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Old 4th Jul 2019, 12:59 pm   #61
ColinTheAmpMan1
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Wow, such a lot of replies!

Firstly, David: mea culpa on the subject of UNC/UNF - I assumed (wrongly) that such a small screw would have to be a fine thread rather than a coarse one. My excuse is that I'm not a mechanical engineer.

Alan: I was a research organic chemist and I think I can say with some confidence that of the solvents that I mentioned, only benzene, toluene and xylene are aromatic hydrocarbons. Acetone, petroleum ether and all of the chloro- and fluoro- solvents are not aromatic. If anyone wants to know, aromatic chemicals must have at least one benzene-like structure within them, it has little or nothing to do with them having an aroma.

Manuals: As far as I can tell, all manuals have the Beaverton address on the front page. I am aware that Beaverton-made Tek equipment serial-numbers start with "B" and that equipment produced in Heerenveen has no first letter (both of my 475As were made in Heerenveen). I think that these serial-number issues have been discussed before on this forum and/or elsewhere, so I won't expand on it. My 475A manual has the part-number 010-2162-00, but contains change information sheets in the back relating to Holland-made stuff (not strictly correct - Holland is a part of the Netherlands, but it may be that Heerenveen is in Holland region).
I don't own a 465 or 465B scope, but I do have both manuals. The 465 manual is #070-1330-00 and the 465B is #070-4273-00. Both manuals have change information sheets for the Guernsey-type scopes.
Richard, in my 465B manual, section 5 is "Adjustment Procedure" and page 5-14 relates to checking vertical gain, volts/div variable range, ADD mode and compression and expansion. No mention of disassembly. Section 6 deals with Maintenance, removal of the attenuator assemblies starting on page 6-14. Incidentally, if you think that the 465B manual is big, the 468 manual beats it hands-down. Two volumes; vol. 1 is approximately 1.5" thick and vol. 2 a modest 1.0".

Regards, Colin.
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Old 4th Jul 2019, 2:05 pm   #62
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Quote:
Originally Posted by ColinTheAmpMan1 View Post

Firstly, David: mea culpa on the subject of UNC/UNF - I assumed (wrongly) that such a small screw would have to be a fine thread rather than a coarse one. My excuse is that I'm not a mechanical engineer.

Alan: I was a research organic chemist and I think I can say with some confidence that of the solvents that I mentioned, only benzene, toluene and xylene are aromatic hydrocarbons. Acetone, petroleum ether and all of the chloro- and fluoro- solvents are not aromatic. If anyone wants to know, aromatic chemicals must have at least one benzene-like structure within them, it has little or nothing to do with them having an aroma.

Regards, Colin.
Like you Colin I wrongly assumed that the screws would have a fine rather than a course thread. We live and learn.

I wasn't at all intending to question your comments about solvents. Please accept my apologies if it came across that way. My point was that the so called aromatic solvents are a real threat to the Tek attenuator boards and that the alcohols are ok. You will have a better understanding than I do of the risks associated with the other solvents you mentioned. By the way, I do appreciate that the term 'aromatic' in this context has nothing to do with odour.

My brain already hurts from thinking about the serial number implications of Guernsey machines so I'm not even going to start considering those made in another European factory!

Alan
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Old 4th Jul 2019, 2:09 pm   #63
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

A point with all of the tek scopes is don't assume ANY manual makes sense. I've had the correct manual and the correct scope both from the correct region and it was completely different.

HP had their act together far better than Tek did.
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Old 4th Jul 2019, 2:30 pm   #64
ColinTheAmpMan1
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

OK, so I've dug an email out of my collection which came from the Tekscopes Forum. It regrettably doesn't refer to gear that wasn't produced at Beaverton and was essentially a reply to an enquiry as to whether Tek serial-numbers had any information on the date of production. I repeat the text here:

"I did work at Tek for nearly 20 years. The serial number system is simple, but does not incorporate manufacturing date.
The leading letter is the location of manufacture. “B” represents product manufactured in Beaverton. The following six digit numeric field is the actual serial number, starting with 000101. Major modifications may roll the fifth digit. So a normal sequence could be for example B001294, B001295, B010001, B010002... In older times, Tek did not put a break in the serial numbers, but this requires the documentation updates follow the actual serial number where the change was made, as it is difficult to accurately predict the exact serial number the supply chain will implement the change in advance.
As I had written previously, production supervisors did keep logs of the serial number output by week, but this data was not uploaded into central data bases. Perhaps this has changed with recent production, which for the most part has totally moved outside of the US.
- Steve
".

