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Re: 2432 calibration battery?
Ross, Alex Schonfeld has a bad reputation for selling fake 2465's.? I don't think many people in this group would have anything to do with him.? Just FYI.Jim FordSent from my T-Mobile 4G LTE Device
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-------- Original message --------From: si_emi_01 <wellington@...> Date: 4/21/22 9:28 AM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] 2432 calibration battery? Yes, it does.It is located on the A12 Processor Board. It is a 3.5V 1.6AH Lithium Thionyl Chloride Battery. The Generic Part Number is: LTC-16P-CO-F-S. The only one I can see on Mouser is the LTC-16M version which they are out of stock until 5/23/2022. The 2465 Series uses a LTC-7P Battery that is 700mAH. The Batteries come in two flavors. One that is just a Battery, the other has a built-in 1.6k Resistor with a Series 1N5817 Schottky Diode (this is to prevent shorting and reverse Charging of the Battery in parallel configurations). The LTC-16P doesn't appear to have that feature.There is a procedure that can be performed that will preserve your RAM contents if the Battery isn't dead and you want to be pro-active. I would imagine it is probably paralleling the SRAM with an external supply greater than the 3.5V limited by a series Resistor while you change the old Battery. Just guessing here, you would have to make sure it is safe.Alex Schonfeld repairs and calibrates Tektronix Oscilloscopes. I had him calibrate my 2465B a few years ago after I replaced the Battery in mine. He does good work. Maybe he can help you.Depending on the Serial Number of your Oscilloscope, some Processor Boards use an integrated NVRAM (Battery Backed-up SRAM). The 2440 Processor uses a Dallas DS1230AB part that includes an SRAM and Back-up Battery in the same package. It can be replaced with later version NVRAM or FRAM chips. I don't know if they did that with the 2432 Oscilloscope. Maybe someone else on the List can provide that information. The TekWiki only one Service Manual on their site and it shows the Battery version.Ross-----Original Message-----From: [email protected] <[email protected]> On Behalf Of Bert HaskinsSent: Thursday, April 21, 2022 9:33 AMTo: TekScopes@...: [TekScopes] 2432 calibration battery?Does this scope have calibration data stored in battery backed ram?I have one of these in absolutely pristine condition that I hardly ever use.Thanks,?? Bert
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Re: Thinking on CRT restorations for double peaking tubes.
Looked up Glyptal. I would suggest the red 1201. I am thinking that is the
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original formulation. On Thu, Apr 21, 2022, 1:15 PM JRN <ir25@...> wrote:
Dave, |
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Re: 2465 Calibration
Also correct. Thanks for pointing that out.
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Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Mark Litwack Sent: Thursday, April 21, 2022 8:01 AM To: [email protected] Subject: Re: [TekScopes] 2465 Calibration Just a minor point of detail... The 2445 and 2465 (not A or B version) scopes don't have a battery. They have a GI ER1400 EAROM which is an early version of EEPROM. The ER1400 datasheet claims 10 year data storage. The EAROM in my 2465 is 38+ years old and hasn't lost anything yet (although I have backed it up). -mark On Wed, Apr 20, 2022 at 07:30 PM, si_emi_01 wrote: ...
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Re: DM501A Input Leakage Source
Hi Roman,
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Just for grins, what happens if you touch the input terminal of the plug-in while in dc volts mode? Don't touch ground the ground terminal at all -- just be an antenna. If the reading rises, try connecting a capacitor (say, some nanofarads) across the input terminals of that plug-in. A small amount of line noise pickup can be aliased down to dc by dual-slope converters. This test will tell you whether that's happening here. Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 4/21/2022 06:24, romeo987 wrote:
Tom, |
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Re: 2432 calibration battery?
Yes, it does.
