Date   

Re: Fast probe prices?

snapdiode <snapdiode@...>
 

Yikes, with that layout, I am skeptical. What is the flatness over its bandwidth and what is its true -3dB point? It's basically an antenna: sure, it'll get a signal through, but you can't really rely on it for any kind of absolute measurements.

An SMA attenuator has to be 50 ohms on both its ports, so I don't see how it would be a problem, unless its terrible. Of course each extra connection is itself a potential discontinuity but that's unavoidable. Keep 'em clean, specifically inside the connector where you can see the dielectric. Any junk in there that creates an air gap can get problematic as you get up there.


Re: Fast probe prices?

Jonathan Pyle
 

I just ordered one of these, which I think does basically the same thing:

https://www.ebay.com/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope-RF-cable-included/332393676082

I am not sure about the voltage output so I also ordered some SMA feed-through attenuators to avoid overloading the input of my 1S1. (However, whether the use of attenuators introduces problems with impedance matching, I don't know.)

If you watch Mr. Carlson's Lab on YouTube, he has a similar circuit available on his Patreon:
https://www.youtube.com/watch?v=NlbC-cMIBTY
https://www.patreon.com/MrCarlsonsLab

The only downside is that you have to provide your own D.C. power.


Re: Fast probe prices?

snapdiode <snapdiode@...>
 

An active probe with hi-Z inputs and an amplifier to provide a 50 ohm output isn't cheap.

For the 1S1, I have the P6032 but it's only 850MHz and the plastics degrade quickly and STINK. Then there's the Type 282 Amplifier.

https://w140.com/tekwiki/wiki/282

I have a few lying around. Price is not too bad, this one went for 57$ US.

https://www.ebay.ca/itm/Tektronix-282-015-0074-00-Probe-Power-Adapter/291628446566?hash=item43e668f366:g:ftMAAOSwwE5WXKFP

Then you can find some sort of reasonable probe to hook up to that but of course there are few 500MHz+ passive probes since they usually have too high an input capacitance. Tek had the P6010 that was "wide bandwidth" but even it doesn't quite match the risetime of the sampler, and indeed it depends on the length of the cable.

You didn't say what you want to probe, if it's your own circuits I have put SMBs with a SMT resistor as a power-tap probe. Amplitude calibration is up to you, but you will get quite nice results, if you can live with the stolen power from the signal resulting in a lower signal amplitude. That's why I go for a 1K and use the 1S1. SMB cables aren't too expensive. Mating to the GR-874 is up to you.


Fast probe prices?

 

I just did a little searching for fast probes that match 50 ohm (sampling) inputs. The table on Tekwiki shows only P6150 or P6156 would have the necessary speed. But on ebay the prices are an unpleasant surprise!

If those prices are representative, I can see why a 453 ohm metal film resistor on the end of a piece of good (e.g. PTFE) 50 ohm coax is a common and far cheaper alternative, although the ground hardware still needs to be worked out...

Or the circuit has 50 ohm ports built into it, for direct connections with SMA cables...
thoughts?


Re: FG502 doesn't start at some specific settings

Eric
 

I had an FG 507 and a FG 501A both had very bizarre issues with them and the waveforms were terrible and would some times collapse to DC. I would recommend before you go down the rabbit hole too far clean the cam switch contacts on the timing cam. Then clean them again. Then clean them again. Through the repair process I cleaned them a few times and checked every part on the board. Replace a few filter caps then did a moderately aggressive clean on the timing cam switches. The 4th moderately aggressive timing clean did the trick it needed less then steel wool but more then paper and alcohol.

Both units had the same issue with dirty switches, your milage may vary. As I only have a sample size of 2.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of durechenew via groups.io
Sent: Sunday, March 21, 2021 7:45 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] FG502 doesn't start at some specific settings

For Mark,
I do not say it's not possible, but I believe no capacitor will warm up in a minute. Plus, there are conditions when it starts right-away (lower/higher frequencies).
There are (usually) two other plugins (DC502 and DM501A, great instruments - after some improvements) that always start and work without problem.
There is no IC in that stage.
A transistor with leakage current - one of the ideas I have in mind and didn't verify yet (specially Q204, Q210).