Perhaps this shines a little light on the topic.
Colin.
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Old 4th Jul 2019, 5:18 pm   #65
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Good afternoon from a rather damp and breezy Tiree,

I see plenty of banter on the manual front which is good to see.

On the more mundane matter in hand - contacts - a simple word SUCCESS

The last week has taught me a lot about a small area of the oscilloscope, so thank you to all those who guided me through the maze and fog, I've come out the other end. If only I could wind the clock back I could save myself 4 days of trying to clean these contacts in situ and failing to do so. 3 hours out of the scope today and they are spotless, need my sunglasses to look at them. I've taken a photograph of the bottom set of 10 contacts for anyone that has never seen them "out of the box" (if I can load the picture). There are 5 contacts that Tektronix must have spent hours working out how best to hide from being cleaned. They have more defensive armour than the south coast beaches in World War II. Note the silver metal shroud around 2 of them to prevent an approach from the top with 3 blobs of solder just in front to prevent attack from the front. Another set are hidden behind a screw very strategically placed and the fifth behind a plastic bracket for the cam. And that is the easy to get at set of contacts from channel 2. Channel 1 has the same defensive system, but the added bonus of cam 2 providing complete cover.

My recommendation to anyone in the same boat, by all means try to clean them in situ and you may be lucky. Use a multimiter to work out which pairs are not working and if they turn out to be the bottom sets below attenutaor module 10X take the unit out and save a lot of time and frustration and really get them clean.

Maybe I had a really bad set due to the barn storage for goodness knows how long. Anyway its done.

I've only done a very quick test to make sure I get a response from all settings as I can only turn the cam with extreme effort due to the fact I'm waiting for the replacment grub screws to arrive. I'm not going to attempt using the old ones in case I can't get them back off. Hopefully, Postie will bring them in the next couple of days.

As for initial observations:

1) I think I'm one attenuator module down as I have to swap one over to make it work, but I suspected that already. I'll confirm when I've done some proper testing.

2) The trigger seems a bit odd. When I switch on and use the calibrator for a square wave, the trigger does not automatically work. I have to go to NORM and set the A Trigger manually, then when I switch back to AUTO its fine. It also seems a bit jittery at times, then fine. Any thoughts on likely causes? - don't tell me more contacts somewhere...........

3) All other buttons seem to work, although I do need to learn how to "drive it". I'm going on instinct and memories from school!

What next? Postie brought my new supply of IPA today and I said I'd got 2 more bits in the post, the filter and grub screws, so I can sort those out easily. Do some more testing and prove the faulty attenuator module and then sort out the trigger jitters.

All in all, over the moon........

Thank you once again for all the comments and help, I wouldn't have got here without it. I'm looking forward (I think) on how to tackle the trigger next.

Hopefully, be back soon with some test results once my grub screws arrive.

Regards, Richard
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Old 4th Jul 2019, 7:55 pm   #66
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Glad to hear it’s heading in the right direction.

Trigger might be switches. Sorry for the bad news! The timebase is easier to get out if that’s any consolation!
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Old 4th Jul 2019, 8:03 pm   #67
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Mr B beat me to it. Very likely to be switch contacts again but well done for the excellent progress. It has been an entertaining thread thus far touching as it has on a number of interesting issues.

Alan
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Old 4th Jul 2019, 8:16 pm   #68
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Hi Richard,

Its great to hear good news. Did you order the grub-screws with with sharp conical points or the cup-point ones? The latter are the correct ones, I think. I ordered 40 of those today and they are due to arrive tomorrow! What service!

