Date   

Re: Looking for an S52

Ed Breya
 

I thought powering up an S-52 was just recently discussed over the past week or so, and settled that yes it is possible, and yes, it will run on its own if powered up. The signal will come out if it's working, and can be viewed with a scope.

BTW I think the S-series heads are far more robust than one might think. As I reported a while back in some 7S12 repair discussions, every head problem I have found turned out to be caused by simple (and cheap) things not related to failure of TDs or samplers. Most were mechanical problems like loose SMA connector mounts or internal board connections, and one was a bad 2N3906.

Although the TDs and samplers are fragile and exposed to the outside world, if they were treated with respect in their original environments, they are likely OK. But, who knows the history of any particular unit? It's a crap shoot, but I've had good luck with them.

Ed


For sale: 7704/7904 frames, 576 Curve Tracer

Kevin Oconnor
 

I have a friend, not too eBay savvy, with some equipment to sell.
I don't think he is likely to try shipping these, so maybe local pickup only.
I believe all this stuff is in working order.
All is located in Coopersburg, PA, so someone in the NY area
could get the whole lot.


1 - 7704A mainframe
2 - 7904 mainframes
1 - 576 curve tracer
Plug-ins
7A12
7A26 x2
7A18
7B92 x2
7B92A
7B50
7B71
7A11
7D15 250mhz counter


I long ago got rid of all my 7000 series hardware and manuals, or I'd
likely take them. I'd expect to pay ~$1000 for the 576. The other stuff has
values in the $100-300 range. The lot might go for a deal.
I can PM interested parties the contact info.


Cover removal on a 2236 scope

bim.huck@...
 

I am sure this is a one off problem but here goes.


I have a 2236 scope that I have owned since new. I am guessing that would be close to 40 years!


I went to remove the case to clean a few controls and switches but it won't come off. I have had no trouble in the past with any of my other Tek scopes removing the covers.


It appears to be stuck around the front plate.


Any chance they might have put tape or some adhesive to hold it in place?


Again .... the cover has never been off.


Any and all suggestions welcome before I get physical with it.


Thanks.......Jim


Re: considering a 2213A with "fuzzy trace"

 

That sounds like a deal if you are prepared to do some maintenance.

The 2213A and 2215A were only available from 1985 to 1986 so these
oscilloscopes are old enough that the aluminum electrolytic capacitors
may be worn out.

I doubt there is any problem with the high voltage supply. Regulation
is all primary side so there is just not much to go wrong with it.

The focus resistor chain in models introduced in 1985 and earlier
(2235 and 2236) use carbon composition resistors. They may have
failed and it is an easy repair with the commonly available and
inexpensive VR and HVR series resistors. Later models starting with
the 2230 and I assume the 2220 in 1986 use more reliable high voltage
film resistors.

On Thu, 13 Oct 2016 10:36:56 -0400, you wrote:

I am probably going to look at a 2213A that is offered for sale locally
for $65. The seller's advert indicates "...owned this oscilloscope for
almost 30 years, but have rarely used it. When I tried to use it
recently the trace was very fuzzy, basically too fuzzy to use."

Before I look at this scope, I ask if anyone has any particular
suggestions for things to look out for. I suspect from the description
that it might be a power supply problem, but my past experience is
primarily with 453 and 454 series scopes, so I am asking if there's
anything in particular that I should be aware of- maybe any "major
flaws" associated with the 2213A? And if it is power-supply-related,
I'm hoping it's not HV, as I don't have any HV probes that go above 5 kV.

I don't see anything under Tekscopes "conversations" that seems to
apply. I've purchased the 2213A operations and service manuals for it
from Artek Manuals, and I'm looking them over, but it's a lot to digest.

Thanks in advance for any suggestions that others might have to offer.
My intent is to have this scope for a general purpose "hobbyist" bench
scope for audio and HF (to about 10 or 15 mhz) radio work.