For Ozan,
Are +17V, "+17V (DCPL 1)", -17V, "-17V (DCPL 1)" on sheet <1> stable when cold (not working)?
Always stable (working or not) and (well) within spec, including ripple (I did a full calibration)

In the happy non-working state what are the voltages (partial list is OK if you don't have them all):
1) at the gate of Q200, and collector of Q292. As following: 1.124V at Q200-G, 1.116V at Q292-C (might be higher at gate of Q200, as I'm introducing in the circuit the input resistance of MM - 10 mohms; MM is a Fluke 179)
2) bases of Q230A and Q230B: -0.045V both
3) bases of Q290 and Q292: -9.01V both
4) emitters of Q140 and Q175: -6.47V at Q175-Base and 6.54 at Q140-Base (I don't have measurements for E, worth checking; but why would start at higher frequencies, same devices)

In case gate circuit is acting funny: Voltage at collectors of Q325 and Q315: I didn't verify if it's acting funny, but that circuit should have no influence as long as that input is without signal; and, again, why it starts at other ranges of frequencies?

What are the test points for the different traces?
Ch1: output of plugin (scope it's AC coupled, but no difference if in DC)
Ch2: Q292-C
Ch3: Q230B-B (Q230A and Q230B are pair in the same capsule, in my plugin; seems other SN had separated ones)
Ch4: Q230A-C (AC coupled, DC level is around -9V) Thanks for comments, got something to think about and do tomorrow TT


Re: Beware of old AntiStatic foam

stevenhorii
 

Thanks for the suggestions for the Xcelite handles! I will try them out. I
did try an “antifungal” treatment that worked for a while, but the white
cast came back.

On batteries - I now use rechargeable AA and AAA cells (I like the
Panasonic Eneloop) - these are nickel metal hydride. Never had any leakage.
The only downside of the NiMH chemistry is the 1.2VDC output. Devices that
don’t like a lower voltage (smoke detectors!) may warn you of a failing
battery. There is also a AA cell called a Tenavolts that is rechargeable
and has an output of 1.5VDC. I am not sure what their chemistry is because
most lithium chemistry cells are usually 3.6V but these are a single cell -
no “dummy” needed. They are also rechargeable. They do tend to have a very
flat discharge curve, but when they start to drop in voltage, they drop
fast. The Tenavolts cells come with a charger and I am not sure if other
lithium chargers will work. The Tenavolts cells are also very slightly
larger in diameter than the NiMH and alkaline cells - they will not fit in
at least one of the smoke detectors I have. I have also used the Tenavolts
now for about two years and no leakage problems - but that’s not a very
long time. The Eneloop cells are low self-dicharge cells, so they will
retain their charge for months after a full charge unlike older NiCd and
some NiMH cells. These are sometimes called “precharged” cells because they
come charged and you can use them right out of the package.

On recharging, I use chargers for the NiMH cells that allow a selection of
charging current. Fast charging tends to shorten the lifetime of the
batteries, so I use “soft” charging or 180-200 mA.

Most of the rechargeables do not have the current capability of alkaline
cells, so they won’t last as long in high current drain devices.

On Sun, Mar 21, 2021 at 17:38 - <rrrr6789@gmail.com> wrote:

Steven said:

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

That butyrate plastic deteriorates into butyric acid and yes, I'm told
that that is what gives vomit it's nauseating smell. It's similar to, or
the same, compound found in milk that is going bad so human reaction to
that smell is thought to be a survival mechanism. I soak those old Xcelite
tools in full strength household ammonia and then scrub them with a brass
bristle brush or a tough nylon pot scrubber and that will remove the white
film on the tools. You may need to repeat the process a few times.
Surprisingly, even a brass bristle brush doesn't seem to harm or to scratch
up the plastic handles (YMMV!) I've cleaned several dozens of Xcelite
tools like this over the past 6 or 7 years and I've never found any sign of
damage by cleaning that way.

On Sun, Mar 21, 2021 at 2:49 PM stevenhorii <sonodocsch@gmail.com> wrote:

I think polyethylene foam instead of the black polyurethane foam does not
have the “get goopy and stick to everything” problem. Has anyone had
polyethylene foam degrade like the black stuff? I have not - either black
or white polyethylene has stood the “test of time”. I have seen foam
rubber
turn to dust, but at least it does not (in my experience) get sticky.

Apparently the polyurethane foams also outgas as they degrade and this
can
leave deposits on stuff - think camera optics as many camera carrying
cases
use polyurethane foam.

