Test Equipment Anonymous (TEA) group therapy thread

[Swainster]

RANT ALERT...

One of the NOS parts that I hold great suspicion of is electrolytic capacitors. I see them on eBay etc, sometimes at silly prices, and just shudder. Now I know that 'lytics have a shelf life (I seem to recall that it is fairly short - maybe a couple of years or something like that), but what does this mean in practice? Well, you can reform the capacitors - the major suppliers have advice on this if you google around. But what about the really old stuff e.g. stuff that has been on the shelf for a decade or more?

Anyway, what brought this rant on is that I recently "inherited" a set of component drawers from an ex-employer that closed down their electronics design department. Sadly I missed out by a couple of days on an entire stock room of old HP and R&S test equipment which was scrapped (the 'scrap' man was doing them a favour by emptying it for free ). Amongst other stuff, in these component shelves were about 30 Marcon branded 2200uF 25V 'lytics... and every single one had leaked. They also had that nasty vinegar-like smell that you get from delaminating LCD panels. I opened one up and there seems to be plenty of electrolyte still inside, and they test out fine on an LCR meter, so if it wasn't for the obvious sticky mess and smell, you could easily be tempted into using them in a repair.

Marcon was popular in Keithleys back in the day - perhaps this is an example of the great capacitor plague?

[DC1MC]

Hi Vince, There are LOTS of simple to use parallel input DAC chips out there. anything from 8 to 12 bits are common. Most don't need any "support" logic, not even a clock. Parallel binary in voltage out. A "multiplying" type will even take a variable voltage in (AC bipolar for many) and multiply the voltage (by a value of 0 to 1) according to the digital input. For example 2V in and 128 (binary for an 8 bit  DAC) inputs will give 1V out.

Many many years ago (Blimy nearly 40) I designed an analog gauge for an aircraft that had a complex calibration curve in a ROM. I took 0-10V input. This fed a ADC with free-running clock, Data output connected to the address inputs of the ROM. The data outputs connected to the inputs of a DAC and the output of the DAC drove an analog meter. Not a microprocessor in sight. I didn't even have a PROM progrmmer. It was hand programmed with a bunch of toggle switches. To simplify the PCB layout (hand laid with transfers and tape) to fit it in the case on a single sided PCB I laid the chips side by side and pin to pin. This "scrambled" both the address and data lines Enigma style
So I just scrambled the wiring to the switches in the programmer the same way. Years later I was asked to update the calibration because they had changed the airframe. I had to make up a de-scramber adaptor to go between my progammer and the PROM. I've still got it somewhere.

Robert.

Thanks for the story, I always love them ! 

Good news on the DAC front then... do you have suggestion of brands and models / series that are easily available these days ?
I guess I will want a couple 9 or 10 bit ones.
Problem is that the parametric search on Mouser probably does not allow to filter for "CPU-less" DAC sadly.
So unless I know what models to look for, I could spend my life checking thousands of datasheet one by one....
However as you said, at the least, a multiplier DAC would fit my needs, and maybe it's not unreasonable to expect the parametric search to have a "multiplier" keyword somewhere.... let's see...
Then sort by price, package type, stock/availability....

You were brave programming that EPROM by hand with switches... hopefully it was not a 27C4000....
You were young and motivated I guess 
Sounds like the kids back then who programmed their Altair computer the same way.... sure takes some love....

The only "CPU-less" DAC are the parallel input ones, for 10bit you have exactly 4 available:

https://www.mouser.de/c/semiconductors/data-converter-ics/digital-to-analog-converters-dac/?interface%20type=Parallel&number%20of%20channels=1%20Channel&output%20type=Voltage~~Voltage%20Buffered&resolution=10%20bit&instock=y&rp=semiconductors%2Fdata-converter-ics%2Fdigital-to-analog-converters-dac%7C~Output%20Type

Cheers,
DC1MC

[ch_scr]

Hi Vince, There are LOTS of simple to use parallel input DAC chips out there. anything from 8 to 12 bits are common. Most don't need any "support" logic, not even a clock. Parallel binary in voltage out. A "multiplying" type will even take a variable voltage in (AC bipolar for many) and multiply the voltage (by a value of 0 to 1) according to the digital input. For example 2V in and 128 (binary for an 8 bit  DAC) inputs will give 1V out.

