Test Equipment Anonymous (TEA) group therapy thread

[srb1954]

The tracker didn't specify which year it would be delivered.

The earliest you can now expect it is Thursday January 14th, 2027

[Brumby]

... and then do you know where it will be delivered?

[mansaxel]

No, I think all med wants it to do is play music effing loud enuf to occasionally annoy the neighbors. I was the one who raised the point aboot a DTS/THX decoder, and then the whole gang sortof jumped on the bandwagon.

sorry, med. 

mnem
 

Nailed it.  No 5.1. No 7.1. Just 2 channel LOUD. 

In that case then, why bother with the right-hand side of the drawing? If the Sansui is not loud enough, grab an amp/receiver that has the power you need, upgrade the speakers if they can't handle the power, job done. Most amps will accept 2 CD inputs; CD1, CD2, Tuner, AV or AUX, Tape1, Tape2 and even today Phono, give you 2 sets of speakers A/B switched between A or B and A+B so if you wanted the other set of speakers in another room for example, thats easy to do. That should give you everything that you require with less space and fewer complications and less chance of a hum loop being introduced.

Or is there something else that I'm missing here?

I'm more and more moving towards building with separates. I've got a 12x8 matrix switcher and am driving my four room stereos from it, with front panel control. There is a web interface, telnet control and a serial port. I've got an Arduino sketch that'll drive the serial port and the A/V amp and the TV (I hope) using SoftwareSerial so I can have 1-button control of the chain TV (correct HDMI in) -> matrix switcher -> A/V amp -> speakers.

The thing I'm really into using it for is to adapt a rotary dial to be able to select inputs for the dining area, where the user is a bit removed from other control means and needs a quick way to select the right matrix input, with an extension for selecting the right FM tuner preset from the A/V receiver. (dial 01 ... 12 for input selection, dial 21 ... 28 for tuner presets (also selecting 02 for the physical input from the A/V), dial 31 ... 38 to select another matrix output, then dial 01 ... 12 for input towards that output.)

My inspiration is a very early danish computer which had a rotary dial to input numeric values in addition to the usual (for the period) toggle switches.

I've got eBay auction: # 154156585519 on my watch list; I've got the audio companion to that (same series, same control language, etc) already in operation, as mentioned above.

So, if one wants to do something just a bit more complicated than one place, one source, modest levels, there's a lot to be said for roaming the Bay for used equipment...

[Specmaster]

@mansaxel, that sounds like a living nightmare to me, horrendously long signal cables picking up spurious signals etc, how about the volume control of each amp, how do you propose to remote control those. That sounds more suited to a large powerful amp with a wireless controlled volume and input selector, with the amp having options for switching in separately or altogether sets of speakers in each room as required. 

[mansaxel]

@mansaxel, that sounds like a living nightmare to me, horrendously long signal cables picking up spurious signals etc, how about the volume control of each amp, how do you propose to remote control those. That sounds more suited to a large powerful amp with a wireless controlled volume and input selector, with the amp having options for switching in separately or altogether sets of speakers in each room as required. 

I'm a broadcast engineer. Anything I run longer than 2 metres is balanced. 300 metres is no problem. I've designed (from reference designs) a balancing board to interface consumer equipment into the matrix, which in itself is balanced. Speaker cables OTOH are to be kept short; preferably only inside an active speaker.  I am investigating AES67 TX/RX boxes to get one send/return to the garage, though. I'm trying to keep all signals between house and garage optical, so AES67 on top of EthernetTCP/IP would do just fine.

This is a 25-year plan, realised as suitably vintage devices and funds make themselves available. I'm in no hurry, and everything I do must be usable by the uninterested, at least for the basic functions.

Edit:

The volume controls for each area are local. A simple divider potentiometer across the legs of the balanced line, just before the power amplifier. I'm firmly of the option that volume shall be local, analog and obvious. So a pot it is.

