95mm diagonal is too:
https://www.eevblog.com/forum/testgear/aaron-bs-310s-cro-mini-teardowm/
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Offline teslapand

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Re: Repair Analog Oscilloscope BM 566 A
« Reply #11 on: April 12, 2017, 05:07:46 pm »
Thank you guys.
Because I couldnt repair the scope, I sell them and I am now from problems.Almost 1 years I had try to repair.
 


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