Many many years ago (Blimy nearly 40) I designed an analog gauge for an aircraft that had a complex calibration curve in a ROM. I took 0-10V input. This fed a ADC with free-running clock, Data output connected to the address inputs of the ROM. The data outputs connected to the inputs of a DAC and the output of the DAC drove an analog meter. Not a microprocessor in sight. I didn't even have a PROM progrmmer. It was hand programmed with a bunch of toggle switches. To simplify the PCB layout (hand laid with transfers and tape) to fit it in the case on a single sided PCB I laid the chips side by side and pin to pin. This "scrambled" both the address and data lines Enigma style
So I just scrambled the wiring to the switches in the programmer the same way. Years later I was asked to update the calibration because they had changed the airframe. I had to make up a de-scramber adaptor to go between my progammer and the PROM. I've still got it somewhere.

Robert.

Thanks for the story, I always love them ! 

Good news on the DAC front then... do you have suggestion of brands and models / series that are easily available these days ?
I guess I will want a couple 9 or 10 bit ones.
Problem is that the parametric search on Mouser probably does not allow to filter for "CPU-less" DAC sadly.
So unless I know what models to look for, I could spend my life checking thousands of datasheet one by one....
However as you said, at the least, a multiplier DAC would fit my needs, and maybe it's not unreasonable to expect the parametric search to have a "multiplier" keyword somewhere.... let's see...
Then sort by price, package type, stock/availability....

You were brave programming that EPROM by hand with switches... hopefully it was not a 27C4000....
You were young and motivated I guess 
Sounds like the kids back then who programmed their Altair computer the same way.... sure takes some love....

The only "CPU-less" DAC are the parallel input ones, for 10bit you have exactly 4 available:

https://www.mouser.de/c/semiconductors/data-converter-ics/digital-to-analog-converters-dac/?interface%20type=Parallel&number%20of%20channels=1%20Channel&output%20type=Voltage~~Voltage%20Buffered&resolution=10%20bit&instock=y&rp=semiconductors%2Fdata-converter-ics%2Fdigital-to-analog-converters-dac%7C~Output%20Type

Cheers,
DC1MC

Hi Vince, in case you'd still want to DIY after seeing those, don't bother with 0.1% resistors for the "additional bit" on the R2R networks - rather try to match the (2% tolerance!) value inside the network  (the "flat blue box" resistors might have a nice even spread, at least mine do; so they should have a good selection to match some odd value)

[Robert763]

Hi Vince, There are LOTS of simple to use parallel input DAC chips out there. anything from 8 to 12 bits are common. Most don't need any "support" logic, not even a clock. Parallel binary in voltage out. A "multiplying" type will even take a variable voltage in (AC bipolar for many) and multiply the voltage (by a value of 0 to 1) according to the digital input. For example 2V in and 128 (binary for an 8 bit  DAC) inputs will give 1V out.

Many many years ago (Blimy nearly 40) I designed an analog gauge for an aircraft that had a complex calibration curve in a ROM. I took 0-10V input. This fed a ADC with free-running clock, Data output connected to the address inputs of the ROM. The data outputs connected to the inputs of a DAC and the output of the DAC drove an analog meter. Not a microprocessor in sight. I didn't even have a PROM progrmmer. It was hand programmed with a bunch of toggle switches. To simplify the PCB layout (hand laid with transfers and tape) to fit it in the case on a single sided PCB I laid the chips side by side and pin to pin. This "scrambled" both the address and data lines Enigma style
So I just scrambled the wiring to the switches in the programmer the same way. Years later I was asked to update the calibration because they had changed the airframe. I had to make up a de-scramber adaptor to go between my progammer and the PROM. I've still got it somewhere.

Robert.

Thanks for the story, I always love them ! 

