I still have plenty of used but fully tested parts available for the 2445B, 2455B, 2465B, and 2467B scopes. Includes boards, hybrids, ICs, and CRTs ( no 2467B CRTs). I also have case and chassis parts. US sales only at this time. Please contact me off the list with your questions.
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Re: What calibration items to buy.
Dont tell me you are watching the ppauctions one for the Datron units. I was thinking about bidding too...
Tam
---
With best regards
Tam HANNA (emailing on a BlackBerry PRIV)
Enjoy electronics? Join 8300 other followers by visiting the Crazy Electronics Lab at
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Re: Tek 317 odd trace behavior after warm-up
Thanks for the pictures, it looks funny indeed.
OK, so I guess there is a reason why we keep saying to check voltage rails before anything else ! ;-)
Such a massive deviation over the nominal value will obviously cause weird and wonderfull things all over the scope, so there is no need to spend even one second trying to make sense/trouble shoot your trace problem... the only thing you must concentrate on, is to fix the LV power supply, hoping that it being faulty for God knows how long, did not cause permanent damage to some sections of the scope :-/
Of course the good news is that the LV power supply is very simple in design, and physically easy to access. So trouble shooting it should be quick and probably won't require a scope. Your DMM should probably suffice.
So just work your way from left to right, in a logical fashion... using your DMM while trying to make your measurements as quickly as possible to avoid exposing the scope to such out of spec voltage rails for an unnecessary length of time :-/
1) Check AC voltage at all the secondary windings. I gather this particular transformer is as reliable as the earth going round the sun if not abused, but assuming things is just the only thing not to do when you are trying to trouble shoot anything...Murphy is always there watching every one of us ;-)
2) If the all the secondary windings read OK, then let's now concentrate only on the -150V reference rail : with the scope turned off, check all 4 diodes of the full wave rectifier. Just unscrew the plastic transparent guard plate and check them with your DMM... well might be easier to just check all of the diodes in there, rather than try to identify which ones are actually used in the -150V rail.. only takes a few seconds after all.
3) If all test good, then turn the scope on again, and check the voltage (referenced to ground) at the right side of the 10 ohms resistor R601. As the schematic says, should be +72V
4) Then check that the all important voltage regulator tube, the heart of all this, does give you the expected -85V
This should only take a few minutes and will give you a strong starting point...
Do it and report back :-)
--
Vince
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Re: Tek 317 odd trace behavior after warm-up
Here are some photos I took of the trace behavior. /g/TekScopes/photo/38177/0?p=Name,,,20,1,0,0 While warming up. /g/TekScopes/photo/38177/2?p=Name,,,20,1,0,0 Warmed up, ¡Ý0.1 V/div /g/TekScopes/photo/38177/1?p=Name,,,20,1,0,0 Warmed up, ¡Ü0.05 V/div
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Re: Tek 317 odd trace behavior after warm-up
I've tested the -150V rail with my DMM and it's reading at -204V. o_0 That's a problem. It's throwing off the +100V and +300V rails as well. Turning the R617 (-150V Adjust) pot doesn't seem to do much. Focusing on the -150V part of the LV supply, I've replaced both paper caps with film already and replaced the half-bad 6080 tube with a new one. The 6AN8 tube in that section tests good. That leaves C610 (2-section metal can cap, 160uf and 10uf 450V) and the 5651 tube. The 5651 glows like normal. So I believe my next move will be to remove the can caps and test them with my Eico 950B.
Regarding the Eico, it's not like I'm opposed to using modern instruments. It's more that a) I'm cheap and the Eico and 317 were cheap, and b) the 950B is useful for vintage tube electronics. Some DMMs have a cap testing function, but they don't supply enough voltage to effectively test HV caps like one would find in a vintage hi-fi amp. The 950B isn't lab grade but it's pretty accurate and just as important goes up to 500VDC for leakage testing. That also makes it useful for reforming electrolytics that have been sitting around for a while.
I took some pictures of the strange traces. I'll get them uploaded once I figure out how.
-John
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$100 reward for Tek TDS500, 600, and 700 color CRT driver board schematic/layout
Got a pile of these and most are probably an easy repair. However, the schematic and parts layout in the TDS520B CLIP as well as the TDS544A do not match the later CRT driver boards. I'll pay the first taker $100 who can provide the schematics and parts layout. $75 for the schematic only.
