Date   
Re: 184 Time Mark Gen. - 2nS & 5nS not working

Tom Gardner
 

Make sure you block any DC, and are very careful about the input power! If the DC block is a large capacitor (e.g. works to  kHz rather than MHz), consider whether any transients might be large.

Overkill? Possibly :)

On 08/04/20 03:17, Merchison Burke via groups.io wrote:
If you have a Spectrum Analyser, could that be used to check to 500 MHz output?


On 2020-04-07 9:22 a.m., david via groups.io wrote:
Thanks for the information guys, looks like I don't have the equipment or the knowledge to fix the 500MHz output. Not going to buy Nuvistors if I won't be able to check the results. My 465 is a 100MHz scope, it  shows 130mVpp signal at 200MHz output, so I believe that signal is OK. This 184 is working correctly except for the 500MHz. Only other issue is the 10MHz oscillator frequency does not have enough adjustment range. It is close enough, checking it with a GPSDO at 10MHz it is 9.999xxx, but it is at the limit of adjustment on C11. Any idea why the oscillator is beyond the range of C11 adjustment? Is it just the age of the crystal? Has anyone tried to reduce value of capacitor C11 by putting another cap in series with it? Only need to lower value of C11 a couple pF to fix it. I am amazed at how accurate this 184 is being all analog.
David


Re: 184 Time Mark Gen. - 2nS & 5nS not working

Melvin Gleep
 

Absolutely.

Gesendet von Mail<https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10

Von: Merchison Burke via groups.io<mailto:merchison=yahoo.co.uk@groups.io>
Gesendet: Mittwoch, 8. April 2020 04:17
An: TekScopes@groups.io<mailto:TekScopes@groups.io>
Betreff: Re: [TekScopes] 184 Time Mark Gen. - 2nS & 5nS not working

If you have a Spectrum Analyser, could that be used to check to 500 MHz
output?


On 2020-04-07 9:22 a.m., david via groups.io wrote:
Thanks for the information guys, looks like I don't have the equipment or the knowledge to fix the 500MHz output. Not going to buy Nuvistors if I won't be able to check the results. My 465 is a 100MHz scope, it shows 130mVpp signal at 200MHz output, so I believe that signal is OK. This 184 is working correctly except for the 500MHz. Only other issue is the 10MHz oscillator frequency does not have enough adjustment range. It is close enough, checking it with a GPSDO at 10MHz it is 9.999xxx, but it is at the limit of adjustment on C11. Any idea why the oscillator is beyond the range of C11 adjustment? Is it just the age of the crystal? Has anyone tried to reduce value of capacitor C11 by putting another cap in series with it? Only need to lower value of C11 a couple pF to fix it. I am amazed at how accurate this 184 is being all analog.
David



--
This email has been checked for viruses by AVG.
https://www.avg.com

Re: 2430A Fails Repet

Szabolcs Szigeti
 

Hi,

Yes, you need to use the Dallas nvram, with built in battery. I
suppose it would be possible to restore the external battery but there
are some components that would need to be populated. However, if you
cannot get a replacement nvram (DO NOT buy anything off eBay or
similar sites, they will most likely be fakes, only buy from reputable
source) it is fairly easy to hack an external battery into the chip.
See my earlier post on this, which is actually about a 2430A with
DS1235A nvram. https://groups.io/g/TekScopes/message/136993

There are methods for other nvram models if you have something else
than a 1235A in your instrument.

Once you replace the battery, you will need to do a full calibration,
as specified by the service manual. Do a cold start, do a self cal and
them an ext cal. For the 2430A it will be a quite simple process, if I
remember correctly you will only need a DC source to provide some
voltage levels to the channel and trigger inputs. Look at the service
manual on the exact process. Do not worry, this will restore the scope
to fully working, you do not need to save the old values, etc. Also,
while you are inside the scope, you may as well do the display
geometry adjustment, my experience is that these are almost always off
in old scopes. And it is fun to do, as the scope will provide test
images to set various display parameters.
But whatever you do, study the adjustment section in the service
manual first. And don't forget to have an external fan cooling the CCD
module if you are running the scope without the case. The SM also
points this out.

