--- In TekScopes@..., "Nick" <nick@...> wrote: My AFG5101 has started saying "battery low" when powered on - is that an easy thing to change? Ordered a service manual, however it looks like a Lithium module on one of the end boards - made by Renata and marked 3V and "125-1". I can't find a data sheet for this thing, but I think its actually an encapsulated CR2032 with a couple of 1N4148 diodes - Renata make a similar module called a "175-0", but the "-0" means no internal diodes - they don't make a "175-1" - the suffix "-1" indicates internal diodes - they make a "1000-1" but its too big, however I'm pretty sure its functionally identical, so I can use its layout - I'll check the existing module once I've de-soldered it... I think its going to be easier to make a carrier with a coin cell holder for the 2032 and the two diodes - easier to change the cell in the future too... Also, the LCD contrast is very poor, as is the viewing angle - is there anything I can do about that? Still hoping for an answer on this... Nick
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Re: Photos of a non-illuminated graticule; WAS 576 versus 577
Yes, UV LEDs are the way to go. The old school cameras we discussed had plenty of UV from actual UV lamps, or the high UV content from a xenon flash. The other variable is the UV loss in the plastic layers in front of the CRT. UV LEDs should be readily available. I bought some in the form of small keychain flashlights from a surplus store years ago - there should be even better and cheaper ones around now.
The intense blue LED wavelengths work fine for the modern "white" LED phosphors, but apparently not so much for CRT ones.
Ed
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--- In TekScopes@..., Brad Thompson <brad.thompson@...> wrote:
On 1/24/2012 12:38 PM, Dennis Tillman wrote:
During the discussion of the 576 vs 577 curve tracer I mentioned the 577
graticule was not illuminated which I find annoying every time I want to
take a picture of device characteristics on the CRT.
Later I realized I might be able to take advantage of the storage CRT
flood gun on my 577 D1 to light the screen from inside the CRT. It is
not the solution I was looking for but it does work (with drawbacks).
A more intriguing solution came from Ed Breya, with an explanation of
how it works from David. If you `flash' the phosphor it will glow and
illuminate the graticule from inside the CRT. I tried this with two
different LEDs I had handy and the results were quite promising. <snip>
Hello, Dennis--
Have you tried using ultraviolet-emitting LEDs? IIRC,
one of the --HP-- oscilloscope cameras used a UV emitting
lamp to light up the screen's phosphor and show the graticule.
73--
Brad AA1IP
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Re: 7T11 trace shifting left as time/div rotated.
To be honest I didn't think of that possibility. Anyway, there was a lot to learn from such a silly bad contact.
Albert
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I can only conclude that one of the contacts in the socket had got resistive, and that removing and replacing it has fixed that (or there's a dry joint - I will check that).
Either way, I am very pleased that it works correctly now, but annoyed I could not work out what was wrong.
---
David Partridge
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Re: Photos of a non-illuminated graticule; WAS 576 versus 577
On 1/24/2012 12:38 PM, Dennis Tillman wrote: During the discussion of the 576 vs 577 curve tracer I mentioned the 577
graticule was not illuminated which I find annoying every time I want to
take a picture of device characteristics on the CRT.
Later I realized I might be able to take advantage of the storage CRT
flood gun on my 577 D1 to light the screen from inside the CRT. It is
not the solution I was looking for but it does work (with drawbacks).
