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Yesterday I made the comments at the bottom about the 2235 vs the 2235A CRT differences.
The CRT's are both 154-0861-xx but one has a longer HV lead that the other.
The 2235 uses the 154-0861-00? (several other common 22xx's used this same -00 CRT)
The 2235A uses the 154-0861-10? (several other late production 22xx's used this same -10 CRT)
I said the -10 CRT from the 2235A had the shorter HV lead, and that was absolutely WRONG.
This morning I took the covers off of a 2235 and a 2235A and measured the HV lead lengths.
The -10 CRT in the 2235A has about a 25mm longer HV lead than the -00 CRT in the 2235.
So the 2235A CRT would fit in the 2235 with no modification, but you would need to lengthen the HV lead to use the 2235 CRT in the 2235A.
I hope this isn't too confusing, and I apologize for giving you bad information.
Old age and ignorance are my only excuses.
tom jobe...
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Show quoted text
On 6/19/2018 6:05 PM, tom jobe wrote: Hi George,
That CRT is not all that rare as it came in many models of the 22xx series.
A few common models that also used it are the 2213A, 2215A as well as your 2235 and the 2236.
You can download free manuals of lower quality for many of the 22xx scopes, to see what part number they used.
The CRT uses a component number such as V9870 and may appear with the A6 parts in the listings, or at the end of the electrical parts listings.
As I remember... the CRT for the 2235A and the 2236A is part number 154-0861-10, which seems close enough, but the HV lead to the CRT is enough shorter that it will not work without an HV extender of some sort. They re-arranged the HV multiplier setup on the mainboard of the 2235A and the 2236A to use a shorter HV lead.
You want a -00 CRT for your 2235.
Other scopes that seem like they should use the same CRT part number are the plain 2213 and 2215, but they are both much different.
There are lots of "parts only" scopes for sale on eBay and elsewhere, and you can often buy one of them for not much money, especially if it is located close enough to you to avoid the shipping charges.
I think Sphere in Canada sells that CRT for about $85 plus shipping when they have them in stock, to give you some idea of it's fair worth in US dollars.
The 2235 is a fine scope, and the easiest to work on of all the Tektronix gear I have ever encountered.
It and its peers (from 2213A to 2236) were made in such large numbers that there is a substantial body of knowledge about it, what it's common old age ailments are, etc, etc.
tom jobe...
On 6/19/2018 9:27 AM, georgeK KB1HFT wrote:
I understand that the Tek2235 wants a 154-0861-00 CRT, which seems to be made of Unobtanium.
Are there any known substitutions?
Are there any _available_ known Substitutions?
Thanks in advance!
73
-georgeK KB1HFT
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I built this easy AC Volt Ammeter setup in less than an hour. This is my design - all praise and criticism goes right to the inventor - here! I wonder now how I ever got on without it. /g/TekScopes/album?id=60374Menahem
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Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
Ron
"Finally, what capacitors do you advise to use on the 24x5B A5 board? I am now repairing my second one and need to make choices for at least the electrolytics. Both boards I have are missing pads from missing electrolyte leakage. I clean the boards and replace the pads. But if I replace the capacitors with electrolytic caps it is certain they will fail one day and it is certain they will further damage the board and my replacement pads are not as robust as the originals. I see one seller of rebuilt A5 boards uses tantalum electrolytics. But tantalums are notorious for failure unless significantly de-rated for voltage. For now I have used electrolytics but have started a plan to change them out for tantalums, derated 2:1 or more. "
I personally do not use tantalums. It scares the crap out of me taht when they fail, they short. And to have to clean up that mess - all the failed components around that tant cap - just makes it very unattractive.
Tants came into this world in the late 1960's with one advantage only - small size. As long as there is the real-estate for a regular Elco, then that's what I install.
This is my opinion only, YMMV.
Specifically on the later A5 SMD's?
Long ago, I installed (once only) Panasonic FC SMD's.
Since then, Panasonic FC or Nichicon HE, regular leaded caps, with their leads bent small and cut, standing upright to fit perfectly on the SMD solder pads.
Works great, and I much prefer the reliability of leaded caps over the SMD caps.
Menahem
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On 6/19/2018 12:27 PM, georgeK KB1HFT wrote: I understand that the Tek2235 wants a 154-0861-00 CRT, which seems to be made of Unobtanium.
Are there any known substitutions?
Are there any _available_ known Substitutions?