Pictures attached - one is a pile-o-driver boards that need repair, and the other a close-up of the board I'm talking about. Part # is 678-1402-XX where XX is the revision of the board. Somebody has to have these!
Thanks!
Jay
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Re: 7633 fan possible to repair?
Note that almost anything WD-40 can do, LPS2 can do better.
Zoro has a good deal on it but I have a word of caution :
Open and discard the box outside. I can't directly make an accusation (if that's what it even would be) but coinciding with receiving the package from them we got bedbugs. I can't be sure enough to make a stink about it so, I didn't. Just that now I am careful of everything, I unpack things out in the garage now.
I don't want to impugn their reputation at all, it is just better to be safe than sorry. It was a really good deal, and I bought enough to get a discount, I think it was free shipping or something.
I have used WD-40 and LPS2 on many things for many years and I prefer the LPS2. I have literally sprayed pots from the front without disassembly and it cleaned it because it has some components with extremely low viscosity. (yes, it is not conductive and stays that way)
If you use it to penetrate and want to not make a mess, (like a turntable motor recently) spray only a little into a container as it sprays too hard. Put it in a syringe or on a Qtip right away before all the aromatics evaporate.
The only drawback is that the smell of it sticks around. There is no way to get rid of it except time.
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Re: What calibration items to buy.
Yes, of course - or I could bring some stuff up for you to measure.
I've also got a Solartron 7081, a Datron 1061, and next week I've an eye on a 1081 and a 1271. I've a few decent resistors, 100kohm, 1kohm, and 0-121ohm, and a 1006.37pF mica capacitor.
I've also got a stable source which has been unofficially been measured as 9.999571V. I've a less stable one which has 1.5ppm popcorn noise. The Weston cells are, as far as I'm concerned, noiseless.
My 45kg 7-decade 100kohm KVD in combination with the 7081 gives ~2.5ppm linearity.
Yup, I'm an (incompetent) voltnut.
toggle quoted message
Show quoted text
On 17/03/18 22:43, Robin Birch wrote: Tom,
Think mine¡¯s an unsaturated one - if I drop it down can you measure it ?
Robin
On 17 Mar 2018, at 22:40, Chuck Harris <cfharris@...> wrote:
Hi Tom,
Those look right to me for saturated standard cells.
Find a nice cozy place for them to live, and leave them
alone, and they should last and last.
-Chuck Harris
Tom Gardner wrote:
Having a look at the photos, I may have made a mistake: the 49yo cell has one of the
first two voltages I noted.
On pulling the Muirhead apart and comparing them with a "Muirhead Journal" article,
it appears that:
* they are crystal locked saturated cells
* 1.01859V @ 20C implies a 0.1N solution
* serial number is almost illegible, but it 1702
* date is almost illegible, but is 19-1-*49* !
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Re: What calibration items to buy.
Tom,
Think mine¡¯s an unsaturated one - if I drop it down can you measure it ?
Robin
toggle quoted message
Show quoted text
On 17 Mar 2018, at 22:40, Chuck Harris <cfharris@...> wrote:
Hi Tom,
Those look right to me for saturated standard cells.
Find a nice cozy place for them to live, and leave them
alone, and they should last and last.
-Chuck Harris
Tom Gardner wrote:
Having a look at the photos, I may have made a mistake: the 49yo cell has one of the
first two voltages I noted.
On pulling the Muirhead apart and comparing them with a "Muirhead Journal" article,
it appears that:
* they are crystal locked saturated cells
* 1.01859V @ 20C implies a 0.1N solution
* serial number is almost illegible, but it 1702
* date is almost illegible, but is 19-1-*49* !
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Re: What calibration items to buy.
Hi Tom,
Those look right to me for saturated standard cells.
Find a nice cozy place for them to live, and leave them
alone, and they should last and last.
-Chuck Harris
Tom Gardner wrote:
toggle quoted message
Show quoted text
Having a look at the photos, I may have made a mistake: the 49yo cell has one of the
first two voltages I noted.
On pulling the Muirhead apart and comparing them with a "Muirhead Journal" article,
it appears that:
* they are crystal locked saturated cells
* 1.01859V @ 20C implies a 0.1N solution
* serial number is almost illegible, but it 1702
* date is almost illegible, but is 19-1-*49* !
|
Re: What calibration items to buy.
