Thomas,
Snapdiode is usually pretty tolerant. I would bet that he was
commenting on the spelling, and then only tongue-in-cheek.
Part of surviving on these groups is learning that most folks
don't mean offense when they say the things they do. And, that
a whole lot of conversational clues don't make it through the
channel in a text only mode.
Please keep doing what you are doing. You are fine.
-Chuck Harris
Thomas Garson wrote:
toggle quoted message
Show quoted text
This came directly to me from snapdiode, whoever that is.
I was under the impression that my posts were directed to a group dedicated to the
use and maintenance of Tektronix equipment.
If that is the case, this is a pretty rude message from someone who probably should
know better.
If the inclusion of humor in posts is excluded from that group, I will remember to
avoid its use. I wouldn't want to offend someone I was helping by every word not
being curt and dead serious.
If its about my inadvertent misspelling of Tektronix, get a life! There are much more
diplomatic, and to the point, ways to point out grammatical errors than rude emails
with vague innuendo.
If my posts are somehow not going to the Tektronix group, I apologize and ask that I
be informed of that, and perhaps provided with more useful commentary on how I might
make the needed correction.
Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the? dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.
On 9/23/20 9:43 AM, snapdiode via groups.io wrote:
"Apparently even Tektronics was not above a well executed kludge."
Please stop this. Bad enough in ebay listings, but here?
|
We get Fed Ex International flat rate boxes, 10 and 25 kg, come in packs of 10, sometimes available at Fed Ex stations.
Very sturdy double walled, and special rate if used for Fed Ex international shipment
In general a double or triple wall carton is much better than single walls.
Beware carrier insurance payment for loss or damage requires proof of the value, and cannot exceed the Customs Declared values
Jon
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Don't bet on the shipper doing a good packing job. I watched a UPS Store employee do a pack job on a an antique porcelain vase: Packed it in a poly bag. OK, that's good. He then placed it in the center of a box that was big enough to hold about 6 of them, fill the box to the brim with foam peanuts and tape it shut. He did not even compress the peanuts. It's also very difficult to get to watch them pack YOUR item.
In some areas, there are independent packing specialists who will pack your shipment, taking full responsibility for safe and intact delivery. However, they charge quite a bit, so much that it often isn't worth doing. Perhaps over the "pond" Pack & Send provides such service.
Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.
toggle quoted message
Show quoted text
On 9/23/20 12:23 PM, greenboxmaven via groups.io wrote: I am well aware that things do go wrong. However, if Fedex or UPS pack the item, they have some incentive to do it well.
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I purchase cardboard boxes from a local supplier that specializes in paper products and shipping supplies. There is usually one or more such companies in any moderately metropolitan area. For reference, here in all of south western Oregon, regional population is a well under 200,000. Often these companies also carry janitorial supplies and deliver.
The cardboard boxes I use by choice are designated for heavy items. For some items shipped overseas, I use double wall. I completely line them with 1.5 to 2" polystyrene foam (because it's softer than the rigid sheets) cut from 4x8 sheets of residential insulation (from Home Depot). Faces, with any type of display and/or knobs get spacers to minimize the possibility of their damage from that side of the package getting mashed. After protecting the face, I literally roll the unit up in three layers (sometimes more if necessary) of 24" bubble wrap, which I purchase in a roll that's about 4 to 5 feet in diameter from the same place I get boxes. I use lots of Duck brand clear packing tape in the wrapping process in order to turn the bubble wrapped item into a modern plastic mummy. I use enough bubble wrap to make sure the mummy fits snugly into the foam lined box.
I do charge for this. I don't make a profit on packing, but I want my time (at dock labor rates, not bench rates) and expenses covered. This is made clear up front.
I have successfully shipped expensive collector grade professional and home audio equipment, some with vacuum tubes, to SE Asia, Australia, Europe and the UK as well as around the US and Canada. I have also shipped to S. America, which I no longer do because the buyers I have encountered are a PITA and the customs personnel in many countries there are completely untrustworthy.
