Test Equipment Anonymous (TEA) group therapy thread

[Cubdriver]

Besides, I like coffee with my sugar and half-and-half.   

-Pat

Sugar in coffee? Bleah!   Half-and-half? 

I like my coffee like I like my women.

[Cubdriver]

Bitter and murky.   

[med6753]

Clean up and tear down of the 2235.

Front panel cleaned up nicely. The case has multiple scuffs and dirt is embedded in the paint. It will need re-spray.



Peek-a-boo inside. First glance I see no evidence of prior repairs or Gorilla activity.


 

Underside.



Geez, getting the PSU cover off was like breaking into Fort Knox. But surprise is it looks all original. I have a virgin here and I'm gonna bust her cherry.  Tomorrow I'll pull together the BOM for capacitor/part replacement.

[Cerebus]

Yuck. The coffee has a HP-ish color. 

Call that a cup of coffee? This is a cup of coffee:



If it's not as black as Louis Armstrong in a light-proof room, it's not black enough.

(I really thought that was a cup of builders tea with way too much milk in it, not coffee.)

[mnementh]

BLEEEEARRRRGHHH!!! Black coffee is for bitter people with dried up little souls. Like Sid. 



Half a gallon (slight exaggeration) of properly cooked Columbian coffee, enough artificial sweetener the coffee itself gets cancer, and 3 glugs of heavy cream. Every once in a while, on my day off, a couple Everything bagels toasted almost to burnt, then too much butter and too much Philly cream cheese. Alternately, substitute a toasted baguette or croissants with all the above.

The breakfast of breaditarian dwagons. 

mnem
I do miss that mug terribly... 

[vk6zgo]

Is there something I don't know about old TI BC183L trannystors, auction of 20 sold for £210. 
eBay auction: #314026002138



Or much better price from Langrex, 10 for £2.25. https://www.langrex.co.uk/products/bc183l-92-npn-transistor-x1opcs/

David

Or 100 for £3.20 (plus VAT) from ESR Components.

https://www.esr.co.uk/shop/contents/en-uk/d2112001_AC_to_BC_Series.html

Could be some daft thing, like with valves, where only a Mullard ECC81 with the code from such and such a factory and a particular anode construction will do, as its musicality and sheer sonic competence is overwhelming.

It does make a bit of sense with valves, as back in the twilight of their use, there were some dodgy brands around, so I wouldn't pay as much for a Zaerix as for AWV, Siemens, RCA, Sylvania, Philips, or Mullard.

The problem, these days, is that the desirable brand may be repackaged "pulls" rejected for "O.O.S" after testing, way back in the '70s/'80s, which some sharpie got their hands on.

A very common reason for valve replacement back in the day was heater/cathode leakage, causing hum problems in valves which were otherwise OK.

The enthusiasm for DC heater supplies amongst audiophiles may originate in this condition, as back in the golden age of valves, such measures were incredibly rare with indirectly heated tubes.

Big stuff, like high power Transmitting tubes had directly heated cathodes, so the filaments were either fed by individual centre tapped
transformers, with the secondary centre tap returned to ground, & the two outer ends heavily by-passed for RF, or in later years, by very large DC supplies.

[Zoli]

I offered some transistors once, they were free to collector.....

And charged to the emitter, I suppose 

Only if they didn't collect from my base.

mnem
Not enough soggy ol' boots in all the land... not near enough...

I can send you over a few from my trifting... for throwing purposes, OC

[mansaxel]

Yes, but you have to have the mythical golden ear to hear the difference, because none of our expensive (back in the day) test gear is capable of measuring the incredible increase in the signal quality.  It’s clearly audible (to them) but otherwise immeasurable.  Don’t question, you tin-eared heathen!
       

-Pat

It is remarkable how much these golden ears refrain from actually finding out if they have been swindled or not -- mention something like double-blind testing to them and you will forever be branded an Un-Believer.  Such testing of course will reveal that standard 0,75mm² (just below AWG18) zipcord is a perfectly fine speaker cable at moderate lengths.  I think that the 'phools secretly know and fear that this is true, but being caught would be so horrible.

And it has to be double-blind; for the subtle cues of someone in the know will mess the results up.  This goes back to a early 1900s study in animal psychology, involving a certain German horse, called Der kluge Hans.

[med6753]

C902 lower right. There's C903 hidden behind that transformer. Must go ASAP.

[vk6zgo]

Anyone in the UK with a serious amount of HP gear to diagnose? Here's someone (not me) selling almost every HP card extender you could think of: https://www.ebay.co.uk/sch/emjo_90/m.html?item=314114703504&rt=nc&_trksid=p2047675.m3561.l2562

McBryce.