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It is located on the A12 Processor Board. It is a 3.5V 1.6AH Lithium Thionyl Chloride Battery. The Generic Part Number is: LTC-16P-CO-F-S. The only one I can see on Mouser is the LTC-16M version which they are out of stock until 5/23/2022. The 2465 Series uses a LTC-7P Battery that is 700mAH. The Batteries come in two flavors. One that is just a Battery, the other has a built-in 1.6k Resistor with a Series 1N5817 Schottky Diode (this is to prevent shorting and reverse Charging of the Battery in parallel configurations). The LTC-16P doesn't appear to have that feature. There is a procedure that can be performed that will preserve your RAM contents if the Battery isn't dead and you want to be pro-active. I would imagine it is probably paralleling the SRAM with an external supply greater than the 3.5V limited by a series Resistor while you change the old Battery. Just guessing here, you would have to make sure it is safe. Alex Schonfeld repairs and calibrates Tektronix Oscilloscopes. I had him calibrate my 2465B a few years ago after I replaced the Battery in mine. He does good work. Maybe he can help you. Depending on the Serial Number of your Oscilloscope, some Processor Boards use an integrated NVRAM (Battery Backed-up SRAM). The 2440 Processor uses a Dallas DS1230AB part that includes an SRAM and Back-up Battery in the same package. It can be replaced with later version NVRAM or FRAM chips. I don't know if they did that with the 2432 Oscilloscope. Maybe someone else on the List can provide that information. The TekWiki only one Service Manual on their site and it shows the Battery version. Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Bert Haskins Sent: Thursday, April 21, 2022 9:33 AM To: [email protected] Subject: [TekScopes] 2432 calibration battery? Does this scope have calibration data stored in battery backed ram? I have one of these in absolutely pristine condition that I hardly ever use. Thanks, Bert |
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Re: 2465 Calibration
Just a minor point of detail... The 2445 and 2465 (not A or B version) scopes don't have a battery. They have a GI ER1400 EAROM which is an early version of EEPROM.
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The ER1400 datasheet claims 10 year data storage. The EAROM in my 2465 is 38+ years old and hasn't lost anything yet (although I have backed it up). -mark On Wed, Apr 20, 2022 at 07:30 PM, si_emi_01 wrote:
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Re: DM501A Input Leakage Source
Greg,
Thanks for your response. I realize that this leakage does not affect the utility of the meter one whit. I am just trying to improve what I have, because I can. Academic, of course, but interesting. I am just a retired old bloke who loves to play. Not particularly interested in measuring fA and pV, but only in making my two instances of this meter as good as they can be. And I am intrigued that you appear to be in a lab that has 70¡¯s vintage 501As alongside Fluke 8588s. Says a bit for the longevity of this Tek stuff. I guess that¡¯s why we love to play with it! Just out of curiosity, what sort of offset do you see on yours on 200mV DC range, OC input? Is it always positive? Roman |
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Re: DM501A Input Leakage Source
Tom,
Thanks for your input. I do note that you are very generous with your advice on this board - as are many others. I really appreciate it. In this case, I think your first and third points are well made. As to the second, that is almost certainly true of a normal scope amplifier input, but in this case there are no such devices ¡°left¡± of the A/D chip itself, which I have absolved by test as the cause. Roman |
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Re: DM501A Input Leakage Source
Gudjon,
Thanks for your input. I have seen this, but it doesn¡¯t actually address switch removal :-(. But do those long plastic actuators unclip easily from the switch itself? Looks like it might be a plastic part just itching to be broken unless one does it just right! Roman |
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Re: Thinking on CRT restorations for double peaking tubes.
Thanks for this Dave. I need to roll this around a bit and understand how to hook everything up but it sounds like everything can be done here in the lab. Just need to understand where the grounds go and how all the references work out. To keep heater and cathode near the same potential.