[Zucca]

I'm a broadcast engineer. Anything I run longer than 2 metres is balanced.

A M E N

[AVGresponding]

This makes me so angry, just seems so unnecessary:

https://www.ebay.co.uk/itm/Tektronix-TDS-714L-Four-Channel-Long-Recorder-Colour-DSO/393085246948




A couple for the Yankees to have a tilt at, HP seems to be a rebadged Yokogawa:

https://www.ebay.co.uk/itm/C173258-HP-4262A-LCR-Meter-w-Option-010/333856862827



https://www.ebay.co.uk/itm/G173305-EIP-Microwave-351C-Autohet-Counter/293957563533




Been a few of these lately, might be a good time to get one cheap:

https://www.ebay.co.uk/itm/Thandar-Portable-Oscilloscope-SC110A-RS-Components-10Mhz/254834485896




Here's a couple for the Canadianians:

https://www.ebay.co.uk/itm/Tektronix-222PS-Power-Scout-Portable-Oscilloscope-with-manual-case-several-pr/293957155862


https://www.ebay.co.uk/itm/Heathkit-IT-28-Capacitor-Checker-Working-Ready-To-Use/293957158634




Not sure what a "Comuntication" module does, but it doesn't sound good...   

https://www.ebay.co.uk/itm/Tektronix-Tds-3GV-Oscilloscope-Comuntication-Module/284143966139

[Robert763]

32 channel, 25MHz => i wouldn't bother with it.

You can probably make leads, but halfway decent grabbers will cost >£1.50 each

Haha I wouldn't touch it with a ten foot pole, I was just being nosy. If it needs pods like the TTi LA's do, you'll need more than some ribbon cable and a few grabbers.

I have a TTi TA320S and the pods are pretty much unobtainium at reasonable prices.

Old non-mainstream LAs are pretty much worthless. That one is ony worth the case and some parts. I'd maybe give £5 at a rally, it's not worth shipping.  Even usable ones are cheap. Last one I aquired was a HP 1662A 68 Channel 250MHz timing, 100MHz state. It came with pods cables AND grabbers for £0. I've seen a newer Tek one sit unsold at a Rally for £25 including pods and leads.

[med6753]

No, I think all med wants it to do is play music effing loud enuf to occasionally annoy the neighbors. I was the one who raised the point aboot a DTS/THX decoder, and then the whole gang sortof jumped on the bandwagon.

sorry, med. 

mnem
 

Nailed it.  No 5.1. No 7.1. Just 2 channel LOUD. 

In that case then, why bother with the right-hand side of the drawing? If the Sansui is not loud enough, grab an amp/receiver that has the power you need, upgrade the speakers if they can't handle the power, job done. Most amps will accept 2 CD inputs; CD1, CD2, Tuner, AV or AUX, Tape1, Tape2 and even today Phono, give you 2 sets of speakers A/B switched between A or B and A+B so if you wanted the other set of speakers in another room for example, thats easy to do. That should give you everything that you require with less space and fewer complications and less chance of a hum loop being introduced.

Or is there something else that I'm missing here?

My setup is similar to what you typically encounter in a vehicle. 2 channel stereo with front speakers, rear speakers, and the listener (me) essentially in the middle. Both the Sansui and the Pioneer have more than enough power each to drive to the volume I want without clipping or distortion. (In fact, I have tons of reserve power). Having 2 separate amps to drive the fronts and rears give me the flexibility to balance the sound front and rear as I see fit.

There are many different ways to achieve the same thing and this is how I chose to do it and it's going to stay as is. It sounds fine to me and that's all that matters. 

[Robert763]

This makes me so angry, just seems so unnecessary:

https://www.ebay.co.uk/itm/Tektronix-TDS-714L-Four-Channel-Long-Recorder-Colour-DSO/393085246948

That seller, Pro-Avit.london has had a lot of equipment with similar damage. It's obviously deliberate and probably malicious. I've come across similar when a company went bust or was taken over and people laid off. Someone taking the view "if I can't have it, I'll make sure you can't have it either".

