Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Out of that list, the only thing that really caught my eye was the Phillips meters, might have been able to repair mine with the parts unless they were working already. You could have said that there was a bloke in Sainsbury car park flogging the gear from his car boot

[bd139]

I did consider that but the cash disappearing out of the account from a cash machine at Kempton is going to look even dodgier 

[mnementh]

I did consider that but the cash disappearing out of the account from a cash machine at Kempton is going to look even dodgier 

That's what PayPal at the local grocery is good for. 


mnem
I would never do THAT. 

[mnementh]

...

It looks like you cheated... just ground them thinner until the booger went away. I guess I can't blame you; trying to regrind the cutting surface correctly is very hard, especially on shear action cutters like these where having them perfectly parallel is critical.

Yes, this is a case of picking your battles; the conservative action was probably the better choice. 

LOL well, metal had to come off from somewhere   The Knipex cutters don't appear to come apart which would have been necessary to address the bevelled cutting edge. Still required grinding along the same plane as original otherwise you lose the parallelism of the edges - tongue at right angle needed. Anyway, it was this or the scrap bin.

Maybe I should just buy a pair of these: https://www.amazon.co.uk/dp/B00BL0CCW2/?coliid=IPR94213PMK5M&colid=H3H2EGOSGO8H&psc=0&ref_=lv_ov_lig_dp_it

Yeah, that was what I figured after rethinking it.

These are a bit more reasonable for cutting hardened wire; not sure if you have them on your Amazon though.

https://www.amazon.com/Orthodontic-tungsten-carbide-inserts-Linkers/dp/B01JYHNQX2

https://www.amazon.com/DDP-ORTHODONTIC-TUNGSTEN-SUPERIOR-STAINLESS/dp/B01LNKH0EO/


mnem
Moose are not good at water-skiing.

[tggzzz]

At Kempton, emptying my brain I saw:

1. Thurlby pulse generator £15
2. 2x HP SA's £160 each
3. 1x dead HP180T scope £15
4. 1x marconi 2019A £195
5. 1x Racal counter £40
6. 3x TTi PL supplies £20-25 each
7. 1x knackered DMM no brand £1
8. 2x Philips LCD based meters £25 each
9. 1x Tek 2215 £60 (bit high!)
10 1x Tek 2225 £95

Oh, that's poorer than I expected; glad I didn't go.

But then again, chatting to a stall holder a couiple of months ago lead us to agree that the April one was less good for selling than the November one. So guess which one they cancelled.

[tggzzz]

There are advantages to provincial meets At the Chippenham one I got a lovely 4 "decade" Dekastat variable resistor for £10; the movement is almost pornographic "Decade" is nominal, since each decade really does go from 0 to 10 (or 11), making the max resistance 121.1ohms.

Oh yes, good decision; it's obvious you just barely escaped with your gonads intact as it is... 

There are advantages to being divorced.

The remaining problem is that it is beginning to take over daughter's bedroom - but I have the whip hand there since she has even more useless junk in there!

Speaking as a long-time flea market veteran, I learned long ago to keep a 4S LiPo and 300W inverter (Used to be a 16V drill pack and a 150W inverter but I upgraded about 10 years ago) and a small DMM in my pocket. I've NEVER regretted it; bargaining from a position of ignorance is always the weaker hand. 

I'm not sure I'd let someone poke/test one of my instruments with a 240V square wave

[Mr. Scram]

Yeah, that just means that if it's broken you are the one who just bought it.

[bd139]

At Kempton, emptying my brain I saw:

1. Thurlby pulse generator £15
2. 2x HP SA's £160 each
3. 1x dead HP180T scope £15
4. 1x marconi 2019A £195
5. 1x Racal counter £40
6. 3x TTi PL supplies £20-25 each
7. 1x knackered DMM no brand £1
8. 2x Philips LCD based meters £25 each
9. 1x Tek 2215 £60 (bit high!)
10 1x Tek 2225 £95

Oh, that's poorer than I expected; glad I didn't go.

But then again, chatting to a stall holder a couiple of months ago lead us to agree that the April one was less good for selling than the November one. So guess which one they cancelled.