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Zen -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Dave Brown Sent: Thursday, April 21, 2022 1:20 AM To: [email protected] Subject: Re: [TekScopes] Thinking on CRT restorations for double peaking tubes. I am passing this on from an ex-CRT engineer I know at the museum. - Dave 1. Increase the nominal 6.3V heater to 8V at least, possibly 10V if the cathode current is very weak 2. Keep heater and cathode very near the same potential 3. Apply AC voltage to the control grid, up to +6V Max. compared to cathode 4. Set the first anode at +100 to 150V to collect the electrons 5. Limit reactivation time to ~10 minutes; 20 minutes Max. Here¡¯s a 2015 note from Thomas Electronics where they recommend operation with cathode current for 24 hours: Normal CRT operation with cathode current is always good, especially in storage tubes where the flood gun electrons can form an ion pump. Mesh storage CRTs at Tektronix (in the 7613, 7623, etc.) had the best vacuum levels measured. Re: Potential leaks in glass-to-metal seals. Glyptal can be applied to the cracked glass, or before straightening badly bent pins. |
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Re: Thinking on CRT restorations for double peaking tubes.
I am passing this on from an ex-CRT engineer I know at the museum. - Dave
1. Increase the nominal 6.3V heater to 8V at least, possibly 10V if the cathode current is very weak 2. Keep heater and cathode very near the same potential 3. Apply AC voltage to the control grid, up to +6V Max. compared to cathode 4. Set the first anode at +100 to 150V to collect the electrons 5. Limit reactivation time to ~10 minutes; 20 minutes Max. Here¡¯s a 2015 note from Thomas Electronics where they recommend operation with cathode current for 24 hours: Normal CRT operation with cathode current is always good, especially in storage tubes where the flood gun electrons can form an ion pump. Mesh storage CRTs at Tektronix (in the 7613, 7623, etc.) had the best vacuum levels measured. Re: Potential leaks in glass-to-metal seals. Glyptal can be applied to the cracked glass, or before straightening badly bent pins. |
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Re: 2465 Calibration
If you have ever calibrated a 2465 or 2467 series Oscilloscopes, it is best to have the correct equipment because it takes a long time to calibrate one. It is a very manual, time-consuming operation to perform CAL 01 and CAL 02 Steps and they have to be performed all at once.
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Having the correct equipment available (for me anyway), makes it less frustrating and it flows "easier" with the right stuff. That equipment being: 1 Tektronix TM504 or TM506 - to house and power the Calibration Modules 1 Tektronix PG506 - Voltage Generator(200uV to 50V DC or Square Wave), High Amplitude and Fast-Rise Generator 1 Tektronix TG501 - Time Mark Generator (1ns to 5 Second) 1 Tektronix SG503 - 50 kHz Reference & 250kHz to 250MHz Constant Amplitude Generator and RG-223 Cable 1 Tektronix SG504 - 50kHz Reference & 245MHz to 1050MHz Constant Amplitude Generator and Leveling Head Tunnel Diode Pulser, Overload tester, etc. Misc. Cables, Attenuators etc. I would recommend you have the right equipment if you need to calibrate one or many. The Batteries and/or Battery Backed-up SRAM Modules in these are old and you lose calibration parameters when it dies, forcing you to go through the calibration procedure. Just my opinion, of course. Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of jimbert4 via groups.io Sent: Wednesday, April 20, 2022 4:29 PM To: [email protected] Subject: Re: [TekScopes] 2465 Calibration Seems like everyone is overly concerned about the accuracy of the calibration equipment. How accurate can an oscilloscope like this measure periods and voltages? On the horizontal axis there are 50 divisions and you could measure times on it to about double that, so call it 100. That's only 1% accuracy. Most waveform generators, even inexpensive ones are spec'd at less than 20ppm (.002%) frequency accuracy and a few ppm stability. The vertical axis is even less at 40 divisions, so readings to about 80 or 1.25%. The oscilloscope may beat most waveform generators' voltage specs, I'm not sure. Here's a spec from a $200+, 80 MHz waveform generator: Amplitude resolution 1mVpp Amplitude stability ¡À 1% ¡À1 mVpp (@ 1 kHz,>10 mVpp) Amplitude flatness ¡À1%(0.1dB)<10MHz ; ¡À2%(0.2dB)<10MHz~50MHz ¡À10%(0.9dB)<50MHz~70MHz; ¡À20%(1.9dB)<70MHz~80MHz So the amplitude stability is of the same order as the vertical axis, at least at 1 kHz, and flatness gets way worse at the higher frequencies. (I'm not sure what flatness means. Does it refer to the voltage variation across a particular frequency range?) But how accurate do I need to measure a signals amplitude on an oscilloscope anyway? |