Good news on the DAC front then... do you have suggestion of brands and models / series that are easily available these days ?
I guess I will want a couple 9 or 10 bit ones.
Problem is that the parametric search on Mouser probably does not allow to filter for "CPU-less" DAC sadly.
So unless I know what models to look for, I could spend my life checking thousands of datasheet one by one....
However as you said, at the least, a multiplier DAC would fit my needs, and maybe it's not unreasonable to expect the parametric search to have a "multiplier" keyword somewhere.... let's see...
Then sort by price, package type, stock/availability....

You were brave programming that EPROM by hand with switches... hopefully it was not a 27C4000....
You were young and motivated I guess 
Sounds like the kids back then who programmed their Altair computer the same way.... sure takes some love....

The only "CPU-less" DAC are the parallel input ones, for 10bit you have exactly 4 available:

https://www.mouser.de/c/semiconductors/data-converter-ics/digital-to-analog-converters-dac/?interface%20type=Parallel&number%20of%20channels=1%20Channel&output%20type=Voltage~~Voltage%20Buffered&resolution=10%20bit&instock=y&rp=semiconductors%2Fdata-converter-ics%2Fdigital-to-analog-converters-dac%7C~Output%20Type

Cheers,
DC1MC

If you go to 12 bits you have more choice with similar cost
https://www.mouser.co.uk/c/semiconductors/data-converter-ics/digital-to-analog-converters-dac/?interface%20type=Parallel&number%20of%20channels=1%20Channel&output%20type=Voltage~~Voltage%20Buffered&resolution=12%20bit&instock=y&rp=semiconductors%2Fdata-converter-ics%2Fdigital-to-analog-converters-dac%7C~Output%20Type&sort=pricing

[factory]

RANT ALERT...

One of the NOS parts that I hold great suspicion of is electrolytic capacitors. I see them on eBay etc, sometimes at silly prices, and just shudder. Now I know that 'lytics have a shelf life (I seem to recall that it is fairly short - maybe a couple of years or something like that), but what does this mean in practice? Well, you can reform the capacitors - the major suppliers have advice on this if you google around. But what about the really old stuff e.g. stuff that has been on the shelf for a decade or more?

Anyway, what brought this rant on is that I recently "inherited" a set of component drawers from an ex-employer that closed down their electronics design department. Sadly I missed out by a couple of days on an entire stock room of old HP and R&S test equipment which was scrapped (the 'scrap' man was doing them a favour by emptying it for free ). Amongst other stuff, in these component shelves were about 30 Marcon branded 2200uF 25V 'lytics... and every single one had leaked. They also had that nasty vinegar-like smell that you get from delaminating LCD panels. I opened one up and there seems to be plenty of electrolyte still inside, and they test out fine on an LCR meter, so if it wasn't for the obvious sticky mess and smell, you could easily be tempted into using them in a repair.

Marcon was popular in Keithleys back in the day - perhaps this is an example of the great capacitor plague?

Similar problem here, I bought all the components from work, when they downsized to one product and converted the lab into office space.

I'm reluctant to use NOS Panasonic or Rubycon, seen those leaking in the drawers when they were still at work, I purged at lot of them before the EOL of the lab, along with those hazmat filled Plessey caps.

Since then I've found these NOS Frako caps peeing themselves. 


Also the Mullard/Philips axial caps, they are either really good or really badly dropped in capacitance. This was a known problem with certain products at work too, NOS boards were just the same, we had to change the caps before using. 


Only ones I trust are the RIFA electrolytics, had a few sealed boxes of those from the late 90s, shame they are often to large to fit the TE I'm repairing, see the above Frako pic for size comparison.

David

[factory]

You have too much imagination.... I would just use a high-pressure washer at full blast....

I would be reluctant to wash scopes the way Tek did, it might have been OK when the TE was fairly new, but 50+ years later I would be worried about finishing off HV transformers and similar unobtanium parts, after all the insulation materials don't usually improve with age.

As for pressure washing, Shango066 did this with a really filthy TV chassis, despite drying in the Commiefornia sun, it still ended up with the PCB shorting in multiple places and even ceramic tubular caps burning up.   