Szabolcs

Gary Robert Bosworth <@grbosworth> ezt írta (időpont: 2020.
ápr. 8., Sze, 2:04):


Can anyone give me the complete low-down on the Ram Battery back-up issue. My CMOS battery ran down, and I now get the 4000 Front Panel low battery error message. Do we HAVE TO replace the Dallas Ram chip block? If I have to replace the backup data black block, will the 2430A automatically do a calibration and load the new calibration data into the Dallas chip? My 2430A does not have an external battery, and there is a wire connecting the + and - terminal pads where the battery would go. Does this mean that I MUST use the same type of internal battery Dallas block? I put a 3.7 Volt Lithium backup battery in the place where the jumper was, but it had no effect on the operation of the scope. I can press the Auto Setup button and the scope works perfect, but the next time I power up the scope it gives me the same 4000 FPP error code again.


Re: Tek 576 Curve Tracer HV Replacement Transformer

 

Thank you Michael, Chuck.

Your reasonable explanations assure me that I haven't overseen something.
The resistor seems to be there for good engineering, a reasonable protection that has practically zero cost.

Ernesto

Re: Tek 576 Curve Tracer HV Replacement Transformer

Mlynch001
 

On Tue, Apr 7, 2020 at 09:34 PM, Ernesto wrote:


Michael, Chuck,

Why is a resistor in series with the multiplying ladder necessary? Isn't the
internal helical coating of the CRT a load and a drainage means of the ladder
capacitors?
In the 547 there is a 1 Mohm 1/4 watt resistor after the ladder, followed by a
500pF capacitor to ground.
In the 7704A there is no visible resistor, and the do-it-yourself circuit does
not show one inside the X14 module.

Ernesto
Ernesto,

I do not know the answer to that question. Chuck indicates that it to prevent being killed by a high current- high voltage from an accidental shock. What I do know is that the Tektronix specifications for the 152-0552-00 call for a series resistance of 510k ohms. This is found in the TEKTRONIX Cross Reference manual. The pictures of a DIY multiplier by member Marcus PP5MS can be seen in a series of pictures at this link:

https://groups.io/g/TekScopes/album?id=13113

Marcus - PP5MS 465-475 HV multiplier

His version clearly shows a resistor in series. His looks like 47K Ohm to me. His x ray also shows something in the Anode wire that could be a resistor.

I do not know all the technical reasons for this. But the specification is there, so there must be a good reason for this resistance.

I will defer to the sharper members to explain it to me.

If I build one of these, I want to match the original as closely as possible.

--
Michael Lynch
Dardanelle, AR

Re: Tek 576 Curve Tracer HV Replacement Transformer

Chuck Harris
 

The resistor is there to protect the tripler if the anode
lead is suddenly shorted to ground. It will drag the capacitors
to ground without allowing the current to get high enough to
damage anything... in theory.

However, if the capacitor simply blows up due to the surge
of high voltage/current across the resistor, how does it matter
that the diodes are still good, but the resistor is shattered
into an open circuit condition?

In the 547, that resistor is a 10M 1/4 watt carbon composition
resistor. But the capacitors in the 547 are quite a bit larger
than I believe the 465's tripler's uses.

In the 547's case, I think they were trying to protect the
wayward technician that gets across the live HV. It could
cause a heart arrhythmia in a properly connected person.

-Chuck Harris

Mlynch001 wrote:

On Tue, Apr 7, 2020 at 06:42 PM, Chuck Harris wrote:


I don't have a schematic of the tripler, so I don't know where this
resistor is located.

I suspect that it is in series with the anode lead. That is often done
for safety reasons. They don't want a full discharge of the tripler's
capacitors to stop your heart...

It was probably a carbon composition resistor, and probably 1/4 watt.

-Chuck Harris

Mlynch001 wrote:
I do have a question about the load resistor. I think it is supposed to be
about 470K Ohms? Does this need to be a special resistor or can you use a
1/2W metal film resistor?
Chuck,

There are some pictures in the TEKScope archive. One of our members posted a lot of pictures, including X-Ray pictures of the internal structures. They show the resistor soldered between the last diode in the chain and the end of the anode wire. I don’t have any carbon comp resistors of that resistance rating, but tons of 1/4W metal film and carbon film resistors. Would either those types be acceptable for this application? I can probably find some carbon comp resistors if absolutely necessary.

