Date   
Re: TDS 3014 TDS 3000 scope Strange display "System Error " report, on BootUp, ... with no effect on scope function: repair of, or Clearing / Reset this Error Log ?

 

On Mon, Oct 22, 2018 at 07:34 PM, garp66 wrote:


1) there might be a Boot up RAM or NVram battery (in the display section) that
has gone south, providing faulty parameters ?

-- Any replacement Nvram battery possible, wherever that is ? ?
There is a DALLAS DS1742W-150 Timekeeping RAM that might or might not be the problem.
Some time ago I had a TDS 3014B that got stuck on the flash screen. Fortunately I had
a scrapped main board from another TDS 3000 and as last resort before scrapping it I
took the DALLAS chip from the scrapped board and installed in the scope. Much to my
surprise it solved the problem so it could be worth replacing yours.

Another thing to watch out for is the F/W version. There was one version that
could mess up the NVRAM quite good due to some memory address issues. It was v3.12.

/Håkan

Re: 2247A PSU Troubleshooting

 

On Mon, Oct 22, 2018 at 03:22 PM, <Nirokeforums@...> wrote:


It doesn’t boot. Nothing happens when I turn it on.



I reassembled and powered up to test the power headers on the underside of the unit. They are all basically dead, however I did measure some mV on one of the high voltage pins.
Did you check the mains fuse and switch?

Raymond

Re: 2247A PSU Troubleshooting

Nicholas Keller
 

Fuse: yes.

Switch: no, and I should have because that’s an easy one and have had bad
switches on other gear

Thanks, Raymond, I will check the switch tonight after work

Nick



On Mon, Oct 22, 2018 at 10:14 PM Raymond Domp Frank <@Raymond>
wrote:

On Mon, Oct 22, 2018 at 03:22 PM, <Nirokeforums@...> wrote:


It doesn’t boot. Nothing happens when I turn it on.



I reassembled and powered up to test the power headers on the underside
of the unit. They are all basically dead, however I did measure some mV on
one of the high voltage pins.
Did you check the mains fuse and switch?

Raymond



Re: TEK 475 Q1478 2n5859

Chris Wilkson
 

Is it in a TO-39 (metal) case?
Try findchips.com. Several sources to choose from, though Mouser is out of stock.

Re: TEK 475 Q1478 2n5859

piodelreal@...
 

Yes it is TO-39, thank you

Best regards.

Pio

Re: 2445A calibration

maxim.vlasov@...
 

Just wanted to ask your advice,

On the local auction someone put 2445a (exactly the same like mine) for the bargain price - 100 USD delivered. I wonder whether this is worth buying. Apart from a missing knob, the scope is an a good working order and calibration seems valid (no question marks at least). The seller seem to know about how to test the scope, since he put a picture with multiple traces showing different signals. Screen seems bright, sharp and not distorted.
I wonder, would you buy one more (even if you haven't planned this) for such a price?

P.S. If this auction would appear 2 weeks before, I would likely ditch mine that time, since the effort seem to be almost unfeasible.

Re: 2445A calibration

John Ferguson
 

After seeing a tip here on a 2465 for sale for $50 plus shipping, I bought it.  It was advertised as having a bad horizontal switch - it had been dropped on it.  Well they were right, it was bad.  I was able to get a replacement panel for it complete with all the controls for $37 IIRC.  Now it works great.  A few years back I bought a 2445B on which everything worked except the parametric functions.  I thought it would be good to buy another 2445B for parts. When it came, everything on it worked except Channel 1 which was very noisy - turned out to have a fried attentuator.

At this point, I decided it might be good to have one of them calibrated.  I sent the one needing a new attenuator to one of our members who does this sort of thing, and had the PS recapped, the A-5 Board smt caps replaced and the NVRAM replaced with a socket and a FRAM. It came back really nice with a great trace and everything working. I now have a certain to be good 2445b, a 2445b which can be used manually and seems pretty good, and the 2465 which also seems ok.

This is nuts.

I need to get rid of at least one of these, but can't bring myself to part with them.

john

On 10/23/18 3:49 PM, maxim.vlasov@... wrote:
Just wanted to ask your advice,

On the local auction someone put 2445a (exactly the same like mine) for the bargain price - 100 USD delivered. I wonder whether this is worth buying. Apart from a missing knob, the scope is an a good working order and calibration seems valid (no question marks at least). The seller seem to know about how to test the scope, since he put a picture with multiple traces showing different signals. Screen seems bright, sharp and not distorted.
I wonder, would you buy one more (even if you haven't planned this) for such a price?

