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But, alas, what you say is not true. It once was, back when
electrolytic capacitors used rather caustic electrolytes that
ate away the aluminum oxide dielectric layer, but that hasn't
been the case for about 30 years.

It is just fine to raise the voltage rating of an electrolytic
capacitor used as a decoupling cap, filter, bypass, whatever.

It is also just fine to buy only 10uf 160V caps, and use them
to replace both the 10uf 100V caps, and the 10uf 160V cap in
the 2465's power supply.

Just like it was fine when you specified 330uf 50V caps to
replace both the 250uf 20V and the 180uf 40V caps in the
power supply.

This isn't audio gear where you have to worry about how the
end user might "feel" about your choice. You can use valid
technical reasons.

If you need some evidence to back my assertions, grab any old
bag of electrolytic capacitors that have been sitting on the
shelf for years, and measure the capacitance. They will all
measure at the nominal value... after years of being operated
at the extremely low voltage of 0V. I have just such a bag
of nichicons from a project where I overbought the caps. This
was back in the 1970's. They all still read 2200uf +/- 10%.

-Chuck Harris

M Yachad wrote:

Probably best to sand it down and come up with some kind of paint to make it look decent.? I know of no patch for anodize finish that would have a chance of blending in.
Bob

Let's get some clarity on this.

A decoupling cap can USUALLY have the CAPACITANCE increased, but NOT the voltage rating.
Sometimes the cap's VOLTAGE rating should even be decreased, according to the actual circuit voltage.
I hope that's clear!

On these 180uf/40V, the optimum substitute IN THIS CIRCUIT is a 330uF or 470uF/50V, preferably Nichicon PW or HE, but DEFINITELY NOT Panasonic EB. That "updated" list is completely misleading, by listing Panasonic EB caps as "suitable".

On the 10uF/100V caps, with about 80VDC going through them, you do NOT install a 10uF/160V to save money, by buying 10/160's for both the 10/100 and 10/160. You put the correct-rated cap in the correct place.

C1115 and 1132 are WRONG in the manual.
What you pulled out, is EXACTLY what you reinstall.
The 250uF/20V caps are replaced with 330uF or 470uF/25V. PW or HE. Nothing else.

The Film caps as follows - all VISHAY, and ALL confirmed available from Mouser.
I do NOT know about Digikey.
2.2nF BFC233660222 Qty 2
10nF BFC233660103 Qty 1
56nF BFC237241563 Qty 1
68nF BFC233810683 Qty 2

These all have the correct lead pitch, and all fit PERFECTLY, both physically and electrically.

And a last word of caution - if you're looking at other brands/models to save a few cents, then DON'T!
The headaches are NOT worth it.
"Only a rich man can afford to buy cheap"

If somebody would like to take it upon himself to update the "updated 2018" cap list onsite here with regard to these salient points, it would save a lot of newbies and hobbyists headaches, as they trust the knowledge of the men who put this list together, and there should NOT be any errors in that list.

Best of luck!

Menahem Yachad
Jerusalem Israel

Congratulations, Albert!
Must give you that well-known satisfaction that makes us spend so much time on these instruments!

Raymond

Thank you for posting your findings.? Here is a complete answer with rationale for some of my choices.? Hope this helps.

You wrote:>

C1065??? .056 ?F???250??? MTLZD??? ??? .056?F??? 300??? Vishay Polyester?Film??? 399-7635-ND?
The lead spacing is to wide for the replacementpart.? Should be 7.62mm but the part is 14.50mm. I could not find a partthat fits from Kemet or Vishay @ Digi-key.

You are right.? I am sorry I still have that information inthe list.? I gave up trying to fit thatlarge cap and accepted one from Panasonic:?P12080-ND I think it’s a decentchoice but not perfect.

You wrote:>

C1050??? 0.22 ?F???400??? PLSTC??? ???0.22??? 400??? Kemet Polyester???495-4473-ND
The lead spacing is not far enough, are you addingtinned copper wire to lengthen the lead or is this a mistake?