I think the November venue was probably more expensive. Lots of pre-Christmas events hike up the prices around then.

Forgot to mention. Going rate appears to be £7.50/kg for grab bags of parts. Shitty old parts. Used to be 50p when I used to buy them in the 1990s and they had nice stuff like piles of Philips parts! Surplectronics were gouging people for a quid for 2x 2n2222a's as a metric for pricing.

I was actually only there for 20 minutes in total. It was worth going for me because it was literally a 30 minute and £5 total distraction from my planned route of the day but I'm glad I didn't drive more than a few miles.

I'm actually thoroughly asking myself if it's really worth going to these sorts of events. As a fine example, I just ordered a set of bitx transceiver boards from India for just over a tenner. I can populate them from stock parts I have plus about 20 quid in expenditure from CPC and have a mono band SSB transceiver. I couldn't walk out of there with anything reasonably functional or lines up with my objectives and bucket list for less than £100.

Likewise, a good win for you on the Tek time-mark generator. But I've got a Si5351 board (qrp labs) here plugged into a shitduino that has 3x synthesized outputs up to 200MHz and it cost in total about £15 and I didn't have to go out

Also discovered the joys of FT8 recently. Amateur radio where you don't have to talk to anyone or be sociable which suits me. Managed 4350 miles on my first QSO!

Actually this is the golden age of everything. Why go down the road and buy some crap when you can get some gold delivered to you from the other side of the planet (or the same country next day) for 1/10th of the price?

[Specmaster]

I did consider that but the cash disappearing out of the account from a cash machine at Kempton is going to look even dodgier 

Numpty, cash points nearer to home that you could have gone to before arriving at Kempton 

[mnementh]

Speaking as a long-time flea market veteran, I learned long ago to keep a 4S LiPo and 300W inverter (Used to be a 16V drill pack and a 150W inverter but I upgraded about 10 years ago) and a small DMM in my pocket. I've NEVER regretted it; bargaining from a position of ignorance is always the weaker hand. 

I'm not sure I'd let someone poke/test one of my instruments with a 240V square wave

Yeah, that just means that if it's broken you are the one who just bought it.

Meh... if it acts funny powered from an inverter, just more reason to haggle it down. 

I'm not going to take ANYBODY'S WORD FOR IT without seeing it powered up with my own eyeballs. Not sure about your side of the pond, but even the cheap inverters I've bought over here are at least modified sine wave for decades; have to be with all the DC-DC converter powered TVs ever since the days when RCA was actually a brand, and now laptops. A 200W travel transformer will of course assuage any such fears, and only weighs as much as your battery. 


Good hunting,


mnem
*A few volts shy of a full charge*

[bd139]

That’s not a bad idea with a portable inverter. Would put the shits up any crapmongers instantly.

[tggzzz]

I was actually only there for 20 minutes in total. It was worth going for me because it was literally a 30 minute and £5 total distraction from my planned route of the day but I'm glad I didn't drive more than a few miles.

I'm actually thoroughly asking myself if it's really worth going to these sorts of events. As a fine example, I just ordered a set of bitx transceiver boards from India for just over a tenner. I can populate them from stock parts I have plus about 20 quid in expenditure from CPC and have a mono band SSB transceiver. I couldn't walk out of there with anything reasonably functional or lines up with my objectives and bucket list for less than £100.

Likewise, a good win for you on the Tek time-mark generator. But I've got a Si5351 board (qrp labs) here plugged into a shitduino that has 3x synthesized outputs up to 200MHz and it cost in total about £15 and I didn't have to go out

Actually this is the golden age of everything. Why go down the road and buy some crap when you can get some gold delivered to you from the other side of the planet (or the same country next day) for 1/10th of the price?

You have to be really selective, both in terms of whether something is wanted/needed, good, and the alternatives. Plus, whether it is likely to be fleabayable.

My habits are largely kept in check by having a full house and an inability to throw anything out.

[tggzzz]

That’s not a bad idea with a portable inverter. Would put the shits up any crapmongers instantly.

