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Re: 2445 EPROMs
Unless his posts have gone missing, there should be a record of previous posts on the subject by any number of people.? From what I understand, in the conversion, there are parts left out, so while the scope reports a higher bandwidth, certain compensation networks are not included, so the resultant response is not the same from the "upgrade" to the proper model.? Further than that I will not say, but there were other issues with the transaction.
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Harvey On 4/21/2022 10:27 PM, Bob Headrick wrote:
I do not think Chuck is back - message #163375 was years ago. I see him occasionally in the HP/Agilent group. IMHO it was a great loss for this group. |
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Re: Dogbone Capacitors
I have seen them in stuff as early as early 1930s, never found a bad one, effectively ceramic with silver on either side of the tube. dif temp coefs.....dawgbone
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¸é±ð²Ô¨¦±ð On 4/21/22 5:42 PM, Jeff Dutky wrote:
Were the tubular "dogbone" capacitors unique to Tek, or were they a commonly available third-party component in the 60s and 70s? Does anybody have any information on how these were made? Was there a "correct" jargon for them? |
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Re: Dogbone Capacitors
Jeff Dutky wrote on 4/21/2022 8:42 PM:
Were the tubular "dogbone" capacitors unique to Tek, or were they a commonly available third-party component in the 60s and 70s? Does anybody have any information on how these were made? Was there a "correct" jargon for them?Hello, Jeff-- IIRC,? tubular ceramic capacitors were (or are available as NOS) for many years-- at least into? the late 1930s. The process begins with formulating the ceramic dielectric mixture that gets extruded into tubular bodies which undergo firing. Next, a silver solution gets applied to the inside and outside of the tubular ceramic body.? The capacitor undergoes another heating cycle, which converts the silver solution to internal and external metallized electrodes, leaving clearance to solder wire leads to the exposed silver on the body's ends.? A varnish, paint or resin coating protects the outside electrode and provides a surface for marking capacitance. Breakdown voltage is dependent on the ceramic tube's wall thickness, and capacitance and temperature ?coefficient are determined by the ceramic mix. In jargon, they're indeed called "dogbone" (or "dawgbone") capacitors for their shape. I'm looking through my batch of tubular caps and finding a 1000 mmf N750F "Ceramicon" dogbone made by Erie that's? 2 inches long by 1/4 inch diameter. A DE-5000 LCR meter reads 1016 pF at 100? KHz; I'll? guess that it's a 500 volt part. On the other extreme, there's a dogbone cap that measures 1/4 inch long by 1/8 inch diameter which reads 12.6 pF at 100? KHz; it's marked with colored dots which denote 13 pF; based on size, I'll guess it's rated for 100 volt maximum. I don't recall ever replacing a dogbone cap in any equipment although ?I've seen them used in European-manufactured tube radios of the 1950s. Failure modes might include silver migration due to a combination of a flawed external coating, high ambient humidity and applied DC voltage. 73-- Brad AA1IP -- Sent from Postbox <> |
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Re: Dogbone Capacitors
The parts I remember seeing in surplus in the late 1950's, so even older, was a hollow ceramic tube, with a wire at each end of the tube, wrapped around the tube for a couple of turns before the part was painted and color code dots added. I assume one plate of the cap was plated on the outside of the ceramic tube and the other pale, on the inside of the tube.
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John KK6IL On 4/21/2022 5:42 PM, Jeff Dutky wrote:
Were the tubular "dogbone" capacitors unique to Tek, or were they a commonly available third-party component in the 60s and 70s? Does anybody have any information on how these were made? Was there a "correct" jargon for them? |
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Re: Dogbone Capacitors
Fairly common. I have seen them in Collins 51J receivers and in my RCA AR-88 receiver. They are ceramic caps often temperature compensating type. I am drawing a blank on the name of the well known maker of capacitors who made them. I don't know the history or the mechanical construction. They are high quality caps which seldom fail. You are probably aware that the characteristics of "low K" ceramic and "high K" ceramics are quite different. Low K, AKA NPO or CG0 are very reliable and do not change with age while Hi-K ceramics do age and have some undesirable characteristics like high dielectric storage and variation of capacitance with voltage and temperature. The Lo-K type are made in various grades of temperature characteristic for compensation. I just tried to find the name of the company who made a lot of these things but could not. Some ceramics were made in the dog-bone style and some as ceramic or bakelite case axial types.
