Date   
Re: Opening up a P5205 for inspection

Jack
 

Hi.a thought, ..do get a very clear un-astigmatic photo of it in case you need to have another created.
My Regards
Jack

Opening up a P5205 for inspection

DW
 

I have a P5205 differential probe that has a offset issue when switching the attenuation from 500x to 50x and the overage light doesn't seem to come on or any sound either. I would like to open up this probe up for inspection but I have a question in doing so. From a previous post it is from my assumption the screws are hidden below the front label and in order to get to them I would have to puncture the label? Is it possible to peel the label without damage? Thanks

Re: Scope wanted, England.

Harvey White
 

On Thu, 22 Nov 2018 19:06:41 +0000, you wrote:

I gave my 475 away as it needed fixing and I didn't want any more
projects, a week
later I find myself wanting a scope and nearly buying a little chinese
hand held thing!
I don't recommend the little Chinese cell-phone sized scopes as an
only scope. They are very portable, but quite limited in what they
do.

The Tektronix 2000 series can be nice, not totally familiar with them,
but they have been well rated.

Research would be indicated, I think.

A 2430A is not a bad scope...

Harvey
Guess I might as well buy another proper scope.
Thanks in advance for all the top condition scopes I am going to be
offered..

richard


Re: Tektronix 475A intermittent / lazy sweep

 

On Wed, Nov 21, 2018 at 03:20 PM, Chris Smith wrote:


Quick victory photo of the 475A: https://i.imgur.com/5rFHnmB.jpg
Great. I was almost 475ed out with this one here. Well it only had three or four problems...no need to whine about it right ?

What I wanted to mention though is that looking at the 465(B here, not sure about the non B) the 475 sweep has one more range, faster. That may account for the slight difference in the part number. I would figure out a way to check it out on 0.01 uS/div. It doesn't generate the ramp so linearity should be fine, it might be a matter of triggering. Also it is quite possible that specimen of U600 will be fine, but not necessarily ALL of them would do.

Sometimes this type of part is like harddrives. They format them to higher and higher capacities until they start getting errors and set it up for just below that. So in the lower grade (if you can call it that) IC it might or might not work fine but the higher grade IC definitely will. It could be just fine.

Scope wanted, England.

richard knight <richard@...>
 

I gave my 475 away as it needed fixing and I didn't want any more projects, a week
later I find myself wanting a scope and nearly buying a little chinese hand held thing!
Guess I might as well buy another proper scope.
Thanks in advance for all the top condition scopes I am going to be offered..

richard

Re: Clearing error log in THS720A

 

On Thu, Nov 22, 2018 at 07:06 PM, Raymond Domp Frank wrote:


Also, ISTR that 1 GSa/s worked but the display quality wasn't 100%. I have to
admit I don't quite remember.
And lots of error messages turned up in the Error Log.
I should add that I didn't spend much time on it before deciding to revert so your results may be better.
ISTR also that the time base setting allowed for a faster sweep than the 720A's. The faster sampling rate and the faster time base were what I was interested in. Still, I decided to revert, maybe just because of the error log growing all the time, don't remember.
The link in my previous message gives access to all the info I had available.

Raymond

Re: Clearing error log in THS720A

 

On Thu, Nov 22, 2018 at 05:40 PM, garp66 wrote:

Rick,
Please see below.

So... What of the THS 730a upgrade ?
Have a look here:
https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/
I think I got all my info there.

What exactly were the problems with that ?
It worked but the bandwidth didn't reach 200 MHz, probably because the THS730A uses different attenuators.
Also, ISTR that 1 GSa/s worked but the display quality wasn't 100%. I have to admit I don't quite remember.
And lots of error messages turned up in the Error Log.

& how can each issue, in detail, be solved ?
If I knew, I wouldn't have returned back to the 720A... setup.

I have a THS720a and would like to upgrade it to the THS 730a.
Raymond

Re: Clearing error log in THS720A

garp66
 

So... What of the THS 730a upgrade ?
What exactly were the problems with that ?
& how can each issue, in detail, be solved ?

I have a THS720a and would like to upgrade it to the THS 730a.

thanks,
rick

Re: Tek 2465ADM problems.

gsl@...
 

Thanks.
I followed the procedure of the service manual: I moved the jumper on "cal" of course, but it is impossible to start the calibration routine: simply at each calibration step, by pressing the "upper coupling" button, the result is "pass" or "fail" in the case of step n. 4!