I seriously considered getting a car 12V->mains inverter for use in a field (e.g. Dunstable), and using that with a ferroresonant constant voltage transformer to reduce the harmonics. Unfortunately the general opinion is that the transformer would present an unacceptable load to the inverter.

BTW, a portable inverter wouldn't worry me - if a buyer doesn't trust what I say, I'm perfectly happy not to sell

[Specmaster]

Do I sense that a portable inverter is now on your project list?

[tggzzz]

Do I sense that a portable inverter is now on your project list?

Probably not. Too high energy for my tastes, and the alternative is to take pictures of X working at home, and fleabay it.

Radio hams are pretty stingy - they are more interested in buying stuff very cheaply or that almost works. Hence if it works well it will probably be too expensive for their tastes.

Having said that, I have flogged a pretty good Tek 485 (1.25ns risetime rather than 1ns) and Tek 1502 for reasonable sums at Kempton before - where they could see them working.

[Cerebus]

...

It looks like you cheated... just ground them thinner until the booger went away. I guess I can't blame you; trying to regrind the cutting surface correctly is very hard, especially on shear action cutters like these where having them perfectly parallel is critical.

Yes, this is a case of picking your battles; the conservative action was probably the better choice. 

LOL well, metal had to come off from somewhere   The Knipex cutters don't appear to come apart which would have been necessary to address the bevelled cutting edge. Still required grinding along the same plane as original otherwise you lose the parallelism of the edges - tongue at right angle needed. Anyway, it was this or the scrap bin.

Maybe I should just buy a pair of these: https://www.amazon.co.uk/dp/B00BL0CCW2/?coliid=IPR94213PMK5M&colid=H3H2EGOSGO8H&psc=0&ref_=lv_ov_lig_dp_it

Yeah, that was what I figured after rethinking it.

These are a bit more reasonable for cutting hardened wire; not sure if you have them on your Amazon though.

https://www.amazon.com/Orthodontic-tungsten-carbide-inserts-Linkers/dp/B01JYHNQX2

https://www.amazon.com/DDP-ORTHODONTIC-TUNGSTEN-SUPERIOR-STAINLESS/dp/B01LNKH0EO/


mnem
Moose are not good at water-skiing.

I have a pair of RS 544-487 cutters that are sadly no longer in the RS catalogue. The nearest they currently have are these:



Which are RS Stock Number 208-2004 and, although fractionally bigger (160mm versus 145mm for mine), seem to be the replacement for them. Note the compound joint, which makes cutting tough stuff a lot easier. Mine have served me since 1993 and are as good as new - they still pass the "Squeeze and look at where the cutting edges meet against the sky" test. I've used them to cut piano wire, component leads, everything. They're small enough and have a neat enough nose to substitute for typical electronics side cutters for all but the finest work. Now the bad news, the replacements cost £69 + tax, mine were a similar price (in real terms) but with 25 years under their belt and easily another 25 years life in them that's not expensive. Both the old and the new are RS branded, I don't know who the OEM was.

[neo]

I desoldered the ds1225 from my  2465B, when i tried to read it all i get is a screen of "AA"! did i screw up?! 

[tggzzz]

I desoldered the ds1225 from my  2465B, when i tried to read it all i get is a screen of "AA"! did i screw up?! 

You won't get the best answer here.

1) search elsewhere on this forum
2) there's a good thread about this on the TekScopes forum
3) if still necessary, post in this forum's "Repair" section.

[neo]

I desoldered the ds1225 from my  2465B, when i tried to read it all i get is a screen of "AA"! did i screw up?! 

You won't get the best answer here.

1) search elsewhere on this forum
2) there's a good thread about this on the TekScopes forum
3) if still necessary, post in this forum's "Repair" section.

The tek scopes forum doesn't go in depth as to what it should look like, i'm just asking if it is in fact blank.  I'm panicking because i think i screwed up.   

[tggzzz]

I desoldered the ds1225 from my  2465B, when i tried to read it all i get is a screen of "AA"! did i screw up?! 

You won't get the best answer here.

