Date   

Re: TM 500 Digital Multimeter Recommendations

 

Be careful with blindly selecting the DM501/a, 502/a DMMs. there's a LOT of switch contacts in there,
with MANY interacting poles. I have found every single one of these to need service on the switches, and
I am certainly not alone in that regard.  they just do not age so well, thanks to the switches.

the DM504A has a dramatically reduced and simplified switch count, and looks and works a lot better
than a long-in-the tooth DM501-502A.  just saying, if you are going to have only one, look for the really
good one.

again, only my $0.02 worth on this topic. sadly, I see none on ebay at the moment.

regards,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)


Re: eBay / PayPal Changes and our alternatives

Shirley Dulcey KE1L
 

PayPal WAS owned by eBay at one time. eBay bought PayPal in 2002 and spun
it off to its shareholders in 2015. (PayPal became a public company, but
initially all the stock was given to eBay shareholders.) After that the
companies had a partner agreement.

eBay announced that Adyen would become their primary payment processor in
2018 and Adyen started to handle credit card payments for eBay in 2019.
PayPal remains a secondary payment processor, and you can still use PayPal
to process a credit card transaction by selecting PayPal payment and then
choosing to use your card (rather than a balance) on the PayPal site.

The transition of seller payouts to Adyen did not happen until this year.

The reason for the switch appears to be money. Adyen paid eBay $70 million
in cash and $83 million in stock to become their primary payment processor.
It's also possible that data privacy was an issue; European customers may
have been reluctant to give banking information to a US-based company, a
country with weaker privacy laws than the EU. PayPal is the devil we know,
but our data may actually be safer with Adyen. (Of course there is also the
fact that PayPal already has the info for many of us, so changing
introduces another point of attack.)

Aside from the matter of having to give banking information to a non-US
company, issues with Adyen include that their fee structure is less
transparent than PayPal's, and that there is no option to get a cash-back
debit card. I usually spend any money I receive from PayPal with that card
and get back 1.5% of what I spend, effectively cutting the PayPal
transaction fee in half. (New debit card holders only get 1%; I got in
early.)

On Thu, Aug 6, 2020 at 11:41 AM Michael W. Lynch via groups.io <mlynch003=
yahoo.com@groups.io> wrote:

Dennis,

I always "assumed" that was the case, as I am sure that others did as well.

Being a contractual/partnership relationship, that makes the final results
less "bizzare". Easier to get rid of a partner than an arm or a leg.

Thanks for the correction.

Sincerel,

--
Michael Lynch
Dardanelle, AR




Re: 7834 Missing Trace

Roger Evans
 

Minor addition - the highest voltages on these boards are the +/- 15V.

Roger


Re: 7834 Missing Trace

Roger Evans
 

That is a very illuminating picture! The two boards that you see edge on in your first picture, one of which is the A6 Logic Board, connect through to the main interface board (the one about 1cm or so to the left, it carries the four plugin connectors) via a whole host of gold plated pins and sockets. If you look at the A6 Logic Board schematic, <4> in the manual, then there are a run of connectors on the left and right hand edges of the schematic with two letter labels like FA, FS, GG,GE .... These carry most of the signals that are routed to the Logic Board from the plugins, in particular these pins carry the Z axis signal (FQ) and the A and B intensities (FV and FU at the bottom of the schematic). The board, probably isn't bent, just very badly misaligned, either through a ham fisted repair or a severe knock. So it is quite likely that the relevant connectors are on the side that is not inserted properly and have moved that crucial millimetre when you removed the plugin!

Reassembling these board pairs can be a pain since you need to align so many pins at once, Tek made it a lot easier by arranging for the sockets to be slightly oversized at entry and tapering down farther in. If you do decide need to separate the boards, make sure nothing is bent (it is not a disaster if they are, just a good bit more difficult) or broken, and reassemble. It would be very worthwhile to have a look at the corresponding place on the left hand side of the chassis to see if there is anything amiss there that could explain why the left hand vertical slot is not working.

Since the scope was working a day or two back you might get away with just trying to realign the A6 board in place and not worry about disassembling too much. You do run the risk of a moderate bump in future causing the board to move again.

Hopefully you will have a very rare and desirable scope working again fairly soon. Then it would be time to worry about the calibrator issue. To dispel any doubt about the calibrator and how the manufacturers of a DMM have interpreted RMS readings I would just measure a DC supply and see how far the trace moves when you move the input coupling selector between GND and DC.

