Oscilloscope repair help needed

H

hadihf

New Member

• Nov 28, 2006

• #1

Hi,

I have an old Trio Oscilloscope type CS-1022. It has a problem that the trace is very bright. I cannot reduce it with intensity control. If I rotate the intensity clockwise I hear a high frequency pitch. Any help will be greatly appreciated. Also can somebody has a schematic/service manual?


Regards

 

H

hadihf

New Member

• Nov 29, 2006

• #2

scope repair help needed

Can somebody help please....

 

R

Russlk

New Member

• Nov 29, 2006

• #3

The high frequency noise is probably the high voltage supply complaining about the load. Check the resistors in the CRT circuit, the bias is off. Most likely one of the resistors has gone open, should be easy to find.

 

mvs sarma

Well-Known Member

• Dec 1, 2006

• #4

Hi generally you find a series resistor to intensity control. it might have opened up-- check and replace.

 

H

hadihf

New Member

• Dec 1, 2006

• #5

Scope Repair

Thanks for all your help.

I got a service manual ...the intensity control center viper (red arrow) does not have series resistance?

Regards

 

Attachments

• HV.pdf

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C

CanonMan75

New Member

• Dec 1, 2006

• #6

hadihf said:

Thanks for all your help.

I got a service manual ...the intensity control center viper (red arrow) does not have series resistance?

Regards

Click to expand...

What intensity control? I can't see it next to the red arrow

 

H

hadihf

New Member

• Dec 1, 2006

• #7

scope repair

This is just part of schematic showing HV portion. The intensity control (10k)has one end to +5v and other to ground. the center is marked with arrow going to the transistor pair. Anyway now that i purchased the schematic I am confident to repair it. I will post the results.

Thanks

 

C

CanonMan75

New Member

• Dec 1, 2006

• #8

hadihf said:

This is just part of schematic showing HV portion. The intensity control (10k)has one end to +5v and other to ground. the center is marked with arrow going to the transistor pair. Anyway now that i purchased the schematic I am confident to repair it. I will post the results.

Thanks

Click to expand...

Ah.... that makes more sense now

 

audioguru

Well-Known Member

Most Helpful Member

• Dec 1, 2006

• #9

What a complicated circuit just to make 2000V.
My old 'scope has a high voltage winding on its power transformer.

 

H

hadihf

New Member

• Dec 2, 2006

• #10

Scope repair

It is 6kv actually

 

H

hadihf

New Member

• Dec 8, 2006

• #11

Hi,

I fixed it .. The diodes D4 & D5 were replaced with 1N4004. Its working fine now.

Regards

 

hotwaterwizard

Active Member

• Apr 14, 2007

• #12

Can you send the service manual to me or post it?