If I have some custom-fitted black foam in a transit case, I put the item
in a plastic bag and before putting it back in the case.

Another “plastic rot” question. I have a set of Xcelite tools. One of
them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off
butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

A comment on Duracell batteries. I am pretty sure there are counterfeits
out there - particularly the “bulk packs” with no Duracell label on the
outside. Here’s an article on fakes:


https://www.thecounterfeitreport.com/product/106/Duracell-Coppertop-AA---AAA-Batteries.html

When I have had Duracell batteries (the AA ones in particular) leak, on
checking, they were the ones I bought in unlabeled bulk packs. I
generally
remove batteries from equipment I am not going to use frequently.

Steve Horii

On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info>
wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed
not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti
static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies
and
a multimeter that way, so now cells get removed from rarely used
items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that
were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen





















Re: FG502 doesn't start at some specific settings

Ozan
 

1) at the gate of Q200, and collector of Q292. As following: 1.124V at
Q200-G, 1.116V at Q292-C (might be higher at gate of Q200, as I'm introducing
in the circuit the input resistance of MM - 10 mohms; MM is a Fluke 179)
2) bases of Q230A and Q230B: -0.045V both
Q292C is connected to the diode bridge CR245/CR248/CR250/CR246. With 1.116V at CR245 cathode (and CR248 anode), CR245 should be off, CR248 should be on, CR246 should be on, CR250 should be off (this assumption can be confirmed using the Q230A base voltage from below).

In this condition all the current from CR248 is dumped to R248 and all the current from CR246 is dumped to R240. Expected base voltage of Q230A is:
97.6*(17-0.6)/(3.01k+97.6)=0.515V. However, you are measuring -0.045V. Most likely diode CR246 is bad or R245 could be bad (bad solder, bad resistor etc).

I would focus on the hysteresis bridge (bridge at the base of Q230a) first.

Ozan


Re: FG502 doesn't start at some specific settings

durechenew@...
 

For Mark,
I do not say it's not possible, but I believe no capacitor will warm up in a minute. Plus, there are conditions when it starts right-away (lower/higher frequencies).
There are (usually) two other plugins (DC502 and DM501A, great instruments - after some improvements) that always start and work without problem.
There is no IC in that stage.
A transistor with leakage current - one of the ideas I have in mind and didn't verify yet (specially Q204, Q210).

For Ozan,
Are +17V, "+17V (DCPL 1)", -17V, "-17V (DCPL 1)" on sheet <1> stable when cold (not working)?
Always stable (working or not) and (well) within spec, including ripple (I did a full calibration)

In the happy non-working state what are the voltages (partial list is OK if you don't have them all):
1) at the gate of Q200, and collector of Q292. As following: 1.124V at Q200-G, 1.116V at Q292-C (might be higher at gate of Q200, as I'm introducing in the circuit the input resistance of MM - 10 mohms; MM is a Fluke 179)
2) bases of Q230A and Q230B: -0.045V both
3) bases of Q290 and Q292: -9.01V both
4) emitters of Q140 and Q175: -6.47V at Q175-Base and 6.54 at Q140-Base (I don't have measurements for E, worth checking; but why would start at higher frequencies, same devices)

In case gate circuit is acting funny: Voltage at collectors of Q325 and Q315: I didn't verify if it's acting funny, but that circuit should have no influence as long as that input is without signal; and, again, why it starts at other ranges of frequencies?

What are the test points for the different traces?
Ch1: output of plugin (scope it's AC coupled, but no difference if in DC)
Ch2: Q292-C
Ch3: Q230B-B (Q230A and Q230B are pair in the same capsule, in my plugin; seems other SN had separated ones)
Ch4: Q230A-C (AC coupled, DC level is around -9V)
Thanks for comments, got something to think about and do tomorrow
TT


Re: Beware of old AntiStatic foam

Richard Knoppow
 

I mostly had problems with aa and aaa cells. The bad AA cells had two dots on the bottom.  These leaked when brand new.  Duracell stopped making them for a while . The current crop seem to be ok.Sent from my Samsung Galaxy smartphone.

