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Re: word recognisers

 

Roy,

I'm definitely in the "collectible compulsive" category. I've got a use case, but it's also more of a compulsion (building a 6809-based personal computer, decoding the display interface on a GRiDcase 3 laptop, working on a Varian 620f minicomputer, etc.). I've got a Sony/Tek 308 that works, a 7D01 that needs repair, and a non-Tek LA that passes all self-tests, so a Tek 1240/1241 would just be a (possibly more capable) toy on my bench.

I enjoy using vintage test equipment, but the LAs (other than the 7D01) don't feel vintage to me (I mean that they literally feel like a newer generation of equipment, in terms of the kinds of controls they use and how it physically feels to operate them), and I don't get the same kind of thrill from seeing the traces on the CRT that I do for a nice, analog scope.

-- Jeff Dutky


Re: Type 284 Pulse Generator strange output.

Jared Cabot
 

I think I figured it out, usual PEBKAC error. :D

Seems I had to tweak the internal and external TD Bias settings a bit more to get it to fire properly.
I think it's working ok now hopefully.

Seems to get better risetime than my Leo Bodnar pulse gen, 4.6nS for the Tek, 5.4nS for the Leo Bodnar (on a 60MHz TDS210 at least).

Waveform:
https://i.imgur.com/z7JvVcT.png

Leading Edge Detail:
https://i.imgur.com/TpU8u9I.png


Re: word recognisers

Harvey White
 

Unlike some, I do use a logic analyzer, but it depends very much on the application.

I do FPGA design, so monitoring all those digital outputs is a task.  I also look at SPI, which needs fast.  I2C can be done with cheapies.  Neopixel hardware (and software) drivers produce a rather complex output, and my digital scopes don't really have enough storage, nor quite the triggering capabilities.

I've also built a CPLD that does I2C serial to parallel to use the state machine in the LA.

What generally is (more or less generation limited) would be the state machine use of multiple probes to analyze microprocessors, all the status lines, all the data and address lines drove the 100 channel plus logic analyzers.  If you're debugging hardware at that level, or multiple inputs to decode/subsystems, then you still need a multiple channel LA.  That said, how many do FPGA designs?  It's good to use the simulators, but simulators generally assume perfect signals (been there, didn't work, had to change the design).

Debugging display panel drivers is also something that an LA can do well.  Scopes only have so many channels, and unless digital, lack sufficient storage (and may still lack it).  A conventional analog storage scope (and I have one), has the same limitations. Most of the signals on flat panel displays are repetitive enough that storage may not be the problem.

Messing around with packet communications can use an LA, or a specific packet decoder (to be built......).

So I'd say it's what you're doing.  A mixed signal DSO generally doesn't seem to have enough channels for the digital, although 8 or 16 handles a bunch of things, as long as the interface doesn't drive you up a wall.

Scopes, 7904, 2430, 7104, TDS 540A  LA 16500B, 16702B, 1660.  I can make do with most of it, although some specific packet decoding is not a bad thing.

Harvey

On 10/13/2021 1:09 PM, Roy Thistle wrote:
On Tue, Oct 12, 2021 at 03:57 PM, Harvey White wrote:

I happen to like HP logic analyzers,
Yes, I agree... and of course it's a preference thing... but HP LAs appeal to many here, while HP scopes lose out to Tek.
Lots of old HP LA holding down the basement floor everywhere... they're not tools most will ever need.... no good for modern work... and much better/cheaper solutions available for working on old logic.
HP Infiniums that turn up... you know, fished out a dumpster somewhere...an put up on that online site... are way overpriced... and IMO, just not that good.


Re: Type 284 Pulse Generator strange output.

Eric
 

On my phone so I will not be a wordy as usual. The tunnel diode is not
firing. Unfortunaly you will need to service the air line. The GOOD news is
the tunnel diode is most likely good of you are getting that waveform.
Zenwizard has a few videos on you tube a out rebuilding these.