I've also bought a beat up looking computer base unit at a bankrupcy auction and on opening it up found it stuffed full of memory modues and co-processors in anti-stactic bags. Someone had stripped all the extra memory out of the othe machines and stashed it. Presumably they were intend to make off with the "broken" one or buy it at auction. I don't know if it was done at the auction house or the original company. This was back when memory was worth a lot.

When the MOD used to have auctions by the stillage and before CCTV you would see similar thingsgoing on. Hiding small valuable parts in oter boxes, splitting matched items between lots etc during viewing.

[Specmaster]

Not sure what a "Comuntication" module does, but it doesn't sound good...   

https://www.ebay.co.uk/itm/Tektronix-Tds-3GV-Oscilloscope-Comuntication-Module/284143966139
[/color][/size][/b]

If anyone is thinking about going for this interface, think carefully and make sure to ask loads of questions about it first to satisfy yourself about its suitability and is working etc. I say this because when I looked at it, I noticed that its here in my city, Chelmsford and I thought that it seemed to be rather expensive, so I checked on the sold list to see what others had been sold for, and I was shocked to discover that the very same unit had been by the seller on the 14th November 2020 and now they are reselling it. So it has obviously been returned for some reason, it might be that it is faulty and the seller has no way of testing it etc?

Then again it might be perfectly OK and the original buyer had second thoughts, either way I thought having discovered this, I thought it would be very wrong if I did not post this warning  to my fellow TEA friends here.

[AVGresponding]

Not sure what a "Comuntication" module does, but it doesn't sound good...   

https://www.ebay.co.uk/itm/Tektronix-Tds-3GV-Oscilloscope-Comuntication-Module/284143966139
[/color][/size][/b]

If anyone is thinking about going for this interface, think carefully and make sure to ask loads of questions about it first to satisfy yourself about its suitability and is working etc. I say this because when I looked at it, I noticed that its here in my city, Chelmsford and I thought that it seemed to be rather expensive, so I checked on the sold list to see what others had been sold for, and I was shocked to discover that the very same unit had been by the seller on the 14th November 2020 and now they are reselling it. So it has obviously been returned for some reason, it might be that it is faulty and the seller has no way of testing it etc?

Then again it might be perfectly OK and the original buyer had second thoughts, either way I thought having discovered this, I thought it would be very wrong if I did not post this warning  to my fellow TEA friends here.

So it could very well be munted!   

[Specmaster]

This makes me so angry, just seems so unnecessary:

https://www.ebay.co.uk/itm/Tektronix-TDS-714L-Four-Channel-Long-Recorder-Colour-DSO/393085246948

That seller, Pro-Avit.london has had a lot of equipment with similar damage. It's obviously deliberate and probably malicious. I've come across similar when a company went bust or was taken over and people laid off. Someone taking the view "if I can't have it, I'll make sure you can't have it either".

I've also bought a beat up looking computer base unit at a bankrupcy auction and on opening it up found it stuffed full of memory modues and co-processors in anti-stactic bags. Someone had stripped all the extra memory out of the othe machines and stashed it. Presumably they were intend to make off with the "broken" one or buy it at auction. I don't know if it was done at the auction house or the original company. This was back when memory was worth a lot.

When the MOD used to have auctions by the stillage and before CCTV you would see similar thingsgoing on. Hiding small valuable parts in oter boxes, splitting matched items between lots etc during viewing.

Yep, that sounds about right to me as well. I see that it was calibrated 1/5/2019 so it is highly likely that it was malicious damage. I also know that they get a lot of their stuff from the BBC and other broadcast companies, and he often has video cameras, lenses and recording equipment as well.