Having a look at the photos, I may have made a mistake: the 49yo cell has one of the first two voltages I noted.
On pulling the Muirhead apart and comparing them with a "Muirhead Journal" article, it appears that:
* they are crystal locked saturated cells
* 1.01859V @ 20C implies a 0.1N solution
* serial number is almost illegible, but it 1702
* date is almost illegible, but is 19-1-*49* !
(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/?action=dlattach;attach=280936;image
(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/?action=dlattach;attach=280934;image
(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/?action=dlattach;attach=280932;image
toggle quoted message
Show quoted text
On 17/03/18 19:44, Chuck Harris wrote: If your cells are unsaturated, and if they were portable, they
most certainly are, their as new voltage was 1.0190-1.0194 @ 20C.
They would be discarded when they reached 1.0183V.
If your cells are saturated, which is typical of those used
in a large standards lab, they would have a new voltage of
1.018636 - 0.00060N - 0.00005N^2, where N is the normality of
the sulfuric acid added to the saturated CdSO4 electrolyte.
Measurement is, of course, is at 20C.
The only way I know of telling which is which, is to read the
plate (if it has one), or to look at the glass "H" tube, and
see if it has a cluster of CdS04 crystals at the interface to
the mercury bearing electrodes. The saturated type will, the
unsaturated type won't.
I don't think I have ever seen a saturated type that wasn't in
a rather big "air" bath cabinet.
The unsaturated type typically come in bakelite molded
enclosures with screw terminals. They can easily be tossed
about, and stand alone. They are what you would find at a
school, or in a portable potentiometer or bridge.
A little shaking, or movement doesn't bother the unsaturated
type, much, but will completely wreck a saturated cell.
-Chuck Harris
Tom Gardner wrote:
On 17/03/18 12:11, Chuck Harris wrote:
It has been so long since Weston last made standard cells of any
stripe that it is doubtful that yours is measuring within its
accurate range. I wouldn't be too sure.
I have four saturated cells. At ~16C, and measured with an hp3468a, which is believed
to read 0.014% low, they are
1.01867
1.01870
1.01850
1.01866
One of the latter two is dated 1949.
When measured with my Solatron 7081 (which I can't be bothered to power up for this),
the cells act as thermometers around 20C (40uV/C) :)
I would imagine that by now, Weston's site has
been cleaned of most of its mercury and cadmium contamination,
and is probably only just barely considered a superfund site... I've seen some on fleabay that would have been sent by post!
What type (saturated or unsaturated), and what voltage is your
cell reading?
OBTW, a 10M DVM is a little on the high side as far as loading
goes for a standard cell. Protocol requires that you to use a
balanced bridge type measurement, and draw no current from the
cell.
-Chuck Harris
Robin Birch wrote:
I¡¯ve got an old Weston standard cell that sits on my bookshelves and I check the
DVMs against that. I¡¯ve never calibrated it but it seems close enough. I don¡¯t
really ask much of my calibration, within two or three decimal places is fine.
Robin
On 17 Mar 2018, at 05:28, Craig Sawyers <c.sawyers@...> wrote:
assume
|
Re: What calibration items to buy.
To Chuck,
OBTW, your thermocouple calibrator is not even in the same
league as your 5.5 and 6 digit DVM's... it is kind of like
comparing a pro baseball game to the toddlers playing T ball.
-Chuck Harris
Ok, I'm thick headed, and I most likely am missing something. I fully
understand
the first part of your response. In regard to the Ectron 1100 the Tek
"calibration"
is really just re-establishing the mfgr specs with docs. And yes, "worth" is
very relative.
And I also appreciate the transfer standard issue. In a crude way it is like
buying a new car.
You only know its value at the instant you pay the dealer. Drive it off the
lot ant its value is
no longer well known. Finding a buyer for it in a later year is like taking
the standard back to the Cal Lab.
But you need to cut the fog for me on your final comment. I think you are
saying that
no matter how good an adjustment and cal is made to the Ectron 1100, the
zener reference and DAC
with 5 digit control of 0000.0-9999.9mv/000.00-999.99mv/00.000-99.999mv
ranges is poor compared to the
Fluke 8840A 5.5 digit or HP3457A 6 digit ADCs. I think you are saying that
the 1100 would need to span the
full range of the DVMs and then some to be useful, not covering the DVM
range in steps. Am I close?