Re: 2445A slow

Chuck Harris
 

Just like that. It fits just fine.

The backup battery should last about 30 years. The life
is shortened if the scope is stored in a very hot environment.

-Chuck Harris

Steve wrote:


LOL, so you're saying just put a 100uf 25v radial and solder it to the legs in it's proper polarized pattern? If so cool! Also I checked the voltage of the backup battery while I had the A5 board out and it was teetering between 3.6/7 so I didn't bother ordering one from Mouser.

Re: Tek 576 Curve Tracer HV Replacement Transformer

Tom Bowers
 

Ernesto,

Why is a resistor in series with the multiplying ladder necessary?
I have un-potted the X14 multiplier from a 7904 and there is a 10 Meg Ohm
1/2 W Carbon resistor on the output high voltage lead, connected to the
last diode in the ladder.

The reason I had to un-pot one was to design a replacement, as I had blown
it up by discharging it. If there is even the slighted difference in the
value of the capacitors, a sudden discharge applies unequal voltages to the
diodes and at some point a diode gets destroyed. When doing this, the full
21KV is applied across the 10 Meg resistor.

Carbon is important because it is more forgiving to such a voltage
overload. A metal film resistor is not as forgiving. A 1/2 W resistor has a
higher voltage overload capability than a 1/4 W resistor. In the
replacement that I am building, I intend to put three 3.3 Meg 1/2 W carbon
resistors in series on the output lead.

To anyone who knows where X Ray images might be located, I would certainly
appreciate a clue so I could look at them. Also, I can share pictures of
the one I un-potted. Not pretty, but maybe somewhat useful.

Tom Bowers

On Tue, Apr 7, 2020 at 8:34 PM Ernesto <ebordon@...> wrote:

Michael, Chuck,

Why is a resistor in series with the multiplying ladder necessary? Isn't
the internal helical coating of the CRT a load and a drainage means of the
ladder capacitors?
In the 547 there is a 1 Mohm 1/4 watt resistor after the ladder, followed
by a 500pF capacitor to ground.
In the 7704A there is no visible resistor, and the do-it-yourself circuit
does not show one inside the X14 module.

Ernesto



Re: Tek 576 Curve Tracer HV Replacement Transformer

 

Michael, Chuck,

Why is a resistor in series with the multiplying ladder necessary? Isn't the internal helical coating of the CRT a load and a drainage means of the ladder capacitors?
In the 547 there is a 1 Mohm 1/4 watt resistor after the ladder, followed by a 500pF capacitor to ground.
In the 7704A there is no visible resistor, and the do-it-yourself circuit does not show one inside the X14 module.

Ernesto

Re: 184 Time Mark Gen. - 2nS & 5nS not working

Merchison Burke
 

If you have a Spectrum Analyser, could that be used to check to 500 MHz output?

On 2020-04-07 9:22 a.m., david via groups.io wrote:
Thanks for the information guys, looks like I don't have the equipment or the knowledge to fix the 500MHz output. Not going to buy Nuvistors if I won't be able to check the results. My 465 is a 100MHz scope, it shows 130mVpp signal at 200MHz output, so I believe that signal is OK. This 184 is working correctly except for the 500MHz. Only other issue is the 10MHz oscillator frequency does not have enough adjustment range. It is close enough, checking it with a GPSDO at 10MHz it is 9.999xxx, but it is at the limit of adjustment on C11. Any idea why the oscillator is beyond the range of C11 adjustment? Is it just the age of the crystal? Has anyone tried to reduce value of capacitor C11 by putting another cap in series with it? Only need to lower value of C11 a couple pF to fix it. I am amazed at how accurate this 184 is being all analog.
David

--
This email has been checked for viruses by AVG.
https://www.avg.com

Re: Tek 576 Curve Tracer HV Replacement Transformer

Mlynch001
 

On Tue, Apr 7, 2020 at 06:42 PM, Chuck Harris wrote:


I don't have a schematic of the tripler, so I don't know where this
resistor is located.

