Test Equipment Anonymous (TEA) group therapy thread

[nfmax]

Just diagnosed a dead woofer in one of the Rogers LS4a speakers in my dining room. I bought these second hand 25 years ago.

We had Rogers speakers all over the place at BFBS Cologne, in the late 70's. Mostly driven by Quad power amps. I had a pair of LS3/5a in the O/B van. Fond memories...

The LS4a's are not a BBC design. But I do drive them from a Quad 405-2 power amp

[factory]

Got the -hp- nixie counter from eBay for the minimum bid. So now have to decide wether to collect or let em ship:

Good to hear it's going to a good home. 
In my opinion it's best to go & collect if it isn't too far away, that way you don't risk shipping damage, nothing worse than this happening to a nice condition item. 


David

[med6753]

Well this Type 547 is driving me up the wall. After I completed all the repairs and calibration and returned it to it's upright position it has successfully gone through multiple burn-in cycles and ran for over a week and a half with no issues. Then the intermittent sweep issue reared it's ugly head again. What happens is the trace collapses to half it's size. Exercising the mag switch will usually bring it back, but not always. I tried changing both 6DJ8 horizontal output tubes thinking one might by microphonic but no change. So as shown yesterday pulled it out and the Siglent DSO monitoring the horizontal. Except the sucker won't fail. But I have some suspicions as to what the culprit is.

When I first got the scope to power up it had no horizontal sweep at all. That turned out to be bad Q564. I replaced it with an OEM Germanium 2N2207. Later on during repairs the trace would suddenly go into X5 or X10 all by itself. That turned out to be a dirty switch plus Q554 was bad. Replaced that with original 2N2207. Now I have this intermittent trace collapse issue and I'm suspecting either Q554 or Q564 or possibly both. I did some research and Tek on later S/N's changed both these transistors to silicon 2N4890 with no changes required to the circuit. Ah ha. Well, I found some NOS Motorola 2N4890. I'm tempted to just say screw it and get rid of the 2N2207's but I want to find out for sure they are the issue. So for now I'm holding off and playing wait and see.

Now before anyone suggests using freeze spray to try to shake out the bad part might I remind you that there is +350V floating around up there and after the freeze spray melts into water droplets I don't think that will be a good thing. 




           

[Saskia]

Someone working their way through the looong list at the IRT auction, I see... 

Currently several thou in in bids. Watching some stuff for some additional thou's

[med6753]

Well how you doing I think I found something. This pulse into the grid of V589 ain't supposed to have that downward spike on it. So I adjusted C591 and presto almost gone. I found a null point and then it grows again. The issue? Maybe. According to schematic there's no spike. So we'll see. Trace continues to be rock steady.

[Saskia]

Hmm. Lot 2990  in that IRT auction shows a signal converter and a Keysight DSO/MSO in the background which is not listed.
just wondering ...

[mnementh]

Well this Type 547 is driving me up the wall. After I completed all the repairs and calibration and returned it to it's upright position it has successfully gone through multiple burn-in cycles and ran for over a week and a half with no issues. Then the intermittent sweep issue reared it's ugly head again...

That scope... she love you loooooong time!!! 

Keep at it, med... you'll get it.

mnem
just think of it as job security...

[med6753]

Well this Type 547 is driving me up the wall. After I completed all the repairs and calibration and returned it to it's upright position it has successfully gone through multiple burn-in cycles and ran for over a week and a half with no issues. Then the intermittent sweep issue reared it's ugly head again...

That scope... she love you loooooong time!!! 

Keep at it, med... you'll get it.

mnem
just think of it as job security...

It's more like the fat lady singing OUT of key. 

[mnementh]

Well, you could always take up a less frustrating hobby... like maybe... I dunno... ummm, do they have batshit crazy street preachers where you hole up in the wilds of New York...? That's always a low pressure gig...

mnem
 

[Saskia]

https://youtu.be/DjydOI4MEIw

[mnementh]

Dusty Springfield... now there's a blast from the past. 

mnem

[mnementh]

Aww jeez... I picked the bones of last night's roast chicken for my lunch, and went to the loo afterwards. Come back and find that my son, trying to be helpful, had already taken the carcass and container from my desk and processed them into garbage and compost.

Unfortunately, I hadn't weighed the carcass, so have no idea how much I actually ate. Aside from that it was less than 380 grams, the before weight.

mnem
And I can't even get mad, because he was being helpful...

[Specmaster]

Well how you doing I think I found something. This pulse into the grid of V589 ain't supposed to have that downward spike on it. So I adjusted C591 and presto almost gone. I found a null point and then it grows again. The issue? Maybe. According to schematic there's no spike. So we'll see. Trace continues to be rock steady.

That is a classic example of why they say that to fix a scope, you need a scope 

[cyclin_al]

Aww jeez... I picked the bones of last night's roast chicken for my lunch, and went to the loo afterwards. Come back and find that my son, trying to be helpful, had already taken the carcass and container from my desk and processed them into garbage and compost.