I doubt that the scope could be repaired cheaply either, those BNC's look special to me and the range selectors I'm pretty sure would not be off the shelf standard parts either

[factory]

A couple for the Yankees to have a tilt at, HP seems to be a rebadged Yokogawa:
https://www.ebay.co.uk/itm/C173258-HP-4262A-LCR-Meter-w-Option-010/333856862827

Looks very HP to me, the case parts & controls certainly are, it's part of the tie up with Yokogawa so that they could sell HP TE in Japan.
A lot of HP's resistance & LCR meters were built in the Japanese factory, sometimes you may even find one with a YHP badge on the front. Some US HP TE was also made locally in Japan, one I'm looking for is the 5233L counter.

David

[med6753]

A couple for the Yankees to have a tilt at, HP seems to be a rebadged Yokogawa:
https://www.ebay.co.uk/itm/C173258-HP-4262A-LCR-Meter-w-Option-010/333856862827

Looks very HP to me, the case parts & controls certainly are, it's part of the tie up with Yokogawa so that they could sell HP TE in Japan.
A lot of HP's resistance & LCR meters were built in the Japanese factory, sometimes you may even find one with a YHP badge on the front. Some US HP TE was also made locally in Japan, one I'm looking for is the 5233L counter.

David

As David mentioned this has something to do with Japan's restrictive policies concerning foreign companies, like U.S. companies,  doing business in that country. In order to get into the Japanese market you must partner with a Japanese company. That's why you see Sony/Tektronix and in this case hp/Yokogawa.

[factory]

The HP & YEW (Yokogawa Electric Works) joint venture goes all the way back to 1963, link for those that actually look at them.   

https://www.hpmuseum.net/divisions.php?did=39

David

[factory]

This makes me so angry, just seems so unnecessary:
https://www.ebay.co.uk/itm/Tektronix-TDS-714L-Four-Channel-Long-Recorder-Colour-DSO/393085246948

That seller, Pro-Avit.london has had a lot of equipment with similar damage. It's obviously deliberate and probably malicious. I've come across similar when a company went bust or was taken over and people laid off. Someone taking the view "if I can't have it, I'll make sure you can't have it either".

I've also bought a beat up looking computer base unit at a bankrupcy auction and on opening it up found it stuffed full of memory modues and co-processors in anti-stactic bags. Someone had stripped all the extra memory out of the othe machines and stashed it. Presumably they were intend to make off with the "broken" one or buy it at auction. I don't know if it was done at the auction house or the original company. This was back when memory was worth a lot.

When the MOD used to have auctions by the stillage and before CCTV you would see similar thingsgoing on. Hiding small valuable parts in oter boxes, splitting matched items between lots etc during viewing.

Yep, that sounds about right to me as well. I see that it was calibrated 1/5/2019 so it is highly likely that it was malicious damage. I also know that they get a lot of their stuff from the BBC and other broadcast companies, and he often has video cameras, lenses and recording equipment as well.

I doubt that the scope could be repaired cheaply either, those BNC's look special to me and the range selectors I'm pretty sure would not be off the shelf standard parts either

The BNC's look directly attached to the circuit board and the range selectors will be some kind of rotary encoder.
It doesn't looks any better on the back, but it must have usable enough parts for someone with another as it's got enough bids.

David

[factory]

Well I'm not sure if a gorilla was responsible for the burnt resistors being lower than 100kΩ, as I discovered the very first batch of HP 5325A's (prefix 820) came with a 82Ω resistor for R3, but this counter is a later 844 prefix and the input amplifier boards have no space for the capacitor C20 that is in parallel with the 100kΩ. I wouldn't normally do this but I decided to modify both boards to match the 844 prefix manual, i.e. how it should have left the factory.
 

First I had to strip all the components from the burnt areas & clean the carbonised remains away, some Araldite was needed to fill in where one board was damaged.


The components were all tested, one Zener diode had failed, testing the remaining ones I have decided a 3.3V Zener matches the spec of the rest of them (approx 3.8V at 10mA), one of those has been temporarily fitted & I have ordered a couple of the original 3.83V part as they weren't too expensive (part no. 1902-3059).