That is a dilemma.? The original fitment is an axial capacitorwith the leads spaced about 33 mm.? Icould find one from Illinois Capacitors 1572-1684-ND ?with a body that is 29 mmlong. ??It costs 1.14 USD and will workwell.? There is also one from Vishay BC2609-NDThat is 31 mm long for 3.48 USD.?I chose to add leads to a radial cap by TDK 495-4473-ND This only cost 0.82 USD but it was not a good choice.? My next recap will be either the Illinois Capacitor or the Vishay.? They might be abit long but there is ample room to raise them from the board and bend theleads back to fit the holes. ?

You wrote>

C1130??? 10 ?F???100??? ELCTLT??? ??? 10?F??? 160??? Nichicon PW???493-11888-3-ND
Link bring up minimum quantity of 500, I think youcan use this link instead? ?
FYI I ordered these and they sent the wrong part.I will find out sometime tomorrow if they have corrected the issue and post anupdate.

Sorry for the confusion.? Digikey corrected my order (from 493-11888-3-ND to 493-11888-1-ND) but I did notcorrect the list.? I meant instead 493-11888-1-ND which is the same cap in small quantities.? I prefer it over your suggestion because ithas a much higher life rating (5000 hours) but only costs 0.08 USD more. ?

You wrote>

For C1120??? 10 ?F???100??? ELCTLT??? ? -->???? 10 ?F??? 160? ,
Can I use is there some benefit to using a 160V cap??

The choice of 160 Volt caps was done years ago bysomeone who made the original list.? Ionly updated it to get longer life.? Multiplemembers of the forum have used 160 Volt substitutes with no reports ofproblems.? I have not looked for 100 voltparts with long life ratings.? But Iprefer my suggestion over the ones you linked to because of the lifetimeratings.

You wrote>

C1132??? 10 ?F???160??? ELCTLT??? ??? 10 ?F???160??? Nichicon PW
I pulled out a 250uf 20v from this location

C1115??? 250?F??? 20??? ELCTLT?????? 330 ?F??? 50??? Panasonic EB
I pulled out a 10uf 160v from this location

I seem to remember reading this is also an error in thedocumentation.

Actually, Tektronix documentation is incorrecthere.? You pulled a 20 volt cap from thelocation MARKED C1132 and a 160 volt cap from a location MARKED C1115.? The markings are interchanged by Tek on everydocument I find for these power supplies.??Take care when putting things back.?Use your Ohm Meter to check that C1115 is connected to L1115.

You wrote>

Also can I use a 20v 10uf cap for C1115 or is the 50V better?I'm just remembering what Menahem said about larger caps... I'm justremembering what Menahem said about larger caps...

The 50 Volt capacitor had a better lifeexpectancy.? Menachem has a good pointabout ESR of higher voltage caps.? But Ithink you will find that in these lower voltages there is little difference inESR between 20 volts and 50 volts.? So Ichose for other reasons.? Sometimes justto make a bulk order of one part number, sometimes because it looked moreuniform on the completed board.? Butalways for higher life and higher capacitance.?(Take note, higher capacitance is not always a good thing so check theapplication before deviating from spec.)

My CSA803 now passes the Self test and Extended diagnostics test.
In an earlier message I wrote that some if the 5 IR sensor groups were never selected during a full scan cycle. It appeared that this was due to a faulty 3-to-8 line decoder 74LS138. I replaced this IC and bingo.
In hindsight I am not 100% sure that it was the IC itself, or a bad solder joint to one of the 3 input lines. After replacement the operation of this IC was not stable. I resoldered the 3 input pins and that cured the problem. Previously I had checked everything for continuity with an ohmmeter and found no bad joints, but now with a probe I saw that the slightest pressure on the pins or on the board changed the results.