Downloaded the 7504 manual this morning, I would have salvaged all the metal package transistors (expensive to buy new), the custom ICs which Tekwiki indicates were used in many of the 7000 series scopes, the 120V Zener (limited choice from local suppliers for the higher voltage ones), any other transistors/ICs that are difficult to get these days, the Fairchild uLogic parts from the readout board, RCA 3028 from regulator board etc.

The frame I would have kept any external parts that could be destroyed, by a combination of crap packaging and courier abuse  , as well as the usual parts that develop legs & walk off, eg. the feet.
Did the RF shield strip fit the 7603, that you were looking to replace under the modules?

David

[Vince]

DAC = thanks people for your help.

Had a look at the search results for the 12 bit ones Robert posted.

First / cheapest one is not cheap, almost 10 Euros a pop... in this day and age how can these things still cost so much money....  :'(

Anyway, it still requires many control signals, at least to latch the data (can't do on the fly conversion), as well external caps.
... funny part is, the datasheet says it uses an R-2R ladder inside... well then just cut the crap and just sell me your 12 bit bare ladder then, for cheaper, would make my day...

Next model after that, more expensive and requires a CPU, needs registers insise to be written to.

I think it all goes to choosing the 2 Euro R-2R ladders, at least for a first prototype.... will use "proper" DACs only if experiments show it is strictly necessary...

Hi Vince, in case you'd still want to DIY after seeing those, don't bother with 0.1% resistors for the "additional bit" on the R2R networks - rather try to match the (2% tolerance!) value inside the network  (the "flat blue box" resistors might have a nice even spread, at least mine do; so they should have a good selection to match some odd value)

I am surprised you remember about that box of resistors, you have quite an amazing memory...

As mentioned earlier, the 2% tolerance stated in the datasheet makes no sense for an 8 bit DAC.... so I am thinking, the only way this can work, is if all the resistors are trimmed to be close to each other, much tighter than 2%. That's the only way.  So for example, all resistors in the ladder would be say at -2%, or all at +1.25%, or whatever...

So if I buy say a 10K ladder, the resistors can be anywhere between 9.8K and 10.2K, but if one is say 10.15K then they would all be damn close to 10.15K (and 20.30K of course, for the 2R ones...)

So what I need to do, is to measure what the actual resistance is, then match it a multi-turn trimmer in series with a fixed resistor.

The ladders are available in DIP packages. takes more board space than SIL packages, but it does give you probe point to let you tap all the "R" resistors of the ladder, individually.
The "2R" one can be easily measured with either package type, between the output pin and the MSB pin.  That would do it for a prototype.

Then once I know what value I need, I can replace the trimmer and fixed resistor, with a single precision one.


Today at work I had nothing to do at all all afternoon, so I started working on my design.
Turns out my original envy of using only discrete logic chips could spiral into a mess...so I am now steering towards a single chip/MCU solution.
The data stream I have to process runs at about 15kHz, with pulses about 8µs wide.

I use AVR MCU's, have an old ATmega32 in DIP package in stock from my last project....15 years ago.
It can run at 16MHz, so an instruction time of 0.065µs or something if I have my maths about right. single cycle instructions mostly, by the time I get a rising edge from the pulse, I can execute quite a few instructions long before the pulse neds, never mind before the next pulse comes in. I don't need many instructions to do what I need to do.
So at least back oif the envelope, it possibly could work, so worth a try.  Using a micro would also allow me use easily any "real" DAC, and let me modify / fine tune the design much more easily/faster/cheaper than a H/W discrete solution....

I could maybe even get rid of the ladders and just use the internal PWM channels as a DAC.... but that would be a bit too optimistic I think. I would need a very low RC time constant to get the required responsiveness I guess, hence would need the PWM to run at a very high frequency that the MCU could not provide I think. I mean if it runs at 16MHz, and would use IIRC a 10 bit PWM register, then at best the PWM would run at 15kHz.... piss poor, won't cut it.

So I guess I need to dig out my 15 year old "Dragon" USB AVR programmer..... 15 years.... I hope I can remember how to use all the tool chain and program these things...

Might use the ATmega128 collection that Zoli sent me. More I/Os .... and a much more compact quad SMD package.



@Factory : OK so I guess I can finalize my part of your Mouser order then... what I listed previously... + a few R-2R ladders....