Re: OT: NEARC Jan/Feb/Mar 2018 Article "Matching Tubes For Audio Service"

johnasolecki@...
 

I'd appreciate copies of those 2 articles as well.

Thanks,

John

Re: Clearing error log in THS720A

 

If you connect a PC running a terminal program to the serial port
of the THS you can try sending first PASSWORD PITBULL and then ERRLOG CLEAR.
Håkan gave me above advice. It turns out to achieve what I wanted: The error log is cleared.

Raymond

Re: P6137 Probe Hybrid Tips Wanted

Craig Cramb
 

I can help with these if you are interested. They are new tips. $40 US each. Send me email if you want.
Craig

Re: 7854 RAM card upgrade only - any interest?

 

Cliff,

If you google jdownj@... the first hit you get is for Nathan's Twitter
account. If you follow the link provided you can see his last retweet was
two weeks ago on Oct 26.

Who knows what else you might find on the internet.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Cliff Carrie
Sent: Wednesday, November 21, 2018 8:59 AM
To: leonard scheepsma <tubes.leonard@...>; TekScopes@groups.io
Subject: Re: [TekScopes] 7854 RAM card upgrade only - any interest?

I initiated this thread around March 2016.
Nathan Johnson (Tekscopes member) developed the prototype around that
time. It was a single card ROM / low power RAM replacement with onboard
battery backup.

I believe it was at an advanced stage of testing with a couple of
changes outstanding. Around March 2017 Nathan moved across the US and
took a new job.
I have sent him personal follow-up emails several times, most recently
in July and October of this year. He has not replied.

This also happened immediately after he moved and he did reply in March
2017 when I posted on Tekscopes asking if anyone knew how to contact
him.

He has always said he hoped to complete the project, so I have waited
patiently for him to get comfortable in his new career and residence. I
also offered to help bring the project to completion by assisting
(possibly using other interested Tekscopes members).

So, once again I humbly ask: Does anyone know how to contact Nathan
Johnson?

Regards, Cliff Carrie
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of leonard
scheepsma <tubes.leonard@...>
Sent: Monday, November 19, 2018 5:35 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7854 RAM card upgrade only - any interest?

Curious.. more than a year further.. did the new board ever see
daylight?
Leonard (7854 owner from NL)



--
Dennis Tillman W7PF
TekScopes Moderator

Re: Tek 2465ADM problems.

Craig Cramb
 

IThe way that you should deal with a Keeper battery replacement is locate the + and- voltage that is coming out of the battery and the first components it is connected to R2770 and CR2770 to the board and add your own 3.5VDC . Then unsolder and resolder in the new keeper battery at this point then disconnect the added power from the board. All should be ok to hold the original data. This retains the Cal data as the battery is replaced.
Yes now it is a complete calibration to be done to restore the scopes correct operation.

Craig

On Nov 21, 2018, at 11:08 AM, gsl via Groups.Io <gsl=libero.it@groups.io> wrote:

Hello,
Problems 2465A DM: after replacing the 3.5Volts lithium battery, the following message appears at power on: "TEST 04 FAIL 13 <017F> Does anyone know what the problem is?
Thanks.

Re: Tektronix 475A intermittent / lazy sweep

tom jobe <tomjobe@...>
 

Thank you George,
For the best 22xx tip of the year, from a chronic offender of your excellent advice about installing that extra screw on the right hand side in the back!
Your advice is applicable to many 22xx scopes, such as the 2213A, 2215A, 2235, 2236 and many others.
tom jobe...

On 11/21/2018 4:59 PM, george edmonds via Groups.Io wrote:
Hi Chris
I have a beyond repair 2235 here, it has blown up the smpsu transformer.  I keep it as a spare parts mule for my two 2236's which are my standard bench scopes.  I have had the Tek IEC mains input filter emit the magic smoke on a number of occasions, not quite as bad as a Selenium rectifier for smell, but, close.
One thing I have found with the 223X scopes is that people leave out the rear right hand side case screw which deprives the power supply heat sink of some of the case cooling.
CATS is always a good rally for prices as it is the last South of England rally until Canvey on the 3rd February next year, some of the traders do not wish to hold stock until then.  I will be at Canvey next year, again as a trader.
73 George  G6HIG


On Thursday, November 22, 2018 12:11 AM, Chris Smith via Groups.Io <chrisjsmithuk=icloud.com@groups.io> wrote:

Hi,

At the CATS rally (South London) a Tek 465B with the DM module sold for £30 it was clean, complete and had a very sharp focus.  I would have purchased it, but, I have now moved on to the next generation of Tek scopes.  I did buy a 2430A with a power supply fault for £25.
Good luck with your 475A, a lot of users consider it the best portable scope that Tek made.
73 George G6HIG, now living in Dover
Small world! I actually went to the CATS rally as well. I saw that 465B. I skipped that as I’d just grabbed a “working" 2235 for a respectable £25 with a hope that I will end up with at least one working analogue scope!  Unfortunately the power supply in it was rather unhealthy. I replaced literally everything suspicious in it i.e. electrolytic caps, RIFAs and the Schaffner filter but unfortunately the main switching MOSFET decided to let go after an hour. I think the design of the 2235 power supply is somewhat marginal. The SOA on the IRF710 that was in it was very tight! Replacement bits arriving tomorrow for that as well. Hopefully it hasn’t caused any transformer damage. Cost a new (better) MOSFET, diode and driver transistor. SMPS controller still works by the looks.

Hope your 2430A doesn’t give you as much trouble or stink the house out with magic smoke!

Best regards,

Chris M0XTE







Re: Tektronix 475A intermittent / lazy sweep

george edmonds
 

Hi Chris
I have a beyond repair 2235 here, it has blown up the smpsu transformer.  I keep it as a spare parts mule for my two 2236's which are my standard bench scopes.  I have had the Tek IEC mains input filter emit the magic smoke on a number of occasions, not quite as bad as a Selenium rectifier for smell, but, close.
One thing I have found with the 223X scopes is that people leave out the rear right hand side case screw which deprives the power supply heat sink of some of the case cooling.
CATS is always a good rally for prices as it is the last South of England rally until Canvey on the 3rd February next year, some of the traders do not wish to hold stock until then.  I will be at Canvey next year, again as a trader.
73 George  G6HIG

On Thursday, November 22, 2018 12:11 AM, Chris Smith via Groups.Io <chrisjsmithuk=icloud.com@groups.io> wrote:


Hi,

At the CATS rally (South London) a Tek 465B with the DM module sold for £30 it was clean, complete and had a very sharp focus.  I would have purchased it, but, I have now moved on to the next generation of Tek scopes.  I did buy a 2430A with a power supply fault for £25.
Good luck with your 475A, a lot of users consider it the best portable scope that Tek made.
73 George G6HIG, now living in Dover
Small world! I actually went to the CATS rally as well. I saw that 465B. I skipped that as I’d just grabbed a “working" 2235 for a respectable £25 with a hope that I will end up with at least one working analogue scope!  Unfortunately the power supply in it was rather unhealthy. I replaced literally everything suspicious in it i.e. electrolytic caps, RIFAs and the Schaffner filter but unfortunately the main switching MOSFET decided to let go after an hour. I think the design of the 2235 power supply is somewhat marginal. The SOA on the IRF710 that was in it was very tight! Replacement bits arriving tomorrow for that as well. Hopefully it hasn’t caused any transformer damage. Cost a new (better) MOSFET, diode and driver transistor. SMPS controller still works by the looks.

Hope your 2430A doesn’t give you as much trouble or stink the house out with magic smoke!

Best regards,

Chris M0XTE

Re: Tektronix 475A intermittent / lazy sweep

Chris Smith <chrisjsmithuk@...>
 

Hi,

At the CATS rally (South London) a Tek 465B with the DM module sold for £30 it was clean, complete and had a very sharp focus. I would have purchased it, but, I have now moved on to the next generation of Tek scopes. I did buy a 2430A with a power supply fault for £25.
Good luck with your 475A, a lot of users consider it the best portable scope that Tek made.
73 George G6HIG, now living in Dover
Small world! I actually went to the CATS rally as well. I saw that 465B. I skipped that as I’d just grabbed a “working" 2235 for a respectable £25 with a hope that I will end up with at least one working analogue scope! Unfortunately the power supply in it was rather unhealthy. I replaced literally everything suspicious in it i.e. electrolytic caps, RIFAs and the Schaffner filter but unfortunately the main switching MOSFET decided to let go after an hour. I think the design of the 2235 power supply is somewhat marginal. The SOA on the IRF710 that was in it was very tight! Replacement bits arriving tomorrow for that as well. Hopefully it hasn’t caused any transformer damage. Cost a new (better) MOSFET, diode and driver transistor. SMPS controller still works by the looks.