1) search elsewhere on this forum
2) there's a good thread about this on the TekScopes forum
3) if still necessary, post in this forum's "Repair" section.

The tek scopes forum doesn't go in depth as to what it should look like, i'm just asking if it is in fact blank.  I'm panicking because i think i screwed up.   

This is still an inappropriate thread for your question.

I'm surprised that you feel that discussions titled "tektronics 2465b 400mhz nvram battery info" are not "in depth" since they include messages like:
"Since you wrote and debugged a read/write program, you obviously have a way to fully restore your entire NVRAM at will. If you have the time, you're in a good position to show that 1e00 - 1fff is sufficient, or not, for fully restoring the calibration information.  If successful, it would allow others to do a backup with only a video capture, and only deal with the more complicated procedure of restoration should they lose their NVRAM.  (Or just get a re-cal, I know...) Your already developed procedure could also be used by those who opt to do so, but it would only need to capture 512 bytes, and would only need to be a simpler one-step procedure. I would try it but I do not have a 2465B.  The video capture and restoration of only 1e00-1fff has been shown to work on a 2465A."

[neo]

I desoldered the ds1225 from my  2465B, when i tried to read it all i get is a screen of "AA"! did i screw up?! 

You won't get the best answer here.

1) search elsewhere on this forum
2) there's a good thread about this on the TekScopes forum
3) if still necessary, post in this forum's "Repair" section.

The tek scopes forum doesn't go in depth as to what it should look like, i'm just asking if it is in fact blank.  I'm panicking because i think i screwed up.   

This is still an inappropriate thread for your question.

I'm surprised that you feel that discussions titled "tektronics 2465b 400mhz nvram battery info" are not "in depth" since they include messages like:
"Since you wrote and debugged a read/write program, you obviously have a way to fully restore your entire NVRAM at will. If you have the time, you're in a good position to show that 1e00 - 1fff is sufficient, or not, for fully restoring the calibration information.  If successful, it would allow others to do a backup with only a video capture, and only deal with the more complicated procedure of restoration should they lose their NVRAM.  (Or just get a re-cal, I know...) Your already developed procedure could also be used by those who opt to do so, but it would only need to capture 512 bytes, and would only need to be a simpler one-step procedure. I would try it but I do not have a 2465B.  The video capture and restoration of only 1e00-1fff has been shown to work on a 2465A."

I was referring more to the teardown thread...

Edit; There is a difference between an in-depth answer and an in-depth answer i can understand and this may not be an "appropriate" thread but i figured someone here could maybe give me at least some clue. Sorry to have wasted your time and space.

I understand nothing past the 1970s, digital electronics make me go 

[mnementh]

I think we have a simple misunderstanding here; that of OT vs reasonable place to ask for help. This is not an unreasonable place to ask for help; you just have to understand that it's a gamble as to whether anyone here has actually done the repair you're contemplating and can help. If not, then you'll not get anyone who can answer; it's that simple.

Other threads may be more likely to have users with the knowledge in question; that doesn't necessarily mean they have the time or inclination to help neo grok in fullness.

I don't think it was unreasonable for neo to ask in here; he knows there are a lot of good-hearted folks who frequent the forum who would be INCLINED to help, and maybe even able & willing to break it down into simpler terms he can more readily digest. This is often not the case with more technically-oriented threads.

When asking for help, you need to consider both; I think he just decided to ask here where he felt like he had friends first.

neo, I don't know enough about the data structure of the NVRAM in question to help you read it with an EEPROM burner; that was why I suggested you do the "shoot video of the memory dump from within the service menu" method mentioned in several of the threads I linked to when you first asked about this.

Right now, what I'd do is clean up the pins on the chip, install a low-profile DIP socket on the mainboard and then reinstall the DS1225 to see if the scope still appears to work properly. If so, get that video back up of the data ASAP.


Cheers,

mnem
I fought the lawn and the lawn... LOST! 

[neo]

I think we have a simple misunderstanding here; that of OT vs reasonable place to ask for help. This is not an unreasonable place to ask for help; you just have to understand that it's a gamble as to whether anyone here has actually done the repair you're contemplating and can help. If not, then you'll not get anyone who can answer; it's that simple.