P.S. If this auction would appear 2 weeks before, I would likely ditch mine that time, since the effort seem to be almost unfeasible.


Re: 2445A calibration

maxim.vlasov@...
 

On Tue, Oct 23, 2018 at 01:11 PM, John Ferguson wrote:


This is nuts.
Thank you John,

For me also it's difficult to walk by this advertised 2445a, especially, since it seems like it has nothing broken at all...
And for many things including the phase measurements the analog scopes are still my preferred choice (XY mode on the recent digital machines is more of a gimmick).

Re: 2247A PSU Troubleshooting

tekscopegroup@...
 

I have a 2247A myself, excellent GP scope.

One of the first recommended things to do I was told is replace all the rectifier diodes in the A18 LV power supply that have ZM or ZS markings on them as they are well known to get leaky after "some time" (quoting the very knowledgeable person that sent me this recommendation). Replace these diodes with MUR160 600V 1Amp, you easily get them at Mouser, Digikey, etc. On my scope all of them had either of the above suspect markings, so just to be safe I replaced all of them. Whole procedure takes maybe an hour or two, your mileage may vary.

Of course for an instrument this age, needless to mention to also check filter caps, specially if you see higher than normal ripple on any of the supply rails.

Suspect diodes are Tek PN 152-0400-00 (total 17 diodes) with alternate PN given as MB2501. These are the on-board part locator numbers:
-CR2202
-CR2204
-CR2205
-CR2208
-CR2209
-CR2210
-CR2211
-CR2212
-CR2213
-CR2214
-CR2215
-CR2216
-CR2218
-CR2227
-CR2228
-CR2235
-CR2236

Hope that helps.
Alex

475 Probe Calibration problem with x10 probes

n2msqrp
 

I have two 475 scopes. Both have developed a similar probe calibration problem on one channel. I am using the scope calibration signal. I have verified results with multiple probes

First scope - Channel 1 probe calibration tests fine with x1 and x10 probles. Channel 2 calibration tests fine with a x1 probe but the waveform has a sloped rise and fall time when testing with a x10 probe on a vertical sensitivity setting of .5v/div and above.

Second scope - Channel 1 probe calibration tests fine with x1 probes but the waveform is a spike when testing with a x10 probe with vertical sensitivity setting of .5v/div and above. Channel 2 probe calibration works fine with x1 and x10 probes.

Has anyone seen this problem?

Mike N2MS

Re: 2247A PSU Troubleshooting

Nicholas Keller
 

Thank you, Alex. This must have been the suggestion I saw here not too
long ago, I just got the impression that the diode list was an abridged
tally of what “should” be checked and replaced. When I pull the board
again, I will check these diode markings. Unfortunately I can’t test for
ripple yet as there is no power getting to the supply rails. I’ll report
back when I’m able to make some progress. Thanks again!

Nick

On Tue, Oct 23, 2018 at 8:09 PM <tekscopegroup@...> wrote:

I have a 2247A myself, excellent GP scope.

One of the first recommended things to do I was told is replace all the
rectifier diodes in the A18 LV power supply that have ZM or ZS markings on
them as they are well known to get leaky after "some time" (quoting the
very knowledgeable person that sent me this recommendation). Replace these
diodes with MUR160 600V 1Amp, you easily get them at Mouser, Digikey, etc.
On my scope all of them had either of the above suspect markings, so just
to be safe I replaced all of them. Whole procedure takes maybe an hour or
two, your mileage may vary.

Of course for an instrument this age, needless to mention to also check
filter caps, specially if you see higher than normal ripple on any of the
supply rails.

Suspect diodes are Tek PN 152-0400-00 (total 17 diodes) with alternate PN
given as MB2501. These are the on-board part locator numbers:
-CR2202
-CR2204
-CR2205
-CR2208
-CR2209
-CR2210
-CR2211
-CR2212
-CR2213
-CR2214
-CR2215
-CR2216
-CR2218
-CR2227
-CR2228
-CR2235
-CR2236

Hope that helps.
Alex



Type G plugin versions

cmjones01
 

For a while I've been looking for a differential amplifier plugin for my 535A scope. While I really want a Z, W or 1A5, I couldn't resist a type G plugin at a great price locally. It was missing a knob and one valve but otherwise in great shape.

While getting it working, I've found that it's very different from what's documented in the manual available on TekWiki for the 53/54G. My plugin contains four 12AU6s, two 6AK5s and a 12AT7, as do the ones in the photos on TekWiki. The schematic in the manual, however, has two 12AU6s and three 12AT7s. The front panels are the same, though.

http://w140.com/tekwiki/wiki/G

What's going on here? Were there two versions of the plugin? I'd like to find the right manual for the plugin I've got.