If the equipment I am shipping has vacuum tubes, I will either remove them and individually wrap each and place them inside a small box that is included within the main box, or I will custom build a unit enclosing inner cardboard box and line it with shaped soft foam that holds all tubes snugly in their sockets. I recently did that for a pair of 5 (five!) channel 56 year old recording mixers that have a street value of about $5000.00 each. I did add 1/4" plywood sheet to the inside of the cardboard walls for that package. One shipment packed thusly, in 20+ years of doing shipping, had contents so damaged as to render it junk. The fork lift tine hole in the side of the box that a flashlight could clearly show penetration of more than half way trough the steel chassis packed inside was evidence enough for the insurance adjuster to authorize a full value claim. Some times it doesn't matter how well you pack something. If the baggage handler pushes your box out of the bay door of a 747 without having a conveyor or stairs in place, it probably wont matter how well you packed it.
Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.
toggle quoted message
Show quoted text
On 9/23/20 11:12 AM, Dave Seiter wrote: My favorite is polyethylene foam planking,..........
|
This came directly to me from snapdiode, whoever that is.
I was under the impression that my posts were directed to a group dedicated to the use and maintenance of Tektronix equipment.
If that is the case, this is a pretty rude message from someone who probably should know better.
If the inclusion of humor in posts is excluded from that group, I will remember to avoid its use. I wouldn't want to offend someone I was helping by every word not being curt and dead serious.
If its about my inadvertent misspelling of Tektronix, get a life! There are much more diplomatic, and to the point, ways to point out grammatical errors than rude emails with vague innuendo.
If my posts are somehow not going to the Tektronix group, I apologize and ask that I be informed of that, and perhaps provided with more useful commentary on how I might make the needed correction.
Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.
toggle quoted message
Show quoted text
On 9/23/20 9:43 AM, snapdiode via groups.io wrote: "Apparently even Tektronics was not above a well executed kludge."
Please stop this. Bad enough in ebay listings, but here?
|
Dave,
Those electrolytics are defective. They have been running hot. Time to replace them. I hope that this helps!
GOD Bless and Thanks,
rich!
toggle quoted message
Show quoted text
On 9/23/2020 9:39 PM, Dave Casey wrote: I spoke so highly of my 571 last month. When I recently went to use it, I
was getting some artifacts in the display so I have set out to investigate.
Unfortunately you can tell this wasn't designed in Beaverton because you
have to remove the CRT to get the main board out. There are some large
Roedenstein electrolytics used for supply smoothing that have a bit of a
dome to the end of them. Not sure if these were flat when new, but they
don't appear to be leaky (neither physically nor electrically). There is
significant noise (100-200mVpp) on the supplies, but it's not line ripple.
It appears to be around 2 MHz and is two similarly disruptive pulses around
200ns out of phase.
In the process of disassembly, I have pulled and saved the three EPROM
images. Two run the 8032 controller, and one runs the NS405 "terminal on a
chip" that is used to draw the display and printer output.
I haven't exhaustively perused the images, but the graphics ROM has some
ASCII easter eggs I noticed. After the usual Tektronix copyright statement
is "Written by: Folkert ten Brummelhuis (started). Sjoerd J. Punter" and
soon after "[Makke yn Frysl?n]" which is Frisian for "Made in Friesland",
the province in which Heerenveen is situated. Later in the ROM the phrase
"Joke Mirjam Esther" appears twice, about (but not exactly) 64 bytes apart.
I believe these are three given names commonly used in the region, perhaps
the names of those endeared to one or both programmers.
Dave Casey
On Fri, Aug 21, 2020 at 1:31 PM Dave Casey via groups.io <polara413=
[email protected]> wrote:
I stand corrected; can confirm, my S/N also starts with H. Thanks!
Dave Casey
On Fri, Aug 21, 2020 at 5:12 AM zenith5106 <hahi@...> wrote:
On Fri, Aug 21, 2020 at 05:49 AM, Dave Casey wrote:
Built by Sony-Tektronix.