[Vince]

Downloaded the 7504 manual this morning, I would have salvaged all the metal package transistors (expensive to buy new), the custom ICs which Tekwiki indicates were used in many of the 7000 series scopes,

I have salvaged of course all the boards, so all the trannies and customs IC are still there with me 

As for the bigger trannies, mounted to the chassis, I found many with RCA part numbers on them so I scrapped them immediately. Last year when I was sorting all my old junk, every single time I had an RCA part with an RCA P/N# on it..... never... never.... NEVER would I find a datasheet for it or even basic specs in some old databook ! I now despise RCA parts with a passion, and refuse to waste my time with them.

So I only kept a couple TO3 packages, because they had actual, meaningful 2Nxxxxx part numbers on them : 2N3773 and 2N3669 .... have not looked them up yet, I am sure they are fascinating beasts.

the 120V Zener (limited choice from local suppliers for the higher voltage ones),

Hmmm... I remember that some hinged panel on the left side of the scope, had a few stud diodes mounted on it... maybe they these Zeners... I didn't salvage them because I failed to unscrew them, my tools didn't fit. The flats on the body were so thin that I could not grab them.

RCA 3028 from regulator board etc.

Not sure I have these. The scope had been mutilated in the PSU area. At the back of the scope, I think must have been mounted big heatsinks with the beefy pass transistors on them... but all that had been stolen, and the electrical harness that exited the back of the scope to connect to those transistors, had been cut flush...
I had the part of the PSU that had the big can caps mounted on it. I salvaged the biggest of the cans as I said, because it's so huge it looked scary... and sexy at the same time.

Did the RF shield strip fit the 7603, that you were looking to replace under the modules?

That's an idea !!! ... sadly my brain did not think of it, bummer !!!! 
Oh nooooo...........   

[m k]

I have now an educated guess for PCII/IIA.

At the beginning only one production place for controller chips was used, VLSI at AV.
Different other components were used, partnumbers -01 and -02.
Special case was also available, partnumber -08.
Maybe around spring '91 revision upped to E and stayed there for many years.

Unfortunately I can't find that VLSI chip with B version GAL picture anymore.

Then around '97-'98 something happened and new partnumber appeared, F-01.
First guess, old revision E was upped to partnumber and new revision style was picked, REV.1 and REV 001.
New production location for controller chip was also picked, NI chip at NAS.

Then partnumber was upped to G and support logic was upped to version B, chip source was still NAS.
Dataset is very limited but seems that revision was also changed to hand written NG23 over 1 on printed sticker.
Then partnumber was upped to H and revision returned to printed REV.1 but support logic B stayed.

Next new chip location appeared around '00, EAI and partnumber upped to H-02, revision was also upped to REV.2.
Maybe around this time last VLSI chips came available, since their partnumbers are H-02 but chips dated few years back.
Dataset is very limited but VLSI chip revisions were REV.1 instead of what NI chip was, their support logics are also not visible.
Same time frame EAI NI chip appears on partnumber J with revision REV 001, same partnumber has also revision REV 3.1 but chip details are too blurred.

So controllers are, maybe partially and maybe only once but still sort of programmable.
REV.E is old 8 bit version but anything after that is internally 16 bit and uses those new API functions.

[Vince]

So I only kept a couple TO3 packages, because they had actual, meaningful 2Nxxxxx part numbers on them : 2N3773 and 2N3669 .... have not looked them up yet, I am sure they are fascinating beasts.

Just looked them up... 2N3773 is an NPN, 140V 16A, 30A peak.... sure can be useful 
However the 2N3669 surprised me.... it's not a trannystor, it's a thyristor ! A Thyrinnistor....   apparently meant to rectify mains voltage. American scope so this one is specced to handle 120V mains not 240V we have here.

I am tired, good night TEA... 

[factory]

I have salvaged of course all the boards, so all the trannies and customs IC are still there with me 

As for the bigger trannies, mounted to the chassis, I found many with RCA part numbers on them so I scrapped them immediately. Last year when I was sorting all my old junk, every single time I had an RCA part with an RCA P/N# on it..... never... never.... NEVER would I find a datasheet for it or even basic specs in some old databook ! I now despise RCA parts with a passion, and refuse to waste my time with them.