I suspect that it is in series with the anode lead. That is often done
for safety reasons. They don't want a full discharge of the tripler's
capacitors to stop your heart...

It was probably a carbon composition resistor, and probably 1/4 watt.

-Chuck Harris

Mlynch001 wrote:
I do have a question about the load resistor. I think it is supposed to be
about 470K Ohms? Does this need to be a special resistor or can you use a
1/2W metal film resistor?
Chuck,

There are some pictures in the TEKScope archive. One of our members posted a lot of pictures, including X-Ray pictures of the internal structures. They show the resistor soldered between the last diode in the chain and the end of the anode wire. I don’t have any carbon comp resistors of that resistance rating, but tons of 1/4W metal film and carbon film resistors. Would either those types be acceptable for this application? I can probably find some carbon comp resistors if absolutely necessary.

--
Michael Lynch
Dardanelle, AR

Re: 2430A Fails Repet

Craig Cramb
 

On Apr 7, 2020, at 7:04 PM, Gary Robert Bosworth <@grbosworth> wrote:

Can anyone give me the complete low-down on the Ram Battery back-up issue. My CMOS battery ran down, and I now get the 4000 Front Panel low battery error message. Do we HAVE TO replace the Dallas Ram chip block? If I have to replace the backup data black block, will the 2430A automatically do a calibration and load the new calibration data into the Dallas chip? My 2430A does not have an external battery, and there is a wire connecting the + and - terminal pads where the battery would go. Does this mean that I MUST use the same type of internal battery Dallas block? I put a 3.7 Volt Lithium backup battery in the place where the jumper was, but it had no effect on the operation of the scope. I can press the Auto Setup button and the scope works perfect, but the next time I power up the scope it gives me the same 4000 FPP error code again.


Re: 2445A slow

Steve
 

LOL, so you're saying just put a 100uf 25v radial and solder it to the legs in it's proper polarized pattern? If so cool! Also I checked the voltage of the backup battery while I had the A5 board out and it was teetering between 3.6/7 so I didn't bother ordering one from Mouser.
--
Kind Regards,

steve

Re: 2430A Fails Repet

Gary Robert Bosworth
 

Can anyone give me the complete low-down on the Ram Battery back-up issue. My CMOS battery ran down, and I now get the 4000 Front Panel low battery error message. Do we HAVE TO replace the Dallas Ram chip block? If I have to replace the backup data black block, will the 2430A automatically do a calibration and load the new calibration data into the Dallas chip? My 2430A does not have an external battery, and there is a wire connecting the + and - terminal pads where the battery would go. Does this mean that I MUST use the same type of internal battery Dallas block? I put a 3.7 Volt Lithium backup battery in the place where the jumper was, but it had no effect on the operation of the scope. I can press the Auto Setup button and the scope works perfect, but the next time I power up the scope it gives me the same 4000 FPP error code again.

Re: 184 Time Mark Gen. - 2nS & 5nS not working

Melvin Gleep
 

I have not had the need, but I do not see any reason why putting a cap in series would not be worth trying.

Gesendet von Mail<https://go.microsoft.com/fwlink/?LinkId=550986> für Windows 10

Von: david via groups.io<mailto:davide_us=yahoo.com@groups.io>
Gesendet: Dienstag, 7. April 2020 15:23
An: TekScopes@groups.io<mailto:TekScopes@groups.io>
Betreff: Re: [TekScopes] 184 Time Mark Gen. - 2nS & 5nS not working

Thanks for the information guys, looks like I don't have the equipment or the knowledge to fix the 500MHz output. Not going to buy Nuvistors if I won't be able to check the results. My 465 is a 100MHz scope, it shows 130mVpp signal at 200MHz output, so I believe that signal is OK. This 184 is working correctly except for the 500MHz. Only other issue is the 10MHz oscillator frequency does not have enough adjustment range. It is close enough, checking it with a GPSDO at 10MHz it is 9.999xxx, but it is at the limit of adjustment on C11. Any idea why the oscillator is beyond the range of C11 adjustment? Is it just the age of the crystal? Has anyone tried to reduce value of capacitor C11 by putting another cap in series with it? Only need to lower value of C11 a couple pF to fix it. I am amazed at how accurate this 184 is being all analog.
David

Re: Tek 576 Curve Tracer HV Replacement Transformer

Chuck Harris
 

I don't have a schematic of the tripler, so I don't know where this
resistor is located.