No,not Sony-Tek. It was built by Tek Netherlands (SN begin with H) and as
far as I remember it was also designed by them.
/H?kan
|
I spoke so highly of my 571 last month. When I recently went to use it, I was getting some artifacts in the display so I have set out to investigate. Unfortunately you can tell this wasn't designed in Beaverton because you have to remove the CRT to get the main board out. There are some large Roedenstein electrolytics used for supply smoothing that have a bit of a dome to the end of them. Not sure if these were flat when new, but they don't appear to be leaky (neither physically nor electrically). There is significant noise (100-200mVpp) on the supplies, but it's not line ripple. It appears to be around 2 MHz and is two similarly disruptive pulses around 200ns out of phase. In the process of disassembly, I have pulled and saved the three EPROM images. Two run the 8032 controller, and one runs the NS405 "terminal on a chip" that is used to draw the display and printer output. I haven't exhaustively perused the images, but the graphics ROM has some ASCII easter eggs I noticed. After the usual Tektronix copyright statement is "Written by: Folkert ten Brummelhuis (started). Sjoerd J. Punter" and soon after "[Makke yn Frysl?n]" which is Frisian for "Made in Friesland", the province in which Heerenveen is situated. Later in the ROM the phrase "Joke Mirjam Esther" appears twice, about (but not exactly) 64 bytes apart. I believe these are three given names commonly used in the region, perhaps the names of those endeared to one or both programmers. Dave Casey On Fri, Aug 21, 2020 at 1:31 PM Dave Casey via groups.io <polara413= [email protected]> wrote: I stand corrected; can confirm, my S/N also starts with H. Thanks!
Dave Casey
On Fri, Aug 21, 2020 at 5:12 AM zenith5106 <hahi@...> wrote:
On Fri, Aug 21, 2020 at 05:49 AM, Dave Casey wrote:
Built by Sony-Tektronix.
No,not Sony-Tek. It was built by Tek Netherlands (SN begin with H) and as
far as I remember it was also designed by them.
/H?kan
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Re: Looking for calculator keyboard for 7854
These keyboards come up very often on eBay, and they are quite inexpensive Just give it a little time. Gary On Wed, Sep 23, 2020 at 3:35 PM ciclista41 via groups.io <ciclista41= [email protected]> wrote: More than what you're looking for, but it may interest you, anyhow.
-- Gary Robert Bosworth grbosworth@... Tel: 310-317-2247
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Dave,
It is greatly appreciated. I love to drive and the extra money is very helpful since I am living on Social Security Disability.
GOD Bless and Thanks,
rich!
toggle quoted message
Show quoted text
On 9/23/2020 8:47 PM, Dave Seiter wrote: It's like Uber for scopes! If I ever find a 570 and can't retrieve it myself, I'll keep you in mind!
-Dave
On Wednesday, September 23, 2020, 03:32:29 PM PDT, Richard R. Pope <mechanic_2@...> wrote:
Hello all,
And this is why I offer a premium delivery service. Expensive but
the equipment is handled by just me. It will not be dropped, spindled,
nor mutilated and it is kept in a climate controlled environment. I
will pick up anywhere in the lower 48 and deliver to anywhere else in
the lower 48. Please contact off list for details?
GOD Bless Bless and Thanks,
rich!
On 9/23/2020 4:38 PM, John Williams wrote:
Good advice. Having shipped and received literally hundreds of tube scopes, there is always a few things overlooked. One that is ALWAYS overlooked is the crt. The crt in these old scopes is supported in only two places, that is the front panel and the rear socket. The front support is very rigid. The back support however is usually a white plastic ring that may be used to rotate the tube. Sadly this plastic is the kind that eventually hardens. It does not take much force to break it. Even time can cause it to fail. Now when the packed scope gets dropped by the carrier, and it WILL get dropped, the crt is unsupported and will usually break in half at the neck. All carriers use conveyor belts, and a package this size sometimes falls off the conveyor to the concrete floor. I have even seen the UPS driver, when picking up a box clearly marked fragile in 10 places actually THROW the box into his truck. CRTs are getting very hard to find, so if yours gets broken the whole scope may be junk.