So I only kept a couple TO3 packages, because they had actual, meaningful 2Nxxxxx part numbers on them : 2N3773 and 2N3669 .... have not looked them up yet, I am sure they are fascinating beasts.

the 120V Zener (limited choice from local suppliers for the higher voltage ones),

Hmmm... I remember that some hinged panel on the left side of the scope, had a few stud diodes mounted on it... maybe they these Zeners... I didn't salvage them because I failed to unscrew them, my tools didn't fit. The flats on the body were so thin that I could not grab them.

It a through hole part 1N3046B, the stud mount diodes were probably the LV rectifiers.

RCA 3028 from regulator board etc.

Not sure I have these. The scope had been mutilated in the PSU area. At the back of the scope, I think must have been mounted big heatsinks with the beefy pass transistors on them... but all that had been stolen, and the electrical harness that exited the back of the scope to connect to those transistors, had been cut flush...
I had the part of the PSU that had the big can caps mounted on it. I salvaged the biggest of the cans as I said, because it's so huge it looked scary... and sexy at the same time.

Again through part, look up CA3028, might be marked 156-0033-00, this is a 100MHz RF/IF amp in TO99 can package, why they are on the LV regulator board I don't know. 

Did the RF shield strip fit the 7603, that you were looking to replace under the modules?

That's an idea !!! ... sadly my brain did not think of it, bummer !!!! 
Oh nooooo...........   

Opps.......... give us more time to help in the future and hopefully we can avoid this happening again. 

David

[TERRA Operative]

Here's pictures of the NI GPIB cards I have on me.

Third one is on the way, ebay photos were a bit too blurry to see the GAL version numbers.

[HenryFeng]

What's the mouser part number for the 177 toggle switch? I was looking to replace mine for a long time.

Thanks,
Henry

Annddd, now I have a Tek THS720 (with carry bag and charger) on the way... It has the usual burnt polarizer on the LCD, but it seems to work according to the pictures in the listing.

I'll upgrade it to a THS720P and update the firmware if needed. Might even try and see if the TDS210 to TDS220 upgrade hack (Tell the scope it is the higher model then run the appropriate adjustment routine before rebooting it) will work to upgrade this THS720 to a THS730. ([EDIT] Just looked at the schematics, might be a case of swapping resistors and maybe one or two other parts to make the upgrade)
Probably end up doing the LED backlight mod, and building a new battery pack while I have it in pieces.

Will be handy for working on the car and for the youtubes, easier to lay on the bench under the camera than the TDS220..


Should provide a few hours of fun giving it a bit of love on the healing bench.

Oh so you are expanding your old Tek scope expertise to this line of prodcuts as well ?!

GREAT !.... because I really like them and would get one one day.
Very low on my priority list money wise, so it's only a remote idea.
But just in case, get whatever model is the top of the range, give it all the mods it can take, polish it up, and stack it on that TDS 784D that's marked "Vince".
It should not increase the price of shipping all that much I would think...

Ha, I'll keep an eye out for another one.




Tonight's work was replacing the typically snapped off 'Left Right' toggle switch on the 177 test fixture for my Tek 577 curve tracer.
Got a switch from Mouser (they cost way too much for what they are, but such is life) and pulled the toggle lever out and replaced the broken one in the switch in the fixture.
You can't buy the whole switch in the test fixture configuration, but as the switch is part of a series using common parts to build up the needed configuration, there are many common parts, so swapping the lever was just a simple matter of knocking out a pin to extract the lever, then performing open heart surgery with a little rocket science to reinstall in in the test fixture.

While I was there, I replaced the carbon composite resistors with equivalent metal film (gotta order a 22Meg 1/2W still) and it all went rather painlessly.
Now to find some replacement knobs for the front.

Next I'll have to lug the 577 onto the bench and figure it out. I know there's at least one shorted tant in it so far...

But before that, I'm waiting on parts to build my calibration and retro gaming PC, and I have a TM5006A mainframe to finish repairing, and a toaster to fix, and a shitty 30MHz scope to get the triggering working, and, and, and.....