That was a pretty good picture of the attenuator that you took. If you have a dead attenuator module, I might have a replacement if you know what the attenuation factor is (I have a parts-donor 466). I thought that I remembered MrB saying that he had some spares, too, or did I misread that?

You might have a misconception of the meaning of "auto" on the time-base trig mode switches. All it means is that in the absence of a vertical signal to trigger on, the time-base will free-run showing a horizontal line. In "norm", the time-base does not free-run and a blank screen is seen. The trigger level and slope controls operate in both modes. I can't think of much of a reason for the two modes, apart from preventing the phosphor from getting burnt-out when a bright horizontal line is displayed for a too-long time. I always turn the brightness down low if I'm leaving a scope unattended for any length of time, anyway.

I hope you don't have any problems with the dual timebase cam-switches, they are a real pig to make sure that the A and B time-base knobs are properly aligned. Also the pull-shaft for the delayed time-base can break in the middle.

Something else that I should have mentioned is that I now believe that my original ideas on the sequence of the parts of the filter were wrong. After looking at a number of manuals, it looks as though the filter element should be the outermost one and thus easy to remove and replace. I was convinced that I was right as my original fiddly solution quietened the fan noise down so much. I have now sorted out the filter on the 475A with DM44 that I "inherited" from MrB with the filter in the right place. At first, the noise came back and I wondered what I had done wrong, but with a bit more effort, I was able to fiddle with the position of the impeller on the fan-motor shaft. It has to be far enough out to not bind on anything, but close enough in to avoid touching the filter-housing and making a noise doing so. All a bit touch-and-go, but I think I have got there now and have a quiet fan (I hope).

Cheers, Colin.

Last edited by ColinTheAmpMan1; 4th Jul 2019 at 8:30 pm. Reason: Stuff about the fan and its filter.
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Old 4th Jul 2019, 8:17 pm   #69
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Yes I've got a whole scrapper 465 here so if anyone needs any bits let me know.

Edit: I've included a picture below of one of the crimes I found inside a Tek recently just because I feel the world needs to see what condition they can turn up in :
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Old 4th Jul 2019, 10:46 pm   #70
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

This very interesting thread reminded me, or rather gave a whack over the head, that I need to take a better look at the three 465s I have. One is ex-BBC with the old '70s BBC TV logo stamped into the case and broadly works. One I think I stuck power up and something oscilloscopey happened or possibly not. One seems bereft of life.

I may need your advice on one in particular that has a board with burnt components on that is in neither early or late manual though it has the correct Tek part number on the board for the position it's in. For another day at the moment though.

Andrew
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Old 4th Jul 2019, 10:47 pm   #71
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Evening,

It's the 2X attenuator that's faulty so if either of you have one spare I'd be most grateful.

The grub screws I ordered are not pointed, I decided they wouldn't be right. According to DHL it will be delivered tomorrow which is fantastic service, but that will be to Oban. They should get dropped of at a storage garage and then get picked up by someone coming back to the island. Then the local garage or a crofter (farmer) will deliver it on the island. Unless it comes over on the "Amazon " plane in which case it could be quicker. Everyone helps out, it's great.

Colin, I'm sure you are right about the auto switch and my understanding, I've just been looking at the manual re. the trigger, auto, various settings the pull out delay timer, not to mention the delay time position "micrometer" type wheel. I admit I'm a bit lost. It's not really bed time reading, I'll do some more investigation on all this.

Hopefully, if I get the grub screws tomorrow I can do some experimenting and see if this all makes any sense. In the meantime I'll continue cleaning the inside and when Postie brings the filters I'll follow your fixing method above.

Regards, Richard
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Old 4th Jul 2019, 10:57 pm   #72
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Richard.