I have also received scopes in their original Tektronix shipping box, unopened. There is no way this box could survive shipping conditions today. It always has to be packed inside another box.
I know of no easy answer to this. I have sometimes removed the crt and packed it separately in a proper Tektronix crt box. This is good but increases the cost. I have also received scopes with some packing material around the crt inside the mu-metal shield. As I recall this had limited success. Oh and btw no carrier will insure glass.
Any time you ship it is a crap shoot. All you can do is try to make sure your package can be dropped 6 feet onto concrete and you are ok. Maybe. Good luck.
I
|
It's like Uber for scopes!? If I ever find a 570 and can't retrieve it myself, I'll keep you in mind!
-Dave
toggle quoted message
Show quoted text
On Wednesday, September 23, 2020, 03:32:29 PM PDT, Richard R. Pope <mechanic_2@...> wrote: Hello all, ? ? And this is why I offer a premium delivery service. Expensive but the equipment is handled by just me. It will not be dropped, spindled, nor mutilated and it is kept in a climate controlled environment.? I will pick up anywhere in the lower 48 and deliver to anywhere else in the lower 48. Please contact off list for details? GOD Bless Bless and Thanks, rich! On 9/23/2020 4:38 PM, John Williams wrote: Good advice. Having shipped and received literally hundreds of tube scopes, there is always a few things overlooked. One that is ALWAYS overlooked is the crt. The crt in these old scopes is supported in only two places, that is the front panel and the rear socket. The front support is very rigid.? The back support however is usually a white plastic ring that may be used to rotate the tube. Sadly this plastic is the kind that eventually hardens. It does not take much force to break it. Even time can cause it to fail. Now when the packed scope gets dropped by the carrier, and it WILL get dropped, the crt is unsupported and will usually break in half at the neck. All carriers use conveyor belts, and a package this size sometimes falls off the conveyor to the concrete floor. I have even seen the UPS driver, when picking up a box clearly marked fragile in 10 places actually THROW the box into his truck. CRTs are getting very hard to find, so if yours gets broken the whole scope may be junk.
I have also received scopes in their original Tektronix shipping box, unopened. There is no way this box could survive shipping conditions today. It always has to be packed inside another box.
I know of no easy answer to this. I have sometimes removed the crt and packed it separately in a proper Tektronix crt box. This is good but increases the cost. I have also received scopes with some packing material around the crt inside the mu-metal shield. As I recall this had limited success. Oh and btw no carrier will insure glass.
Any time you ship it is a crap shoot. All you can do is try to make sure your package can be dropped 6 feet onto concrete and you are ok. Maybe. Good luck.
I
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Tektronix 475A B Delayed only triggering with A Trigger Slope
Hi folks! Once again I am stumped and asking for some assistance.
This is another scope I have been refurbishing. The power supply has been fully gone through and has all new filter capacitors and 1 new bridge rectifier. It has been well cared for in regards to being kept indoors, loved and not abused. But the previous owner did not attempt to make repairs and it had 6 or 7 different issues. I traded a fully refurbished 2445A for it (plus front cover and a 475A service manual) since I liked it so much (I have way too many scopes!). Anyways, this is the final issue.
Tektronix 475A, when Horizontal Display - B Delayed is selected only the A Trigger Slope knob allows me to trigger and light the triggered bulb. The B Trigger slope knob was previously showing some changes to the signal. When there was a single bad tunnel diode in the circuit and you turned the B knob to the right the trace would just fold up and disappear. But in regards to actually triggering the signal it has had no effect even after I replaced the bad tunnel diode and corrected that situation.
When B'Dly'd is depressed J2-6 changes from 5v to -8v and I did check transistors in the various horizontal circuits branching from B Dly'd but I was hoping someone can help narrow down what circuit might allow this to happen. I have not checked any components on the A7 Timing board yet since its hard to get to.
