Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1715507 times)

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Online mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24125 on: February 01, 2019, 02:27:40 pm »
unpacking HP 8556A



Unpacking HP 19511-80014...  :-DD

mnem
Oh, I kill me...  :P
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24126 on: February 01, 2019, 02:44:20 pm »
Jackpot! Racal 9915 arrived.

Did some deep research on options on these and this paid off. Unmarked with no options logged on the back. However research points to low serial numbers having the 9442 OCXO standard installed because the standard xtal osc was too crap to ship at the time. If you look carefully at the back panel you can see grey plastic sticking through the hole. The standard crystal osc doesn't have the grey plastic around it. Thus it has an OCXO in it.

And it did. £26 well spent!

Built like the proverbial brick shit house like all Racal kit is. Weighs in just under 4KG with batteries (which are dead of course and will be removed!). Currently being left to reach room temp as it's been in a PF warehouse and van overnight. Some pictures:

Date codes indicate assembly in 1977. Last cal was 2007.

Nuclear bomb proof engineering. Hardly any plastic at all!



Top view



OCXO Standard



Very happy  :-+
Nice snag, you certainly find the bargains [emoji106]
Who let Murphy in?
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24127 on: February 01, 2019, 02:45:52 pm »
Nice score!  :-+ Brick shit houses are always preferable to wooden ones.  :-DD

Oh and.....





 :-DD :-DD :-DD
Especially in the current temperature [emoji1787]
Who let Murphy in?
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24128 on: February 01, 2019, 02:48:59 pm »
Unfortunately OCXO is knackered. Am hacking Bliley one into it now :D

See: https://www.eevblog.com/forum/testgear/repairing-off-frequency-racal-9442-ocxo/msg2167999/#msg2167999
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24129 on: February 01, 2019, 02:50:34 pm »
Is that a pack of NiCd A cells?!? I don't think I've seen one IRL of those since my first gig straight out of college...  :palm:

It is indeed. Pack weighs a ton. Also has burned out the series resistor on the board when they went short. Not a problem.

OCXO is fecked. I am starting a separate thread for it.

Shocking. ;) At least it's not Ceylon cells.  [emoji14]  Planning to do a NiMH or Lixx upgrade? And what's the little blue one next to it? A pack of alkaline coin cells to retain user parms?

What? No takers? Not even a WILD-ASS GUESS? Some lot of computer nerds you are...  [emoji14]

That's a BIOS diagnostic code display card for the PCI bus, why? I don't take it, I don't need it.
Another Kewpie doll, please! This time for the Cap'n!

A POST Card... yes.

I know; it's a relic from a bygone era as most proper MBs have it built in nowadays. But once upon a time it was one of the earmarks of a real IT tech, along with a PSU tester. You "Admins" can suck it; I'm talking about the grunts in the field here. ;)

https://forums.autodesk.com/t5/fusion-360-ideastation/absolute-coordinates-amp-grid-level-guides/idi-p/5111642

Fucking seriously, AutoDesk? NO ABSOLUTE COORDINATES? Are you insane?!?    |O

mnem
I think I've leaked a bit... and have definitely gone a bit frosty.  :o
I was just going to reply and say it was a bios checker /reporter as I have one of them and also a psu tester [emoji23][emoji23] what professional engineer wouldn't?
Who let Murphy in?
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24130 on: February 01, 2019, 03:00:53 pm »
I had one when the ISA bus was a thing. After that I just google the beep codes or swear at it and throw it in the trash
 

Offline Martin.M

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24131 on: February 01, 2019, 06:24:10 pm »
this is my new toy, the 8556A  :)

 
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Online Terry01

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24132 on: February 01, 2019, 06:35:40 pm »
this is my new toy, the 8556A  :)

Very nice!  :-+
Sparks and Smoke means i'm nearly there! 8)
 

Online mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24133 on: February 01, 2019, 06:57:44 pm »
I had one when the ISA bus was a thing. After that I just google the beep codes or swear at it and throw it in the trash

Yes, well... as it was my job to FIX them that wasn't an option, at least until after the 2nd or 3rd triage.  :-DD I still had to make a best effort at actually repairing the damned things, though. 

mnem
The post-extraction instructions my dentist gave me say "Liquid diet" and "No alcohol"... So... WHICH IS IT?!?  :o
 

Online mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24134 on: February 01, 2019, 07:01:39 pm »
this is my new toy, the 8556A  :)
Very nice!  :-+

Ditto!  :-+

mnem
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Offline Mr. Scram

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24135 on: February 01, 2019, 07:01:54 pm »
Thank god for an era where replacing something is cheaper than fixing it. Spend some time trying to work it out. Doesn't work? It's cheaper to buy new. In the trash it goes.

Lots of good stuff to be had if you're willing to put in the effort to actually fix it too.
 

Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24136 on: February 01, 2019, 07:04:47 pm »
this is my new toy, the 8556A  :)

Very nice!  :-+
 

Offline Inverted18650

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24137 on: February 01, 2019, 07:06:52 pm »

On another note: I said TO HELL WITH IT and I am the proud new owner of the brand new Keithley DMM7510..pics when it arrives!