[TERRA Operative]

What's the mouser part number for the 177 toggle switch? I was looking to replace mine for a long time.

Thanks,
Henry

Here you go:

https://www.mouser.jp/ProductDetail/502-41206X

You can't use the switch frame without adjusting the phenolic part with a Dremel or file or similar (You'll see what I mean) but using this video, you can relatively easily take the switch frame out of your 177 and replace just the lever by knocking out the pin.

https://youtu.be/arHu4FGOAls

Just be sure to wrap the switch in a bit of masking tape to hold it together so it doesn't spring apart and shoot across the room.




I wonder if it would be possible to source a quantity of just the levers from Switchcraft for cheaper per piece than buying the entire switch assembly?

[m k]

pic1,
different board material and top is missing few through holes.

pic2,
final layout but DIPs are questionable.
Shared IRQ mismatch and PCII address would be HDD 1F0.
Maybe it was originally in a machine without fixed disk.

pic3,
DIPs 6 and 7 are also up.

pic4,
also questionable settings.

pic5,
address is COM1 3F8.

pic6,
DIPs 6 and 7 are up again.

pic7,
missing picture found, it's from China so was missed earlier since there pictures are usually too bad.
But now other things than IRQ are also questionable, the partnumber and controller combo, J-01 and VLSI chip is a special one.
Maybe it's just the very end of VLSI stock.

DIPs 6 and 7 are most likely nothing with PCIIA but being up seems to be some sort of a norm.
I've also wondered that REV.E1, is it E or 1.

Few different style VLSI stamps came also up, dates were yywwBV, alternate copies?
Dates and serials were legit from last millennia so maybe paranoia of today's reality is taking its toll.

Firefox history made also some odd things, one after the other links to same picture of google pictures.
Maybe it's just how google does things when you pick something from more contents section.

[Vince]

the 120V Zener (limited choice from local suppliers for the higher voltage ones),

It a through hole part 1N3046B, the stud mount diodes were probably the LV rectifiers.

Found it in the parts list.... apparently it was mounted on the chassis... which means it's gone now, oh well.

... Again through part, look up CA3028, might be marked 156-0033-00, this is a 100MHz RF/IF amp in TO99 can package, why they are on the LV regulator board I don't know. 

Ah, I DO have these !    I do have the LV power supply board. There are 5 of these RCA CA3028A

[Vince]

Wow, good luck today, another rack mount Tek 7000 scope just popped up on leboncoin.fr !

https://www.leboncoin.fr/equipements_industriels/2321227498.htm

And boy that's value for money !

A type 7844, only 60 Euros, in good nick, shown working, has readout, a BLUE phosphor, a DUAL BEAM CRT, 4 plugins/bays, and goes to 400MHz !

All that for only 60 Euros ?!

OF COURSE... it's local pickup only and the seller is too far away 
I will have lo learn to be content with my humble 7603.... at least it's got an extra large CRT, that's going for it...

[factory]

the 120V Zener (limited choice from local suppliers for the higher voltage ones),

It a through hole part 1N3046B, the stud mount diodes were probably the LV rectifiers.

Found it in the parts list.... apparently it was mounted on the chassis... which means it's gone now, oh well.

... Again through part, look up CA3028, might be marked 156-0033-00, this is a 100MHz RF/IF amp in TO99 can package, why they are on the LV regulator board I don't know. 

Ah, I DO have these !    I do have the LV power supply board. There are 5 of these RCA CA3028A

Zener must have been somewhere in the HV section of the chassis, some nice pictures here; http://golddredgervideo.com/kc0wox/tek/7504/detailedpictures.htm

That R7844 looks very nice. 

David

[Neomys Sapiens]

Annddd, now I have a Tek THS720 (with carry bag and charger) on the way... It has the usual burnt polarizer on the LCD, but it seems to work according to the pictures in the listing.

I'll upgrade it to a THS720P and update the firmware if needed. Might even try and see if the TDS210 to TDS220 upgrade hack (Tell the scope it is the higher model then run the appropriate adjustment routine before rebooting it) will work to upgrade this THS720 to a THS730. ([EDIT] Just looked at the schematics, might be a case of swapping resistors and maybe one or two other parts to make the upgrade)
Probably end up doing the LED backlight mod, and building a new battery pack while I have it in pieces.