The current drive resister at the back of the air line has most likely
drifted high. There is a very narrow current range where the td behaves.
The waveform looks like you are getting forward positive drive current but
not negitive drive current.

https://youtu.be/8kweJOFoi1g

If my phone behaved this should be one of the rebuilds.

Eric

On Wed, Oct 13, 2021, 1:54 PM Jared Cabot via groups.io <jaredcabot=
protonmail.com@groups.io> wrote:

I am using a HP 50 ohm terminator (11048C) already, but here is the
waveform with DC coupling:

https://i.imgur.com/YhTbdAe.png


Thanks!
Jared


On Thu, Oct 14, 2021 at 02:48 AM, Tom Miller wrote:


Can you use 50 ohm term and DC coupling?






Re: Type 284 Pulse Generator strange output.

Jared Cabot
 

I am using a HP 50 ohm terminator (11048C) already, but here is the waveform with DC coupling:

https://i.imgur.com/YhTbdAe.png


Thanks!
Jared

On Thu, Oct 14, 2021 at 02:48 AM, Tom Miller wrote:


Can you use 50 ohm term and DC coupling?


Re: Type 284 Pulse Generator strange output.

 

Can you use 50 ohm term and DC coupling?

On 10/13/2021 1:38 PM, Jared Cabot via groups.io wrote:
I recently acquired an almost mint condition Type 284 Pulse Generator, except it has an issue with the pulse output.
It only gives a strange waveform that doesn't look right to me...

https://i.imgur.com/0Mh748i.png

Does anyone have any pointers for where I should start looking? I'm hoping the snap-off diode isn't dead...



Thanks all,
Jared.



--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Tek 465b

Roy Kalawsky
 

Just wondering if anyone has managed to clean attenuator switch banks in a 465.

I know IPA should be used but not sure how to get this into the switch.


Type 284 Pulse Generator strange output.

Jared Cabot
 

I recently acquired an almost mint condition Type 284 Pulse Generator, except it has an issue with the pulse output.
It only gives a strange waveform that doesn't look right to me...

https://i.imgur.com/0Mh748i.png

Does anyone have any pointers for where I should start looking? I'm hoping the snap-off diode isn't dead...



Thanks all,
Jared.


Re: word recognisers

Roy Thistle
 

On Tue, Oct 12, 2021 at 03:00 PM, snapdiode wrote:


I would have liked to have period-correct equipment for tooling around my
Commodore stuff. It's not rational, just silliness.
No... I get it (an it may yet be silliness) but having older stuff is sometimes required for replicating measurements... and it can make you feel like your back in the 1980s too. Problem is... a lot of people... theses days want to be in the 1980s... so time travel is costing more these days... and getting to be for the well heeled only. (Thank you YouTube!, and audiophiles everywhere too!)
--
Roy Thistle


Re: Series 71 Switch Repiar

 

Bruce,

Good to know, for several reasons: first, my original plan was to epoxy the switch body back in place after cutting the heat staked pins, and trying to free the stuck switch with silicone would probably foreclose that option. I'm leaning toward reattaching the switch body with screws and nuts, however, because it will give me better control of downward pressure. Second (off topic), I've been experimenting with casting replacement knobs, and I've been very unhappy with the mold release compound that I've been using (my epoxy casts have been sticking to the molds so that the only way to remove them has been to destroy the mold), and silicone lubricant may be a solution to that problem.

-- Jeff Dutky


Re: word recognisers

Roy Thistle
 

On Wed, Oct 13, 2021 at 01:45 AM, Tim Phillips wrote:


the 7A42 plug-in
Probably... if I live long enough to get around to it... I'll post some stuff about 7A42.
But, I looked at it... and in it... and just looking at it makes me think there's not much chance of it working.

