Hi Paul,
Your welcome !
Yes I agree, it's sometimes very hard to change these IC. I love the items where Tektronix had the good idea to use sockets for quite all the semiconductors...
Good luck !
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Re: 7854 Repair & Restoration
I picked up a set of PX625 mercury cells that should work to replace the one bad battery that my 7S14 has.
I'm definitely interested in changing out the cells for a more permanent fix in the future, but for now the unit is fully functional. I have a massive number of repairs to get done and lately have had very little time for my hobby as a whole. I've not yet even had a chance to fully figure out if U50 is bad on this 7854.
Unfortunately, the one thing taking current priority when I have any time at all to do so, is wrapping up one of these 485's so I can get it listed and sold. (I have a couple tickets I forgot to pay, so now I'm risking a license suspension!) In my endeavor to simply calibrate the 485, I found that BOTH of my 106's have a common issue which renders them absolutely useless for driving a TD pulser!!
So my apologies go to those who have been helping me with this 7854 and also to those following along. I really wish I had more time! I pray that I can catch a break soon....
Thank you all for all the help and knowledge! One of these days I will have a firm grasp of all the fundamentals and enough experience to be a real contributor to this great gathering of minds and resources.
-Brian
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Re: 7854 RAM card upgrade only - any interest?
Cliff,
I have been in contact with Solanotraders over the past several months due to a large number of purchases from them. If no one has asked them about the diagnostic card buyer, I can do so. I think it's probably worth a shot at least. I'm wishing I would have just purchased that unit when I had the chance...
It's quite likely that you can count me in for 2 of these RAM/ROM boards. I'm hoping I don't have to butcher the 2nd scope to resolve the vertical amplifier issue on my better 7854. I'll be going through a few manuals to see what scopes share the same vertical amp board so I can try to pick up a cheap board donor scope.
-Brian
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Thank you David & Philippe - I'll try swapping out the 7447, I've got plenty lying around. Unfortunately it is not socketed, and it's partially buried under the RF section.
Philippe - that's a great page, thanks for sharing! Google translate seems to be handling it OK.
cheers,
Paul
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Hello,
I purchased the DE-5000 from one of the ebay sources about 2 months ago, took about a month to get here(NC, USA). after unwrapping popped a battery in it and started using it immediately mainly for going through pile of dropped 603 smd caps ( yea im cheap that way). I got it with the smd probe which is spring loaded after a while your hand gets tired. Measures my lowest value caps 20pf no problem, also has auto component detect.
Anyway I still have alot to learn about this product and reading the post on this topic was very helpful thanks to all the members that replied.
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Re: Tektronix 576 577 Safety Shield cover for Curve tracers
Be warned the "Health and Safety" thought police will be after you :)
Dave
-----Original Message-----
:
:
Just short out the interlock inside and keep your fingers out the way" I miss having Deane's take on real world electronics. Well I miss Deane full stop. I shudder to think what he thought of ROHS - he (like me and I would think many others) used is mouth as a third hand to feed solder into a joint; when this list muttered about lead he pointed out that he had done it that way all his working life and had absolutely no problem. Craig
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Re: 5440 low-voltage power supply
So that leaves a z-axis problem. I do not think it can be just a
timebase unblanking problem because that should not affect the
readout. > No readout either? I thought you just missed the trace. If no readout either, David is right of course and my grid bias adjustment won't help. Raymond
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Re: Tektronix 576 577 Safety Shield cover for Curve tracers
Be warned the "Health and Safety" thought police will be after you :)
Dave
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Show quoted text
-----Original Message----- : : Just short out the interlock inside and keep your fingers out the way" : Craig
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PS501 PS503A large Sprague Capacitors
I repaired two of these and on both the 3000 ?F resp. 4500 ?F (C10/C20 resp. C10/C110) Spraguelytics were the culprits. Exchanging them against some 35V types I had laying around in much smaller outline and larger capacity made the units work again.
Only it doesn't look very nice and I would rather build in some devices that fit into these plastic holders.
Are there still sources for these original Sprague capacitors?