From a few days ago; EDIT: I did not actually BUY and PAY for the meter until yesterday. I ended up going with eBay store "ValueTronics INT'L." Looks like it shipped today and I am hoping to have it by mid-week! Shout out to ValueTronics for hooking me up.

Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24138 on: February 01, 2019, 07:14:31 pm »
Valuetronics is awesome; have had nothing but good experiences with them. They ship fast and pack well, and they are pretty flexible on prices. They usually accept my offers.
 
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Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24139 on: February 01, 2019, 07:19:28 pm »
Performed some functional tests of the 7A16A, 7A18A, and 7A26 plug-ins and I have the results. When I get a new to me functional scope, or in this case plug-ins, there are certain basic criteria that I look at and if they pass I consider it “calibrated”. There is no way I can do a “by the book” calibration because I don't have the proper equipment and in reality unless there's been major repairs or some dimwit has been in there twiddling pots it really isn't necessary. The criteria I consider important are:

Vertical gain. Example: does a 0.5V p-p waveform appear as such?
Trigger. Does the waveform trigger and is it stable?
Compensation. 1KHz square wave flat with no peaking or rounding?.
High frequency test. Does a 1MHz and 10MHz square display accurately?
Sweep speed. Is it linear and accurate?
Trace quality. Bright and sharp focus?

In the case of these plug-ins only the first 4 apply. The sweep and trace are determined by the mainframe and the timebase plug-in. Here's my test set up. The Feel Tech function generator is for the 1KHz square wave. The Heath IG-4244 Scope Calibrator is for the 1MHz and 10MHz square. The 2465 is powered up and on standby in case something don't look right.



So how did these plug-ins perform?

Vertical gain: All 3 plug-ins were dead nuts.
Trigger: Solid Trigger on all 3.
Compensation: The 7A18A and 7A26 are perfect. The 7A16A has both peaking and roll off issues. While attempting to adjust it the trace is dancing around again. I guess I'm going to have to pull this attenuator assembly apart and give it a more extensive cleaning. Luckily it's easy to get to. Into the project cue.
High frequency test: Both the 7A18A and 7A26 are OK. The 7A16A because of the problems above shows extensive peaking at high frequencies.

This is MY rabbit hole. :-DD  As soon as Inverted18650 gets back to me with a shipping cost I'm going to have a 7704A to play with.  :-+


 
   
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Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24140 on: February 01, 2019, 07:34:07 pm »
No sooner did I post above and I get a phone call. It's my woman. (In case you don't know she's NYPD cop) She's in the ER again. Got knocked down again breaking up a fight. This time the injuries are more extensive including hitting her head. In a lot of pain. X-rays pending. She'll call me later with the results. They may keep her overnight.

I may be making a trip down to NYC tonight. Damn.
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Offline capt bullshot

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24141 on: February 01, 2019, 07:35:55 pm »
A couple have leaked a bit and gone frosty. They're duff for sure.

Admitted, I don't like leaking cells too. But a bit of leakage doesn't necessarily mean that they're dead. Depends on how they were treated, deep discharge including internal short is less harmful to them than constant trickle charging with too high a current.
Safety devices hinder evolution
 

Offline factory

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24142 on: February 01, 2019, 07:41:46 pm »
this is my new toy, the 8556A  :)

That has reminded me to unbox my 8556A that has been sitting in the kitchen for about two weeks, I'm now covered in bits of packing foam, also noticed the warning about using with a modified IF section.... I wonder if it's been done as the 8552A is below the serial no's listed on the cover.

Acquiring a mass component hoard from my employer is the cause of my delay, think I need to join component collector anonymous... where do I sign up? :D

David
 

Offline capt bullshot

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24143 on: February 01, 2019, 07:42:44 pm »
Quote
Compensation: The 7A18A and 7A26 are perfect. The 7A16A has both peaking and roll off issues. While attempting to adjust it the trace is dancing around again. I guess I'm going to have to pull this attenuator assembly apart and give it a more extensive cleaning. Luckily it's easy to get to. Into the project cue.
High frequency test: Both the 7A18A and 7A26 are OK. The 7A16A because of the problems above shows extensive peaking at high frequencies.

Might be something else, in case it isn't adjustable:
http://wunderkis.de/tek-7/index.html
- not the dancing wave part, this is a defect within the CRT, but the "Non-square square waves", here the culprit was a small 1.8pF cap.
Safety devices hinder evolution
 

Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24144 on: February 01, 2019, 07:54:00 pm »
Quote
Compensation: The 7A18A and 7A26 are perfect. The 7A16A has both peaking and roll off issues. While attempting to adjust it the trace is dancing around again. I guess I'm going to have to pull this attenuator assembly apart and give it a more extensive cleaning. Luckily it's easy to get to. Into the project cue.
High frequency test: Both the 7A18A and 7A26 are OK. The 7A16A because of the problems above shows extensive peaking at high frequencies.