Hope your 2430A doesn’t give you as much trouble or stink the house out with magic smoke!

Best regards,

Chris M0XTE

Re: 7854 RAM card upgrade only - any interest?

 

Hi Cliff,

Nathan last replied to TekScopes on 10/06/17, #140341 when he said:
I'm still here! I didn't realize I'd missed emails from Cliff or others. My
apologies.
I am finally unpacking the lab now, and getting set up again. I am going to
post the design files as soon as I can
via Newton Mail
[https://cloudmagic.com/k/d/mailapp?ct=pi&cv=9.8.55&pv=11.0.1&source=email_f
ooter_2]

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Cliff Carrie
Sent: Wednesday, November 21, 2018 8:59 AM
To: leonard scheepsma <tubes.leonard@...>; TekScopes@groups.io
Subject: Re: [TekScopes] 7854 RAM card upgrade only - any interest?

I initiated this thread around March 2016.
Nathan Johnson (Tekscopes member) developed the prototype around that
time. It was a single card ROM / low power RAM replacement with onboard
battery backup.

I believe it was at an advanced stage of testing with a couple of
changes outstanding. Around March 2017 Nathan moved across the US and
took a new job.
I have sent him personal follow-up emails several times, most recently
in July and October of this year. He has not replied.

This also happened immediately after he moved and he did reply in March
2017 when I posted on Tekscopes asking if anyone knew how to contact
him.

He has always said he hoped to complete the project, so I have waited
patiently for him to get comfortable in his new career and residence. I
also offered to help bring the project to completion by assisting
(possibly using other interested Tekscopes members).

So, once again I humbly ask: Does anyone know how to contact Nathan
Johnson?

Regards, Cliff Carrie
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of leonard
scheepsma <tubes.leonard@...>
Sent: Monday, November 19, 2018 5:35 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7854 RAM card upgrade only - any interest?

Curious.. more than a year further.. did the new board ever see
daylight?
Leonard (7854 owner from NL)



--
Dennis Tillman W7PF
TekScopes Moderator

Re: Tektronix 475A intermittent / lazy sweep

george edmonds
 

Hi Chris
At the CATS rally (South London) a Tek 465B with the DM module sold for £30 it was clean, complete and had a very sharp focus.  I would have purchased it, but, I have now moved on to the next generation of Tek scopes.  I did buy a 2430A with a power supply fault for £25.
Good luck with your 475A, a lot of users consider it the best portable scope that Tek made.
73 George G6HIG, now living in Dover

On Wednesday, November 21, 2018 11:20 PM, Chris Smith via Groups.Io <chrisjsmithuk=icloud.com@groups.io> wrote:


Hi,

On 21 Nov 2018, at 15:20, george edmonds via Groups.Io <G6HIG=yahoo.com@groups.io> wrote:

Hi Chris
Where in the world are you?
I am in Dover UK and have a scrap 465 if you need parts from it.
73 George G6HIG
Am in UK (London). Thanks for the kind offer. I will drop you a message if I get some time to look at the 465. I fear it is beyond repair however. I’ve already had the entire vertical out and the attenuator cams are shot. There is also some slightly dodgy looking rework on channel 2. I am mostly keeping it around as a donor scope for the 475A at the moment or if another 465 if one passes by.

Very happy with this scope now. Everything appears to work and the calibration is still pretty much spot on. Just needs a good panel strip down and clean which I will undertake at the weekend. I took the liberty of swapping the bezel, blue perspex sheet and illumination assembly from the 465 and a couple of feet as they were in much better condition.

Quick victory photo of the 475A: https://i.imgur.com/5rFHnmB.jpg

Best regards,

Chris M0XTE

Re: Tektronix 475A intermittent / lazy sweep

Chris Smith <chrisjsmithuk@...>
 

Hi,

On 21 Nov 2018, at 19:54, Roger Evans via Groups.Io <very_fuzzy_logic=yahoo.com@groups.io> wrote:

You can find the 155-0049-xx IC in several of the 7000 series timebase plugins (7B50A, 7B53A, 7B80, 7B85, 7B92A maybe others as well. You might be lucky and find a scrap one at a good price.
Thanks for the tip. That’s really helpful. There are usually quite a few 7000 plugins passing by on eBay here. Also a good source of knobs!

Best regards,

Chris M0XTE