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Re: S-52 only works with lowered +15 V power supply
Probably to decrease parasitic inductance on the power and ground pins.? Wirebonds make great inductors, and as the edge speeds increased, ground and power bounce became a problem.? V = L*di/dt.? I
By Jim Ford · #168915 ·
Re: S-52 only works with lowered +15 V power supply
74L series of chips should be checked for pin compatibility with anything else.? Not sure why they did that, but that's been a design problem for any number of years when substituting. Also, not all
By Harvey White · #168914 ·
Re: S-52 only works with lowered +15 V power supply
That is true for other 74 series.? Should always check pinout.? Example, 74L,LS,W: 95, 85, 78, 72, 74 and maybe others. Carl Hallberg (W9CJH)
By Carl Hallberg · #168913 ·
Re: S-52 only works with lowered +15 V power supply
While checking the circuit I just discover that SN74L93 and SN74LS93 are NOT pin-to-pin compatible! I was using the "classical" 7493 datasheet from Texas Instruments datasheet and wondering how it
By unclebanjoman · #168912 ·
Re: S-52 only works with lowered +15 V power supply
Work still in progress. Yesterday I put a normal metal film resistor in parallel with the other two (R65/R68). Measured total resistance now is 1,33 ohm. OK. Behavior is almost unchanged. With +15 V
By unclebanjoman · #168911 ·
Re: 7603 HV oscillator doesn¡¯t start up
It isn't that they were selected, the 2N3055 devices at the time were all homotaxial and had low beta compared to more modern versions. Even with this in play some HV circuits were cranky and wouldn't
By ROLYNN PRECHTL K7DFW · #168910 ·
Re: Wikipedia is not an appropriate topic for TekScopes. WAS repair tools: Autotransformers/variacs
I'm against it. We've got the curated (and excellent) Tekwiki. Marketing campaigns don't belong on any of the wikis.
By Roy Thistle · #168909 ·
Re: Tektronix 2230
Hi Bert OK it means in my case t906. Do you have the schematic for 2230 so that we can confirm the transformer. Thanks.
By Saroj Pradhan · #168908 ·
Re: Tektronix 2230
No, I mean the HV supply, the one that runs off the input AC and supplies the +40V. Shorted turns make it draw too much current.
By Bert Haskins · #168907 ·
Re: Tektronix 2230
Hi Bert Thanks for your concern and suggestion. But it operates normally with external power supply (in my case I used 38v dc across tp950 and tp940). Saroj
By Saroj Pradhan · #168906 ·
Re: Wikipedia is not an appropriate topic for TekScopes. WAS repair tools: Autotransformers/variacs
<http://w140.com/tekwiki/wiki/Main_Page> nonIonizing EMF wrote:
By Chuck Harris <cfharris@...> · #168905 ·
Re: Wikipedia is not an appropriate topic for TekScopes. WAS repair tools: Autotransformers/variacs
Would be nice if more Tektronix related information was on Wikipedia. Thinking I can make a Tekwiki wiki on Wikipedia and maybe add on the Tektronix Wikipedia Wiki also. Looks like the following
By nonIonizing EMF · #168904 ·
Re: Tektronix 2230
First, let me say that I have several 223x family scopes and had very few problems with them. I did hav
By Bert Haskins · #168903 ·
Re: Tek 564 on DFW Craigslist for cost + shipping [taken]
Ok, but by who? You? Colin.
By Colin Herbert · #168902 ·
Re: Tek 564 on DFW Craigslist for cost + shipping [taken]
as the subject says, taken.
By Oz-in-DFW · #168901 ·
7603 HV oscillator doesn¡¯t start up
Assembly: CRT Circuit (8) New el. caps. Transistors checked with multimeter (don¡¯t own a working curve tracer until the said 7603 is repaired. So stupid!). Read that TO-3 are factory selected and
By C G <f1gwr@...> · #168900 ·
Re: Tek 564 on DFW Craigslist for cost + shipping
I am interested in the scope. I have a Fedex account, so if you can drop it off at one of their locations I can take care of the shipping costs from my end. I have a specific use for the scope and it
By greenboxmaven · #168899 ·
Tek 564 on DFW Craigslist for cost + shipping
I don't need it, but I figure I'll rescue it later today as I'll be in that neighborhood. He wants $25. You can have it for that plus whatever actual shipping is to you. I'll box it up and weigh it as
By Oz-in-DFW · #168898 ·
Re: 475 questions
Hi Bruce, Don't get discouraged by your initial problems and spectacular fireworks. Do you have phone with an camera? Sometimes the more experienced techs can spot what is wrong from pictures. It
By Ondrej Pavelka · #168897 ·
Re: Tek 603 - question on transistor heatsinking material
Steve, I guess in all the years I have never seen a semiconductor mounted via a conductive pad when connection to the thermal surface is required or desired. Usually the device is directly mounted to
By Greg Muir · #168896 ·