Will be handy for working on the car and for the youtubes, easier to lay on the bench under the camera than the TDS220..


Should provide a few hours of fun giving it a bit of love on the healing bench.

Oh so you are expanding your old Tek scope expertise to this line of prodcuts as well ?!

GREAT !.... because I really like them and would get one one day.
Very low on my priority list money wise, so it's only a remote idea.
But just in case, get whatever model is the top of the range, give it all the mods it can take, polish it up, and stack it on that TDS 784D that's marked "Vince".
It should not increase the price of shipping all that much I would think...

Ha, I'll keep an eye out for another one.
.
.

You both know that a THS3024 exists?
 

[TERRA Operative]

Yeah, would love one, but none have hit rhe used market here in Japan yet, at least not nearly in the price range I'm looking at...
(I don't thing I've ever seen one pop up on Yahoo Auctions.. They are all probably still in use and too good to liquidate to surplus...)

Besides, the THS7xxx series are at the price point now that I can go ham with mods with reckless abandon and not be tooooo upset if it all goes pear shaped.

[Vince]

You both know that a THS3024 exists? 

No I didn't know about these, but that's fine because I don't like it... looks ugly, like a modern cheap chinese thing.
Doesn't ooze that retro feeling that the 700 series does. 

[Vince]

Besides, the THS7xxx series are at the price point now that I can go ham with mods with reckless abandon and not be tooooo upset if it all goes pear shaped.

Lucky you. Here prices are insane.... a couple months ago prices somehow dropped quite a lot and I saw a few in a row that were in the 250/500 Euros bracket.... but sadly prices recently have recovered their usual insane price.... look at this one for sale at the moment....

https://www.leboncoin.fr/autres/2315262650.htm

... 1,300 Euros... more than I paid for my car. In Japanese money it must be about 25,000 trillion bucks, I am sure.... you definitely wouldn't want to "experiment" with that...

Of course for that price you don't get to see a signal on the screen, nevermind  a clean self test screen capture no.... that would be an extra 1,000 Euros I guess 

[Robert763]

That "Tektronix" handheld is a rebadged Fluke 190-2xx
My R&S FSH-3 SA uses the same case.

[factory]

Got some bad news for those who buy TE, TE parts or TE manuals from the US, with "ebay global shipping program", it's being slowly replaced with an even worse service called "ebay international shipping program", this is bad for both buyers & sellers.

For buyers, you no longer get a automatic discount applied for multiple items  , just found this buying two manuals, as before with GSP sellers have no influence on this, you can't "request total" and they can't combine shipping to reduce the international part.
Also the tracking seems to be next to useless, I've got a HP counter which went with this dis-service, tracking ended at Chicago on the 13th, I'm getting worried it's been classified as a restricted item, the third party company being used is Asendia.  Apparently tracking is limited once it leaves the US.

From Asendia; This shipment was sent via a postal carrier offering limited tracking. For any delays, please contact your local post office and provide the tracking number

For sellers, I've read that they only cover up to $100, if a buyer then claims they could be out of pocket for any extra, I can't confirm this as the T&Cs are crap, but it is mentioned by people in the ebay dot com community forum, along with no refunds for shipping.
The manual seller told me, many items no longer have international as an option & some have less choice of countries they can go to, since being transferred from GSP.
I was wondering why quite a lot of items on my watch list no longer have international shipping available, this confirms it. 
Because the tracking is bullshit  , sellers will almost certainly get an increase in claims and will probably get fed up & quit international shipping altogether.

Well done ebay at screwing up international shipping. 

David

[TERRA Operative]

I remember back in the day where the seller would go to the post office and send an item anywhere in the world. I remember doing it myself as a seller too.

Now everything costs a minimum of $25-30 to ship..
Need that specific little part that costs a couple bucks and should cost the same to ship anywhere in the world? Nope $25+ to pay freight-forwarder parasites their insane cut instead of just being sent from the local post office.