This seller is getting some ridiculous bids on a lot of few dozen very used OC44s. What makes these cruddy transistors so valuable ?

The only people I can think of who'd want them are restorers of 1960s transistor radios, which have a bit of a following.

You can get NOS from a few suppliers, but they are over £10.

They were usually used in autodyne converter stages of such radios, along with OC45s in the IF, & the OC7x series devices for audio.
They are usually replaceable with the "2N" or "2S" series used in other brands of radio.

A modern silicon PNP will need bias changes, & may have too much gain, causing instability.

£10!!----they were only around 2 quid when they were new!

[mansaxel]

A different Tektronix mug showed up the other day on our favorite bank account evacuation site, so I snagged it.  It arrived today.  Smaller than the cobalt blue one (still my favorite) but nice to have another, different one.



-Pat

Yuck. The coffee has a HP-ish color. 

LOL - First off, I don't think I want Tek-truquiose turquoise coffee - doesn't seem appealing.  Don't think I'll let the creamer get that far 'off'.   

Besides, I like coffee with my sugar and half-and-half.   

-Pat

Edit - I kan tipe.   

The logo would do much better if the contents weren't coloured like UK Staff Sergeant tea. 

This of course has electronic implications too, and since we're now on probation for offtopic violation, I'm going to prove this by quoting the service manual of the Yamaha PM1800 mixing desk, in which it is written the following phrase: "Un-sweetened black coffee is probably the least harmful".  This is in the context of cleaning the mixer after exposure to spilled drinks. Their recommended procedure was distilled or de-ionised water and toothbrush, which worked a treat. Classic umbrella drinks or sweet sodas were not even remotely as friendly to the device.  I think this is a major contribution to me drinking my coffee all black ever since. I much prefer my sweets on food, like toast with jam and cheese. Which I'm getting right now, away from electronics, of course.

[med6753]

Yuck. The coffee has a HP-ish color. 

Call that a cup of coffee? This is a cup of coffee:



If it's not as black as Louis Armstrong in a light-proof room, it's not black enough.

(I really thought that was a cup of builders tea with way too much milk in it, not coffee.)

Well if you like your coffee dark and bitter then Starsucks would be right up your alley. Worst coffee on the planet.

Mellow Colombian with just the right amount of half-and-half. Not whole milk. Doesn't cut it. And no sugar.   

[mansaxel]

BLEEEEARRRRGHHH!!! Black coffee is for bitter people with dried up little souls. Like Sid. 

Like me!



As you can see from this on-topic picture comparing my US-bought 8060a to my Norma standard, where I accidentally got some "extra items" in, the proper cup is black, and there's some yoghurt with müsli, and my own english muffins, with Gruyère cheese, butter (Valio, from Finland; unless you go the whole  nine yards and import from France, the best butter I've had) and apricot jam.

Muffins do deserve a special mentioning; I had some ready because the other day, as we were having grilled salmon for dinner, with 'taters and hollandaise sauce, the wife found that the sauce was plentiful and there would be leftovers. So she stated that Eggs Benedict would be nice for breakfast the next morning.. Accordingly, a dough was set, rose overnight, and breakfast was served. No pics with multimeters from that event, so you'll have to imagine the poached egg on ham with sauce.

[tautech]

C902 lower right. There's C903 hidden behind that transformer. Must go ASAP.

That transformer is a common mode choke, part of the mains input filter. 

[Robert763]

Not much TEA today Went to Ely and amongst other things I visited a charity shop connected to the animal shelter we got our dog from. In a bin was a Canon EOS 40D camera. It said untested due to no battery charger. It did have a body cap, strap, battery and fast 8GB CF card. At £30 it was worth a punt. They offered a refund if it didn't work but I'm not going to ask a charity for  refund... My current DSLR is a EOS 20D bought new back in 2004 for $1400 (in the USA). So this would be a bit of an upgrade.
Got home, charged battery and - nothing, dead. So to TE. Got the Fluke 8060 out. Battery read OK and some continuity across contacts in the camera. However the contacts on the battery looked greasy. So quick wipe with contact cleaner, stuck it back in and it all works. Not a bad DSLR. "only" 10 megapixels but the overall image quality beats the 15 MP 50D that replaced it.

Also got a chance to check the resistance of the Current probe cal fixture Fluke sez Bam 50R (no, not taken with the Canon, it was taken before I went out).
 