Unfortunately, I hadn't weighed the carcass, so have no idea how much I actually ate. Aside from that it was less than 380 grams, the before weight.

mnem
And I can't even get mad, because he was being helpful...

Opportunity to talk about becoming more green, with the 3Rs, for next time:

Reduce
- I am sure you would have done a fine job of reducing the leftovers if you had the chance to finish
ReUse
- Use that carcass with some rice (barley if you have a turkey carcass) to make a soup; it makes the loads of veggies into some of the best tasting veggies ever!
Recycle
- I recommend recycling it before certain other kinfolk go as far as using the leftovers to make headcheese ...  YMMV

[dl6lr]

Got the -hp- nixie counter from eBay for the minimum bid. So now have to decide wether to collect or let em ship:

Good to hear it's going to a good home. 
In my opinion it's best to go & collect if it isn't too far away, that way you don't risk shipping damage, nothing worse than this happening to a nice condition item. 


David

Yeah, that's my problem. It's roughly 3h one way. Will try to arrange for a weekend in Berlin (I know, noone wants to go to Berlin  )

[Saskia]

No rice for mnem. Would bump him outta Keto and he would not like that.

[med6753]

No rice for mnem. Would bump him outta Keto and he would not like that.

Yep, no rice. No good. If I were Asian or Puerto Rican I would have to shoot myself.   

[Saskia]

On Keto no carbs. No bread, no noodles, potatoes, rice, cake, candy, soft drinks, fruit juice, nothing with high fructose corn sirup, ...

Actually, when on Keto, you need to cut down on anything containing carbs and religiously observe your daily intake limits.

Today I probably got bumped out of Ketosis. Also, I am wolfishly hungry after all that runnin for the past couple of weeks.

[tautech]

Med, are you really poking the HV innards of that scope with a 1x probe ?
The additional capacitive loading in 1x certainly could be effecting the stability of the circuitry and giving you false info.

[med6753]

Med, are you really poking the HV innards of that scope with a 1x probe ?
The additional capacitive loading in 1x certainly could be effecting the stability of the circuitry and giving you false info.

Nope, 10X probe. I did not change the settings on the scope.

[tautech]

Med, are you really poking the HV innards of that scope with a 1x probe ?
The additional capacitive loading in 1x certainly could be effecting the stability of the circuitry and giving you false info.

Nope, 10X probe. I did not change the settings on the scope.

Ah OK all good then. 

So showing 1x input attenuation was just a test to see if we were being observant enough ? 

[YurkshireLad]

On Keto no carbs. No bread, no noodles, potatoes, rice, cake, candy, soft drinks, fruit juice, nothing with high fructose corn sirup, ...

Actually, when on Keto, you need to cut down on anything containing carbs and religiously observe your daily intake limits.

Today I probably got bumped out of Ketosis. Also, I am wolfishly hungry after all that runnin for the past couple of weeks.

It'll be interesting to see if your body can switch into keto mode more easily once you've done keto. I feel it's easier for me to get into keto after losing 40lbs years ago.

[tggzzz]

Oh dear. The weakness of my will is only to apparent.

I couldn't resist this diddy scope for £36+shipping - my second (and probably last) thing made by Sinclair/Thurlby.

Let's hope the trace still works when it arrives.

[Saskia]

On Keto no carbs. No bread, no noodles, potatoes, rice, cake, candy, soft drinks, fruit juice, nothing with high fructose corn sirup, ...

Actually, when on Keto, you need to cut down on anything containing carbs and religiously observe your daily intake limits.

Today I probably got bumped out of Ketosis. Also, I am wolfishly hungry after all that runnin for the past couple of weeks.

It'll be interesting to see if your body can switch into keto mode more easily once you've done keto. I feel it's easier for me to get into keto after losing 40lbs years ago.

it is. I can get back into keto within 2 or 3 days.

[mnementh]

Aww jeez... I picked the bones of last night's roast chicken for my lunch, and went to the loo afterwards. Come back and find that my son, trying to be helpful, had already taken the carcass and container from my desk and processed them into garbage and compost.

Unfortunately, I hadn't weighed the carcass, so have no idea how much I actually ate. Aside from that it was less than 380 grams, the before weight.

mnem
And I can't even get mad, because he was being helpful...

Opportunity to talk about becoming more green, with the 3Rs, for next time:

Reduce
- I am sure you would have done a fine job of reducing the leftovers if you had the chance to finish
ReUse
- Use that carcass with some rice (barley if you have a turkey carcass) to make a soup; it makes the loads of veggies into some of the best tasting veggies ever!
Recycle
- I recommend recycling it before certain other kinfolk go as far as using the leftovers to make headcheese ...  YMMV

Great idea, but sadly, I'm the only zoop-eater in the whole house.  I can't have it, so straight to the compost. 

mnem
         
*~mnem's infamous split-pea zoop~*