--
Christoph
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Re: Tektronix 576 577 Safety Shield cover for Curve tracers
Hi Raul,
The item you linked is in fact the better (= latest) 576/577 Safety Shield. This to accomodate two of the later (a little wider) A-Series of Curve Tracer Test Adapters (e.g. A1002). Its PN is 337-1194-02.instead of the older 337-1194-00/01.
Greetings,
Egge Siert
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Hello,
Yes, it may be the 7447, or more rarely a bad contact between the 7447 and the segments.
A suggestion, if like me you prefer well formed 6 and 9, you can replace the 7447 by a 74ls247.
I change it on all my tek plugin and the display is better.
You can see it on my website (sorry in French)
You can find 74ls247 on ebay
TM500
TM500 Ce site utilise des frames. Si vous ne voyez pas les menus ¨¤ gauche, cliquez Ici Pr¨¦sentation J'ai commenc¨¦ l'electronique vers 10 ans ¨¤ l'aide...
View on philippe.demerliac.fr...
Preview by Yahoo
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Re: Shootout of Substitute SG504 heads = a better head.
On Sat, 26 Mar 2016, mosaicmerc@... [TekScopes] wrote: ksi@..., same as in mail headers... Hi Sergey:
Can you send me an Email for Paypal pls?
Your new head is ready.
mosaicmerc@...
AncelB
On Sun, 20 Mar 2016, mosaicmerc@... mailto:mosaicmerc@... [TekScopes] wrote:
Please count me in for one fully assembled head. I do have original SG504
one but it won't hurt to have a replacement :)
------------------------------------
Posted by: mosaicmerc@...
------------------------------------
------------------------------------
Yahoo Groups Links
--- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * *
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Re: Shootout of Substitute SG504 heads = a better head.
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Re: Shootout of Substitute SG504 heads = a better head.
Hmm...I'm mosaicmerc AT y.a.h.o.o. c_o_m
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Re: Shootout of Substitute SG504 heads = a better head.
Hi Dennis:
Pls contact me.. your new head is ready...
mosaicmerc@...
Hi Ancel,
Very impressive results.
I would like to see how the original Tek head designed by George Steen compares to both yours and David's heads. Of course the Tek head was designed 40 years ago but it would be informative to know how they all compare. I have both.
When you finally produce boards for sale I would like to buy one and repeat the tests I did on George's head and David's head and include your head in the tests
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Re: Shootout of Substitute SG504 heads = a better head.
Hi Sergey:
Can you send me an Email for Paypal pls?
Your new head is ready.
mosaicmerc@...
AncelB
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Show quoted text
On Sun, 20 Mar 2016, mosaicmerc@... mailto:mosaicmerc@... [TekScopes] wrote:
Please count me in for one fully assembled head. I do have original SG504
one but it won't hurt to have a replacement :)
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Odd ball Tek made plugin from the 60's
It started its life as a 11B2A, which was a timebase for the 647/A's
Tek plugin Custom Mod for Memcor
Tek plugin Custom Mod for Memcor Add Photo To Cart DSCN2098 Date: 03/26/2016 Views: 1 New Add Photo To Cart DSCN2099 Date: 03/26/2016 New Add Photo To Cart DSCN2100 Date: 0...
View on petelancashire.com
Preview by Yahoo
Custom mod'ed for a company called Memcor, which at one time made commuications equip for the military as a division of E-Systems
Anyone have any information ?
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Re: 5440 low-voltage power supply
I agree; what you saw with the beamfinder pressed is the sweep and
readout.
So that leaves a z-axis problem. I do not think it can be just a
timebase unblanking problem because that should not affect the
readout.
Scanning the schematics, I find that the horizontal unblanking signal
*and* the readout intensity signal go through the same connector and
cable to the readout board. You might want to check those connectors.
If U1000 on the readout board is in a socket, reseat it.
Check that Q340 on schematic 5 is good or at least not shorted. I
think removing it will restore the readout if the transistor is bad.
I would print up a set of schematics to mark up and make things easier
to understand but maybe you will not need to do that.
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On Sat, 26 Mar 2016 16:47:21 -0500, you wrote: Raymond,
You are correct the Q850 was bad and a replacement MJE800 restored the +15v.