These may be helpful, both on a 465B

https://www.youtube.com/watch?v=BKjJ...E068E0&index=5

https://www.youtube.com/watch?v=OFGm...E068E0&index=4
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Old 4th Jul 2019, 11:06 pm   #73
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Quote:
Originally Posted by Radio Surfer View Post
It's the 2X attenuator that's faulty so if either of you have one spare I'd be most grateful.
PM me your address and I'll drop one in the post FOC.
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Old 4th Jul 2019, 11:12 pm   #74
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Hi Andrew,

Thanks for the attached links, I'll take a look.

With 3 x 465's you should get something really good or 3 times the headaches. Have I seen a picture of your BBC one on the forum as it rings a bell?

I'm enjoying this challenge and it's certainly better than the alternative which is outside painting, not an easy task on Tiree as the wind blows the paint of your brush before you get it on the wall. The wet weather at the moment is giving me an excuse to stay indoors!

Regards, Richard
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Old 4th Jul 2019, 11:13 pm   #75
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Thank you Mr B, on its way.
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Old 5th Jul 2019, 7:41 am   #76
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Quote:
Originally Posted by MrBungle View Post
Yes I've got a whole scrapper 465 here so if anyone needs any bits let me know.

Edit: I've included a picture below of one of the crimes I found inside a Tek recently just because I feel the world needs to see what condition they can turn up in :

Attachment 186193
UGH! In fairness Tek underrated the bridge in the 465/475 series, and the later manuals have different and higher current parts substituted, then resubstitued etc. So early 'scope bridge death is fairly common. But a kludge looking like that is a crime.

Craig
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Old 5th Jul 2019, 8:25 am   #77
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Bit of a failure on my part here. Went to hook out the 2x attenuator for Radio Surfer and found my 465, being an early model, doesn't have a 2x attenuator in it! It has 10x and 100x ones but the 2x and 5x are done using discrete circuitry to control the amplifier gain.

If anyone else has one available, please drop a post in.

I will sit in the corner and face the wall for a bit
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Old 5th Jul 2019, 11:22 am   #78
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

A while back someone near me was selling a scrap 465 which I thought might be a useful source of spares for my 465B. However, when I looked into the possibilities in more depth it became apparent that the two models were almost like completely different scopes. The circuit structure and design is very similar of course but most of the boards are laid out differently and even the switching arrangements are not the same. Rightly or wrongly I decided to pass on the opportunity.

I don't know but I think Colin's 466 storage version, mentioned earlier, may well be based on the 465 and not the 465B.

Alan
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Old 5th Jul 2019, 11:48 am   #79
Radio Surfer
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Morning from a damp and sutiable day for fiddling with oscilloscopes.

Thank you for the efforts to try and locate the attenuator module.

My grub screws arrived at 11:00 am, great service as it was an early boat today. I went for stainless steel ones, any fixings I order are usually stainless steel due to the salty atmosphere here. I only ordered them on Wednesday evening, have yours arrived Colin?

The video links Andrew posted have been very helpful in my understanding (or clearly lack of it). This has raised another question (dunce cap at the ready).

In the videos, it was clear that when the chap demonstrating turned some of the knobs counterclockwise, the white dots were in a totally different place to mine. Could someone advise me please where the dots should be for the 7 rotational knobs at the bottom, some probably don't matter such as intensisty, focus, but the Hold Off/Norm looks as though the white sport should be at the top when at its fully rotated counter clockwise position.

Also, the delay time position when fully rotated counterclockwise on mine stops at 2 on the outer scale. I assume it should be 0. The photo might make this clearer. If that's the case presumably I just undo the grub screw and realign?

I've been cleaning the rotational pots, as best I can by standing the scope on its end and hoping Servisol will dribble down the shaft. Some have clearly improved and are less "scratchy", but I can barely turn the focus knob. Probably not something that is used much once set. Any tricks in getting at these "sealed units".

I've yet to tackle the big Time/Div cam and contacts, any comments on what to do, or not to do?

Kind Regards, Richard
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Old 5th Jul 2019, 12:09 pm   #80
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Default Re: Tektronix 465b oscilloscope CH1 & 2 issues

Mine stops at 2 as well Richard which I think is 'normal'. Not pretending to know why - I'll leave that to someone with more knowledge.

Alan
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