That was a jammy find with the 40D, not sure I'd agree about it having a better image capability than the 50D, which I have, I also have the 7D and the 50D is my camera of choice for what I use it for. I find that the reason why I favour it over the 7D, even though the 7D has way more pixels, but the focusing system on the 7D cannot offer me a single spot focus in any quadrant, it always presents me with multiple zones of focus and as such, if shooting through say a chain link fence, will tend to focus more on any part of the fence rather than the plane on the opposite side.  The 40D has the ability to provide me with multiple zone or just a single zone and with the single can shoot through the holes of the fence, ignoring the fence as long I focus on the single spot through it.

The 40D, has 5Mp fewer pixels than the 50D and 2Mp more than the 20D and I find that the 7D has a far better image quality on subjects that are not confused by the multiple focus points, such as a single plane in blue sky. YMMV.

The image capability was based on the DXO Mark testing https://www.dxomark.com/Cameras/  D40 scored 64 D50 was 63. 
A full frame sensor DSLR would be nice but I'd rather put the money into glass.

[med6753]

That transformer is a common mode choke, part of the mains input filter. 

I stand corrected. But since I'm sitting I sit corrected too. 

[Robert763]

What's an audiophool? And why are they smashing up chewb gear?

People who pay a lot of money for things they believe will improve the sound of their hifi, including particular subtypes of valve, solid silver loudspeaker cables, particular brands of capacitor and audiophile IEC mains cables. All of this is highly dubious on an engineering basis.

Some valves which were never considered audio valves back in the day, such as E180F and ECC88 have become popular in these circles. E180F had gold flashed pins for solid technical reasons, but gold flashed pins clearly improve the sound.

I've even seen adverts for little towers to hold speaker cables up off the floor to improve the sound quality and reduce losses to the floor, presumably by the capacitive effect?   

If the floor is conductive that really does have an effect. When EMC testing aircraft equipment the cables have to be spaced 50mm above the ground plane. Typically this is done with blocks of polyethelene foam or bit of wood. The effect is of couse at RF.

[bd139]

BLEEEEARRRRGHHH!!! Black coffee is for bitter people with dried up little souls. Like Sid. 

You rang. Sitting here drinking the stuff 

Engineers and IT folk exist on the stuff mostly.

Edit: med knows how to coffee like an engineer 

[bd139]

Well I got woken up at 3AM by a system crash alert going off so definitely not hitting Rugby rally today after last night’s second thoughts. I wish everyone going good luck and bad luck. Good luck on finding something and bad luck for finding anything which I will be finding next week at MKARS 

Going to keep an eye out for OC44 transistors at these things now. I made fortune on the old OC81D’s back in peak pedals so perhaps it’s time for another round. Was getting £10 each and had most of a box of 500 of them. I bought half a car and a lot of curry with those transistors 

[med6753]

The 2235 service manual that I downloaded from TekWiki has cut off parts of the schematics which were originally a fold out page. Artek Manuals to the rescue. The schematics are complete since they imaged the entire fold out page as one sheet. I don't know why I bother going to any other source. Artek stuff is always superior and cheap. $6.95 USD for a downloadable link. 

Edit....oh here is some real dumbassery. Heard on scanner. Mental health worker goes to work and leaves keys in car. Comes out later and car is gone. Calls cops. Cops find car further down the road abandoned and wrecked.

D'OH. 

[bd139]

Check my thread on it. There are uploaded full pull outs later in the thread. Also I posted the full PSU schematic.

BTW tek wiki scans are shit. Some of the 465 and 465B manuals have missing pages. So annoying.

[Cubdriver]

Yes, but you have to have the mythical golden ear to hear the difference, because none of our expensive (back in the day) test gear is capable of measuring the incredible increase in the signal quality.  It’s clearly audible (to them) but otherwise immeasurable.  Don’t question, you tin-eared heathen!
       

-Pat

It is remarkable how much these golden ears refrain from actually finding out if they have been swindled or not -- mention something like double-blind testing to them and you will forever be branded an Un-Believer.  Such testing of course will reveal that standard 0,75mm² (just below AWG18) zipcord is a perfectly fine speaker cable at moderate lengths.  I think that the 'phools secretly know and fear that this is true, but being caught would be so horrible.

And it has to be double-blind; for the subtle cues of someone in the know will mess the results up.  This goes back to a early 1900s study in animal psychology, involving a certain German horse, called Der kluge Hans.

Years ago on an audio forum, there was a big discussion when several of the resident Golden Ears insisted that new speaker cables sounded noticeably (to them) better after they'd been 'broken in', and these individuals insisted that they could clearly distinguish between raw and seasoned (for lack of better terms) speaker cables.  Needless to say, that sane people in the thread - thankfully all but the two or three GEs - felt that this was utter bovine excrement, and told them so in no uncertain terms.  They continued to insist that there was a difference that they could reliably and confidently discern between fresh and broken in speaker cables.