By the way, the traces on storage CRTs are nothing like as bright as the standard CRTs, they should be very sharply focussed and as soon as the trace starts to broaden turn the brightness down.

Good luck with the repair.

Roger


Re: TM 500 Digital Multimeter Recommendations

robeughaas@...
 

I would avoid the TM501. It is an object lesson in the difference between accuracy and precision. It is precise to 4 1/2 digits; it is not accurate to 4 1/2 digits. It has an A/D converter made of op amps and discretes which is not stable. It has a high-frequency isolated power supply which contributes noise. Every Tek DVM after the DM501 used IC A/D's and a quiet linear isolated supply using an on-board 60-Hz transformer.

Like Walter, I like the DM504A. I have one on my bench. But the problem with the DM504A is that it is self-calibrating. The calibration procedure is guided by the internal microprocessor but you must have the specified voltages, currents and resistances at the proper times. This requires a Fluke Meter Calibrator.

I had a DM504A with bad AC accuracy which was caused by a leaky C104 33uF Tantalum. I replaced it with an aluminum electrolytic. I had another DM504A go totallly nutzo, which appears to be unredeemable.

Bob

--
Bob Haas


Re: TM 500 Digital Multimeter Recommendations

Stephen
 

On Thu, Aug 6, 2020 at 04:54 AM, Andy Warner wrote:

Interleaved answer.

There can be a myriad other reasons for an updated model including: cost
savings, customer requests, component EOL.
It doesn't always have to be monotonic progress towards ever improving
specs.
Apparently...

I will admit to not owning *a single* meter that has V & I on the same pair
of jacks.
V & I???? I don’t understand what you mean.

I have a couple of DM501A modules, they are fine workhorse meters - if you
can find one at a price you like, get it.
That was my first impression, just a gut feeling. I just needed a confirmation.

Thanks


Re: eBay / PayPal Changes and our alternatives

 

I missed this follow-up announcement from eBay on April 19, 2018 which says
buyers will still be able to use PayPal to pay for goods until July 2023.
After I read this my conclusion was that this notice was very carefully
written to deliberately avoid any mention at all about eBay requiring
sellers to switch to Ayden which they will still have to do. That tells me
that eBay still thinks they can force sellers to move to Ayden.
Ebay must be very confident they will not lose many sellers by making them
switch to Ayden. Time will tell.
Dennis Tillman W7pF
------
eBay and PayPal today confirmed the signing of a previously-announced
agreement to offer PayPal as a way to pay on eBay until July 2023. This new
agreement builds on the payments partnership between the companies to make
PayPal available as a payment option on eBay's new intermediated payments
model.

"PayPal has been a great partner for eBay, and as part of our new payments
experience PayPal will continue to be a key form of payment for our global
customers," said Devin Wenig, president and CEO, eBay. "We are pleased to
continue to offer PayPal as a form of payment on eBay and look forward to a
continued, strong partnership with PayPal going forward."
------
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dennis
Tillman W7pF
Sent: Tuesday, August 04, 2020 4:41 PM
To: TekScopes@groups.io
Subject: [TekScopes] eBay / PayPal Changes and our alternatives

I believe the following excerpts from a Feb. 1, 2018 eBay announcement
should be viewed with skepticism until the details become clear. I thought
that it was important to repeat these parts of the announcement since many
members of TekScopes are current users of eBay and of PayPal and may not be
aware of the upcoming changes on eBay.
------
On Feb. 1, 2018 eBay announced that it will be replacing PayPal with Adyen
as its primary payments provider.
Ebay will continue to let customers use PayPal as an option for checking out
until July 2023, but most of eBay's payments will be processed by Adyen by
2021. Adyen, a start-up based in the Netherlands, is an online payment
company that provides businesses with backend payment services including
credit card processing and point-of-sales (POS) systems.