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Re: 2465 Calibration
Seems like everyone is overly concerned about the accuracy of the calibration equipment. How accurate can an oscilloscope like this measure periods and voltages? On the horizontal axis there are 50 divisions and you could measure times on it to about double that, so call it 100. That's only 1% accuracy. Most waveform generators, even inexpensive ones are spec'd at less than 20ppm (.002%) frequency accuracy and a few ppm stability. The vertical axis is even less at 40 divisions, so readings to about 80 or 1.25%. The oscilloscope may beat most waveform generators' voltage specs, I'm not sure. Here's a spec from a $200+, 80 MHz waveform generator:
Amplitude resolution 1mVpp Amplitude stability ¡À 1% ¡À1 mVpp (@ 1 kHz,>10 mVpp) Amplitude flatness ¡À1%(0.1dB)<10MHz ; ¡À2%(0.2dB)<10MHz~50MHz ¡À10%(0.9dB)<50MHz~70MHz; ¡À20%(1.9dB)<70MHz~80MHz So the amplitude stability is of the same order as the vertical axis, at least at 1 kHz, and flatness gets way worse at the higher frequencies. (I'm not sure what flatness means. Does it refer to the voltage variation across a particular frequency range?) But how accurate do I need to measure a signals amplitude on an oscilloscope anyway? |
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FS: Four NOS Tektronix tubes in boxes
Tektronix tubes
Four tubes: 154-0016-00, ¡°Tube 7M 6AL5¡± 154-0022-00, ¡°Tube 7M 6AU6¡± 154-0187-00, ¡°Tube 9M ECC88/ 6DJ8¡± 154-0278-00, ¡°Tube 9M 6BL8/ECF80¡± In boxes, as-is, untested. I have ended up with a rather varied collection of tubes, something that I really don't do anything with and within that collection I found the four tubes listed. Boxes are in pretty good shape as you can see from the picture (which it turns out I cannot attach.) Seems like a waste for them not to go to someone that can use them. There are some others of the same types (but not specifically in Tektronix boxes) that I¡¯m glad to include. Make offer plus shipping and insurance. USPS money order. Paypal by arrangement. Located in Everett, WA. 73, Grant KB7WSD |
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Re: 321A 2N2207 transistor replacement: Ge-Si replacement sensitivity in the timebase
As it turns out, all the 6 AF118¡¯s are bad. 2 are completely dead, and the 4 others show a diode across EC.
KSA992 are not available in my area, and I don¡¯t feel like ordering them online. BC556B are available though. Is there anything wrong with using the AF118 I ordered? They were original to my unit after all. Thanks Dave, but ordering 2N4890 from Boca would be quite expensive from Europe. Not a good option. I tried replacing all 6 of them with 2n2907A. After doing so, not only the problem I have did I not disappear, but another one popped up. Sparkles spots are randomly appearing on the trace. They were not present before. Not a good sign. To summarize, the original issue was no ALT whatsoever, and no Delayed Time base. When in regular ALT position, only A is displayed. I can easily go pickup some BC556B¡¯s tomorrow. |
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Re: 321A 2N2207 transistor replacement: Ge-Si replacement sensitivity in the timebase
Thanks for doing the research, Dave! I had not seen a datasheet with a 2.3pF value, but seeing that the ICmax spec is 50mA, I'm pretty sure you're right. The 3906 typically has around that value of Cob, but the breakdown voltage requirements rule out its use.
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--Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA 94305-4070 On 4/20/2022 13:46, Dave Wise wrote:
Thanks for making me work harder, Tom. |
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