Might be something else, in case it isn't adjustable:
http://wunderkis.de/tek-7/index.html
- not the dancing wave part, this is a defect within the CRT, but the "Non-square square waves", here the culprit was a small 1.8pF cap.

Thanks for the link. That issue affected the 7A18A. Mine is OK. I'm having problems with the single channel 7A16A. Now it might have the same or similar input network but mine is not as badly compensated as shown in that link. I suspect my issue is more dirty contacts more than anything else. We'll see once I get it apart and clean it.
« Last Edit: February 01, 2019, 08:15:15 pm by med6753 »
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24145 on: February 01, 2019, 08:05:40 pm »
Well Racal OCXO problem turned out to be a little more difficult than expected but I decided I fancied doing a good job of this one.

Sorry this is a bit image heavy.

Basically the Racal 9442/5 was trash, not worth fixing and was dispatched straight to the bin. The operating point drifted straight past 5MHz and couldn't be adjusted into it whatever I tried. Reducing the oven temperature would have done the job but with unknown side effects and I'd have to reverse engineer the module. Screw that.

Plan B. Use the Bliley module I just got my hands on in it (I ordered a spare the other day as well!). After examining the schematic for the counter, I noticed that the main IC on it expected 10MHz not 5MHz but Racal only made 5MHz OCXO modules so there was a frequency doubler in it. So this was entirely unnecessary for the 10MHz Bliley module. I reused the analogue to TTL input circuitry and bypassed the doubler, stealing part of it to provide a stable buffer for the doubler and the main counter IC. This involved snipping out a 7400, resistor and capacitor and soldering a jump wire.

The existing module had an interface compatible with the new module but the new module needed a trimmer adding. Decided to knock up a PCB for this. Rather than wait for China I used a bit of FR4 and just hand drew it out for etching. Took some thinking and measuring then the holes were drilled then it was cleaned and then traced out.



Into a sink of boiling water containing a tupperware tub full of ferric chloride. Yum. Poked around with a cocktail stick low tech style.



Out, cleaned and tinned (tinning isn't great as it was done with an iron and solder but it'll do):



Populated. The trimmer is on the back so it's available in the "calibration hole" in the back of the unit.



Now the board was modified. IC4 was removed and pins 1-6 jumped. C36 and R60 were removed. This effectively bypasses the doubler.



Board then installed.



Does it work? Woohoo it did! Went through careful cal after this and is bang on the mark now.



Quick test with the MFJ doohickey at 150MHz to check channel A.



Job done  :-+

 
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Offline GreyWoolfe

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24146 on: February 01, 2019, 08:09:44 pm »
I had one when the ISA bus was a thing. After that I just google the beep codes or swear at it and throw it in the trash

I still have one.  Mine has a flat ribbon cable with an extra 7 segment display on it so you can still see the codes when you can't see the display on the cards.  I even have the book that tells me the error codes for various bioses.  Biosi?  It had its fair use back in the day and I keep it out of a bit of sentimentality.
That which doesn't kill you still requires a co-pay.
 

Offline Inverted18650

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24147 on: February 01, 2019, 08:10:29 pm »
No sooner did I post above and I get a phone call. It's my woman. (In case you don't know she's NYPD cop) She's in the ER again. Got knocked down again breaking up a fight. This time the injuries are more extensive including hitting her head. In a lot of pain. X-rays pending. She'll call me later with the results. They may keep her overnight.

I may be making a trip down to NYC tonight. Damn.

Hope she's fine and get home to you tonight.

My truck started acting up right after the cold snap so I haven't been able to do anything during the day. Got boxes stacked and backed up but as soon as I figure out how bad the fuel line leak is, I will be able to fix it or have it taken into Land Rover. If i cannot fix it myself Ill borrow one of my neighbors spares (they have 5 cars, 2 drivers) if he'll let me OR I will go rent one to get things rolling again. OF COURSE it would happen AFTER i spend $4,000 on a new meter...DAMN YOU MURPHY!
« Last Edit: February 01, 2019, 08:16:35 pm by Inverted18650 »
 

Offline Mr. Scram

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24148 on: February 01, 2019, 08:12:14 pm »

On another note: I said TO HELL WITH IT and I am the proud new owner of the brand new Keithley DMM7510..pics when it arrives!

From a few days ago; EDIT: I did not actually BUY and PAY for the meter until yesterday. I ended up going with eBay store "ValueTronics INT'L." Looks like it shipped today and I am hoping to have it by mid-week! Shout out to ValueTronics for hooking me up.
Congratulations man, that's an awesome bit of kit. And sorry for encouraging your bad habits. ;D
 
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Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #24149 on: February 01, 2019, 08:17:20 pm »
More Wera screwdriver pr0n, today I received the set with PZ#1 and PZ#2, which I desperately needed.

I'm sold on these screwdrivers. I used to swear by a set of Stanley "FatMax" branded screwdrivers that I keep in my portable tool bag, but these are better made and imo have better ergonomics.
 
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