As this carried on, discussions of a test began, and a means to perform one began to solidify.  It was to go something along these lines:

• The Golden Ears would publish instructions on how to make their magical speaker cables.
• A chosen, technically competent member in the thread would build several sets of cables to the published spec.  (Let's say six pairs for this example)
• The newly built, identical cables would be sent to a different forum member, who would mark them individually in some fashion - number, letter, color code, something.
• That forum member would then send the cables to yet another, who would apply the specified 'break in' procedure to at least one pair, and no more than five pairs, keeping a record of which cables were 'broken in' and which were not.
• He would then send the cables on to the selected Golden Ear, but with no indication as to which were which break-in wise.  He would also send a signed list of the cables and their status to a different, trusted forum member.
• The Golden Ear would listen to the cables, and determine with his superlative hearing which ones had been broken in and which hadn't, then send a signed list of his conclusions to the same forum member from above who had received the list from the member who'd broken in the cables.
• That member would then publish scans of both the lists for comparison.

This is the gist of the thoroughness of the plan that evolved over several days of discussion, though not exact as this happened at least 7 years ago.

Interestingly, as the test plan began to coalesce, the enthusiastic participation of the Golden Ears in the thread began to taper off until they completely dropped out.  No one could understand why they buggered off when presented with a test plan after all their previous insistence about us plebs just not being able to hear as well as they could... 

-Pat

[med6753]

BLEEEEARRRRGHHH!!! Black coffee is for bitter people with dried up little souls. Like Sid. 

You rang. Sitting here drinking the stuff 

Engineers and IT folk exist on the stuff mostly.

Edit: med knows how to coffee like an engineer 

Please don't insult me by calling me an engineer. 

[Cubdriver]

A different Tektronix mug showed up the other day on our favorite bank account evacuation site, so I snagged it.  It arrived today.  Smaller than the cobalt blue one (still my favorite) but nice to have another, different one.



-Pat

Yuck. The coffee has a HP-ish color. 

LOL - First off, I don't think I want Tek-truquiose turquoise coffee - doesn't seem appealing.  Don't think I'll let the creamer get that far 'off'.   

Besides, I like coffee with my sugar and half-and-half.   

-Pat

Edit - I kan tipe.   

The logo would do much better if the contents weren't coloured like UK Staff Sergeant tea. 

This of course has electronic implications too, and since we're now on probation for offtopic violation, I'm going to prove this by quoting the service manual of the Yamaha PM1800 mixing desk, in which it is written the following phrase: "Un-sweetened black coffee is probably the least harmful".  This is in the context of cleaning the mixer after exposure to spilled drinks. Their recommended procedure was distilled or de-ionised water and toothbrush, which worked a treat. Classic umbrella drinks or sweet sodas were not even remotely as friendly to the device.  I think this is a major contribution to me drinking my coffee all black ever since. I much prefer my sweets on food, like toast with jam and cheese. Which I'm getting right now, away from electronics, of course.

Yeah, I thought of that after I'd added the half-and-half.  Also figured I'd take some ribbing on here because I add so much, but will continue to do so, as that's how I like it.

-Pat

[Cubdriver]

Not much TEA today Went to Ely and amongst other things I visited a charity shop connected to the animal shelter we got our dog from. In a bin was a Canon EOS 40D camera. It said untested due to no battery charger. It did have a body cap, strap, battery and fast 8GB CF card. At £30 it was worth a punt. They offered a refund if it didn't work but I'm not going to ask a charity for  refund... My current DSLR is a EOS 20D bought new back in 2004 for $1400 (in the USA). So this would be a bit of an upgrade.
Got home, charged battery and - nothing, dead. So to TE. Got the Fluke 8060 out. Battery read OK and some continuity across contacts in the camera. However the contacts on the battery looked greasy. So quick wipe with contact cleaner, stuck it back in and it all works. Not a bad DSLR. "only" 10 megapixels but the overall image quality beats the 15 MP 50D that replaced it.

Also got a chance to check the resistance of the Current probe cal fixture Fluke sez Bam 50R (no, not taken with the Canon, it was taken before I went out).

My old 20D is sitting in a drawer somewhere here.  It needs a new shutter - wore the old one out taking time lapses of the house renovation - whatever contact in there that tells it that it's cocked is apparently broken off - put a battery in and it just starts recocking over and over.

-Pat