Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1632988 times)

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Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34925 on: July 16, 2019, 02:23:35 pm »
Was that before or after you powered up the 475?
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34926 on: July 16, 2019, 02:27:05 pm »
I knew that was coming  :-DD
 

Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34927 on: July 16, 2019, 02:29:27 pm »
Wouldn't want to disappoint you.    ;D



Do you have success?
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34928 on: July 16, 2019, 02:30:29 pm »
Not sure yet. Had to take a break to do some work  :--
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34929 on: July 16, 2019, 02:33:42 pm »
Standing by with 911 on speed dial and potential words of condolences.  :-DD
An old gray beard with an attitude.
 

Offline Mr. Scram

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34930 on: July 16, 2019, 02:41:17 pm »
Standing by with 911 on speed dial and potential words of condolences.  :-DD
"Bd139 was a brave man, but unfortunately born with penisfingers. His condition has lead to the demise of many a machine and ultimately his own. We wet our tips in silence."
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34931 on: July 16, 2019, 02:56:14 pm »
It's the verticals. I've done them before a couple of times :(

Decided feck it and will do it.
Once you started, there was never a chance that you'd not do it today, you got the bug now.

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Will watch for a puff of smoke coming from the East.  :-DD :-DD
That would be a mushroom cloud then

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Who let Murphy in?
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34932 on: July 16, 2019, 02:59:43 pm »
Standing by with 911 on speed dial and potential words of condolences.  :-DD
"Bd139 was a brave man, but unfortunately born with penisfingers. His condition has lead to the demise of many a machine and ultimately his own. We wet our tips in silence."
With it looking like a bombs gone off at bd's I guess that I missed the cloud then.

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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34933 on: July 16, 2019, 03:47:55 pm »
Not dead, no explosions.



Not celebrating yet. There appears to be a couple more problems: wont trigger on channel 1 (looks like switch issue as it does on norm), trace "zoom" changes slightly occasionally (reckon thats HT supply feedback), horizontal pot is bust (one on the 465 is good so I'll steal that). For another day.

So this nifty 200MHz scope cost £5 and the multiplier and missing case parts I had in my parts mule 465 in the cupboard.

Best bit: the attenuators work properly  :-DD

Honestly I think this was wonky out of the factory. Looking at the insides there's no crud in it at all and no soot under the HT shield so it hasn't had much "up time". Going to leave it running for 2-3 hours and see if it's just got some damp in it as there's evidence of damp storage on the frame.
« Last Edit: July 16, 2019, 03:50:57 pm by bd139 »
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34934 on: July 16, 2019, 03:57:56 pm »
Good deal, progress!  :-+ And having good attenuators is definitely a plus.  :phew:
An old gray beard with an attitude.
 
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34935 on: July 16, 2019, 04:08:31 pm »
Not dead, no explosions.



Not celebrating yet. There appears to be a couple more problems: wont trigger on channel 1 (looks like switch issue as it does on norm), trace "zoom" changes slightly occasionally (reckon thats HT supply feedback), horizontal pot is bust (one on the 465 is good so I'll steal that). For another day.

So this nifty 200MHz scope cost £5 and the multiplier and missing case parts I had in my parts mule 465 in the cupboard.

Best bit: the attenuators work properly  :-DD

Honestly I think this was wonky out of the factory. Looking at the insides there's no crud in it at all and no soot under the HT shield so it hasn't had much "up time". Going to leave it running for 2-3 hours and see if it's just got some damp in it as there's evidence of damp storage on the frame.
If its not been used much, might it be oxidized contacts? Good work so far though, might be worth that fiver after all then?

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Who let Murphy in?
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34936 on: July 16, 2019, 04:15:27 pm »
not sure it is.

HT just blew up  :-DD

Looks like the fuse has gone so this might actually be more taunting tantalum twats.
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34937 on: July 16, 2019, 04:47:36 pm »
not sure it is.

HT just blew up  :-DD

Looks like the fuse has gone so this might actually be more taunting tantalum twats.
Perhaps you need to revise your advice you gave that other person asking about swapping out capacitors. Instead of on demand as they fail, to swapping anything that is approaching 30 years old?. I thought that you did swap them all, especially those bastard tants on Tek scopes anyway?
Who let Murphy in?
 