Mike N4MWP


Re: Power supply odor

Ed Breya
 

I don't know if anyone among us knows the exact formulation of capacitor electrolytes, but the stink of a cooked Al electrolytic capacitor is usually similar to the that of leaked antifreeze burnt on a hot engine. I have always believed and still do, that it's some kind of glycol-based stuff.

Ed


considering a 2213A with "fuzzy trace"

Mike Dinolfo
 

I am probably going to look at a 2213A that is offered for sale locally for $65. The seller's advert indicates "...owned this oscilloscope for almost 30 years, but have rarely used it. When I tried to use it recently the trace was very fuzzy, basically too fuzzy to use."

Before I look at this scope, I ask if anyone has any particular suggestions for things to look out for. I suspect from the description that it might be a power supply problem, but my past experience is primarily with 453 and 454 series scopes, so I am asking if there's anything in particular that I should be aware of- maybe any "major flaws" associated with the 2213A? And if it is power-supply-related, I'm hoping it's not HV, as I don't have any HV probes that go above 5 kV.

I don't see anything under Tekscopes "conversations" that seems to apply. I've purchased the 2213A operations and service manuals for it from Artek Manuals, and I'm looking them over, but it's a lot to digest.

Thanks in advance for any suggestions that others might have to offer. My intent is to have this scope for a general purpose "hobbyist" bench scope for audio and HF (to about 10 or 15 mhz) radio work.

Mike N4MWP


Re: Looking for an S52

 

On Thu, 13 Oct 2016 10:11:47 -0400, you wrote:

On 10/13/2016 09:37 AM, David davidwhess@gmail.com [TekScopes] wrote:

Sorry, I lost track of the conversation.

I wonder if a 3S2 or 3S5 will power a S-52. Yep, the manual even says
so. I looks like it works in any S series sampling head instrument.

I did not find special instructions in the manual for powering it like
AncelB suggested but the theory section does mention that it only
requires +15 and -12.2 volts.
Well, I could power it up, but without the requisite plugin, how would I
determine if the durn thing actually works?

Ancel, I could send it out to you, and you could check it in one of your
plugins. If it works, then you could send me the money. If it doesn't
work, just send it back.

Mark
For simple testing, I think just to powering it up and looking at the
output on the fastest 50 ohm terminated oscilloscope which is
available would be sufficient. I am not sure if these drift out of
adjustment but my guess is that the most common failure is damage to
the tunnel diode from an external source.

The service manual has instructions for more complete testing but if
the output looks good, then I might forgo them because of the risk of
damaging the S-52.


Re: Looking for an S52

Mark Wendt
 

On 10/13/2016 09:37 AM, David davidwhess@gmail.com [TekScopes] wrote:
On Thu, 13 Oct 2016 08:06:00 -0400, you wrote:

On 10/13/2016 07:56 AM, David davidwhess@gmail.com [TekScopes] wrote:
On Thu, 13 Oct 2016 07:18:05 -0400, you wrote:

On 10/12/2016 06:29 PM, AncelB mosaicmerc@yahoo.com [TekScopes] wrote:
You can test it w/o a 7000.

Check it's manual for how to power it up directly.
Oh, I have a number of 7000 mainframes. I just don't have the 7S12
plugin that I can connect the head to.

Mark
A 7S11 will also work to power an S-52.
Don't have one of those either. ;-) Been on my list of wanted plugins,
along with the 7S12 and 7T11 but haven't pulled the trigger yet.

Mark
Sorry, I lost track of the conversation.

I wonder if a 3S2 or 3S5 will power a S-52. Yep, the manual even says
so. I looks like it works in any S series sampling head instrument.

I did not find special instructions in the manual for powering it like
AncelB suggested but the theory section does mention that it only
requires +15 and -12.2 volts.
Well, I could power it up, but without the requisite plugin, how would I determine if the durn thing actually works?

Ancel, I could send it out to you, and you could check it in one of your plugins. If it works, then you could send me the money. If it doesn't work, just send it back.