A more intriguing solution came from Ed Breya, with an explanation of
how it works from David. If you ???flash??? the phosphor it will glow and
illuminate the graticule from inside the CRT. I tried this with two
different LEDs I had handy and the results were quite promising. <snip> Hello, Dennis-- Have you tried using ultraviolet-emitting LEDs? IIRC, one of the --HP-- oscilloscope cameras used a UV emitting lamp to light up the screen's phosphor and show the graticule. 73-- Brad AA1IP
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Photos of a non-illuminated graticule; WAS 576 versus 577
During the discussion of the 576 vs 577 curve tracer I mentioned the 577 graticule was not illuminated which I find annoying every time I want to take a picture of device characteristics on the CRT. ? Later I realized I might be able to take advantage of the storage CRT flood gun on my 577 D1 to light the screen from inside the CRT. It is not the solution I was looking for but it does work (with drawbacks). ? A more intriguing solution came from Ed Breya, with an explanation of how it works from David. If you ¡®flash¡¯ the phosphor it will glow and illuminate the graticule from inside the CRT. I tried this with two different LEDs I had handy and the results were quite promising. ? BUT there is a gotcha. The results are highly dependent on the CRT phosphor and maybe the CRT construction. This is apparently the case among the same model scope. For instance I have two 7603 scopes. One 7603 has a slightly more blue CRT than the other which I always assumed was due to the piece of protective plastic in front of the CRT. One glows brightly in a sickly green color from a Blue LED I tried, the other barely glow at all when illuminated with the same LED. My 7104, 7854, SC502, and Wiltron 640 RF analyzer (a Tek 5000 OEM scope display with a purple phosphor) glow brightly. But a 603 and 608 (storage) monitor glow dimly white. My 7844 glows dimly somewhat like my second 7603. It has a similar blue looking CRT. ? Unfortunately my 577 (the CRT looks more green) and SC502 (the CRT has a pale green/white appearance) which are both storage CRTs barely glow at all so this isn¡¯t going to help me to take pix of transistor characteristic curves. ? Most of these impromptu tests were done with an LED that I marked as ¡°3.0V, 40mA, Very Bright, 394nM Blue¡±, with a clear lens. As far as I can tell this LED has a standard 30 degree dispersion angle. When I got a good response it illuminated the CRT across a wide area so the phosphor is quite excited and there is probably little need for a diffuse lens if you use 4 LEDs at a time ¨C one each to illuminate each quadrant of the CRT. The other LED I tried was a 485nM one I just got. It was different from the first LED in brightness (my eye could be completely wrong because these LEDs are near the edge of human optical sensitivity) and in color and it yielded much less interesting results. ? I am familiar with phosphor response curves but I was quite surprised at the variation I got. I don¡¯t see any pattern to this at all except that as a class the storage CRTs were likely to be among the dimmest. I have the ideal instrument to do a more thorough test of the time dependent phosphor responses to various light sources ¨C a 7J20 Rapid Scan Spectrometer plug-in ¨C but that would take a lot of time to do. ? Dennis ?
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-----Original Message----- From: David, Wednesday, January 11, 2012 6:59 PM ? The flash does not serve to illuminate the graticule.? Instead it activates the CRT phosphor which then backlights the graticule from behind.? The picture is taken after the flash. ? >-----Original Message----- >From: Ed Breya, Wednesday, January 11, 2012 3:10 PM >? >A while ago I junked out a big old HP scope camera that had one or two >small "black light" UV flourescent lamps that illuminated the CRT face, >presumably to make the phosphor glow and backlight or contrast the >graticule lines - or, it may have been some kind of writing rate >enhancer. The camera didn't function, and didn't fit any standard bezels, so I never saw the effect. >Maybe this technique using UV LEDs could be considered for some >interesting experiments. >? >I know the Tek C-5 camera has a xenon flash to get the graticule >without any other illumination, so it seems like some kind of direct >lighting should be workable. With high-power "white" LEDs, it should be >no problem getting good brightness if the optics can get decent >uniformity - maybe with a big diffuser surrounding the lens. >? >Ed ?
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Re: Total beginner with newly acquired 475 with issues
Take care when you test power supply.I had repared 4 Tek475.
But with the last something wrong occured the K tube filament burned!!!Something I d never explained as I have more than 40 years experience!
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Hi,
I am building some 7K plugin kludges and need blank front panels. The 2 1/2"x5" panels with the turned up ends would be my first choice. ? 2 1/2x4 7/8" flat panels would be my second choice. They should be between .05 and .1 inches thick and be made of aluminum or lexan plastic. My immediate need is for three with the possibility of more later. Please respond off list with total cost prices. The material should be free from scratch or holes.
Jerry Massengale
jmassen418a@...