The repair time was nothing compared to the total time I spent to find the problem. I nearly completely reconstructed the schematics of the A9 Front Panel Control board and A10 Front Panel board, and the way all circuits are operating. Interesting and "on the fly" I got more insight in the CSA803. Once you know where and what to probe it's fairly simple to detect non-functioning IR pairs.
A silly mistake: after resoldering, all horizontal pairs worked well but still a few of the vertical pairs didn't. Then I realized that the distance from IR Led to sensor is much larger for vertical pairs than for horizontal pairs, and I used the bare board -- without the frame of "lenses" which are supposed to concentrate an IR Led light better on the corresponding sensor. With that frame in place all pairs worked fine.

Hey all,

I've just gotten a 1A4 plugin that has some numbers gouged deep into front. I'd like to do something to make it look better than having the numbers gouged in the front. Does anyone have any suggestions for how to cover up or remove scratches in aluminum anodize? It also looks like under the anodize, it's bead blasted or sand blasted or something to give the uniform finish. Not sure how to replicate this. Any suggestions?

Best,
Evan

Thanks Rich, I'd appreciate that info.

Unfortunately, this one's a goner. I decided to do a "quick" CRT check and rejuvenation attempt, since I found a correct socket on-hand. I wired it up and hit it with a B&K 470. It was unresponsive - so much so that I thought the 470 wasn't working right, which led to a wild goose chase of checking and rechecking the 470 and the wiring, but all seemed normal. The CRT had virtually no K emission at all, and was even dimmer yet when put back in-circuit, so the process did not help, but definitely did something to it. The CRT was too far gone, or too skimpy on K coating anyway. This is the first CRT I've tried that didn't show at least some improvement.

I'll be saving some of the RF sections and parts for possible re-use, so it's good to have schematics, etc for reference. I've already popped the CRT vacuum and put it in the e-waste box for the next recycling run, and the carcass will be stripped soon. Oh well, good thing it was only ten bucks, so no big loss. I got another rejuvenation data point, and some parts out of the deal.

Ed

Kevin wrote:

"This topic brought back memories from an unrelated area of my past. Years ago I was an avid home brewer and wine maker, and needed to recycle bottles with labels. I used a product called Straight-A Label Remover. 2tbsp/gal hot water and soak overnight. Even the most stubborn label would have sluffed off of its own weight by morning! Never was sure what was in it, but but it had that slick feel. Maybe highly ionic or something."

It was likely trisodium phosphate (TSP), a very common cleaner for water-based washing.

Ed

On Thu, Jun 14, 2018 at 06:03 am, zenith5106 wrote:

H?kan

Hi H?kan,

Thanks for the response and link - much appreciated. You are absolutely correct but.before replacing the IC I removed and cleaned the IC Socket (with switch cleaner). The original IC was then re-inserted with the same results. The fault only cleared after replacing the IC I obtained from a cannibalised Tek 465B. Note that I have also cleaned and re-inserted most of the transistors and IC's (sockets - took a long time!) due to possible poor contact, plus cleaned all the switches.

Edward Thomas

This topic brought back memories from an unrelated area of my past. Years ago I was an avid home brewer and wine maker, and needed to recycle bottles with labels. I used a product called Straight-A Label Remover. 2tbsp/gal hot water and soak overnight. Even the most stubborn label would have sluffed off of its own weight by morning! Never was sure what was in it, but but it had that slick feel. Maybe highly ionic or something.

Kjo

On Thu, Jun 14, 2018 at 01:53 am, <edward@...> wrote:

Hi Dieter,

Thanks to Fabio's detailed and clever reasoning (you're very gifted Fabio), I
have found the issue with the Alt mode. The problem turned out to be a
defective U4391 (74LS02) that can be found on diagram 8 (Horizontal Display
Logic A&B Sweep Generator). When measuring pin 3 on this IC there was no
change in state (stayed low) when operating the ALT button in the "Horiz
display" section on the front control panel (after checking the switch first).
Replacing this IC from a butchered 465B restored the Alt mode and the scope
now reliably displays two traces :)

Note that your problem might be caused by a different component failure or
break in the Vert Alt Sync path, but if you follow Fabio's excellent
diagnostics, you will find the problem. Good luck, and another big THANKS to
Fabio, I owe you a drink!