Thanks in advance!
73
-georgeK KB1HFT If you want to buy one of these, contact me off list. Thanks, Bert
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Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
On 20 Jun 2018, at 11:26, M Yachad <yachadm@...> wrote: OK, I had a look at Google sheets.
Looks doable initially, but HOW would I upload it and make it accessible for the group, on the Group's Google account, if the group even has a Google account? When I¡¯ve been involved in similar efforts in the past, others who wish to edit the document are given access by the owner. Access to an entire group would be effectively public access, which is perhaps a bad idea. I doubt anyone would damage it maliciously, but the opportunity for accidental blunders would be very high.
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Re: FS: Tektronix scopes on craigslist; North of Boston, MA
Thanks for the kind words, hope that 7844 serves you well.
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Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)
OK, I had a look at Google sheets.
Looks doable initially, but HOW would I upload it and make it accessible for the group, on the Group's Google account, if the group even has a Google account?
Menahem
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Hi Russ,
You probably downloaded more manuals now (as indicated by Dennis) if you hadn't done so already. Note that you need the manual corresponding to your S/N, below or above B250000, though the later manual shows more voltage and waveform details which may or may not be applicable to the earlier version.
The requirements for regulated voltages are always in the first steps of a calibration procedure; same here.
It's difficult to find the proper pages in the pdfs compared to paper manuals. Strange enough the tab "Adjustment Locations 1" in my late manual shows arrows pointing to all LV test points whereas these are missing (except +55 V) in some or all pdfs Fig. 8-19. You might consult Fig. 8-18, pdf page 236 in "tektronix_465_oscilloscope_full_sm.pdf".
Albert
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On Tue, Jun 19, 2018 at 03:51 pm, <musicamex@...> wrote:
The fuse inside
the 465 tests 24.5 V on both sides of the fuse, but i couldnt find a diagram
with test point values.
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Re: ALPS printer for labels, was Tek push-button lettering using pressing iron transfer of laser printed text on non-sticking paper
I thought this sounded like a good idea, until I looked at the price of the obsolete ALPS MD1000, the inks, and the paper. Too hot for my pocket, by a factor of ten. Craig There's a kit out there to make your own dry transfer decals. It gets fairly involved, but I used it to make some labels for a 465 I was restoring. It worked fairly well, but it was such trouble that I tracked down an ALPS printer to make decals.
Making black legends is trivial compared to making replacement white legends. I think the ALPS printer is the only way to do that for mere mortals except for screen printing.
Paul
On Tue, Jun 19, 2018 at 12:39:20PM -0700, thespin@... wrote:
I have an ALPS MD1000 I have dedicated to decals. I might buy some water slide decal paper and try this for the cal button on my 576 curve tracer.
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Hi Russ,
Welcome...
The 24.5V you measure on the internal fuse is actually the unregulated side of the +15V power supply, suggestimg that this very power supply does have juice to work from.
Curiously, it's this +15V supply that powers the FAN circuit.
So, it seems this power supply is a good starting point to start checking.
A lot on the 465 relies on the +15V rail and there are a lot of small tantalum decoupling capacitors spread everywhere in this rail.
They are prone to get shorted, sometimes poorly shorted, when they will heat and become visibly burnt, but sometimes they will go dead shorted and then they don't heat and will trigger the current overload protection of the power supply.
A good way to tell is by measuring the voltage drop across the current sense resistor that makes the over current transistor to conduct and drop the output voltage.
It's usually a resistor of less than 1 Ohm (I don't have the manual of the 465 at hand right now) and it mustn't be dropping more than 0.5V.
Please let us know how were the readings of all the low voltage power supplies.
Regards,
Fabio
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Show quoted text
On Tue, Jun 19, 2018 at 03:51 pm, <musicamex@...> wrote:
Hi, I am a music teacher in Mexico to help keep kids here. I also teach how
to repair and build musicians gear including tube amps. I recently acquired a
Tek 465 donated to the program. There is no screen display and despite the 2
fuses are good and the power switch on light does show power is getting to at
least part of the scope.