Mark


Re: Looking for an S52

 

On Thu, 13 Oct 2016 08:06:00 -0400, you wrote:

On 10/13/2016 07:56 AM, David davidwhess@gmail.com [TekScopes] wrote:
On Thu, 13 Oct 2016 07:18:05 -0400, you wrote:

On 10/12/2016 06:29 PM, AncelB mosaicmerc@yahoo.com [TekScopes] wrote:
You can test it w/o a 7000.

Check it's manual for how to power it up directly.
Oh, I have a number of 7000 mainframes. I just don't have the 7S12
plugin that I can connect the head to.

Mark
A 7S11 will also work to power an S-52.
Don't have one of those either. ;-) Been on my list of wanted plugins,
along with the 7S12 and 7T11 but haven't pulled the trigger yet.

Mark
Sorry, I lost track of the conversation.

I wonder if a 3S2 or 3S5 will power a S-52. Yep, the manual even says
so. I looks like it works in any S series sampling head instrument.

I did not find special instructions in the manual for powering it like
AncelB suggested but the theory section does mention that it only
requires +15 and -12.2 volts.


Re: Looking for an S52

Mark Wendt
 

On 10/13/2016 07:56 AM, David davidwhess@gmail.com [TekScopes] wrote:
On Thu, 13 Oct 2016 07:18:05 -0400, you wrote:

On 10/12/2016 06:29 PM, AncelB mosaicmerc@yahoo.com [TekScopes] wrote:
You can test it w/o a 7000.

Check it's manual for how to power it up directly.
Oh, I have a number of 7000 mainframes. I just don't have the 7S12
plugin that I can connect the head to.

Mark
A 7S11 will also work to power an S-52.
Don't have one of those either. ;-) Been on my list of wanted plugins, along with the 7S12 and 7T11 but haven't pulled the trigger yet.

Mark


Re: Looking for an S52

 

On Thu, 13 Oct 2016 07:18:05 -0400, you wrote:

On 10/12/2016 06:29 PM, AncelB mosaicmerc@yahoo.com [TekScopes] wrote:
You can test it w/o a 7000.

Check it's manual for how to power it up directly.
Oh, I have a number of 7000 mainframes. I just don't have the 712
plugin that I can connect the head to.

Mark
A 7S11 will also work to power an S-52.


Re: 2465A vertical jitter

 

If you use line triggering, does the vertical jitter on the trace
freeze into place at a sweep speed of like 1ms/div?

What does the ripple on the low voltage power supply outputs look
like?

On 12 Oct 2016 23:40:54 -0700, you wrote:

My 2465A is exhibiting jitter in the vertical axis. This jitter is present in all - traces, cursors, and readouts. There is no jitter visible in the horizontal axis.

The input to U600, the vertical output amplifier - measured differentially at R405 and R404, is stable. The output - measured differentially at L633 and L628 displays the jitter. I've "tweaked" both R638 (Gain) and R639 (Vertical Center) to make sure it wasn't a faulty pot. No change.

I'm suspecting U600, but I'm not in a hurry to try to replace it. I have a spare main board with U600 on it, although I don't know if the IC is good. I would like to refrain from replacing U600 until I can eliminate any other problem areas.

Any suggestions on what else in the vertical output might be causing jitter? Has anyone seen this, and fixed it by replacing U600.

I do have a TDS360 available for troubleshooting.

Thanks,

Gary Appel


Re: Looking for an S52

Mark Wendt
 

On 10/12/2016 06:29 PM, AncelB mosaicmerc@yahoo.com [TekScopes] wrote:
You can test it w/o a 7000.

Check it's manual for how to power it up directly.
Oh, I have a number of 7000 mainframes. I just don't have the 712 plugin that I can connect the head to.

Mark


Re: Power supply odor

 

I was just using it as short for ethylene glycol and propylene glycol.

On 13 Oct 2016 03:08:11 -0700, you wrote:

What caps use Glycol?

"Glycol" by itself isn't a compound - and nearly all in the Glycol group are odorless....