I suspect that it is in series with the anode lead. That is often done
for safety reasons. They don't want a full discharge of the tripler's
capacitors to stop your heart...

It was probably a carbon composition resistor, and probably 1/4 watt.

-Chuck Harris

Mlynch001 wrote:

I do have a question about the load resistor. I think it is supposed to be about 470K Ohms? Does this need to be a special resistor or can you use a 1/2W metal film resistor?

Re: 2445A slow

Chuck Harris
 

The cap is 100uf, 25V. When I replace it, I just stand up a
radial leaded cap, and roll my eyes in wonderment at why they
used a radial cap in that position...

-Chuck Harris

Steve wrote:


I thought I had replied but obviously didn't . I put the 4.7/10 tantalum back in it's proper place. I have some NOS Sprague orange drop 4.7 35's but figured I'd just leave the tent alone and not try and sub in a 35 volt cap where a 10 volt cap even though both are tantalums. I should be getting parts in tomorrow to do the power supply lytics. I looked at the anode board, I have 8 caps and only one is an electrolytic axial cap. I can't see it well enough to know it's value without going into the service manual and I would have to dissasemble the HV supply to raise the board enough to remove it, Problem is I know I don't have any axial caps that size or value. I have 1uf/50 and 2 470/100, i don't do much with axial caps these days unless I'm working on a reel to reel or tube amp so I order them as needed. I'm not sure how critical it is to change that cap or the others on that board but if they are critical then I will order the parts to change them all.

Re: Tek 576 Curve Tracer HV Replacement Transformer

Chuck Harris
 

Tam,

I accept that you are a vulgarian who needs to reference
some elimination or procreation bodily function in every
utterance. Most children out grow of that phase.

...But...

Why do you insist on editing Tektronix out of history?

Danaher started as DMG in 1969, and didn't even incorporate
under the Danaher name until 1984. They didn't buy Tektronix
until 2007.

Danaher didn't exist in any form when the 576 was first
offered for sale.

Danaher didn't exist in any form when the 7000 series was
first offered for sale.

Danaher wasn't even incorporated when the 465 was first
offered for sale... nor when the 2465, its replacement was
first offered for sale... nor the 5000 series, nor the 7904,
nor the 7104.... need I go on?

Do you think that Tektronix is not worthy of being remembered?

You are puzzling me man.

-Chuck Harris

Tam Hanna wrote:

I don't have such a Danaher oscilloscope, but two printers. If anyone wants a part, I'll fart one out.

Tam
---
With best regards
Tam HANNA (emailing on a BlackBerry PRIV)

Enjoy electronics? Join 14k other followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/



Re: 2445A slow

Steve
 

I thought I had replied but obviously didn't . I put the 4.7/10 tantalum back in it's proper place. I have some NOS Sprague orange drop 4.7 35's but figured I'd just leave the tent alone and not try and sub in a 35 volt cap where a 10 volt cap even though both are tantalums. I should be getting parts in tomorrow to do the power supply lytics. I looked at the anode board, I have 8 caps and only one is an electrolytic axial cap. I can't see it well enough to know it's value without going into the service manual and I would have to dissasemble the HV supply to raise the board enough to remove it, Problem is I know I don't have any axial caps that size or value. I have 1uf/50 and 2 470/100, i don't do much with axial caps these days unless I'm working on a reel to reel or tube amp so I order them as needed. I'm not sure how critical it is to change that cap or the others on that board but if they are critical then I will order the parts to change them all.
--
Kind Regards,

steve

Tds1001b upgrade?

filozoph@...
 

Recently I bought TDS1001b. I wonder if anyone managed to upgrade it to 1012b. I tried to use the trick from eevblog, somehow after checking for connection any further step give no response. Any clues if it works with “b” version?
Regards
Mark.