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Re: What calibration items to buy.
If your cells are unsaturated, and if they were portable, they
most certainly are, their as new voltage was 1.0190-1.0194 @ 20C.
They would be discarded when they reached 1.0183V.
If your cells are saturated, which is typical of those used
in a large standards lab, they would have a new voltage of
1.018636 - 0.00060N - 0.00005N^2, where N is the normality of
the sulfuric acid added to the saturated CdSO4 electrolyte.
Measurement is, of course, is at 20C.
The only way I know of telling which is which, is to read the
plate (if it has one), or to look at the glass "H" tube, and
see if it has a cluster of CdS04 crystals at the interface to
the mercury bearing electrodes. The saturated type will, the
unsaturated type won't.
I don't think I have ever seen a saturated type that wasn't in
a rather big "air" bath cabinet.
The unsaturated type typically come in bakelite molded
enclosures with screw terminals. They can easily be tossed
about, and stand alone. They are what you would find at a
school, or in a portable potentiometer or bridge.
A little shaking, or movement doesn't bother the unsaturated
type, much, but will completely wreck a saturated cell.
-Chuck Harris
Tom Gardner wrote:
toggle quoted message
Show quoted text
On 17/03/18 12:11, Chuck Harris wrote:
It has been so long since Weston last made standard cells of any
stripe that it is doubtful that yours is measuring within its
accurate range. I wouldn't be too sure.
I have four saturated cells. At ~16C, and measured with an hp3468a, which is believed
to read 0.014% low, they are
1.01867
1.01870
1.01850
1.01866
One of the latter two is dated 1949.
When measured with my Solatron 7081 (which I can't be bothered to power up for this),
the cells act as thermometers around 20C (40uV/C) :)
I would imagine that by now, Weston's site has
been cleaned of most of its mercury and cadmium contamination,
and is probably only just barely considered a superfund site... I've seen some on fleabay that would have been sent by post!
What type (saturated or unsaturated), and what voltage is your
cell reading?
OBTW, a 10M DVM is a little on the high side as far as loading
goes for a standard cell. Protocol requires that you to use a
balanced bridge type measurement, and draw no current from the
cell.
-Chuck Harris
Robin Birch wrote:
I¡¯ve got an old Weston standard cell that sits on my bookshelves and I check the
DVMs against that. I¡¯ve never calibrated it but it seems close enough. I don¡¯t
really ask much of my calibration, within two or three decimal places is fine.
Robin
On 17 Mar 2018, at 05:28, Craig Sawyers <c.sawyers@...> wrote:
assume
|
Re: What calibration items to buy.
The problem with precision voltage references is
(a) They take time to settle and reach a stable value
(b) They often have thermal hysteresis and so need to be temperature controlled, or in a stable lab
temperature.
Craig
toggle quoted message
Show quoted text
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of hrgerson@...
Sent: 17 March 2018 16:49
To: [email protected]
Subject: Re: [TekScopes] What calibration items to buy.
Wondering if any have experience with the below inexpensive DC Voltage "standard" or similar items
(no affiliation) :
Would these represent practical use to interested TekScope members ?
a)
732A-or-732B/251756273626?hash=item3a9dd7dfda:g:12wAAOSwdndUlMfk
( has a description of their calibration chain).
b)
calibrated/122931267872?hash=item1c9f464920:g:zGQAAOSwXf1aaNlH
( using the LT1021 IC, low cost voltage reference.)
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Re: What calibration items to buy.
On 17/03/18 12:11, Chuck Harris wrote: It has been so long since Weston last made standard cells of any
stripe that it is doubtful that yours is measuring within its
accurate range. I wouldn't be too sure. I have four saturated cells. At ~16C, and measured with an hp3468a, which is believed to read 0.014% low, they are 1.01867 1.01870 1.01850 1.01866 One of the latter two is dated 1949. When measured with my Solatron 7081 (which I can't be bothered to power up for this), the cells act as thermometers around 20C (40uV/C) :) I would imagine that by now, Weston's site has
been cleaned of most of its mercury and cadmium contamination,
and is probably only just barely considered a superfund site... I've seen some on fleabay that would have been sent by post! What type (saturated or unsaturated), and what voltage is your
cell reading?