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I have large pelican style boxes that I ship my R-389, R-390, R-390A and R-391 in with foam inserts. They cost me $290 each but I¡¯ll sell for 175 each. I have 2 extra keeping 4 for shipping radios. I don¡¯t remember how much they cost empty but when I ship a radio I include a UPS label for the return. I also charge a deposit refundable, in case someone wants to keep the box. The deposit is $175 refundable of course but I forget the empty shipping charge. I think it it is $87
If anyone wants one let me know. They also fit many of the o scopes I never tried the 545 size ones.
America does not need to see the tax returns of a billionaire who became a public servant.
America needs to see the tax returns of public servants who became millionaires while being public servants
" Jaeson Lubell¡±
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On Sep 23, 2020, at 09:43, greenboxmaven via groups.io <ka2ivy@...> wrote: ? Fedex and UPS pack things fairly well, I have not had any damage. It can be pricey, but is usually less then traveling to pick something up. Some people offering equipment demand that you pick it up from them. I have accounts with both Fedex and UPS, that allows me to take care of everything from my end and convince reluctant sellers to take items to the stores. I ask everyone who demands pickup only to reconsider and be willing to take the item to a shipper who will take care of the packing and shipping. Bruce Gentry, KA2IVY On 9/23/20 10:31 AM, Eric wrote: Ups , FedEx. At least in the US. Use heavy card board and at minimum 2 inches of loose padding all round for shock. I have gotten them double boxes before and a 576 even in a wooden crate the trick is limiting movement in the box I double boxed a high end computer it made it safely to California from the east side. But it was not cheap to ship. I have also been successful crating things and shipping them freight. Plywood and padding is wonder for protecting the device. On Wed, Sep 23, 2020, 10:26 AM Adam Beasley <abeasley@...> wrote: Is there a good service to use to ship scopes? The only boxes I have available are from Amazon and they are not very sturdy so I wouldn't trust shipping something heavy and expensive in them. Thanks, Adam
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Thanks Thomas. Excellent work.
Erich downloaded the software files from the internet. They may be newer. There is also some calibration software files running around.
Lastly I see the famous Dallas Semiconductor nonvolatile RAM chip in the photos. Not sure that is one of the models that have an internal battery backup. You might check it out before it looses its mind!
Charlie Conger
713 472 9140
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On Sep 23, 2020, at 12:44 AM, Thomas Garson <tgarson@...> wrote:
?My "new to me" TWD120 arrived today. Thank you Charlie.
As Charlie advised in previous email, it did not pass self test, leaving the front panel LED unmistakably solid red.
However, the repurposed IBM laptop external power supply worked admirably so I dove into it.
After removing a number of screws and a cal sticker, I was presented with a single nice and compact SMD loaded PCB. No out-sourced PWM supplies for Tek. The regulator circuitry occupies a compact "can" in one corner.
As I was working w/o a schematic I had to find supply lines on some chips to check voltages. Voltages were good, but one was a bit noisy. DC to DC portion of supply looked good on (Tek 5000) scope. After sniffing around a bit (figure of speech. It did not smell) I noticed several Motorola T10N05e TO-263 type SMD packages near the supply wall, but outside of it. At first I was puzzled as I could find these parts for sale but no data sheet. Figured out they were N-channel power mosfet. I determined they were used for gates to enable/disable DC power feeding from the supply. Interesting. Squinting trough my trusty Swiss Army Knife magnifier (glass lens!) I noticed serious corrosion on the Source solder connection of one of those FETS (Q104: +8v line), which I theorized may have been the source of the noise I has seen. Reflowed the funky joint. Kicked on the power, waited a minute or so for self test to complete: Bingo! LED now turns Green!
That's as far as I got today. Next thing is I have to pull the software for it off of the floppy discs (fingers crossed) for copying over to the server and then burn a back up disk. After that, get my Win98SE PC set up with SCSI (not too big a deal as I used to do a lot of SCSI stuff) and see if I can actually get the thing to work. At the moment, I'm fairly optimistic this will happen in short order.