I replaced a couple of the resistors that had faded markings, fitted the 100kΩ for R3 and a 1000pF capacitor on the rear of the boards, I also added a link on the back to properly repair a damaged track that previously had a bit of IC leg bodged on.
Both boards tested OK on all attenuator settings, guess I'm lucky the protection circuit did it's job & didn't EOL the dual FET. 


David

The later counters with similar input circuits e.g. 5328A used two resistors in series and a capacitor. One resistor around 100R and the other around 1M with a capacitor about 500pF across the high value resistor. Presumably the bigger capacitor gives better low frequency response and the small resistor limits the charging current if you put a fast DC step on the input.

The later 5325 'B' version rated at 20MHz (12.5MHz for 'A' version) uses a similar pair of resistors with a capacitor across one of them, the Zeners are gone though, replaced by two more diodes.
Oddly went back to using Zeners for 5326/7 series.

The 1902-3059 Zeners have arrived today, along with a replacement intensity pot for that brown Philips PM3055 scope I got last year, apparently most of the pots are identical.

Also arrived this morning is the HP 11045A probulator from Germany, I thought it may have been delayed for customs but no it wasn't.  It looks barely used and all the small parts are still there. 




David

[BU508A]

If you are interested in some nice gadgets, this is a cool channel for this topic.
I stumbled over this channel, because I saw in the preview picture of a video the same USB meter which I had introduced here.

What I was finding interesting was this silicone heat resistant mat for your workbench.



Link from the comments sections from the video from above:
https://bit.ly/2WffvHN

Edit:
I have ordered via ebay the model S-180 here:

[Zucca]

Today problem, two pipes A and B.
A is 100mm long, and weight 48g (weight is uniformly distributed in the entire lenght)
B is filled with some many different materials we do not know, but we know its lenght 76.7mm, his COG is 32mm away from one of its ends and its total weight is 370g.

Now we connect the two pipes together side by side so that the two pipes centers are aligned.

Where I should put my finger to hold the entire new structure and keep it balanced?
Oh wait I know the answer already....
Where is the new COG in the pipes lenght direction of the entire new structure?

BTW: I love going back in my student times and yes I already solved it, it was fun, just I wanted to share. Believe it or not it was for my 3D printer upgrade.
PS: Keep your brain always alive.

[bd139]

So it could very well be munted!   

Highly likely 

Will actually be on Discord later...

Getting a hankering for a Heathkit at the moment. Dreamed about buying a shit Heathkit scope last night 

[Zucca]

Will actually be on Discord later...

Me tooo 

[Saskia]

So it could very well be munted!   

Highly likely 

Will actually be on Discord later...

Getting a hankering for a Heathkit at the moment. Dreamed about buying a shit Heathkit scope last night 

I dreamed about winning the lottery and buying a channel island.
No such luck ...

[mnementh]

This makes me so angry, just seems so unnecessary:

https://www.ebay.co.uk/itm/Tektronix-TDS-714L-Four-Channel-Long-Recorder-Colour-DSO/393085246948


https://www.ebay.co.uk/itm/G173305-EIP-Microwave-351C-Autohet-Counter/293957563533

The TDS-714... I disagree. I see the deliberate munting as an opportunity for someone who really needs one but could never afford it. The exigencies of corporate finance & depreciation working in your favor every once in a while.

The 351C... ooooooh. Yummy. Even with no place to keep it, that one tempts me... I have to say... I'm probably lucky it would cost over $200 to get it to me, on top of a winning bid.

The two Canada listings... Not likely to close in my price range, but worth watching, both of 'em.

mnem
 

[AVGresponding]

Given that it looks like the BNC's and range knobs were removed with a hammer, I'd be concerned about board damage.

I expect those BNC's if not an off-the-shelf item, could accept such with some modification.

A crack in the board they are mounted to is another matter though.