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Re: Displayed signal becomes compressed when position is moved to the left
Those are not the problem then. I was thinking that if the multiplexing diodes where not switching completely it would cause clipping in analog mode while allowing the readout and digital display to work correctly. On Tue, 24 Jan 2012 16:55:30 -0000, "david_s5y" <david_s5@...> wrote: Yes for Both A and B.
Yes the timebase still in calibration for the part which is not compressed.
At U7202A/B
STORE .72 and 7.2 (this is lower then on schemtic 7.59)
/STORE .55 and 7.2 (this is lower then on schemtic 7.45)
--- In TekScopes@..., David <davidwhess@...> wrote:
Does the trace compress to the left with both timebases?
For the part which is not compressed, is the timebase still in
calibration?
Unfortunately I suspect the problem is going to be somewhere around
U760 on schematic 7 but I would also check the levels of STORE and NOT
STORE to the right of U760 on schematic 7.
On Mon, 23 Jan 2012 19:31:20 -0000, "david_s5y" <david_s5@...>
wrote:
On a tek 2230 in non-store mode, the displayed signal becomes compressed when position is moved to the left.
So if I have a 5K square wave displayed at .1 Ms the first 1/2 of the wave will be 60% the width if I move it to the right. It also looks like brighter.
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Re: Displayed signal becomes compressed when position is moved to the left
Yes for Both A and B.
Yes the timebase still in calibration for the part which is not compressed.
At U7202A/B
STORE .72 and 7.2 (this is lower then on schemtic 7.59)
/STORE .55 and 7.2 (this is lower then on schemtic 7.45)
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--- In TekScopes@..., David <davidwhess@...> wrote:
Does the trace compress to the left with both timebases?
For the part which is not compressed, is the timebase still in
calibration?
Unfortunately I suspect the problem is going to be somewhere around
U760 on schematic 7 but I would also check the levels of STORE and NOT
STORE to the right of U760 on schematic 7.
On Mon, 23 Jan 2012 19:31:20 -0000, "david_s5y" <david_s5@...>
wrote:
On a tek 2230 in non-store mode, the displayed signal becomes compressed when position is moved to the left.
So if I have a 5K square wave displayed at .1 Ms the first 1/2 of the wave will be 60% the width if I move it to the right. It also looks like brighter.
+==+==+==+==+==+==+==+==+==+==+
---___---___--- <moved to right>
+--- Short and brighter.
V
==___---___---
What needs adjusting
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Re: Displayed signal becomes compressed when position is moved to the left
On Tue, 24 Jan 2012 15:57:34 -0000, "david_s5y" <david_s5@...> wrote: Thanks for the suggestion. I have pushed on the connector. It did not help.
Store mode is currently not working. I currently have Q2105 removed. Gah! I wish you had posted that initially. My suggestions assumed store mode worked or at least that it and the readout lacked any display problems. I am awaiting the arrival of another scope to troubleshoot the storage problem. This could be related.
If I inject a signal at the emitter of Q2105 I can see the signal on the display and it does not compress. But I have not been able to verify the signal path from the Ch 1 and 2 inputs in store mode. I would help if you said where Q2105 is. The service manual lists parts by assembly and there are 24 of them. In non Store the compression occurs on both channels A and B time bases.
It is like the H position is off 1/2 a graticule to the right and the trace is retracing. Like on a TV. Is there H Postion Adjustment? I do not believe this is an adjustment problem. I have seen this happen before when a CRT output amplifier went into limiting because of an open load resistor. The 2230 Horizontal Output Amplifier uses shunt feedback and a constant current load so I would check the resistors and then the transistors. R786, Q789, R776, and Q779 are where I would start. I might look for the distortion in the horizontal signal chain starting from the CRT and moving back toward the Horizontal Preamp. Is the readout similarly warped? If not then it is not the Horizontal Output Amplifier.
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Re: 7T11 trace shifting left as time/div rotated.
