Tektronix 2225

jasont · 11th March 2004, 07:07 PM

I have just been given a Tektronix 2225 Oscilloscope which has a crackling noise coming from the back of it.

I took the case off the noise is coming from the rear of the scope from either a black box connected by a red wire to the front of the tube or a small transformer. I didn't want to start poking about, the black box says 2KV in this area the small transform says 100V DC in this area.

Any thoughts on whats causing the crackling, where to get a service manual, spare part or if i should throw it out.

Bensen · 12th March 2004, 04:50 PM

Hi Jasont,

I bought the same scope two weeks ago on Ebay (240euro incl probes).
I'm also interested in any reply's of this thread, if one day I've the same problem. With the service manual I'm glad to help you. Here is a link of a scanned version of the manual.

http://21944.gel.ulaval.ca/travaux/m...cilloscope.pdf

Ciao

Ben

GaryB · 13th March 2004, 11:20 PM

Quote:

Originally posted by jasont
I have just been given a Tektronix 2225 Oscilloscope which has a crackling noise coming from the back of it.

Any thoughts on whats causing the crackling, where to get a service manual, spare part or if i should throw it out.

You might look at the following thread where people reported that the IEC filter in a Tek 2235 could not stand the European
mains voltage of 240v. Removing the IEC filter fixed the problem.

http://www.diyaudio.com/forums/showt...385#post325385

---Gary (no problems with my 2225 in New York)

Sch3mat1c · 14th March 2004, 01:58 AM

...Could always be HV problems... my 475 has leakage around the CRT's HV connection... need to put some silicone on that some day...

Tim

geoffd · 28th April 2004, 03:34 PM

Ben,

I had a look a the PDF file and it is the Operators Manual, do you have a copy of the Service Manual with the circuit diagrams etc?

I have just brought a second hand 2225 from eBay and I need the calibration instructions.

Best ishes
Geoff

Bensen · 28th April 2004, 04:49 PM

I'm sorry Geoff. But I don't have a service manual or circuit diagrams off this scope.

Hope you'll enjoy this scope. Mine works great, and it's easy to use.

Best regards

Ben

geoffd · 28th April 2004, 07:35 PM

Thanks.

There was one on eBay, but I had to go out near the end of the auction.... I got beaten by 5 cents!

Cheers
Geoff

jackinnj · 29th April 2004, 12:54 AM

you can get reasonable priced TEK service manuals from www.w7fg.com

tekman · 14th October 2004, 11:28 AM

2 GaryB, Bensen:

Reason for the noise is most often this one:
Problem near HV multplier, most often dust and dirt accumulated. Hint: Open the scope, do careful cleaning wit ha soft brush. Switch of at least 5 minutes before opening to let all caps dicharge forshure

BTW: I can't recommend the IEC filter completely. It helps to keep the SMPS noise from the scope supply transmitting via the mains cable - causes often strange side effects in a measurment setup (most likely your own. Hard to diagnose). Replacing the original filter with a good (european 240V standing) mains filter is recommended. Like the ones from "Schaffner", switzerland. Any proven filter (VDE, CSA or what is apropriate for your country) brandname filter will be fine. As long at it can be fitted and takes at least 3 A, max 5 A. More is "overkill" and unnecessary expensive.

2 Sch3mat1c :
I can't recommend silicone in this area. But careful cleaning (isopropyl) and removin all dirt & dust near the HV and along the cables really helped (I had to repair appr. 15 of these).

11th March 2004, 07:07 PM	#1
jasont diyAudio Member Join Date: Mar 2004 Location: North East England	Tektronix 2225 I have just been given a Tektronix 2225 Oscilloscope which has a crackling noise coming from the back of it. I took the case off the noise is coming from the rear of the scope from either a black box connected by a red wire to the front of the tube or a small transformer. I didn't want to start poking about, the black box says 2KV in this area the small transform says 100V DC in this area. Any thoughts on whats causing the crackling, where to get a service manual, spare part or if i should throw it out.

14th March 2004, 01:58 AM	#4
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	...Could always be HV problems... my 475 has leakage around the CRT's HV connection... need to put some silicone on that some day... Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

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12th March 2004, 04:50 PM	#2
Bensen diyAudio Member Join Date: May 2003 Location: Belgium, Limburg, Bree	Hi Jasont, I bought the same scope two weeks ago on Ebay (240euro incl probes). I'm also interested in any reply's of this thread, if one day I've the same problem. With the service manual I'm glad to help you. Here is a link of a scanned version of the manual. http://21944.gel.ulaval.ca/travaux/m...cilloscope.pdf Ciao Ben

28th April 2004, 03:34 PM	#5
geoffd diyAudio Member Join Date: Apr 2004 Location: Murcia, Spain	Ben, I had a look a the PDF file and it is the Operators Manual, do you have a copy of the Service Manual with the circuit diagrams etc? I have just brought a second hand 2225 from eBay and I need the calibration instructions. Best ishes Geoff

28th April 2004, 04:49 PM	#6
Bensen diyAudio Member Join Date: May 2003 Location: Belgium, Limburg, Bree	I'm sorry Geoff. But I don't have a service manual or circuit diagrams off this scope. Hope you'll enjoy this scope. Mine works great, and it's easy to use. Best regards Ben

28th April 2004, 07:35 PM	#7
geoffd diyAudio Member Join Date: Apr 2004 Location: Murcia, Spain	Thanks. There was one on eBay, but I had to go out near the end of the auction.... I got beaten by 5 cents! Cheers Geoff

29th April 2004, 12:54 AM	#8
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	you can get reasonable priced TEK service manuals from www.w7fg.com

14th October 2004, 11:28 AM	#9
tekman diyAudio Member Join Date: Oct 2004	2 GaryB, Bensen: Reason for the noise is most often this one: Problem near HV multplier, most often dust and dirt accumulated. Hint: Open the scope, do careful cleaning wit ha soft brush. Switch of at least 5 minutes before opening to let all caps dicharge forshure BTW: I can't recommend the IEC filter completely. It helps to keep the SMPS noise from the scope supply transmitting via the mains cable - causes often strange side effects in a measurment setup (most likely your own. Hard to diagnose). Replacing the original filter with a good (european 240V standing) mains filter is recommended. Like the ones from "Schaffner", switzerland. Any proven filter (VDE, CSA or what is apropriate for your country) brandname filter will be fine. As long at it can be fitted and takes at least 3 A, max 5 A. More is "overkill" and unnecessary expensive. 2 Sch3mat1c : I can't recommend silicone in this area. But careful cleaning (isopropyl) and removin all dirt & dust near the HV and along the cables really helped (I had to repair appr. 15 of these).

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