-------- Original message --------From: Eric Schumacher <wb6kcn@sbcglobal.net> Date: 3/21/21 4:03 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Beware of old AntiStatic foam Hi KenHere's a second vote for energizers and a bunch of thumbs down for Duracell regarding corrosion. The only good news about Duracell "corrosion" on cell contacts is that CLR cleaner makes it disappear and your contacts look like new. I put corrosion in quotes because actual metal damage occurs much later and the CLR and stiff brush easily removes all that white dust and green stuff. My real question is Why do people buy those things???Eric  WB6KCN-----Original Message-----From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ken, WA2LBISent: Sunday, March 21, 2021 9:19 AMTo: TekScopes@groups.ioSubject: Re: [TekScopes] Beware of old AntiStatic foamThat old foam is awful stuff. I’ve had headphone head bands and ear padscrumble to dust. I’ve also lost ICs that were pressed into the foam.Foam-lined storage cases have damaged or destroyed stored items. Oldmicrophone inserts become dust. There are many other examples...A few years ago, after many leaking batteries - some still new in thepackage, I removed every Duracell battery from every device I own. I’velost a number of flashlights, kid’s toys, remote controls, etc. The worstis the damage done to my electronic test gear. I switched to Energizer and,since then, have not had a single device device damaged by battery leakage.The other item to check is the stick on feet used on so much equipment. Aswe know, they turn to a slimy, sticky mess that also gets on the adjacentsurface and is difficult to remove. At the very least, over time, they“migrate” from their original position and leave a slimy trail.<rant off>KenWA2LBIOn Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info> wrote:> As I've mentioned previously, the latest run of Duracell (guaranteed not> to leak before 10 years) does exactly that, and often in the package.>> The good news is that they will often give you money to replace the> damaged item if you call them.  Their warranty is "repair or replace",> but you do have to call.>> I've had the foam in probe cases crumble, (both HP and Tek), anti static> foam corrode and crumble, etc...>> Harvey>>> On 3/21/2021 9:50 AM, David Slipper wrote:> > Nasty!! I wonder what other time-bombs are awaiting us!?> >> > I'll certainly be checking my stock of bits and spares.> >> > I always assumed that a famous brand of NiMh batteries were supposed> > to be leak proof - Hah! I nearly lost a pair of nice walky-talkies and> > a multimeter that way, so now cells get removed from rarely used items> > and I make a point of checking torches and the like regularly.> >> > Sadly not surprised at anything these days,> > Dave> >> >> > On 21/03/2021 13:07, - wrote:> >> Well, this thread just showed up on EEVBlog.  This is exactly the> >> kind of> >> damage that I used to see happen to IC and to TE accessories that were> >> stored in the old antistatic foam.> >>> >> <> https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen> >>>> --KenWA2LBISent from one of my mobile devices


Re: Beware of old AntiStatic foam

 

Individual responses to butyric acids vary... it's in US chocolate (highest in Hershey's I think), so Europeans have been known to comment that it smells like vomit to them. Not to me! I also have a drawer full of Craftsman screwdrivers and although there is a definite odor, I don't find it unpleasant.

At the risk of aggravating the thread drift, I have replaced the batteries in many of my infrequently-used test equipment with lithium AA cells (expiration dates up to 2035 from the current batch). There are C-cell plastic adapters that hold one AA cell, and D-cell adapters that take two in parallel. No more leaks :)


Re: Beware of old AntiStatic foam

Eric Schumacher
 

Hi Ken

Here's a second vote for energizers and a bunch of thumbs down for Duracell regarding corrosion. The only good news about Duracell "corrosion" on cell contacts is that CLR cleaner makes it disappear and your contacts look like new. I put corrosion in quotes because actual metal damage occurs much later and the CLR and stiff brush easily removes all that white dust and green stuff. My real question is Why do people buy those things???
Eric WB6KCN

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ken, WA2LBI
Sent: Sunday, March 21, 2021 9:19 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Beware of old AntiStatic foam

That old foam is awful stuff. I’ve had headphone head bands and ear pads
crumble to dust. I’ve also lost ICs that were pressed into the foam.
Foam-lined storage cases have damaged or destroyed stored items. Old
microphone inserts become dust. There are many other examples...

A few years ago, after many leaking batteries - some still new in the
package, I removed every Duracell battery from every device I own. I’ve
lost a number of flashlights, kid’s toys, remote controls, etc. The worst
is the damage done to my electronic test gear. I switched to Energizer and,
since then, have not had a single device device damaged by battery leakage.