Ethylene Glycol, perhaps? But then, I've never heard of it in capacitor electrolyte.....


Re: Power supply odor

taylorvandy
 

What caps use Glycol?

"Glycol" by itself isn't a compound - and nearly all in the Glycol group are odorless....

Ethylene Glycol, perhaps? But then, I've never heard of it in capacitor electrolyte.....


2465A vertical jitter

Gary Appel
 

My 2465A is exhibiting jitter in the vertical axis. This jitter is present in all - traces, cursors, and readouts. There is no jitter visible in the horizontal axis.


The input to U600, the vertical output amplifier - measured differentially at R405 and R404, is stable. The output - measured differentially at L633 and L628 displays the jitter. I've "tweaked" both R638 (Gain) and R639 (Vertical Center) to make sure it wasn't a faulty pot. No change.


I'm suspecting U600, but I'm not in a hurry to try to replace it. I have a spare main board with U600 on it, although I don't know if the IC is good. I would like to refrain from replacing U600 until I can eliminate any other problem areas.


Any suggestions on what else in the vertical output might be causing jitter? Has anyone seen this, and fixed it by replacing U600.


I do have a TDS360 available for troubleshooting.


Thanks,


Gary Appel


Re: Tek 491 spec an + 7623A + 475A for sale for $100 (I think) on Craigslist

 

That is a hell of a deal. The part about "Must take all three." makes
me think it is $100 for all three instruments.

The 7623A looks like it has a reasonable set of plug-ins with a 7A26,
early 7A13, and 7B53A. I see covers and manuals also.

On Wed, 12 Oct 2016 20:33:25 -0400, you wrote:

Subject line says it all; looks like a good deal. Although not clear to
me from the listing if it's $100 "for all" or $100 "each". Location is
Manassas VA USA:

<http://washingtondc.craigslist.org/nva/ele/5825094771.html>

I have no connection with the seller. But if this deal is as good as I
think it is, then I'd like for the sale to go to someone from this group
who can appreciate it.

Mike N4MWP


Re: Power supply odor

 

Copydex rubber cement like adhesive is suppose to smell "fishy". Maybe
some other component disintegrated releasing the ammonia:

<https://en.wikipedia.org/wiki/Copydex>

The most common smell I run across in old electronics is from the
glycol leaking out of the big old style aluminum electrolytic can
capacitors.

On 12 Oct 2016 10:10:06 -0700, you wrote:

I have a 2465B that had a burning/fishy odor coming out of the fan exhaust. I removed the power supply and confirmed the odor was coming from it. I thought it was from those film capacitors whose plastic cases were cracked. Just to be safe I replaced all the film and electrolytic capacitors and reinstalled it. I let it run for a couple of days but the smell was still there. I removed the power supply again and gave it a good smell all over. Seemed the smell was coming from the center of the supply that housed the metal plate with plastic sides the sits between the boards. I concluded the smell was coming from the adhesive the held the plactic to the metal plate. I removed the adhesive with acetone and replaced it with some new 3M adhesive I had. Put the power supply back together and reinstalled it in the scope. No smell !! I have a small ball of the old adhesive and it sure smells bad. Wonder why I have newer run across this before with all the 24xx scopes I've repaired?


Re: Power supply odor

 

I wonder if the Tektronix guys had a list of such items like
replacement graticule squares and bottles of CRT vacuum.

On Wed, 12 Oct 2016 17:25:22 -0700, you wrote:

It might be a good time to buy a 2465B Smoke Replacement Kit. :)

Dennis Tillman W7PF


Tek 491 spec an + 7623A + 475A for sale for $100 (I think) on Craigslist

Mike Dinolfo
 

Subject line says it all; looks like a good deal. Although not clear to me from the listing if it's $100 "for all" or $100 "each". Location is Manassas VA USA:

<http://washingtondc.craigslist.org/nva/ele/5825094771.html>

I have no connection with the seller. But if this deal is as good as I think it is, then I'd like for the sale to go to someone from this group who can appreciate it.

Mike N4MWP

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