Online tautech

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34938 on: July 16, 2019, 04:57:01 pm »
not sure it is.

HT just blew up  :-DD

Looks like the fuse has gone so this might actually be more taunting tantalum twats.
Perhaps you need to revise your advice you gave that other person asking about swapping out capacitors. Instead of on demand as they fail, to swapping anything that is approaching 30 years old?. I thought that you did swap them all, especially those bastard tants on Tek scopes anyway?
Yep, 'specially when you've just been in there !  ::)
Impatience always bites you on the bum.
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Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34939 on: July 16, 2019, 04:58:38 pm »
Bastard tants!  :rant: :rant: :rant: :-DD
An old gray beard with an attitude.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34940 on: July 16, 2019, 06:15:41 pm »
Well that was a short lived success but I know a root cause now.

After doing some debugging and pulling the vertical again, I have confirmed that the second multiplier is now dead as well. Not only that but when it went it took the multiplier winding of the HT transformer out too. Turns out this winding is more fragile than the fuse is. Poking around it appears that the HT oscillator feedback resistor from the high voltage side of things (the thick film array one) is shot causing the voltage to shoot up to the overvoltage protection. It has basically been running wedged up there until the multiplier fails. Really I suspect it is a manufacturing flaw that was possible to cal out with the grid bias as there's no sign of use otherwise. Not even any dirt in the fan.

It's dead. RIP. Now 100% BER. So it's now an organ harvesting operation.



Just a quick postscript. I am now officially giving up on restoring old Tektronix scopes. I'm thoroughly done. Many have passed through my hands now and I am not going to do any more. I need a new challenge. Here's the tally though. I think I did good considering everything I bought was broken or for scrap or was supposedly working but wasn't or wasn't shown as working...

Restored (20 scopes)

- 3x 475
- 2x 475A
- 5x 465
- 3x 465B
- 2x 453
- 1x 2235A
- 3x 2225
- 1x 7603

Scrapped (5 scopes)

- 1x 465B
- 1x 465
- 1x 475
- 1x 453
- 1x 2235

I'm not including the 5x Philips, 2x Hameg, 2x HP, 1x Thurlby, 2x LG, 1x Hitachi, 6x Telequipment (3x D83, 2xD61, 1xS61) ones on top of that as well  :-DD

Phew  :phew: ...
« Last Edit: July 16, 2019, 06:26:53 pm by bd139 »
 

Online tautech

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34941 on: July 16, 2019, 06:25:27 pm »
And the Telequipment ones don't even count ?  :-//
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34942 on: July 16, 2019, 06:26:08 pm »
LMAO forgot them. Adding now ....
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34943 on: July 16, 2019, 07:08:11 pm »
For you rf-ily folks... BaoFeng-UV-82HP for $45 from US warehouse: My cart sez delivery by July 19.  :-+

I think there's maybe 3 of the black ones left, and over altogether in 2 hours.

https://smile.amazon.com/BaoFeng-UV-82HP-CAMO-Power-Radio/dp/B00Z52HP10

Cheers,

mnem
*lazily grazing the verdant fields of slAmazon Prime Day*
« Last Edit: July 16, 2019, 07:13:01 pm by mnementh »
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34944 on: July 16, 2019, 07:11:54 pm »

Just for bd139... 
mnem
There... that's better. >:D
« Last Edit: July 16, 2019, 07:26:54 pm by mnementh »
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34945 on: July 16, 2019, 07:50:46 pm »
« Last Edit: July 16, 2019, 08:00:33 pm by mnementh »
 
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34946 on: July 16, 2019, 08:06:03 pm »
Well that was a short lived success but I know a root cause now.

After doing some debugging and pulling the vertical again, I have confirmed that the second multiplier is now dead as well. Not only that but when it went it took the multiplier winding of the HT transformer out too. Turns out this winding is more fragile than the fuse is. Poking around it appears that the HT oscillator feedback resistor from the high voltage side of things (the thick film array one) is shot causing the voltage to shoot up to the overvoltage protection. It has basically been running wedged up there until the multiplier fails. Really I suspect it is a manufacturing flaw that was possible to cal out with the grid bias as there's no sign of use otherwise. Not even any dirt in the fan.