The other item to check is the stick on feet used on so much equipment. As
we know, they turn to a slimy, sticky mess that also gets on the adjacent
surface and is difficult to remove. At the very least, over time, they
“migrate” from their original position and leave a slimy trail.

<rant off>

Ken
WA2LBI


On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info> wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies and
a multimeter that way, so now cells get removed from rarely used items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen
--
Ken
WA2LBI

Sent from one of my mobile devices


Re: Beware of old AntiStatic foam

SCMenasian
 

Ages ago, several of my Xcelite tools developed the whitish handle disease. I figured, at the time, that it
was fungus and applied my standard lo-tech fungus treatment - vinegar. It did the trick.


Re: Beware of old AntiStatic foam

Harvey White
 

I've had the same white fuzz on tools as well.  In fact, my first Xcelite tool kit was odorous out of the box and I've seen the fuzz on a lot of stuff (Craftsman screwdriver, for instance).

On the batteries, these were bought at BJ's, had "DURACELL" plastered everywhere.

When I mentioned the "perfect until" date to the phone droid, I got no argument, just a check in the mail for a meter that had been ruined.  I'd be very surprised if these were fakes.  I do think they had a bad run of AAA batteries, and the AA ones leak when run dow to nothing (I think).

In the cases I have, the blue foam is toast, the gray foam is toast, and the white polystyrene foam is as good as it was on the day it was created.

Harvey

On 3/21/2021 2:49 PM, stevenhorii wrote:
I think polyethylene foam instead of the black polyurethane foam does not
have the “get goopy and stick to everything” problem. Has anyone had
polyethylene foam degrade like the black stuff? I have not - either black
or white polyethylene has stood the “test of time”. I have seen foam rubber
turn to dust, but at least it does not (in my experience) get sticky.

Apparently the polyurethane foams also outgas as they degrade and this can
leave deposits on stuff - think camera optics as many camera carrying cases
use polyurethane foam.

If I have some custom-fitted black foam in a transit case, I put the item
in a plastic bag and before putting it back in the case.

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

A comment on Duracell batteries. I am pretty sure there are counterfeits
out there - particularly the “bulk packs” with no Duracell label on the
outside. Here’s an article on fakes:

https://www.thecounterfeitreport.com/product/106/Duracell-Coppertop-AA---AAA-Batteries.html

When I have had Duracell batteries (the AA ones in particular) leak, on
checking, they were the ones I bought in unlabeled bulk packs. I generally
remove batteries from equipment I am not going to use frequently.

Steve Horii

On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info> wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies and
a multimeter that way, so now cells get removed from rarely used items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen












Re: Beware of old AntiStatic foam

-
 

"Yes my TEAC X-3 just had a "belt melt", it is hard ti understand why they
can't be made in silicone rubber now. That should be practically eternal in
comparison to my lifespan...."

Small drive belts are now made of Kevlar and are bright orange colored.
I used to buy mine from Florida Belting in Orlando, Florida. Excellent
service, BTW. I repaired a ton of HP desktop calculators using their belts.

On Sun, Mar 21, 2021 at 2:26 PM snapdiode via groups.io <snapdiode=
yahoo.com@groups.io> wrote:

On Sun, Mar 21, 2021 at 11:06 AM, Bert Haskins wrote:
Yep they used something like this in drive belts also.

Yes my TEAC X-3 just had a "belt melt", it is hard ti understand why they
can't be made in silicone rubber now. That should be practically eternal in
comparison to my lifespan....






Re: Beware of old AntiStatic foam

-
 

Bruce Gentry said:

One reason polyurethane was so popular for drive rollers and belts is
it's traction. Many tape recorders used them because they could be
smaller and cheaper yet able to grip and carry the power. It is
certainly possible to find replacements that will fit, but often they
will slip under heavy load.

Years ago I talked to one of HP's calculator engineers in Oregon and he
told me that they had about given up on building a reliable card reader for
the HP-65 and similar calculators because of slippage, until they
discovered polyurethane. But it said that it gripped so well that they
could dip the magnetic cards in oil and the polyurethane rollers would
still feed them!

Unfortunately the rollers that HP used in all of their calculators have
all deteriorated with age.