--
Roy Thistle


Re: word recognisers

Roy Thistle
 

On Wed, Oct 13, 2021 at 08:48 AM, Jeff Dutky wrote:


I've held off buying a 1240/1241 because I assumed I would need a bunch of
probes/accessories that would drive the price into the stratosphere.
Hi Jeff:
Unless it a collectable's compulsive buy... why do you need one of those old LAs?
To actually use it, you need the pods and the cables... which usually don't come with them.... but, sometimes they turn up, for a reasonable cost.
Just the same... very few people actually need an LA... and those who want one, and get one... are usually using it to hold down the basement floor.


--
Roy Thistle


Re: word recognisers

Roy Thistle
 

On Tue, Oct 12, 2021 at 03:57 PM, Harvey White wrote:


I happen to like HP logic analyzers,
Yes, I agree... and of course it's a preference thing... but HP LAs appeal to many here, while HP scopes lose out to Tek.
Lots of old HP LA holding down the basement floor everywhere... they're not tools most will ever need.... no good for modern work... and much better/cheaper solutions available for working on old logic.
HP Infiniums that turn up... you know, fished out a dumpster somewhere...an put up on that online site... are way overpriced... and IMO, just not that good.

--
Roy Thistle


Re: word recognisers

Roy Thistle
 

On Tue, Oct 12, 2021 at 04:51 PM, snapdiode wrote:


I would like a Tek 1240, but these are either in terrible condition or too
pricey.
Hi SD
Well... it's hard to find one with the pods, and expansion modules... but they're usually in good shape cosmetically (they're 40 years old!)... and just the analyser (sans pods, modules) isn't much above 100USD... and sometimes you can pick one up for much less.
Even though some people ask a lot for old logic analysers, they don't go for very much... and turn up in a dumpster allot. Every business who used them... back in the day... paid an insane amount for them... but, they became obsolete very quickly (they were/are very generation specific tools.)
I'll bet... if people reading this are working for a business that used them... those old analysers are still holding down a closet floor somewhere... until they eventually get used to line the bottom of a dumpster.


--
Roy Thistle


Re: Series 71 Switch Repiar

Bruce Atwood
 

If you are ever going to adhesively bond (aka glue) any part of the assembly I would not use any silicone product. They are almost impossible to remove and adhesives don't stick to them.


Re: word recognisers

Roy Thistle
 

On Tue, Oct 12, 2021 at 02:57 PM, Roger Costello wrote:


I guess you could also make up a suitable supply as an alternative but it
needs quite a bit of power.
Small...15 volt uni-polar... even bi-polar... pure chinesium... 15 VDC power supplies are quite affordable (less than, or about 20.00 USD)... about 3A or 5A. The quality varies... but, some have a good reasonible/USD. Safety is another issue... but, they are much better, in this regard, than they used to be.

--
Roy Thistle


Re: 172 programmable test fixture plastic latch modelling effort for 3D print replacement (105-0286-00)

 

On Wed, Oct 13, 2021 at 03:33 AM, Gregor Lasser wrote:


So if you have a 172 with an intact latch or a broken latch with all pieces
I would be grateful if you could help me out with this project.
Greg,

I happened to have a NOS latch in my box of small hardware.
Measurements and a few pics could be found here for some time:
www.hakanh.com/dl/temp/172_latch.pdf

/Håkan


Re: word recognisers

 

snapdiode,

I see a bunch of 1240s and 1241s on the unnamed auction site, all around $100 or $150. Most are listed as "parts only" but a few are "pre-owned" which is supposed to mean "working". I've held off buying a 1240/1241 because I assumed I would need a bunch of probes/accessories that would drive the price into the stratosphere.

-- Jeff Dutky


Re: Series 71 Switch Repiar

 

I am nothing if not obscure and limited.

-- Jeff Dutky


Re: Series 71 Switch Repiar

 

Any recommendations on what silicone lubricant to use?

There are many to choose from: two kinds of WD-40 "specialist" (blue and white can vs. black can), 3M (dry and wet versions), DuPont (squeeze bottle), CRC 05074, Permatex, etc.

-- Jeff Dutky

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