Well now, that was interesting, swapping Q280 with Q452 (same type) initially appeared to make things slightly worse, but when I pressed on the top of the FET to straighten it up to get at one of the leads with a probe, the problem disappeared! I swapped the parts back to their original positions, and it still works as I expect (that is the voltage between T=24uS and T=34uS is now sat solidly at 0V).
I can only conclude that one of the contacts in the socket had got resistive, and that removing and replacing it has fixed that (or there's a dry joint - I will check that).
Either way, I am very pleased that it works correctly now, but annoyed I could not work out what was wrong.
Now back to the calibration exercise which should now be a little easier (I hope).
Regards,
David Partridge
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-----Original Message----- From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Albert Sent: 24 January 2012 13:54 To: TekScopes@... Subject: [TekScopes] Re: 7T11 trace shifting left as time/div rotated. Hi David, The half period oscillation is normal. I would first test Q280 before bothering about a replacement type. They should be matched at Id about 1 mA each and Vds about 15 V. Is there any need for a curve tracer? In the absence of triggering you can measure DC levels all around, drain of Q280B (should be 15 V mine 0.7 V), common source a few volts positive, difference between gates (2.2 V?). You can even probe these points during operation; a 10x probe won't disturb the results. Maybe there is another same type dual fet in the 7T11 that can temporarily be used/exchanged? Albert Yes, a slight inbalance I could understand - but +2.2V is a LOT.
Yes you can see the ramp very nicely at 100nS/div. But regardless of the sweep speed there's a very clear problem here. As the ramp stop voltage increases (more negative), the ramp start voltage moves from close to 0V until it reaches about +2.2V when the stabilised stop voltage (after the overshoot) gets to about 4V.
I've uploaded a 3 second video clip here:
<>
Time to pull Q280 and put it on the curve tracer I think. 151-1011-00 seems to cross to dual 2N3822 or 2N5565, neither of which seem readily available - any suggestions on a suitable replacement dual FET?
Thanks
Dave ------------------------------------ Yahoo! Groups Links
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Re: Displayed signal becomes compressed when position is moved to the left
Thanks for the suggestion. I have pushed on the connector. It did not help.
Store mode is currently not working. I currently have Q2105 removed.
I am awaiting the arrival of another scope to troubleshoot the storage problem. This could be related.
If I inject a signal at the emitter of Q2105 I can see the signal on the display and it does not compress. But I have not been able to verify the signal path from the Ch 1 and 2 inputs in store mode.
In non Store the compression occurs on both channels A and B time bases.
It is like the H position is off 1/2 a graticule to the right and the trace is retracing. Like on a TV. Is there H Postion Adjustment?
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--- In TekScopes@..., "johncharlesgord" <johngord@...> wrote:
David,
Is the display also distorted in store mode? If so, it might be a loose connection to one of the horizontal deflection pins of the CRT.
--John Gord
--- In TekScopes@..., "david_s5y" <david_s5@> wrote:
Hi,
On a tek 2230 in non-store mode, the displayed signal becomes compressed when position is moved to the left.
So if I have a 5K square wave displayed at .1 Ms the first 1/2 of the wave will be 60% the width if I move it to the right. It also looks like brighter.
+==+==+==+==+==+==+==+==+==+==+
---___---___--- <moved to right>
+--- Short and brighter.
V
==___---___---
What needs adjusting
|
Re: Tek W Plugin 7000 & up serial.
Jerry,
A scan would be much appreciated. Thanks for taking the time to do this!
Aaron
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--- In TekScopes@..., "technite2001" <precisioncarb@...> wrote:
Greetings to the group.
I found a copy a later W manual with the FET mod. If there is a need I will scan and post it online. Its listed in the change section and is 13 pages (schematic and pictures).
Let me know.
Regards,
Jerry
W2JI
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Re: TAS485 quirks and known issues
Thanks for the info.
From message ?#2894, which is a little history of Tektronix scopes, I found out that the TAS4xx series were made in Beaverton. Already figured out that they were the last tektronix analogue scopes from the mfg date stamped around various places: march 1993.
Here is a link to the tektronix web site??. This link convinced me to get the scope.