Other threads may be more likely to have users with the knowledge in question; that doesn't necessarily mean they have the time or inclination to help neo grok in fullness.

I don't think it was unreasonable for neo to ask in here; he knows there are a lot of good-hearted folks who frequent the forum who would be INCLINED to help, and maybe even able & willing to break it down into simpler terms he can more readily digest. This is often not the case with more technically-oriented threads.

When asking for help, you need to consider both; I think he just decided to ask here where he felt like he had friends first.

neo, I don't know enough about the data structure of the NVRAM in question to help you read it with an EEPROM burner; that was why I suggested you do the "shoot video of the memory dump from withing the service menu" method mentioned in several of the threads I linked to when you first asked about this.

Right now, what I'd do is clean up the pins on the chip, install a low-profile DIP socket on the mainboard and then reinstall the DS1225 to see if the scope still appears to work properly. If so, get that video back up of the data ASAP.


Cheers,

mnem
I fought the lawn and the lawn... LOST! 

Thank you, you hit the metaphorical nail right on it's head, Too late to reinstalled the original, broke a pin on the way out and repaired it well enough to read.

[Specmaster]

I think we have a simple misunderstanding here; that of OT vs reasonable place to ask for help. This is not an unreasonable place to ask for help; you just have to understand that it's a gamble as to whether anyone here has actually done the repair you're contemplating and can help. If not, then you'll not get anyone who can answer; it's that simple.

Other threads may be more likely to have users with the knowledge in question; that doesn't necessarily mean they have the time or inclination to help neo grok in fullness.

I don't think it was unreasonable for neo to ask in here; he knows there are a lot of good-hearted folks who frequent the forum who would be INCLINED to help, and maybe even able & willing to break it down into simpler terms he can more readily digest. This is often not the case with more technically-oriented threads.

When asking for help, you need to consider both; I think he just decided to ask here where he felt like he had friends first.

neo, I don't know enough about the data structure of the NVRAM in question to help you read it with an EEPROM burner; that was why I suggested you do the "shoot video of the memory dump from withing the service menu" method mentioned in several of the threads I linked to when you first asked about this.

Right now, what I'd do is clean up the pins on the chip, install a low-profile DIP socket on the mainboard and then reinstall the DS1225 to see if the scope still appears to work properly. If so, get that video back up of the data ASAP.


Cheers,

mnem
I fought the lawn and the lawn... LOST! 

Thank you, you hit the metaphorical nail right on it's head, Too late to reinstalled the original, broke a pin on the way out and repaired it well enough to read.

If you can read it, then I'd be inclined to do as mnementh suggested with the low profile DIP socket and then just dont push the chip all the way home, it only needs to make contact for just a short period while trying to read it and video the screen.

It seems like a jolly good idea to me, it might just be possible to locate a SIF ZIF socket and fit that so that you don't need to exert any pressure on inserting the chip back and then just lock the lever down to make contact. I may of course be talking utter rubbish as I have no idea of the number of pins you require, nor if you have the space to fit it anyway, or indeed if such a socket is available to suit the chip in question.

Just seems like its well worth the shot anyway, nothing to loose.

[bd139]

If all else fails, crack open a roll of Kynar and do it like MacGuyver.

Edit: this reminds me of a comedy afternoon at university. We had to use 68k dev boards for the debugging tutorial section. We thought at the time it was going to be software debugging. Nope. Each dev board had been sabotaged in some way or another and we were told to just get on with our assignment and debugging was delayed until the following week. 

The boards had two socketed 16kbyte SRAMs on them. Mine and my lab partner’s had a high SRAM pin A8 in folded underneath the IC so it didn’t contact the socket. When you loaded the software it did a jump somewhere weird and fired a trap after a couple of minutes of execution. It took two hours to find this.

Only one other pair found out what was wrong with theirs and that was a dodgy pull up resistor (100 ohm instead of 10k)

Lesson learned: step one always visual inspection