On Sun, Mar 21, 2021 at 3:59 PM greenboxmaven via groups.io <ka2ivy=
verizon.net@groups.io> wrote:

One reason polyurethane was so popular for drive rollers and belts is
it's traction. Many tape recorders used them because they could be
smaller and cheaper yet able to grip and carry the power. It is
certainly possible to find replacements that will fit, but often they
will slip under heavy load.

Bruce Gentry, KA2IVY

On 3/21/21 14:26, snapdiode via groups.io wrote:
On Sun, Mar 21, 2021 at 11:06 AM, Bert Haskins wrote:
Yep they used something like this in drive belts also.

Yes my TEAC X-3 just had a "belt melt", it is hard ti understand why
they can't be made in silicone rubber now. That should be practically
eternal in comparison to my lifespan....









Re: Beware of old AntiStatic foam

-
 

Steven said:

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

That butyrate plastic deteriorates into butyric acid and yes, I'm told
that that is what gives vomit it's nauseating smell. It's similar to, or
the same, compound found in milk that is going bad so human reaction to
that smell is thought to be a survival mechanism. I soak those old Xcelite
tools in full strength household ammonia and then scrub them with a brass
bristle brush or a tough nylon pot scrubber and that will remove the white
film on the tools. You may need to repeat the process a few times.
Surprisingly, even a brass bristle brush doesn't seem to harm or to scratch
up the plastic handles (YMMV!) I've cleaned several dozens of Xcelite
tools like this over the past 6 or 7 years and I've never found any sign of
damage by cleaning that way.

On Sun, Mar 21, 2021 at 2:49 PM stevenhorii <sonodocsch@gmail.com> wrote:

I think polyethylene foam instead of the black polyurethane foam does not
have the “get goopy and stick to everything” problem. Has anyone had
polyethylene foam degrade like the black stuff? I have not - either black
or white polyethylene has stood the “test of time”. I have seen foam rubber
turn to dust, but at least it does not (in my experience) get sticky.

Apparently the polyurethane foams also outgas as they degrade and this can
leave deposits on stuff - think camera optics as many camera carrying cases
use polyurethane foam.

If I have some custom-fitted black foam in a transit case, I put the item
in a plastic bag and before putting it back in the case.

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

A comment on Duracell batteries. I am pretty sure there are counterfeits
out there - particularly the “bulk packs” with no Duracell label on the
outside. Here’s an article on fakes:


https://www.thecounterfeitreport.com/product/106/Duracell-Coppertop-AA---AAA-Batteries.html

When I have had Duracell batteries (the AA ones in particular) leak, on
checking, they were the ones I bought in unlabeled bulk packs. I generally
remove batteries from equipment I am not going to use frequently.

Steve Horii

On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info> wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies and
a multimeter that way, so now cells get removed from rarely used items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen

















Re: 7D15 internal trigger not working

Dan G
 

I just did a quick measurement on my 7D15, with the plug-in installed in a horizontal slot,
and being fed a 1 MHz 5 div p-p sine wave from a vertical amplifier. The 7D15 was set to
measure frequency, TRIGGER B selector set to TRIG SOURCE.

The 5 div signal from the vertical amplifier becomes a 840 mV p-p signal measured
at R117 with a 10X high-Z probe. It is symmetrical about 0V. Observing the signal
here will tell you the effect of the Q203/Q213/Q217 amplification stage, and you
should be able to see any contact resistance issues with cam switch contact
number 12.

R117 is readily accessible with the right mainframe cover removed if you install
the time base in Horizontal slot A, and the 7D15 in the Horizontal slot B.


I hope this helps,

dan


Re: Beware of old AntiStatic foam

greenboxmaven
 

Polyethylene definately seems to be benign and long lasting.  With regard to Xcelite handles and other items, I had to spend my youth in the place many of those stinky plastics were developed and made. The entire town smelled like the plastic, it was not nice. In addition to stinking and getting covered with white crud, the plastics often shrink and warp as they age. One positive thing about those plastics was their feel and grip confort. Many vintage typewriters and teleprinters had keys made of them because they were easier on fingers after hours of typing.

   Bruce Gentry, KA2IVY

On 3/21/21 14:49, stevenhorii wrote:
I think polyethylene foam instead of the black polyurethane foam does not
have the “get goopy and stick to everything” problem. Has anyone had
polyethylene foam degrade like the black stuff? I have not - either black
or white polyethylene has stood the “test of time”. I have seen foam rubber
turn to dust, but at least it does not (in my experience) get sticky.