Thanks
Chris

Re: Type G plugin versions

Jerry Ingordo
 

Hi Chris.
You have an early G plugin. Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual. Log in is simple, create a screen name and password and your in. There may be a waiting period for new users to download. If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

Re: Type G plugin versions

cmjones01
 

Jerry,

Thank you very much for the pointer. That manual matches what I've got. A replacement 12AU6 (most of the vacuum has escaped from one of the ones in the plugin) has just arrived so I'll see if I can get it working.

Regards
Chris

Re: 475 Probe Calibration problem with x10 probes

ef804s tubes
 

I have two 475 scopes. Both have developed a similar probe calibration problem on one channel. I am using the scope calibration signal. I have verified results with multiple probes

First scope - Channel 1 probe calibration tests fine with x1 and x10 probles. Channel 2 calibration tests fine with a x1 probe but the waveform has a sloped rise and fall time when testing with a x10 probe on a vertical sensitivity setting of .5v/div and above.

Second scope - Channel 1 probe calibration tests fine with x1 probes but the waveform is a spike when testing with a x10 probe with vertical sensitivity setting of .5v/div and above. Channel 2 probe calibration works fine with x1 and x10 probes.

Has anyone seen this problem?

Mike N2MS

Hi,

please clean the attenuator contacts ans the pins of the attenuator blocks as well.

Fred

Re: 475 Probe Calibration problem with x10 probes

Colin Herbert
 

This might indeed help, but be cautious when doing it. There are posts on this forum where the correct technique is laid out - it is very easy to damage the cam-operated contacts. Also, note that the material of the attenuator board is a bit special and is easily damaged by heat and various solvents. Briefly, the technique is to put a little IPA (isopropyl alcohol) onto a sliver of ordinary paper and use that to clean the contacts. Check that the contacts are open, slide the ipa-wetted paper between them, close the contacts and then carefully pull the paper out level with the board, as far as possible. This can be done a few times to get all the contaminants off. You can probably ascertain which of the attenuator contacts need cleaning by checking in the service manual as to which attenuators are in circuit when the poor bandwidth is seen.
Good Luck, Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of ef804s tubes
Sent: 24 October 2018 14:27
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 Probe Calibration problem with x10 probes

I have two 475 scopes. Both have developed a similar probe calibration problem on one channel. I am using the scope calibration signal. I have verified results with multiple probes

First scope - Channel 1 probe calibration tests fine with x1 and x10 probles. Channel 2 calibration tests fine with a x1 probe but the waveform has a sloped rise and fall time when testing with a x10 probe on a vertical sensitivity setting of .5v/div and above.

Second scope - Channel 1 probe calibration tests fine with x1 probes but the waveform is a spike when testing with a x10 probe with vertical sensitivity setting of .5v/div and above. Channel 2 probe calibration works fine with x1 and x10 probes.

Has anyone seen this problem?

Mike N2MS

Hi,

please clean the attenuator contacts ans the pins of the attenuator blocks as well.

Fred

Re: Type G plugin versions

Dave Wise
 

Chris's manual is for the 53G (12AU6x2, 12AT7x2, 12AT7), while his plugin is the later, faster G (6AK5x2, 12AU6x2, 12AU6x2, 12AT7). I edited the wiki page to mention that 53G has five tubes while G has seven.

Regards,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jerry Ingordo <gjingordo@...>
Sent: Wednesday, October 24, 2018 3:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Hi Chris.
You have an early G plugin. Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual. Log in is simple, create a screen name and password and your in. There may be a waiting period for new users to download. If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

Re: Type G plugin versions

Dave Seiter
 

My G (serial number just under 10K) has holes in the front panel for the original connectors, but is loaded with BNCs which look factory installed.  Anyone know when this transition took place?
-Dave

From: Dave Wise <david_wise@...>
To: "TekScopes@groups.io" <TekScopes@groups.io>
Sent: Wednesday, October 24, 2018 7:32 AM
Subject: Re: [TekScopes] Type G plugin versions

Chris's manual is for the 53G (12AU6x2, 12AT7x2, 12AT7), while his plugin is the later, faster G (6AK5x2, 12AU6x2, 12AU6x2, 12AT7).  I edited the wiki page to mention that 53G has five tubes while G has seven.

Regards,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jerry Ingordo <gjingordo@...>
Sent: Wednesday, October 24, 2018 3:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Hi Chris.
You have an early G plugin.  Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual.  Log in is simple, create a screen name and password and your in.  There may be a waiting period for new users to download.  If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

Re: 475 Probe Calibration problem with x10 probes

n2msqrp
 

Thanks. Has anyone tried Caig Labs Deoxit?

