开云体育

Guys,
Apologies in advance if I am doing the wrong thing; I posted this question on the TM500 group a while back, but there seems to be little activity over there, while there is a lot of action here ( I have been following for quite a while), and a lot of it to do with the TM500 world. The question is as follows:

I have a couple of SG503s that I decided recently to “get working”. Largely successful to the extent that I can monitor the output level to the required accuracy without the special Knick knacks called out in the manual. But one interesting effect I notice on both units (to a greater extent on one than the other) is, that on the 5-10 and 10-20 MHz ranges, at the extreme low limit of the dial (below 5 and 10MHz respectively) the output falls away to zero. Only on these two ranges.

I have spent a bit of time rummaging around in the circuit, and at the moment it looks as if Q300 (the current source for the oscillator, driven by the leveling amp) can’t quite push enough current to keep the oscillator Q130 going. But before I spend a lot more time, I would like to hear whether this is a common effect, and whether there is a known solution.

Any advice gratefully received .

I have noticed the traceand cursor lines dip down slightly from left to right. They have a slight curve to them. Is there an adjustment that can be made to fix this easily ? The service manual is a little overwhelming.

Regards

Richard

Thanx for that, very helpfull !
搁别苍é

Hey Bob, chill it with the negativity. Let people use the tools they
want to. No one here is worse than the rest.

On Sat, Jul 24, 2021 at 2:00 AM Bob Albert via groups.io
<bob91343@...> wrote:

Roy, ESR is a sort of object for those trying to flount something special. Measuring it is usually a waste of time. If a capacitor's ESR has a high value, that is generally made obvious by a high D when measured properly on a bridge. If you need capacitance, you probably don't want a high D, whether that is from ESR or leakage.
For several years a popular DIY project was to build an ESR tester. I don't think they are worth much. For some reason, most people prefer the short cut of measuring a capacitor with a DMM that has a capacitance function, and those that use them generally have no idea how that device performs the measurement. A proper bridge is the way to test capacitors.
Bob
On Friday, July 23, 2021, 12:59:54 PM PDT, Roy Thistle <roy.thistle@...> wrote:

On Thu, Jul 22, 2021 at 05:00 PM, Ronan wrote:

my topic is not spam

Hi Ronan:
No worries:
Anything, and everything, I post (unless it's in quotes) is all and only just my opinion. (The moderators are the arbiters, not me.)
Thus, it's just and only my opinion that the posts about ESR Meters, on TekScopes, are spam.
To explain... ESR is a parasitic parameter that appears in the component model(s) for a particular realisation of capacitor(s).
ESR has its own parameter(s)... like frequency.
As such, I think the way ESR is popularly interpreted is baloney.

--
Roy Thistle

Here's an article on repairing and servicing these push button switches I just uploaded.
I have serviced a tone of these in my TM500 modules and with a little care, it's relatively easy to do, most often you don't even need to remove them from the PCB.

/g/TekScopes/files/Tekscope%201975%20V7%20N4%20Repairing%20Push%20Switches.pdf

To clean them, I disassemble the switch, clean all the parts with isopropyl alcohol and a small paint brush/Kimwipes (Using a q-tip to scrub inside the switch body), then I use a new q-tip to apply Deoxit red inside the switch body along with some Deoxit on the spring contacts that sit in the central plunger, then finally a reaallllyyy thin smear of plastic safe lithium grease on the plunger and reassemble. I find holding the spring contacts in place in their recesses on the plunger and inserting the whole assembly into the switch body from the rear is the easiest way.
With a little practice, you'll get the feel for it.


Jared.

The following files have been uploaded to the Files area of the [email protected] group.

• /Tekscope 1975 V7 N4 Repairing Push Switches.pdf

By: Jared Cabot <jaredcabot@...>

Description:
How to repair and service push button switches

The thing everybody forgets about 3D printing is that there is no economy of scale once you've amortized the costs of building the model. However I sell things through Shapeways and I consider their pricing much too high. I can only slap a 20% margin on my things at best and remain within the bounds of sanity. OfficeWorks in Australia charges $15 for 15 minutes, again too high. But it's mostly human intervention of course.

However you don't need Shapeways or Tek production quality on these. They only have to hold the side on for opening once a year, and they only need to be considerably better than the sticky tape we've all been using, which isn't hard.

I can print 10 on my $200 home 3D printer in under an hour. As a service to Tek group members I'm prepared to do so for $15 per set of 10, as long as people don't mind removing a bit of stringing and trimming and tolerating a maybe 10% failure rate. Heat gun or hair dryer requried for assembly. Postage from Australia 3182. Don't all shout at once please ;-)

EJP

Greetings,

I used a Dial Thickness gauge AKA snap gauge on the pages of my 1960 Tektronix 517A manual. It indicated the page thickness at 0.0054 inch.

Examining several paper weight to thickness charts I found the following:

24 pound bond = 0.0050 inch

28 pound bond = 0.0060 inch

I did find a reference to 100 pound Coated Text Dull paper stock = 0.0054 inch

I did not find a reference for 26 pound bond.

I hope this helps.

If you have an original Tektronix manual and access to a local print shop, not an office supply store or copy shop, but a place with real offset printing presses, they may be very willing to help determine exactly what paper you seek.

Regards,

Ken

Jeff,

I contacted and worked with Lacy Communications on eBay: to see about getting a 2236 manual. He went to the trouble of finding and correcting a pdf to print up a manual. I think he is very helpful and eager to create a useful facsimile of needed manuals.

