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I recently got a 453A with a shorted power transformer. This short is at the primary side to earth.
As the technical manual does not specify the secondary voltages, I am looking for someone who can inform me about this.
I know the 435 and 454 have similar dc power circuitry connected to these transformers, so I wonder if a transformer from these scopes could be used. I noticed the cooling fan is connected to the secondary side as for the two other models, it is connected to the primary 115V side.
Any help would be appreciated.
Thanks in advance.

Jeff,

These would be pretty easy to make on a small home metal lathe either from steel pipe or rod, if you had one as an example. Not sure where you are located but there might be someone near you on one of these these electronic forums that probably has a second hobby (automotive, machining, etc.) using a lathe. You could end up with a near exact match. A 1/4-28 NF tap is less common than a 1/4-20 NC but are still pretty cheap (~US$3 online).

Regards

Don't forget that you could add washers under the nuts to help extend the length of threaded shaft that it keeps covered/protected.--EricSent from my Galaxy

I just received my shipment of brass threaded inserts and they are slightly shorter than the proper thumb nuts, but they are still more than adequate replacements. They do not interfere with nearby connections, and they are not nearly as ostentatious as I had feared they would be. Their length means, however, that they would not protect the ends of the hollow shaft of the binding post like the original thumb nuts do (which are slightly longer than the shaft they thread onto).

I have one more shipment of candidate parts coming. I will report back once they arrive.

-- Jeff Dutky

Thomas,

The problem with Step 3 is that when a lot of our physical infrastructure was built, prior to the 20th century, you HAD to build industrial centers near water because that was your main source of power, and the best method of transporting materials in and out. Even after the construction of railways, invention of the steam and diesel locomotives, and the harnessing of electric power, lots of industries needed an efficient means of evacuating waste heat from their factories, and a waterway was convenient and effective. Other businesses, and the people who worked in them, built near the industrial centers as well, and that is where we find ourselves today.

Addressing climate change, or addressing our vulnerability to it, is going to be unavoidably expensive. The only question is whether it will be more expensive to do nothing. Also, yes, there are considerable geopolitical difficulties in addressing climate change, including a thorny free rider problem (or maybe it's a prisoners dilemma), as well as considerable headwind from the sunk cost fallacy. Maybe some tragedy of the commons too, but it's been a long time since I took macro economics and I don't bother to recall most of it.

In the meantime, we have to address the problems when and where they happen, because we can't just snap our fingers and have everyone moved out of the way of potential harm, no matter how foreseeable that harm might be. My personal policy, in response to these kinds of disasters, is to give to established aid organizations, because money moves easier than goods, and the aid orgs have the logistics in place to efficiently transform money into action on the ground.

-- Jeff Dutky

John,

There's also the Type 1A2 that is roughly the same thing as a Type CA in terms of functionality (quite a bit wider bandwidth though). I have one that came with my Type 547 estate sale find, and I'm really not using it much. Would consider a trade for other stuff. :o)

Sean

I’m sorry but the biggest polluter in the world is a communist dictatorship. ?And they have stated unequivocally that they are not reducing output but rather they intend to increase it.Sorry again but there is zero PROOF that a few degrees of temperature change is generating floods, hurricanes, wildfires or any other catastrophes. ?You are being manipulated into accepting the new world order on the flimsiest evidence imaginable. ?We were told 15?years ago that Manhattan Island would be underwater by 2020. ?Sea level there has changed about 3 inches. ?There are a slew of possible explanations for the slight temperature changes including the most likely culprit, solar cycles. ?I know the chicken littles out there have convinced themselves, but a little independent research wouldn’t hurt.
George


Sent from AT&T Yahoo Mail for iPhone

another covid free new south welshman from mount warrigal ,wollongong.
VK2TKE

I don't know about things post-covid, but in the past, you could find:

Production overrun parts
Tools, hand and air
Industrial items, production tooling, fixtures
Surplus Tek test equipment
Test leads, probes, cables
Warranty return items (Danger! Will Robinson)
Office equipment and supplies
and ??? else.

Worth a visit if you are near PDX
JimMc

I lucked onto a 544 advertised in the Santa Fe craigslist.
The 1A1 seems good for most use cases. mine is "The third model, from ??? until the end has four-sided V/cm knobs and a FET front-end."