I am not in the same league as most on this site. The 465 makes an average
tube amp look like a lightbulb by comparison. I downloaded the 465 manual and
service manual but really would appreciate a little step by step
troubleshooting help. I always suspect electrolytic capacitors over 10 yrs
old and read that the tantalum caps are also unreliable. The boards look like
the New Mexico balloon fest in places, so, where to start? The fuse inside
the 465 tests 24.5 V on both sides of the fuse, but i couldnt find a diagram
with test point values. Also it doesn't appear that the filament in the CRT is
lit and the fan doesn't activate when the power switch is turned on like with
my TEK 468. The 465 looks like it wasn't abused and has an IBM sticker on it.
It looks like one of the filter caps was replaced as it has a blue plastic
cover unlike the adjacent aluminum can caps. I haven't disassembled or
unsoldered ANYTHING yet. I understand that the 465 is one of the holy grail
TEK scopes and i think it might outlast me if I can get it working again.
Would someone please walk me through getting the display to come on? The main
thing we currently use oscilloscopes for is to track a frequency generator
audio signal through a tube amp, looking for a distorted sine wave to help
isolate where the problem(s) are. So highly accurate calibration isn't
necessary if there is a good clean sine wave when connected to the wave gen.
Thank you in advance, Russ
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Hi Russ,
I won't be any help beyond this point since I never owned a 465 or 468.
Do you have a way to measure the AC current drawn on the power line with a Multimeter when you turn power on. If it is zero then the problem is affecting the entire scope and may be relatively easy to find (blown mains fuse, bad on off switch, etc) but if there is some current draw and the CRT filament is not glowing then there would be some current drawn by the rest of the scope and that would suggest either a bad CRT or bad HV going to the CRT.
Dennis Tillman W7PF
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-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
musicamex@...
Sent: Tuesday, June 19, 2018 5:53 PM
To: [email protected]
Subject: Re: [TekScopes] Tek 465 no display
Thank you for your reply, Dennis. Unless this is radically different
from the 468 re initial control settings, I cant get ANYTHING to appear
on the screen..... I think the CRT is not "lighting up". There is no
filament glow in the tube (observed through the slot in the tubes metal
shield), and the beam finder does nothing. Compared to the 468 the CRT
seems to be "off or out of the circuit" ie not getting filament voltage
and or HV.
I looked more into the fan control and it appears to be temp
controlled, so off when the unit is first turned on? Even with the
power on switch "on" and the indicator light showing power on, the fan
still never comes on for say 30 min. I have not tested it longer than
that.
In the download of the manual, i didnt find FIRST TIME USE, but it
seemed pretty similar to my 468 and other Tek operational tutorials.
Russ -- Dennis Tillman W7PF TekScopes Moderator
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On Tue, Jun 19, 2018 at 05:52 pm, <musicamex@...> wrote:
Thank you for your reply, Dennis. Unless this is radically different from the
468 re initial control settings, I cant get ANYTHING to appear on the
screen..... I think the CRT is not "lighting up". There is no filament glow
in the tube (observed through the slot in the tubes metal shield), and the
beam finder does nothing. Compared to the 468 the CRT seems to be "off or out
of the circuit" ie not getting filament voltage and or HV.
I looked more into the fan control and it appears to be temp controlled, so
off when the unit is first turned on? Even with the power on switch "on" and
the indicator light showing power on, the fan still never comes on for say 30
min. I have not tested it longer than that.
In the download of the manual, i didnt find FIRST TIME USE, but it seemed
pretty similar to my 468 and other Tek operational tutorials.
Russ
Start with checking the LV test points. Of course after you are sure you have the controls set up correctly. HV relies on the LV being correct.
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I'm calling it close enough. The previous owner had turned every var/cap/resistor available and he may sneak into your lab and turn your too. Lock your doors. /g/TekScopes/photo/59361/3?p=Name,,,20,1,0,0 Hey guys. I have done a lot of work to this 465. I had initially planned on selling it to help me buy some plugins for my 7633. I decided I don't want to sell it and am keeping it. Today I checked its rise time with a pg506 fast rise. Both channel 1 and 2 closely resemble each other and they are not close to right. Before I start trying to calibrate this thing, does it look like there is some type of component issue left to fix? I am thinking since both channels are so alike there is something wrong besides just out of calibration. Raymond Domp Frank Jun 18 #148963
On Mon, Jun 18, 2018 at 05:06 am, lop pol wrote:
Seeing that are both channels are essentially the same just seems weird to me.
The vertical output Amp and some other parts, like parts of the channel switch, are common.
Raymond
You have the proper fast rise generator to perform an adjustment. The risk in my opinion is that you destroy a stuck trimcap or trimpot.