Ebay explained that its decision to integrate Adyen's payment processor
would result in lower costs and more control of finances for its merchants.
EBay said its partnership with Adyen's technology would enable sellers to
have a more central view of their data, and to manage and track all
transactions and customer interactions via eBay. EBay said that the
integration of Adyen would also provide customers with "greater choice" when
checking out. "We believe that we can offer a more seamless experience while
giving buyers and sellers more choice for payment and payout options," eBay
Chief Executive Devin Wenig said on a conference call with analysts. The
move is a part of eBay's strategy to "transition to full payments
intermediation," the firm said.
------

One member already mentioned there is a Groups.io site dedicated to the
exchange of Test equipment. If you are interested the link is here:
https://groups.io/g/Test-Equipment-For-Sale-Wanted-or-Exchange

If there are other alternative sites we should know about please let us know
about them. Please provide a link in your reply and indicate if you have any
actual experience with them.

Dennis Tillman W7pF





--
Dennis Tillman W7pF
TekScopes Moderator


Re: TM 500 Digital Multimeter Recommendations

Andy Warner
 

There can be a myriad other reasons for an updated model including: cost
savings, customer requests, component EOL.
It doesn't always have to be monotonic progress towards ever improving
specs.

I will admit to not owning *a single* meter that has V & I on the same pair
of jacks.
I am surprised how prevalent they are among this group.

I have a couple of DM501A modules, they are fine workhorse meters - if you
can find one at a price you like, get it.

On Thu, Aug 6, 2020 at 10:21 AM Stephen <stephen.nabet@gmail.com> wrote:

On Thu, Aug 6, 2020 at 03:33 AM, Colin Herbert wrote:


The first decent-looking one you see on eBay/other offer?
Colin.
Yes, but the reason I’m asking in the first place is that The 501/A is, on
paper, more precise and has 4.5 digits as opposed to the 3.5 digits on the
502/A.
So is there a not so obvious reason to get a 502/A instead of a 501/A? It
would seem that the 502/A would be an improved version of the 501/A, but
the specs seem to apparently indicate otherwise.



--
Andy


Re: eBay / PayPal Changes and our alternatives

Michael W. Lynch
 

Dennis,

I always "assumed" that was the case, as I am sure that others did as well.

Being a contractual/partnership relationship, that makes the final results less "bizzare". Easier to get rid of a partner than an arm or a leg.

Thanks for the correction.

Sincerel,

--
Michael Lynch
Dardanelle, AR


Re: eBay / PayPal Changes and our alternatives

Michael W. Lynch
 

On Wed, Aug 5, 2020 at 11:14 PM, EJP wrote:

It is a sign that people have stopped, or been stopped from, selling this
stuff on e-bay.
Sadly, for those of us in rural areas, E-Bay was one of very few opportunities that we had to get our hands on a wider selection of this gear. Not living in or near a large metro area, there are not the swap meets, large hamfests, electronics resale shops and other sources available to myself and others to obtain this gear at reasonable prices. We have one local Hamfest, which did not happen this year and there are a limited number of enthusiasts in my area.

Loss of e-bay has been no loss to me for several years.<
I am not willing to move to a large metro area to alleviate this problem or facilitate my hobby. So the loss of E-Bay as a reasonable source for test gear has been a major blow. I was fortunate enough to get my hands on some good buys before this madness started. Pricing and shipping, for the most part, are totally out of reason for me at this point. Equipment that I bought two years ago for almost nothing, is now going for an outrageous price and outrageous shipping. I suppose I will need to shop a lot harder and be more selective of what I buy, going forward. Or perhaps, I do have enough test gear?

> The PayPal situation is truly bizarre. It was orignally part of e-bay, then
they spun it off.
Yes, the relationship between E-Bay and PayPal has taken a bizarre twist over the years.

Good times!

Thanks!
--
Michael Lynch
Dardanelle, AR


Re: eBay / PayPal Changes and our alternatives

 

Hi Michael,
Like you, I also thought PayPal was originally "part of eBay".
But in fact PayPal and eBay had a partnership agreement.
Dennis Tillman W7pF

On Thu, Aug 6, 2020 at 03:10 AM, Michael W. Lynch wrote:
<SNIP
It [PayPal] was orignally part of e-bay, then they spun it off.




--
Dennis Tillman W7pF
TekScopes Moderator


Re: TM 500 Digital Multimeter Recommendations

Stephen
 

On Thu, Aug 6, 2020 at 03:33 AM, Colin Herbert wrote:


The first decent-looking one you see on eBay/other offer?
Colin.
Yes, but the reason I’m asking in the first place is that The 501/A is, on paper, more precise and has 4.5 digits as opposed to the 3.5 digits on the 502/A.
So is there a not so obvious reason to get a 502/A instead of a 501/A? It would seem that the 502/A would be an improved version of the 501/A, but the specs seem to apparently indicate otherwise.