A few photos here:
Thomas Garson
Aural Technology, Ashland, OR
By my calculation, the dynamic range of the universe is roughly 679dB,
which is approximately 225 bits, collected at a rate 1.714287514x10^23 sps.
|
Re: Looking for calculator keyboard for 7854
More than what you're looking for, but it may interest you, anyhow.
|
Hello all,
And this is why I offer a premium delivery service. Expensive but the equipment is handled by just me. It will not be dropped, spindled, nor mutilated and it is kept in a climate controlled environment. I will pick up anywhere in the lower 48 and deliver to anywhere else in the lower 48. Please contact off list for details?
GOD Bless Bless and Thanks,
rich!
toggle quoted message
Show quoted text
On 9/23/2020 4:38 PM, John Williams wrote: Good advice. Having shipped and received literally hundreds of tube scopes, there is always a few things overlooked. One that is ALWAYS overlooked is the crt. The crt in these old scopes is supported in only two places, that is the front panel and the rear socket. The front support is very rigid. The back support however is usually a white plastic ring that may be used to rotate the tube. Sadly this plastic is the kind that eventually hardens. It does not take much force to break it. Even time can cause it to fail. Now when the packed scope gets dropped by the carrier, and it WILL get dropped, the crt is unsupported and will usually break in half at the neck. All carriers use conveyor belts, and a package this size sometimes falls off the conveyor to the concrete floor. I have even seen the UPS driver, when picking up a box clearly marked fragile in 10 places actually THROW the box into his truck. CRTs are getting very hard to find, so if yours gets broken the whole scope may be junk.
I have also received scopes in their original Tektronix shipping box, unopened. There is no way this box could survive shipping conditions today. It always has to be packed inside another box.
I know of no easy answer to this. I have sometimes removed the crt and packed it separately in a proper Tektronix crt box. This is good but increases the cost. I have also received scopes with some packing material around the crt inside the mu-metal shield. As I recall this had limited success. Oh and btw no carrier will insure glass.
Any time you ship it is a crap shoot. All you can do is try to make sure your package can be dropped 6 feet onto concrete and you are ok. Maybe. Good luck.
I
|
Re: Front cover for 2225 ?
The cover at $30 is nice but sadly, the shipping to the UK is $65 !!? Way out of my league :-(
My brother claims to be a whizz with a router and claims he can make one out of marine ply.
I've seen his work, and while it will be pretty I suspect it will double the weight of the scope!! ;-)
I've set an Ebay search looking for somat in the UK/EU for the 2213 and 2225 - I may get lucky.
Thanks,
Dave
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Show quoted text
On 23/09/2020 22:14, tekscopegroup@... wrote: There is a seller on ebay that has several 22xx covers at a reasonable price of ~ $30 each, and even sensible shipping that to me in FL shows up as $5.
He specifically states that "it will fit a 2213, and a 2225".
324227818105
.
|
Good advice. Having shipped and received literally hundreds of tube scopes, there is always a few things overlooked. One that is ALWAYS overlooked is the crt. The crt in these old scopes is supported in only two places, that is the front panel and the rear socket. The front support is very rigid. The back support however is usually a white plastic ring that may be used to rotate the tube. Sadly this plastic is the kind that eventually hardens. It does not take much force to break it. Even time can cause it to fail. Now when the packed scope gets dropped by the carrier, and it WILL get dropped, the crt is unsupported and will usually break in half at the neck. All carriers use conveyor belts, and a package this size sometimes falls off the conveyor to the concrete floor. I have even seen the UPS driver, when picking up a box clearly marked fragile in 10 places actually THROW the box into his truck. CRTs are getting very hard to find, so if yours gets broken the whole scope may be junk.
I have also received scopes in their original Tektronix shipping box, unopened. There is no way this box could survive shipping conditions today. It always has to be packed inside another box.
