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Hello *,

I just got a TDS684A. Basically everything is working but the bandwith is a too low (~800MHt). Can there anything be done to increase it?

Removing was not a real problem. While checking your things take care of the components FL301 (EMI-filter) and U301 (RC-combination) at the input of the power supply. They can cause problems after years.

On 26 Jan 2025 3:08 am, Tom Lee wrote:

I’d take a quick look at the supply rails before diving too deeply.

That is a universal principle of electronic servicing - you need to start with the power supplies because a PS problem is a fundamental problem.
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA

Calling Tektronix repair experts. I have a TDS340A where the ZYTEC 2291739 Power Supply literally blew/burnt like 5 component beyond recognition. A little hard work looking at a lots of post and pictures I manage to find all values except for one ZENER DIODE - VR9.

Does anyone have an idea of what voltage this should be? (I assume due to the VR that it is a Zener diode).

I’d take a quick look at the supply rails before diving too deeply. If you have a lot of ripple, that could be your problem right there. Try triggering your scope on Line and see if the modulation pattern is stationary.

Good luck!

Tom
Sent from an iThing; please forgive the typos and brevity

Hey folks, now I'm dealing with a 184 Time Mark Gen, I've had it for many years. Now it seems to have developed a signal super-imposed on the 10MHz oscillator. The 0.1uS push-button pips are the right frequency, at 10MHz, but they go up and down like keys on a piano. (Tough describing) I can slow the trace down on my scope and see similar pips at, or about 1 to 2kc while still buttoned at 0.1uS. It looks like all the divider stages are working (more or less) at putting the right marks out, to the point of putting our pips around 1 to 2kc. I believe the issue starts in the main 10MHz ovenized oscillator. The rest of the stages are doing their jobs, as best they can anyway, at slower speeds things get messy. The 10MHz oscillator is... interesting. The circuit is pretty straight forward and the device as a whole is very interesting. But what would you suppose would introduce such a slower oscillation into the main oscillator? Is it wise to post a few seconds of video here? The clips are about 9mb…

Hello again

Have a working Tek SA 492, SN?B05 1984 , 2500 hrs.

to check power supply for RIFA caps, lytic and tants, the. PSU remove procedure in manual is vague on the location of connectors before you pull it.
Any tips or diagrams ? caps to replace or change ?
Your thoughts and advice appreciated?
Many thanks
Jon

Richard,
I have built one and am still using the scope today.? Let me see if I can find the schematic that I used for the construction of my replacement Multiplier.? Keep in mind that you will still be using a portion of the remaining U550 in concert with the multiplier that you will construct. ??

Michael W. Lynch?479-477-1115 I-Phone
mlynch002@[email protected]@...

Hi,
Found that the HV multiplier on my 465m is defective..My intention is to try building the U550.. Its seem that you found a way to build one !! I would appreciate very much getting a hand on that schematic that you mention on page 281, but I was not able to reach that document..
Best reguard's
Richard
ramacieririchard4@...

Gianni,

Whoa.

I just went to download the Tektronix 7000 ebook (I have a particular love for those and own several) and saw your BMW K100 page.

I used to own a K100 and it was arguably the finest motorcycle I have ever owned, neck and neck with the BMW R1150GS that replaced it when I moved to a place where I needed off-road capability to get to and from my home.

I loved that K100 RS.

DaveD

--
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I don't know about your particular meter but most plates are symetrical and could be flipped over. If so you could apply the new artwork to the reverse side of the plate.

Bill Koski

Gianni,
Every time I look at your books, I am just blown away by the quality and the amount of work you put in to produce such quality. I have done a smattering of such work (at a far less professional-looking level) in a past life, and until you've done it, you cannot comprehend the amount of effort required. You are a GIFT to this hobby and interest! Thank you. I have the new book downloaded and am now going through it. Again, thanks for the superb work!

Wayne

Hi Gianni, downloaded just the 2nd version of the 7K scopes book. Enormous in size but well worth it and a a joy to read.
Thanks for all your work and to share it with us, and don?t forget to warm up the K100 if you have any spare time ;-)
搁别苍é

Thank you Craig!

Take care to avoid brass and aluminum from direct contact with each other. Dissimilar metals result in corrosion if moisture and a current path are present. It might not be a big deal for your meter face but be aware.

On Thu, Jan 23, 2025 at 11:45 PM, Richard Kelly wrote:

Am I correct that brass is equally suitable, will have an equal impact on
meter calibration/accuracy, but might possibly confer slightly more damping?

Al is paramagnetic. Brass... depending on what's in it... is supposed to be diamagnetic.
Brass has about 1/2 the conductivity of Al.
I thought the meters in those 130 were of the D'Arsonval type... and as such.. the 'damping' is done the eddy currents generated in the Al bobbin the meter coil is wound on.
The magnetic fields are 'tightly' confined to vicinity of the coil; because there is an iron core, inside the bobbin.
AFAIK, what's moving is the bobbin, not the meter face plate.
Don't know if the meter face plate is used for shielding... if that's the concern... but either brass, or Al, won't shield against magnetic fields... and while Al is better at shielding strong electric fields... AFAIK... practically brass is as good.
--
Roy Thistle

Indeed, but I'd rather not risk damaging the original.

I've got some 0.5mm aluminium sheet after all, so I will use that.

Gianni,
Was able to download your second version of the 7000 series. Thank you for your desire to keep these instruments alive with all your detail photos and description of operations.

Craig Cramb

Can't you apply the new scale to the back of the existing plate?
73,
Bill, WA2DVUCape May

I need to restore my Tek 130LC meter scale - the red has unsurprisingly 95% disappeared.

I've crafted the artwork, and boy did that take some time as each of the five scales is cunningly non-linear and no two appear the same!

It's now about print and apply, but apply to what? I'd rather keep the original aluminium-backed scale safe as I may have a way to restore it without removing/affecting the existing visible print. What I do have to hand is plenty of suitably thin brass sheet. I'd need to buy aluminium in.

Am I correct that brass is equally suitable, will have an equal impact on meter calibration/accuracy, but might possibly confer slightly more damping?

However, having spent SO long producing the exact artwork, would be shame to undo that with the wrong material!

I just don't have the practical experience here, so would value your thoughts. Thanks.