You might first verify DC levels in the output amplifier stages and perhaps symmetry in the push-pull signals. Often some stages are common-base current driven which makes it more difficult to check signals.
Unlike some other manuals the 465 manuals do not tell which part of the curve is affected by each adjustment.
Which version output amplifier is in your 465, discrete or IC? It seems you use the pre-B250000 manual because of what you said about the 10X magnifier. The B250000-up manual clearly mentions the 10X mag. That manual also shows both versions output amplifier.
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One other thing I failed to mention about your situation, is that people will suggest that you use the CRT out of a 465 or 475 in your 2235.
Will this CRT swap work, Yes... Is it a decent substitution, NO!
This CRT swap is a large step backwards in my opinion, and I have done it.
tom jobe...
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Show quoted text
On 6/19/2018 6:05 PM, tom wrote: Hi George,
That CRT is not all that rare as it came in many models of the 22xx series.
A few common models that also used it are the 2213A, 2215A as well as your 2235 and the 2236.
You can download free manuals of lower quality for many of the 22xx scopes, to see what part number they used.
The CRT uses a component number such as V9870 and may appear with the A6 parts in the listings, or at the end of the electrical parts listings.
As I remember... the CRT for the 2235A and the 2236A is part number 154-0861-10, which seems close enough, but the HV lead to the CRT is enough shorter that it will not work without an HV extender of some sort. They re-arranged the HV multiplier setup on the mainboard of the 2235A and the 2236A to use a shorter HV lead.
You want a -00 CRT for your 2235.
Other scopes that seem like they should use the same CRT part number are the plain 2213 and 2215, but they are both much different.
There are lots of "parts only" scopes for sale on eBay and elsewhere, and you can often buy one of them for not much money, especially if it is located close enough to you to avoid the shipping charges.
I think Sphere in Canada sells that CRT for about $85 plus shipping when they have them in stock, to give you some idea of it's fair worth in US dollars.
The 2235 is a fine scope, and the easiest to work on of all the Tektronix gear I have ever encountered.
It and its peers (from 2213A to 2236) were made in such large numbers that there is a substantial body of knowledge about it, what it's common old age ailments are, etc, etc.
tom jobe...
On 6/19/2018 9:27 AM, georgeK KB1HFT wrote:
I understand that the Tek2235 wants a 154-0861-00 CRT, which seems to be made of Unobtanium.
Are there any known substitutions?
Are there any _available_ known Substitutions?
Thanks in advance!
73
-georgeK KB1HFT
|
Hi George,
That CRT is not all that rare as it came in many models of the 22xx series.
A few common models that also used it are the 2213A, 2215A as well as your 2235 and the 2236.
You can download free manuals of lower quality for many of the 22xx scopes, to see what part number they used.
The CRT uses a component number such as V9870 and may appear with the A6 parts in the listings, or at the end of the electrical parts listings.
As I remember... the CRT for the 2235A and the 2236A is part number 154-0861-10, which seems close enough, but the HV lead to the CRT is enough shorter that it will not work without an HV extender of some sort. They re-arranged the HV multiplier setup on the mainboard of the 2235A and the 2236A to use a shorter HV lead.
You want a -00 CRT for your 2235.
Other scopes that seem like they should use the same CRT part number are the plain 2213 and 2215, but they are both much different.
There are lots of "parts only" scopes for sale on eBay and elsewhere, and you can often buy one of them for not much money, especially if it is located close enough to you to avoid the shipping charges.
I think Sphere in Canada sells that CRT for about $85 plus shipping when they have them in stock, to give you some idea of it's fair worth in US dollars.
The 2235 is a fine scope, and the easiest to work on of all the Tektronix gear I have ever encountered.
It and its peers (from 2213A to 2236) were made in such large numbers that there is a substantial body of knowledge about it, what it's common old age ailments are, etc, etc.
tom jobe...
toggle quoted message
Show quoted text
On 6/19/2018 9:27 AM, georgeK KB1HFT wrote: I understand that the Tek2235 wants a 154-0861-00 CRT, which seems to be made of Unobtanium.
Are there any known substitutions?
Are there any _available_ known Substitutions?
Thanks in advance!
73
-georgeK KB1HFT
|
Thank you for your reply, Dennis. Unless this is radically different from the 468 re initial control settings, I cant get ANYTHING to appear on the screen..... I think the CRT is not "lighting up". There is no filament glow in the tube (observed through the slot in the tubes metal shield), and the beam finder does nothing. Compared to the 468 the CRT seems to be "off or out of the circuit" ie not getting filament voltage and or HV.