All in all is a nice little scope. The only thing that might be deemed as cheap is the fact that the case was the same used in the TDS scopes of the time, therefore is not balanced well (CRT on the side) and has a lot of free space (you could fit another scope in there).
If you would like to see a TAS485 in Europe, just drop me an email, I live in Europe too.
From: magnustoelle
To: TekScopes@...
Sent: Tuesday, January 24, 2012 1:07 PM
Subject: [TekScopes] Re: TAS485 quirks and known issues
?
Good Day, Gala,
I am glad to hear that you are enjoying your TAS485.
You might want to read over these messages, too: #3163 and #2894.
I once had the "pleasure" to have a TAS250 on my bench many moons ago and that unit was simply just not up to the Tektronix standard. It even looked very cheaply made. It had partially unreliable pots and front button switches. Above message 2894 explained to me, why.
I have never ever seen any TAS455/465/475 or TAS485 over here in Europe to be honest...
Cheers,
Magnus
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Re: 7T11 trace shifting left as time/div rotated.
Hi David,
The half period oscillation is normal.
I would first test Q280 before bothering about a replacement type. They should be matched at Id about 1 mA each and Vds about 15 V.
Is there any need for a curve tracer? In the absence of triggering you can measure DC levels all around, drain of Q280B (should be 15 V mine 0.7 V), common source a few volts positive, difference between gates (2.2 V?). You can even probe these points during operation; a 10x probe won't disturb the results.
Maybe there is another same type dual fet in the 7T11 that can temporarily be used/exchanged?
Albert
toggle quoted message
Show quoted text
Yes, a slight inbalance I could understand - but +2.2V is a LOT.
Yes you can see the ramp very nicely at 100nS/div. But regardless of the sweep speed there's a very clear problem here. As the ramp stop voltage increases (more negative), the ramp start voltage moves from close to 0V until it reaches about +2.2V when the stabilised stop voltage (after the overshoot) gets to about 4V.
I've uploaded a 3 second video clip here: <>
Time to pull Q280 and put it on the curve tracer I think. 151-1011-00 seems to cross to dual 2N3822 or 2N5565, neither of which seem readily available - any suggestions on a suitable replacement dual FET?
Thanks
Dave
|
Re: 7T11 trace shifting left as time/div rotated.
Yes, a slight inbalance I could understand - but +2.2V is a LOT.
Yes you can see the ramp very nicely at 100nS/div. But regardless of the sweep speed there's a very clear problem here. As the ramp stop voltage increases (more negative), the ramp start voltage moves from close to 0V until it reaches about +2.2V when the stabilised stop voltage (after the overshoot) gets to about 4V.
I've uploaded a 3 second video clip here: <>
Time to pull Q280 and put it on the curve tracer I think. 151-1011-00 seems to cross to dual 2N3822 or 2N5565, neither of which seem readily available - any suggestions on a suitable replacement dual FET?
Thanks
Dave
toggle quoted message
Show quoted text
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Albert
Sent: 23 January 2012 22:24
To: TekScopes@...
Subject: [TekScopes] Re: 7T11 trace shifting left as time/div rotated.
Hi David,
At the 50 ns range, the slope of the TTH output is 5 V/ 50 ns. You have to set your viewing speed to 10 or 20 ns/div to see this nicely. At 5 us/div all you see is the stabilizing "DC" TTH output after the stop signal was received. Also the horizontal amplifier needs (long) time to stabilize. Just after the hor. output has been sampled, the TTH returns to zero.
In the wait state Q294 conducts and ideally forms a shortcut. Then all depends on how good Q280A and B are balanced. The output at TP286 will differ from zero by the same amount as the "offset" A vs B. A slight difference from 0 V is no problem at all, can be corrected further on by some zero-adj. A large difference could be due to a damaged Q280. A not ideal Q294 would give negative TTH output, not positive.
Albert
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Re: TAS485 quirks and known issues
Good Day, Gala,
I am glad to hear that you are enjoying your TAS485.
You might want to read over these messages, too: #3163 and #2894.