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On 4/21/2022 5:42 PM, Jeff Dutky wrote:
Were the tubular "dogbone" capacitors unique to Tek, or were they a commonly available third-party component in the 60s and 70s? Does anybody have any information on how these were made? Was there a "correct" jargon for them? --
Richard Knoppow dickburk@... WB6KBL |
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Re: Need Help With Tek 453 Weird Problem
On Tue, Apr 5, 2022 at 07:18 AM, diyguitarist wrote:
I did notice that if I put the HorizontalAfter latest fixes is above behavior still there? When the switch is in between nothing is connected to horizontal amplifier. If you are seeing a dot in when switch is in between the issue is before horizontal amplifier. EXT HORIZ amplifier (sheet <10>) only has +12V and -12V supplies. -12V transformer is shared with the HV oscillator, HV oscillator might be coupling. I see that you already checked but you may want to double check the ripple on all the supplies, especially +75V, +12V and -12V, with a scope in AC coupled mode. Note that ripple spec is 2mVpp. C937 on sheet <16>, C1142 and C1151 on sheet <13> could be bad if there is ripple on -12V. Other possibility is sharing noisy equipment on the same power strip, check the scope in another room in another power outlet. Ozan |
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Re: Need Help With Tek 453 Weird Problem
I checked one of my 453s that is above 20,000. The TP voltages in the schematic are right. Check the transistors and diodes in that area. The 3,3mfd condenser could be bad. I have had ones with high ESR I replaced with Nichicon ULD type. R473, R674 and R483 I raised to 1 and 2W respectively. Yours could be high in resistance. The originals are 1/2W carbons. The tunnel diode will be good if you can get a signal to trigger.
The trace problems you describe sound like the astig and geometry(?) need adjusting. Mark |
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Re: Dogbone Capacitors
I have seen them in HP gear too, and I've mainly seen them referred to as 'dogbone' capacitors when referred to specifically.
Unless you specifically want them for an original appearance in a restoration, I suspect that modern MLCC capacitors are generally going to be far better performance-wise. Jared. |
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Re: Need Help With Tek 453 Weird Problem
UPDATE: I have looked at basically every circuit in the scope at this point. I have suspected that maybe there is an oscillation problem somewhere and even made a "snooping loop" as described in this Tektronix document but haven't found anything conclusive (I think).
So I can not find anything wrong other than two test points that seem to be backwards from the schematic. They are in the A Trigger Generator, test points TP485 & TP494. Having all of the scope controls set per Page 1 of the manual schematics, TP485 should be +12.5V and measures -0.32V & TP494 should be -0.98V and it measures +11.42V. These are almost exactly opposite of the schematic. Is there is a mistake on the schematic or do I have a legitimate problem here? This strange problem does definitely seem to be somehow related to the sweep, so I imagine it's more likely I have problem than the schematic being wrong. Interestingly, the snooping loop detects some activity in this same area and nowhere else except for the Z Axis PCB, where there is an oscillator for the CRT HV supply. However, if the problem is with A Trigger circuit, and if A & B sweep is grounded in Ext Horiz mode, then how can I possibly be getting this fuzzy halo around the waveform in X-Y mode? This is what confuses me. Additionally, I did notice one other interesting thing: Although I cannot get just a dot in Ext Horiz mode (I get a dot with an 1/8" line extending horizontally in both directions, about 1/4" total), I can get a beautifully round one in A & B sweep modes using the Norm Trigger setting with no input, if I turn the intensity up enough and move the dot into view with the Horizontal Position control. Not sure what I should looking at here... I'm used to working with positive only voltages and a ground. Any suggestions? |
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Re: 2432 calibration battery?
I have always had a good experience with Alex. I don't see how anyone could "fake" a 2465 Oscilloscope. The hardware is so unique.
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Yes, there are ways to enable additional Bandwidth for some models, Tektronix built them that way. I don't see that as a problem, the capability is already there, nothing needs to be "faked". Just my opinion, of course. Ross -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Jim Ford Sent: Thursday, April 21, 2022 1:09 PM To: [email protected] Subject: Re: [TekScopes] 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 -------- 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: 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 |
Bob Headrick
Jared Cabot
diyguitarist