Apparently the polyurethane foams also outgas as they degrade and this can
leave deposits on stuff - think camera optics as many camera carrying cases
use polyurethane foam.

If I have some custom-fitted black foam in a transit case, I put the item
in a plastic bag and before putting it back in the case.

Another “plastic rot” question. I have a set of Xcelite tools. One of them,
a stubby Philips screwdriver, developed a white coating on it that was
impossible to remove without sanding it off. I could get some of it off,
but it kept re-developing this. None of the other tool handles has done
this. The handles, I believe, are a butyrate plastic that gives off butyric
acid as it oxidizes but they all are and this is the only one that
developed this white coating. The whole tool kit smells rather like vomit
(my wife refers to it as my “vomit tool case”) but this is common with
butyrate plastic-handled tools.

A comment on Duracell batteries. I am pretty sure there are counterfeits
out there - particularly the “bulk packs” with no Duracell label on the
outside. Here’s an article on fakes:

https://www.thecounterfeitreport.com/product/106/Duracell-Coppertop-AA---AAA-Batteries.html

When I have had Duracell batteries (the AA ones in particular) leak, on
checking, they were the ones I bought in unlabeled bulk packs. I generally
remove batteries from equipment I am not going to use frequently.

Steve Horii

On Sun, Mar 21, 2021 at 12:01 Harvey White <madyn@dragonworks.info> wrote:

As I've mentioned previously, the latest run of Duracell (guaranteed not
to leak before 10 years) does exactly that, and often in the package.

The good news is that they will often give you money to replace the
damaged item if you call them. Their warranty is "repair or replace",
but you do have to call.

I've had the foam in probe cases crumble, (both HP and Tek), anti static
foam corrode and crumble, etc...

Harvey


On 3/21/2021 9:50 AM, David Slipper wrote:
Nasty!! I wonder what other time-bombs are awaiting us!?

I'll certainly be checking my stock of bits and spares.

I always assumed that a famous brand of NiMh batteries were supposed
to be leak proof - Hah! I nearly lost a pair of nice walky-talkies and
a multimeter that way, so now cells get removed from rarely used items
and I make a point of checking torches and the like regularly.

Sadly not surprised at anything these days,
Dave


On 21/03/2021 13:07, - wrote:
Well, this thread just showed up on EEVBlog. This is exactly the
kind of
damage that I used to see happen to IC and to TE accessories that were
stored in the old antistatic foam.

<
https://www.eevblog.com/forum/chat/beware-of-old-antistatic-foam/?topicseen











Re: Beware of old AntiStatic foam

greenboxmaven
 

One reason polyurethane was so popular for drive rollers and belts is it's traction. Many tape recorders used them because they could be smaller and cheaper yet able to grip and carry the power. It is certainly possible to find replacements that will fit, but often they will slip under heavy load.

    Bruce Gentry, KA2IVY

On 3/21/21 14:26, snapdiode via groups.io wrote:
On Sun, Mar 21, 2021 at 11:06 AM, Bert Haskins wrote:
Yep they used something like this in drive belts also.

Yes my TEAC X-3 just had a "belt melt", it is hard ti understand why they can't be made in silicone rubber now. That should be practically eternal in comparison to my lifespan....




Re: 7D15 internal trigger not working

Dan G
 

On Sun, Mar 21, 2021 at 01:26 PM, Steve Nossen wrote:

Measured the transistors and Q213 measures 30 ohms from C to E and E to C on
my SImpson 260. Much higher on a DVM but the same in both directions. Seems
leaky to me. Q203 measured more like a diode, conducts in one direction.
Q213 pins are connected to GND and +5V rails with very low value resistors, so
I would be suspicious of any in-circuit resistance measurements.

A non-invasive test of the basic health of these transistors is to
check the operating point voltages of Q203, Q213 and Q217, and compare
them against the expected values provided in schematic <1>. This check
should not need a signal applied to A20/B20, so the plug-in can be operated
in the vertical compartment for ease of access. (Unless, of course, you are
one of the luck few who have a nice 7000 plug-in extender.)

Also, did you remember to clean all attenuator cam switch contacts with
isopropyl alcohol? This would be the first order of business before
attacking the plug-in with a soldering iron.


dan

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