I once had the "pleasure" to have a TAS250 on my bench many moons ago and that unit was simply just not up to the Tektronix standard. It even looked very cheaply made. It had partially unreliable pots and front button switches. Above message 2894 explained to me, why.
I have never ever seen any TAS455/465/475 or TAS485 over here in Europe to be honest...
Cheers,
Magnus
|
Re: 2465B no trace (final ¡ì6)
Yes, it was the hybrid 155-0242-01.
Fastened to its place and everything OK.
A special thanks to Joe Mc Elvenney, G3LLV, who gave me one of those rare specimens!
I just had to re-adjust the bias grid, and will check it again according to the service manual.
I'm just wondering what can be the meaning of "A1 -0.8V ?" displayed on top left of the screen... Have to check in the manual, unless someone knows it...
Many thanks to this community
Regards,
Jose Viana CT1DGN.
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--- In TekScopes@..., "viagioz" <viagioz@...> wrote:
Yesterday envening I've been re-checking VZ OUT and VQ OUT arround DC RESTORER.
The signals in the photos I published are reversed but I updated them.
Signal VQ OUT(waveform 66) is the one which is OK. By setting INTENSITY and
READOUT to mid point and HOLDOFF as well, I can get the same waveform (66) as in
the service manual.
In DC RESTORER, signal 72 is very similar to the manual, except the clamping
levels which depend from VZ OUT.
Signal 65, issued from U950 seems to be really dead:
- Isolating U950 output by dessoldering R1913 and R1920 (in DC RESTORER), VZ OUT
is about 5V not changing with INTENSITY.
- I did not load VZ OUT comming from U950, but I think it is not a current
source (it should vary between +8 and 73V according to Figure 3-9).
- Connecting VZ OUT and VQ OUT with 4K7 resistor, the trace appears and varies
with INTENSITY.
- My last check before removing U950 will be CR987, that supplies U950 thru pins
27 and 28. Anyway, VQ OUT works and supply is the same therefore it may be ok...
Now... is it worth to X-RAY it? Can be the ceramic pad removed from the heatsink
or is it fixed with resin?
I never saw one... yet, but in some manufacturer hybrids the circuitry,
including silicon chips and bounding is visible (Hi-Fi STK power out hybrids). I
gess it is not the case...
It is still a mistery how did it fail during a measurement... and the scope was
in function for few minutes, not really hot...
Regards,
Jose
CT1DGN
--- In TekScopes@..., "Tom Miller" <tmiller@> wrote:
The readout should be set to off, the midpoint, for those two displays. Not sure what effect that will have.
Tom
----- Original Message -----
From: viagioz
To: TekScopes@...
Sent: Wednesday, December 14, 2011 5:26 AM
Subject: [TekScopes] Re: 2465B no trace (cont.¡ì4)
Hi Tom,
Yes, I uploaded 2 photos. They are visible in:
Album: 2465B no trace
Description: Z channel waveforms 65 and 66
(Readout knob is fully counterclockwise, Intensity fully clockwise)
Thanks!
--- In TekScopes@..., "Tom Miller" <tmiller@> wrote:
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Re: TAS485 quirks and known issues
So I guess this thing is bullet proof, since no one knows about any quirks or issues.
Well the scope is working fine, aside from needing calibration. It is amazing to see the technological progress in this scope, I also own a Tek 465 and a Tek 475.?
From: Gala Dragos
To: TekScopes
Sent: Monday, January 23, 2012 2:32 PM
Subject: [TekScopes] TAS485 quirks and known issues
?
I have recently?acquired?a TAS485 and I was wondering if anyone knows what are the usual quirks or known issues with this series of scopes.
Is there a blue shield for this series of scopes, because I like blue.
Thanks.
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Re: Need Manual for Type W, SN 4560 & 5336
Hi to Both and Others,
I hope Jerry will made the scans of the Mod Ducument. Nevertheless in the search for the right Manual see below:
The first one:070-432 or 070-0432-00
Type W (SN 100-6999) : 070-0432-01
Type W (SN 7000 and up): 070-1109-00
Egge Siert
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David Hess
David C. Partridge