I know of no easy answer to this. I have sometimes removed the crt and packed it separately in a proper Tektronix crt box. This is good but increases the cost. I have also received scopes with some packing material around the crt inside the mu-metal shield. As I recall this had limited success. Oh and btw no carrier will insure glass.
Any time you ship it is a crap shoot. All you can do is try to make sure your package can be dropped 6 feet onto concrete and you are ok. Maybe. Good luck.
I
|
Re: Is my Tek 468 beyond repair?
John,
What is the part number and manufacturer of the oscillator?
Under what condition did you measure the voltage? If open circuit, the oscillator is likely defective or expecting a pullup of some sort, or it could be a remarked marginal oscillator. If in circuit, it still could be a bad FF input. One other thing to check. If the replacement oscillator is not the same make/part number as the old one, that extra forth pin might actually be an output enable, instead of a No Connect pin. That is probably a long shot.
I just looked at some photos I took of my A19 board and see it has a Dale XO-33A oscillator on it. It is not what the manual/schematic shows and this part has different specs than the K1122A oscillator. Looking at the spec, it indicates it can sink 16ma of current to make a low and source .4ma for a 2.4V high. It might be worthwhile to repeat the oscillator output test with the load resistor connected to +5 rather than ground. The oscillator on my board appears to pull a high level down rather than drive a low level up to a TTL level. I assume that would mean the oscillator is actually pulling down the high level on the FF pins, not trying to drive the FF pins up to a high. I had suggested much earlier that you try pulling pin 8 of the oscillator up through a resistor to +5 to see if it improves the clock level. Did you try that? Might try a 1K pull up with the scope monitoring the pin and see if you get a clock with a better TTL signal.
Another long shot to try when you have the FFs and the oscillator out, ohm the trace to ground and +5 (power off) and see if there is any resistance. Should be an open circuit. Proceed to add parts and measure as you install them. Could also measure the resistance of the trace before you remove the old FFs to compare with later. Could be an internal short in one of the FFs, some problem between nearby traces or a cold solder joint on one of the FFs. Are the voltage levels all ok on all the pins of the FFs (with the oscillator removed and/or installed)?
However.... Something is not right here as I would say you (and us) are spending too much time analyzing and speculating on this one problem. If you have a good new oscillator and have good new FFs, the circuit should just be fixed and work as it did 30 years ago. I am sure there are hundreds of these scopes, with this design, still working today. Mine is. I would not spend time designing new circuitry unless you wanted to design a new circuit to try to improve Tek's design. You should not have to design anything unless the parts are defective and cannot be replaced. Just my opinion.
Regards
Tony
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Re: Front cover for 2225 ?
There is a seller on ebay that has several 22xx covers at a reasonable price of ~ $30 each, and even sensible shipping that to me in FL shows up as $5.
He specifically states that "it will fit a 2213, and a 2225".
324227818105
|
I am well aware that things do go wrong. However, if Fedex or UPS pack the item, they have some incentive to do it well. I take my chances, traveling across the country to pick something up is out of the question. I have had excellent results with Pack & Send in the UK, they very successfully packed and sent two very heavy receivers and a few smaller but still hefty Eddystone receivers to me with no damage whatsoever.
Bruce Gentry, KA2IVY
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Show quoted text
On 9/23/20 12:47 PM, Bill Perkins wrote: Here's a page on a fabulous, late 570 I sold into Japan in 2000:
and here's a page detailing the crate I made to get there in one piece:
And, just for fun, a page of pix of the internals:
Bill @ PEARL, Inc.
Fedex and UPS pack things fairly well, I have not had any damage.
It can be pricey, but is usually less then traveling to pick something up.
Some people offering equipment demand that you pick it up from them. I
have accounts with both Fedex and UPS, that allows me to take care of
everything from my end and convince reluctant sellers to take items to
the stores. I ask everyone who demands pickup only to reconsider and be
willing to take the item to a shipper who will take care of the packing
and shipping.
Bruce Gentry, KA2IVY
|
Jean-Paul
Gary Robert Bosworth
Timothy
Raymond Cote
Charlie Conger
John Williams