OBTW, a 10M DVM is a little on the high side as far as loading
goes for a standard cell. Protocol requires that you to use a
balanced bridge type measurement, and draw no current from the
cell.
-Chuck Harris
Robin Birch wrote:
I¡¯ve got an old Weston standard cell that sits on my bookshelves and I check the DVMs against that. I¡¯ve never calibrated it but it seems close enough. I don¡¯t really ask much of my calibration, within two or three decimal places is fine.
Robin
On 17 Mar 2018, at 05:28, Craig Sawyers <c.sawyers@...> wrote:
assume
|
Re: What calibration items to buy.
Wondering if any have experience with the below inexpensive DC Voltage "standard" or similar items (no affiliation) :
Would these represent practical use to interested TekScope members ?
a)
( has a description of their calibration chain).
b)
( using the LT1021 IC, low cost voltage reference.)
|
Re: Tek 317 odd trace behavior after warm-up
Hi John,
That's what I get for guessing... :)
Thanks,
Barry - N4BUQ <- Amateur Radio Callsign
toggle quoted message
Show quoted text
Hi Barry,
It's actually the chassis code for my favorite car, the Mitsubishi Lancer
Evolution 10.
Regards,
John - CZ4A
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Re: Tek 2465a grid bias and brightness problems
If 240K works, it wouldn't be a sin to use it.
For all you know, your 2465A CRT could have been replaced with
a CRT from a 2465, or your U950 may be an old revision.
Put another way, tektronix once found 240K to work, and later
found something changed that made 390K work better. Your scope
may need the resistor to be 240K.
Also, at voltages and impedances as high as these, thin films
of environmental gorp (smoke, soot, radon daughters, cleaner
fumes, vacuum pump oil, ...) can easily cause changes like
what you are seeing.
If you want to take a stab at curing this, you could also try
washing the CRT's neck, socket, base, and the HV section's
board, resistors, capacitors, ... very clean, and see what
happens.
Others have found cleaning of these parts to help.
-Chuck Harris
Francesco wrote:
toggle quoted message
Show quoted text
After a lot of testing, I can give some more insight on my problem, and I sincerely need your opinion of experts on the matter. I have replaced and tested with a working U950, a nos and tested complete a9 board and I have checked all the DI and ROI lines from pots to U950, the problem doesn't change. The AC waveform is clamped at the low end by the vz out from intensity pot and U950 vz out but grid bias even if dc restorer works in spec can't completely turn off the crt. It only works if I lower the value of one of the DC restorer resistors out of spec: r1992 is marked on the schematic as a 240k but in reality is a 390k from later 2465 serial numbers on to 2465b (you can see this on material list), if I use a 240k resistor instead of the 390k everything works fine and the crt completely dims off and I can complete cal08 with no problems. Still this is not in spec for a 2465a. It seems a crt problem at this point, have you ever seen anything like this? It seems like a leak between g1 and cathode. Can you give some advice? Should I replace the crt?
Thanks in advance
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Re: What calibration items to buy.
It has been so long since Weston last made standard cells of any
stripe that it is doubtful that yours is measuring within its
accurate range. I would imagine that by now, Weston's site has
been cleaned of most of its mercury and cadmium contamination,
and is probably only just barely considered a superfund site...
What type (saturated or unsaturated), and what voltage is your
cell reading?
OBTW, a 10M DVM is a little on the high side as far as loading
goes for a standard cell. Protocol requires that you to use a
balanced bridge type measurement, and draw no current from the
cell.
-Chuck Harris
Robin Birch wrote:
toggle quoted message
Show quoted text
I¡¯ve got an old Weston standard cell that sits on my bookshelves and I check the DVMs against that. I¡¯ve never calibrated it but it seems close enough. I don¡¯t really ask much of my calibration, within two or three decimal places is fine.
Robin
On 17 Mar 2018, at 05:28, Craig Sawyers <c.sawyers@...> wrote:
assume
|
Re: Tek 317 odd trace behavior after warm-up
Oops ! The last two lines of my previous message, after the signature.. what are they doing here... just ignore them.
Unfortunately unlike forum posts, you can't edit/correct e-mails... once it's sent, it's sent...will proof read better next time, sorry :-/
Vince
|
Vince
Jeff Urban