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Electronics => Repair => Topic started by: aa7ae on January 30, 2022, 12:35:20 am

Title: Tektronix 2465A - How do I remove the fan impeller?
Post by: aa7ae on January 30, 2022, 12:35:20 am

I purchased this Tektronix 2465A DM from an E*BAY seller in 2015 who refurbished it. After a while, I developed a problem where the DMM no longer worked. I decided to crack it open and investigate. I discovered his work on the power supply was less than optimal. He only replaced a few capacitors, but not all of them. He also didn't replace the now cracking RIFA madness developing in here.

How do I carefully remove this fan impeller properly? I don't want to break it, but it's not wanting to come off.

I'll have to rebuild this power supply with all new caps and do it properly.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: tggzzz on January 30, 2022, 12:47:17 am

I presume you are following the instructions in the service manual.

There are many descriptions of the process in this forum and the TekScopes group. IIRC the basic technique is to hold the but stationary with pliers, and use a screwdriver to undo the screw.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: CatalinaWOW on January 30, 2022, 01:04:13 am

And after the screw is loose tap the screw toward the front of the acope.  The screw is tighteng a conical collet.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: aa7ae on January 30, 2022, 01:25:30 am

The screw just broke!  Great. Now I'm dead in the water. What a lousy design this is.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: CatalinaWOW on January 30, 2022, 02:30:19 am

Hey, it worked for thirty plus years.  Not all that terrible.  And it left you enough of a nub to grab and get it out for easy replacement.

I wonder if someone felt the need to put locktite on this screw at some point.  It shouldn't have been that hard to turn.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: TERRA Operative on January 30, 2022, 02:53:28 am

You broke it because you didn't read the manual on how to remove the fan assembly properly..

You need to hold the shaft steady by using the slot in the screw, loosen the nut with a wrench, then give the end of the shaft a tap with the back of your screwdriver's handle, if you do it this way you will never break another collet.

https://w140.com/tekwiki/images/8/8b/070-3831-00.pdf
Page 6-25 has the official procedure.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: tggzzz on January 30, 2022, 09:26:33 am

Quote from: aa7ae on January 30, 2022, 01:25:30 am

The screw just broke!  Great. Now I'm dead in the water. What a lousy design this is.

No, you aren't dead in the water, but you do need to do some research and exercise some imagination.

Yes, that part of the 24x5 range isn't particularly wonderful, but the other parts are.

Title: Re: Tektronix 2465A - How do I remove the fan impeller?
Post by: tggzzz on January 30, 2022, 09:28:34 am

Quote from: TERRA Operative on January 30, 2022, 02:53:28 am

You broke it because you didn't read the manual on how to remove the fan assembly properly..

That might not be entirely fair. I've used the "proper" procedure, and a collet still broke. As others have done, I simply made a replacement collet.