I looked more into the fan control and it appears to be temp controlled, so off when the unit is first turned on? Even with the power on switch "on" and the indicator light showing power on, the fan still never comes on for say 30 min. I have not tested it longer than that.
In the download of the manual, i didnt find FIRST TIME USE, but it seemed pretty similar to my 468 and other Tek operational tutorials.
Russ
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Hi Russ,
Welcome to the group.
The best way to do this would be for you to download the manual for this scope from this web page
Then read the chapter on "First Time Use". That will explain the purpose of each knob and explain how to set each one for first time use.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
musicamex@...
Sent: Tuesday, June 19, 2018 2:50 PM
To: [email protected]
Subject: [TekScopes] Tek 465 no display
Hi, I am a music teacher in Mexico to help keep kids here. I also
teach how to repair and build musicians gear including tube amps. I
recently acquired a Tek 465 donated to the program. There is no screen
display and despite the 2 fuses are good and the power switch on light
does show power is getting to at least part of the scope.
I am not in the same league as most on this site. The 465 makes an
average tube amp look like a lightbulb by comparison. I downloaded the
465 manual and service manual but really would appreciate a little step
by step troubleshooting help. I always suspect electrolytic capacitors
over 10 yrs old and read that the tantalum caps are also unreliable.
The boards look like the New Mexico balloon fest in places, so, where
to start? The fuse inside the 465 tests 24.5 V on both sides of the
fuse, but i couldnt find a diagram with test point values. Also it
doesn't appear that the filament in the CRT is lit and the fan doesn't
activate when the power switch is turned on like with my TEK 468. The
465 looks like it wasn't abused and has an IBM sticker on it. It looks
like one of the filter caps was replaced as it has a blue plastic cover
unlike the adjacent aluminum can caps. I haven't disassembled or
unsoldered ANYTHING yet. I understand that the 465 is one of the holy
grail TEK scopes and i think it might outlast me if I can get it
working again.
Would someone please walk me through getting the display to come on?
The main thing we currently use oscilloscopes for is to track a
frequency generator audio signal through a tube amp, looking for a
distorted sine wave to help isolate where the problem(s) are. So
highly accurate calibration isn't necessary if there is a good clean
sine wave when connected to the wave gen.
Thank you in advance, Russ -- Dennis Tillman W7PF TekScopes Moderator
|
Hi, I am a music teacher in Mexico to help keep kids here. I also teach how to repair and build musicians gear including tube amps. I recently acquired a Tek 465 donated to the program. There is no screen display and despite the 2 fuses are good and the power switch on light does show power is getting to at least part of the scope.
I am not in the same league as most on this site. The 465 makes an average tube amp look like a lightbulb by comparison. I downloaded the 465 manual and service manual but really would appreciate a little step by step troubleshooting help. I always suspect electrolytic capacitors over 10 yrs old and read that the tantalum caps are also unreliable. The boards look like the New Mexico balloon fest in places, so, where to start? The fuse inside the 465 tests 24.5 V on both sides of the fuse, but i couldnt find a diagram with test point values. Also it doesn't appear that the filament in the CRT is lit and the fan doesn't activate when the power switch is turned on like with my TEK 468. The 465 looks like it wasn't abused and has an IBM sticker on it. It looks like one of the filter caps was replaced as it has a blue plastic cover unlike the adjacent aluminum can caps. I haven't disassembled or unsoldered ANYTHING yet. I understand that the 465 is one of the holy grail TEK scopes and i think it might outlast me if I can get it working again.
Would someone please walk me through getting the display to come on? The main thing we currently use oscilloscopes for is to track a frequency generator audio signal through a tube amp, looking for a distorted sine wave to help isolate where the problem(s) are. So highly accurate calibration isn't necessary if there is a good clean sine wave when connected to the wave gen.
Thank you in advance, Russ
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Re: Upgraded, stub tuned, Tektronix SG-504 leveling head back online for a last run
Hello all:
I am shipping the last new SG 504 heads out tomorrow and there are 2 calibrated units c/w lemo cables left in this batch still available.
$119.50 shipped (postal) paypal.
cheers
Ancel
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Shannon Hill
Fabio Trevisan
Ancel