1A4 seems good for emulating Jim Williams with lots of traces displayed...

1A5 seems like a fine one, and can use the P6046 diff probes, (but I'd have to do the cal for P6046, which is long and detailed, and I have P6046's already matched to amps that stay together and work in any scope.)

1A7A would be nice -- same features as 7A22, more sensitive than the 1A1...

Hi All,
My thanks to Jim for the kind words. It's been a year and a half since my loss and I'm integrating that into my life. If the group can indulge me with a quick off topic comment, that would be appreciated. American Society does a very crappy job of dealing with loss, grief and the afterwards of that (whether that loss is a person, a pet, etc). Statistically, about 1/2 of you in this group will deal with great personal loss. And most of you will have a friend that great loss happens to. I can most strongly recommend the book "It's OK That You're Not OK: Meeting Grief and Loss in a Culture That Doesn't Understand" by Megan Devine. It is a book that both helps the person undergoing the loss or can help you understand how you can really help a friend going through it. Free grief classes are also available at most major medical institutions. If anyone would like to discuss further, please PM me. Thank You for the bandwidth and now back to our regularly scheduled Tek repair discussions. :) Gordon

One of my postponed projects is the construction of temperature probes
for my DM5xx meters - mostly because I have some 2 pin Lemo connectors
and a DM501A with no probe.

My research, so far, has turned up the following:

Module Probe Probe type
DM501 P6058 diode connected transistor (also P6601????)
DM501A P6601 Platinum RTD
DM502 P6439 diode connected transistor
DM504 P6602 Platinum RTD
DM511 P6602
DM5110 P6602

and Heraeus RTD sensors can be bought for a reasonable price (around
$5.00 or less) from Digikey.

Thank you both for the ideas/input on the probes. Reading between the lines I am hopefully understanding correctly the P6601 temperature probe is indeed the only option for the DM 501A, so I’m watching and waiting for the right opportunity there.

And thanks for the recommendation on the Probe Master probe set…looks perfect.

Anybody have any recommendations on a good source to check for the AA 501A parts I’m looking for?

Cory Oace

EJP thanks for that important information…to others as well.

So I’m realizing maybe some of my error in communication…I was assuming the reference “rear interface” was specific to the motherboard in the main frame. Does that terminology in this context actually refer to the backplane of the main frame? Like where the multi-pin connectors would be located on a main frame fitted with Option 2? If that’s the case I may have been confusing folks. None of my main frames have Option 2, and I don’t plan on implementing a home-grown retrofit. What I *am* interested in is a few specific interconnections mentioned earlier between main frame slots but just motherboard to motherboard using header pins and wire.

Cory Oace

To bring this back to topic, what are the sorts of things one finds at the store?? Still very curious even if I won't be able to shop there soon.Are the deals good?
? Dan

Good thought, could be that, but if the gain setting pot was intermittent, then I would expect it not to clip, since the amplifiers are designed to enable off screen deflection.

Perhaps another one?

Harvey

On Sat, Jun 6, 2020 at 09:40 AM, Dennis Tillman W7pF wrote:

Only one company is associates with bad IC sockets - that is Texas Instruments

Not all TI sockets were bad even if of course some could fail just like any other brands.
The one that stands out of the crowd is called C-95. In my opinion there is not a question
if it would fail but when. They were not only in TM500's but all over the place at that time.
Typically faults are intermittent and cleaning and reseating may help for some time but it
will eventually come back. If you see those in your instrument count on problems.
They are easily identified by the very unique profile on the short end.

Check on TekWiki here:

My three pictures at the bottom show it while the larger picture shows what I would not generally consider bad.

/H?kan

Great feedback Harvey. I should have thought to inject the timer signal . . . I'll give that a try.

Jared - i found your video a few days ago. Thanks for taking the time to create/upload it.

Sounds like it could be as simple as an intermittent pot in the horizontal section.

On Sat, Jul 17, 2021 at 07:57 AM, Jeff Dutky wrote:

To my mind this emphasizes the importance of close visual inspection for
diagnosis and repair. Sure, lots of things are not visible to the eye, but
some are, and you can save a lot of time and effort by doing the visual
inspection first.

That and your systematic approach, Jeff.

Congratulations!

Cherish that 7603. The big screen is soo nice. I hope you can get your Option 1 out.

Raymond