Perhaps reach out to him to see if he can build the manual you need. If he doesn't already have it on hand.

Dave

Gary Robert Bosworth <grbosworth@...> updated the album TDS2014B screen bottom malfunction: The bottom 1/2 inch of my screen is smeared. I tried to send a photo of my screen, but it did not seem to go through correctly.

Can anyone point me in the direction of what is wrong with my TDS2014B when the bottom 1/2 inch of the display screen is smeared? I will try to send a photo, but at this point I cannot attach the photo to this post.

Thanks, Jeff.

Actually I don’t think this is that issue. The buttons are not “sticky”. This is a different mechanical issue. The resistance mode button, if not held when pressing other buttons, can hyper extend past its normal stop a little bit. That’s not normal. And like I said if it is held in a little the other buttons will latch, and their action is crisp when released. It’s not that feeling like they got costed in honey I’m dealing with on some of my other modules.

Just by memory of the feel, I'd say 24# or 26#

Harvey

I'm resorting to printing one of my own manuals (which doesn't appear to be available in hard copy from the usual suspects, and is thankfully relatively short). I've got it printed now on normal 20 lb paper, but it's much flimsier than the original manuals I have. I'm looking into making a much nicer copy with blue covers and comb binding, and would like to get closer to the quality of the original article.

Does anybody know what weight of paper was used to print the old manuals? If not, I guess I just buy some reams of heavier weight papers and see what feels right.

-- Jeff Dutky

Beware of aluminum electrolytics being sold on the internet. Many of them
have sat on a shelf for more than 30 years and they have developed
corrosion inside which renders them worthless. You can't even remove the
impediment with a high voltage and current limiting.

On Fri, Jul 23, 2021, 17:00 Bob Albert via groups.io <bob91343=
[email protected]> wrote:

Roy, ESR is a sort of object for those trying to flount something
special. Measuring it is usually a waste of time. If a capacitor's ESR
has a high value, that is generally made obvious by a high D when measured
properly on a bridge. If you need capacitance, you probably don't want a
high D, whether that is from ESR or leakage.
For several years a popular DIY project was to build an ESR tester. I
don't think they are worth much. For some reason, most people prefer the
short cut of measuring a capacitor with a DMM that has a capacitance
function, and those that use them generally have no idea how that device
performs the measurement. A proper bridge is the way to test capacitors.
Bob
On Friday, July 23, 2021, 12:59:54 PM PDT, Roy Thistle <
roy.thistle@...> wrote:

On Thu, Jul 22, 2021 at 05:00 PM, Ronan wrote:

my topic is not spam

Hi Ronan:
No worries:
Anything, and everything, I post (unless it's in quotes) is all and only
just my opinion. (The moderators are the arbiters, not me.)
Thus, it's just and only my opinion that the posts about ESR Meters, on
TekScopes, are spam.
To explain... ESR is a parasitic parameter that appears in the component
model(s) for a particular realisation of capacitor(s).
ESR has its own parameter(s)... like frequency.
As such, I think the way ESR is popularly interpreted is baloney.

--
Roy Thistle

Roy, ESR is a sort of object for those trying to flount something special.? Measuring it is usually a waste of time.? If a capacitor's ESR has a high value, that is generally made obvious by a high D when measured properly on a bridge.? If you need capacitance, you probably don't want a high D, whether that is from ESR or leakage.
For several years a popular DIY project was to build an ESR tester.? I don't think they are worth much.? For some reason, most people prefer the short cut of measuring a capacitor with a DMM that has a capacitance function, and those that use them generally have no idea how that device performs the measurement.? A proper bridge is the way to test capacitors.
Bob

Cory,

sounds like classic gummy lubrication on the latches for those pushbuttons. Some spray lubricant usually does the trick, but it might only be temporary. The real solution is to get some more permanent lubrication in place, e.g. light machine oil. There's a flat spring over the front of each latching switch and I try to get some oil on each of those springs, then exercise the switch a bunch of times to get things loosened up and work the oil in to the mechanism.

For my instruments I have been spraying DeoxIT into the back end of the push switch and exercising the switches. If the switch is still sticky I hit the front with some WD-40, on the basis that it will penetrate the gummed up works better. That's been working so far, but I suspect that the WD-40 will evaporate and what remains may get gummy again. So long as that takes more than a few years, though, I'm happy. If they gum up more quickly than that I will try using light machine oil instead.

-- Jeff Dutky

Morris Odell <vilgotch1@...> added folder /Time delay relay hack

---

The following files have been uploaded to the Files area of the [email protected] group.

• /Time delay relay hack/timedelayrelay.pdf

By: Morris Odell <vilgotch1@...>

I have uploaded the schematic of my time delay relay hack to a new folder in the files section

On Thu, Jul 22, 2021 at 05:00 PM, Ronan wrote:

my topic is not spam

Hi Ronan:
No worries:
Anything, and everything, I post (unless it's in quotes) is all and only just my opinion. (The moderators are the arbiters, not me.)
Thus, it's just and only my opinion that the posts about ESR Meters, on TekScopes, are spam.
To explain... ESR is a parasitic parameter that appears in the component model(s) for a particular realisation of capacitor(s).
ESR has its own parameter(s)... like frequency.
As such, I think the way ESR is popularly interpreted is baloney.

--
Roy Thistle