DC 503A Universal counter Service Manual?

Colin Herbert
 

Hi,
I am hunting for a Tektronix original Service Manual for a DC 503A Universal Counter that I have purchased. I have a pdf of this Manual, but I really want an original hard-copy. I have a hard-copy of the DC 503 non-A counter and they differ significantly.
These manuals are difficult to find in the UK, where I live (London). I can find a few on eBay at reasonable prices, but the shipping from the US is generally more than the cost of the Manual. Does anyone have one that they are prepared to sell at a sensible price and with sensible-costing shipping?
TIA, Colin.


Re: TM 500 Digital Multimeter Recommendations

Colin Herbert
 

The first decent-looking one you see on eBay/other offer?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Stephen
Sent: 06 August 2020 15:21
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM 500 Digital Multimeter Recommendations

Ok so, of the 4 most easily available: 501, 501A, 502, 502A, which one would you recommend?


Re: TM 500 Digital Multimeter Recommendations

Stephen
 

Ok so, of the 4 most easily available: 501, 501A, 502, 502A, which one would you recommend?


Re: 7834 Missing Trace

sdferg7@...
 

Sorry about how many replies I'm making. I also noticed the PCB U4494 sits on is quite severly bent, as seen in this album: https://imgur.com/a/fsQ1DrN

I don't see anything shorted to the board behind it, but hopefully a trace isn't broken or anything. I don't believe there is high voltage on that board that could have arced across that gap; correct me if I'm wrong. Is there anything else I can try while waiting for the tool to be delivered?

Shane


Re: TM 500 Digital Multimeter Recommendations

Stephen
 

On Thu, Aug 6, 2020 at 02:39 AM, Colin Herbert wrote:


Is this such a big problem? Almost any multimeter, whether digital or
analogue, will surely have the same problems. Just be careful. As I have heard
before "A,B,C" - "Always Be Checking".
Colin.
Yep. On both my analog/tube DMM and my digital one I have to select what I’m measuring.
The only difference is that the digital one detects the measured range automatically, whereas the tube one has to be set to the right range being measured.


Re: TM 500 Digital Multimeter Recommendations

 

For a Tek TM500 DMM recommendation, I have to go with the *DM504A.*
it's 4 1/2 digit, auto-ranging, True RMS and has split connections for current, thus avoiding the
mis-selection trap of earlier models. plus, it supports temperature with the correct probe.
very simple user interface. spec says 0.07% DC accuracy, wow.  mine always tests better.

it also has the *best looking display Tek ever made in the TM500 series*. it's only detracting feature
is no dB, but I have learned to live with that. I now have one on every TM500 bench, and really
like them. it is also wickedly accurate, and holds the cal very well.  it is a much later design than other
units in the DM5xx series.

anyway, just my $0.02 worth on this topic. you can see info on this unit here:
http://w140.com/tekwiki/wiki/DM504
sadly, the pic does not show it illuminated, but it is outstanding.

all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)


Re: TM 500 Digital Multimeter Recommendations

Colin Herbert
 

Is this such a big problem? Almost any multimeter, whether digital or analogue, will surely have the same problems. Just be careful. As I have heard before "A,B,C" - "Always Be Checking".
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Göran Krusell
Sent: 06 August 2020 13:19
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM 500 Digital Multimeter Recommendations

Hi, do not pick the DM501 or the DM502. If you are measuring voltage and without thinking, like I often do, would turn the switch into the current range your object will be shorted by the multimeter and perhaps damage your object. This has been pointed out by another member some time ago.
Göran


Re: TM 500 Digital Multimeter Recommendations

Stephen
 

On Thu, Aug 6, 2020 at 01:18 AM, Göran Krusell wrote:


Hi, do not pick the DM501 or the DM502. If you are measuring voltage and
without thinking, like I often do, would turn the switch into the current
range your object will be shorted by the multimeter and perhaps damage your
object. This has been pointed out by another member some time ago.
Göran
Yes, I know they’re not auto-ranging. But, on the other hand, they’re also easier to find.
I’m usually very careful with these things, but you’re right, a mistake is never to be ruled out.
And I have made many in the past too.

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