Now I can try and fix the lack of a sweep.
When the beam finder is depressed I get a centered intense sweep of about 1/3 the width of the CRT. Just above it there is a short sweep. I suspect that what I am seeing is the horz. sweep and the readout . My diagrams do not show any normal voltages or waveform s. If someone could give me some idea what the unblanking should be and the voltage. Is there a source to find the expected wave forms and voltages?
Charlie
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ESR and D are somewhat independent.? If ESR is low, D can still be high due to dielectric problems.? And high ESR isn't always a problem.
I guess there is no all encompassing parameter that can characterize a capacitor.? Much depends on the frequency and other aspects of the application.
Further, small capacitors can indicate high ESR when that isn't the case; it depends on the frequency.? In other words, if the capacitive reactance at the test frequency is of the order of magnitude of the ESR, ESR readings are worthless.? The best test is to run a frequency sweep.? Well, maybe the best test is to install and use the capacitor and see if it works.
Sometimes there will be an intermittent, say a loose termination inside the DUT that shows up occasionally.
Series inductance is important as well, especially at higher frequencies.? This includes lead inductance and internal interconnections.? Electrolytic capacitors have their own set of problems, including occasional punching through of the electrolyte that only shows up at higher voltages.? So a voltage test is called for sometimes.
For tuning capacitors we also must deal with temperature coefficient of capacitance, something only measurable by varying the temperature.
And on and on....
Bob
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On Saturday, March 26, 2016 7:53 PM, "David davidwhess@... [TekScopes]" <TekScopes@...> wrote: ? On Sat, 26 Mar 2016 12:54:44 -0600, you wrote: ...
2. You could also consider upgrading to a DER-EE DE-5000, which is an
excellent full function 100kHz LCR meter, and of course measures ESR
as well. This will cost about $120, and you can just buy it from the
current cheapest eBay seller:
The DER-EE DE-5000 would be my first choice and recommendation although I do not know how it performs for in-circuit tests. The idea of using ESR to test capacitors strikes me as poor compared to using D (dissipation). ESR is roughly inversely proportional to capacitance while D is constant so it is easier to spot a bad or at least marginal capacitor using D than ESR. #yiv3981593294 #yiv3981593294 -- #yiv3981593294ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv3981593294 #yiv3981593294ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv3981593294 #yiv3981593294ygrp-mkp #yiv3981593294hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv3981593294 #yiv3981593294ygrp-mkp #yiv3981593294ads {margin-bottom:10px;}#yiv3981593294 #yiv3981593294ygrp-mkp .yiv3981593294ad {padding:0 0;}#yiv3981593294 #yiv3981593294ygrp-mkp .yiv3981593294ad p {margin:0;}#yiv3981593294 #yiv3981593294ygrp-mkp .yiv3981593294ad a {color:#0000ff;text-decoration:none;}#yiv3981593294 #yiv3981593294ygrp-sponsor #yiv3981593294ygrp-lc {font-family:Arial;}#yiv3981593294 #yiv3981593294ygrp-sponsor #yiv3981593294ygrp-lc #yiv3981593294hd {margin:10px 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It is certainly possible for a 7447 or any TTL IC that old to fail. On
my SG503, one of the 7475 latches feeding the 7447 failed. I would
expect 7447s to actually fail more often since they have to operate as
a driver and often run hot.
I would actually suspect bad Texas Instruments sockets first but I
know some of the LED displays in this modules had poor reliability
which is apparently not the issue you are having.
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On 26 Mar 2016 19:16:59 -0700, you wrote: Hi -
I know the DC508 display is a common point of failure, and that Paul Read even offered replacement display boards at one point (Paul, do you still have any?).
I'm wondering if anyone has had a failure mode that wasn't the display itself, but the 7447 instead? In my case, I'm not missing any elements, but certain numbers are malformed, and the same number is malformed in each digit. Does a bum 7447 sound plausible? How do these displays usually fail?
thanks!
Paul
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Raymond Domp Frank
David C. Partridge
Sergey Kubushyn
David Hess