Regards,

Edward Thomas.

Off course you could be right that the IC really was bad. Did you put the original back to confirm ?
Another likely culprit would be bad IC sockets which are known to cause various intermittent problems.
465B from that time are known to have them and if not replaced more problems will probably occur in the future.
To identify the sockets check here:
Note that some of the text and the large picture is incorrect. The smaller pics are right.
/H?kan

I only have a short minute but want to post this.? I will comment more on your other posts later when I have more time.
All Tektronix documentation has the physical locations of C1115 and C1132 interchanged.? You may want to update your documentation of PCB layout to show these two capacitors interchanged.? The power supply will not work if you install new capacitors based on the Tektronix documentation for these two parts.? You can verify the proper positions with your ohm meter.? C1115 positive terminal must connect to L1115.

Hi Dieter,

Thanks to Fabio's detailed and clever reasoning (you're very gifted Fabio), I have found the issue with the Alt mode. The problem turned out to be a defective U4391 (74LS02) that can be found on diagram 8 (Horizontal Display Logic A&B Sweep Generator). When measuring pin 3 on this IC there was no change in state (stayed low) when operating the ALT button in the "Horiz display" section on the front control panel (after checking the switch first). Replacing this IC from a butchered 465B restored the Alt mode and the scope now reliably displays two traces :)

Note that your problem might be caused by a different component failure or break in the Vert Alt Sync path, but if you follow Fabio's excellent diagnostics, you will find the problem. Good luck, and another big THANKS to Fabio, I owe you a drink!

Regards,

Edward Thomas.

C1132 10 ?F 160 ELCTLT 10 ?F 160 Nichicon PW
I pulled out a 250uf 20v from this location

C1115 250 ?F 20 ELCTLT 330 ?F 50 Panasonic EB
I pulled out a 10uf 160v from this location

I seem to remember reading this is also an error in the documentation.
Also can I use a 20v 330uf cap for C1132 or is the 50V better? I'm just remembering what Menahem said about larger caps...

Sorry for multiple posts for all of you on the mailing list. Groups.io really should filter out edits...

For C1120 10 ?F 100 ELCTLT --> 10 ?F 160 ,
Can I use or is there some benefit to using a 160V cap?

Its mostly correct, but I found an error, maybe two.

C1065 .056 ?F 250 MTLZD .056 ?F 300 Vishay Polyester Film 399-7635-ND
The lead spacing is to wide for the replacement part. Should be 7.62mm but the part is 14.50mm. I could not find a part that fits from Kemet or Vishay @ Digi-key.

C1050 0.22 ?F 400 PLSTC 0.22 400 Kemet Polyester 495-4473-ND
The lead spacing is not far enough, are you adding tinned copper wire to lengthen the lead or is this a mistake?

C1130 10 ?F 100 ELCTLT 10 ?F 160 Nichicon PW 493-11888-3-ND
Link bring up minimum quantity of 500, I think you can use this link instead ?
FYI I ordered these and they sent the wrong part. I will find out sometime tomorrow if they have corrected the issue and post an update.

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group.

File: Hameg.zip

Uploaded By: r221b@...

Description:
Hameg 5005 Service and Operating manuals

You can access this file at the URL:
/g/TekScopes/files/Hameg.zip

Cheers,
The Groups.io Team

Upload it to the files section?

Regards

Hello Ed, I used to have a Hameg 5005 which should be the same as your AT 5005. I have the service and operating manuals including schematics and alignment instructions. I'll be happy to send them to you if you send me your email address.

Rich F. r221b@...