It's dead. RIP. Now 100% BER. So it's now an organ harvesting operation.



Just a quick postscript. I am now officially giving up on restoring old Tektronix scopes. I'm thoroughly done. Many have passed through my hands now and I am not going to do any more. I need a new challenge. Here's the tally though. I think I did good considering everything I bought was broken or for scrap or was supposedly working but wasn't or wasn't shown as working...

Restored (20 scopes)

- 3x 475
- 2x 475A
- 5x 465
- 3x 465B
- 2x 453
- 1x 2235A
- 3x 2225
- 1x 7603

Scrapped (5 scopes)

- 1x 465B
- 1x 465
- 1x 475
- 1x 453
- 1x 2235

I'm not including the 5x Philips, 2x Hameg, 2x HP, 1x Thurlby, 2x LG, 1x Hitachi, 6x Telequipment (3x D83, 2xD61, 1xS61) ones on top of that as well  :-DD

Phew  :phew: ...
Well that is a very impressive tally over the years, but maybe the older scopes are getting just a bit to old now and its about time they were allowed to die in peace? The 453 lasted from 1965 to 1974 so they could anything from 45 to 54 years old now and at just 10 hours a week over its life, its had an awful amount of stress and things like multipliers are bound to be extremely fragile by now. So then whats your plan now, start looking at scopes from say the late 80's to 90's or is that it, done now for all time?
Who let Murphy in?
 

Offline BFX

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34947 on: July 16, 2019, 08:41:44 pm »
Welp.... how did this happen?  :scared:



Hmm TiN ... I think my addiction level is to low and I should forced it up :D



May be I will catch you in the next life  :-DD :box:
 
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Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34948 on: July 16, 2019, 08:48:33 pm »
Well I guess I'm now the Lone Ranger for keeping old Tek junk alive since bd is now bowing out.  :-// Currently everything in my Tek tribe is working fine except a 465B that looks like it may have some filter caps in the PSU giving up the ghost. I'll get to it within a few weeks. I got Tonto keeping an eye on it.  :-DD

The Heath S-3 rebuild is done. But unfortunately it's got a few problems which really isn't surprising. First, the square wave that the 2 inputs ride on is extremely unstable. It keeps bouncing around. I suspect a cold solder joint somewhere. Should be easy to track down.

The 2nd problem is interesting. See the scope trace. I only have an input going into "A input" (top trace). Nothing on "B input" and it's gain is zero. The bottom trace should have nothing on it...should be flat line. So there's cross talk in the switching circuit which may or may not resolve itself if I fix the unstable "rider" square wave. And yes, I reversed things.....signal on "B input", nothing on "A" and that has the same crosstalk.



 

I get back to this tomorrow.

 
An old gray beard with an attitude.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #34949 on: July 16, 2019, 09:03:02 pm »
Are you sure that isn't a feature?  :-DD

Well that is a very impressive tally over the years, but maybe the older scopes are getting just a bit to old now and its about time they were allowed to die in peace? The 453 lasted from 1965 to 1974 so they could anything from 45 to 54 years old now and at just 10 hours a week over its life, its had an awful amount of stress and things like multipliers are bound to be extremely fragile by now. So then whats your plan now, start looking at scopes from say the late 80's to 90's or is that it, done now for all time?

Completely agree with all points. The statistical rate of failure is too much of an enthusiast thing now to fight and honestly I don't have the time. You either have to go simpler or newer. Thus I'm going to stick with the DS1054Z as my one and only scope now and give up the analogues. Once they fix all the stuff in the MSO5000 and it's readily crackable I'll hit that. The whole journey has been productive for sure and Jim Williams was very much right with the assertion that a broken scope is an effective classroom. I've learned a hell of a lot of design and diagnostic tricks.

As for what's next, I don't know. Perhaps the Tower of Flukes needs to happen but no more scopes at all!
 


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