Mike N2MS


On October 24, 2018 at 9:44 AM "Colin Herbert via Groups.Io" < colingherbert=blueyonder.co.uk@groups.io
wrote:

This might indeed help, but be cautious when doing it. There are posts on
this forum where the correct technique is laid out - it is very easy to
damage the cam-operated contacts. Also, note that the material of the
attenuator board is a bit special and is easily damaged by heat and
various solvents. Briefly, the technique is to put a little IPA (isopropyl
alcohol) onto a sliver of ordinary paper and use that to clean the
contacts. Check that the contacts are open, slide the ipa-wetted paper
between them, close the contacts and then carefully pull the paper out
level with the board, as far as possible. This can be done a few times to
get all the contaminants off. You can probably ascertain which of the
attenuator contacts need cleaning by checking in the service manual as to
which attenuators are in circuit when the poor bandwidth is seen.
Good Luck, Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto: TekScopes@groups.io ] On Behalf Of
ef804s tubes
Sent: 24 October 2018 14:27
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 Probe Calibration problem with x10 probes

I have two 475 scopes. Both have developed a similar probe calibration
problem on one channel. I am using the scope calibration signal. I have
verified results with multiple probes

First scope - Channel 1 probe calibration tests fine with x1 and x10
probles. Channel 2 calibration tests fine with a x1 probe but the waveform
has a sloped rise and fall time when testing with a x10 probe on a
vertical sensitivity setting of .5v/div and above.

Second scope - Channel 1 probe calibration tests fine with x1 probes but
the waveform is a spike when testing with a x10 probe with vertical
sensitivity setting of .5v/div and above. Channel 2 probe calibration
works fine with x1 and x10 probes.

Has anyone seen this problem?

Mike N2MS

Hi,

please clean the attenuator contacts ans the pins of the attenuator blocks
as well.

Fred





Re: 475 Probe Calibration problem with x10 probes

 

n2msqrp
Oct 23 #151898

I have two 475 scopes. Both have developed a similar probe calibration problem on >one channel. I am using the scope calibration signal. I have verified results with >multiple probes

First scope - Channel 1 probe calibration tests fine with x1 and x10 probles. Channel 2 >calibration tests fine with a x1 probe but the waveform has a sloped rise and fall time >when testing with a x10 probe on a vertical sensitivity setting of .5v/div and above.
Second scope - Channel 1 probe calibration tests fine with x1 probes but the >waveform is a spike when testing with a x10 probe with vertical sensitivity setting of >.5v/div and above. Channel 2 probe calibration works fine with x1 and x10 probes.

Has anyone seen this problem?

Mike N2MS
(quote doesn't seem to work so I put the little arrows in like Usenet, hope it is clear enough)

Unless those switches are dirty at many ranges or something it is not really likely they need to be cleaned and that is it. Therefore, troubleshooting is in order.

A look at the front end on the print tells that in .5V/div and up the X100 attenuator is switched in the circuit. It is bypassed at the more sensitive rages. I assume here that when you wrote "and up" you meant higher in V/div. because "sensitivity" could be expressed the other way, more sensitive being <V/div.

Also note that the X100 is the first in line so is most prone to damage by ridiculously high voltages. (that can happen when they DO NOT LISTEN ! - KEEP IT IN 10X AT ALL TIMES UNLESS YOU REALLY NEED THE GAIN. Better to fry the 9 meg or whatever resistance in the probe than the front end of the scope.

The print does not give details on the internal of the attenuators, and with further examination I find that they are a unit, encapsulated and everything. I'm sure you'll find plenty in the hen's teeth department.

As such, I say most likely there is a resistor in there that is blown open. I also say that most likely it simply goes from the input to the output. Its value should be calculable using the resistance of the output of the attenuator to common. (ground) Maybe 99X that measured value ?

What it is not saying is if all these attenuators are in one package. All but the X10 show no connection to common. (ground) This is more than unlikely so I suspect there is simply an attenuation "block" of sorts. You'll have to determine which pins need the resistor.

Either that or replace it/them. If there are separate ones for each channel at least you can make one good scope out of the pair. If there is only one for both channels you are up the creek.

Actually it occurs to me now that you HAVE a good channel, a precision ohmmeter will tell you the value of resistor you would need to jump it out in the bad channel. You'll have to build that no doubt, unless you know where to buy like a 9.04256 megohm or whatever it is. Be mindful of RF/EMI, keep the leads short and straight as possible.