Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Yeah it was checked at low frequency on Peak LCR45, homebrew ESR meter and shitty uni-t meter. The capacitor is completely open circuit

Ho ok

I think the only différance at other frequencies would be in the ESR, not the capacitance. 

[tonyalbus]

guys, guys...guys... i have an other counter....

[tautech]

89.4V eh, 100V rating caps would be pushing it a bit, 150V I think would be a wise choice.

Not if you analyse many modern designs. 

[BU508A]

@bd139

I have here two caps, Siemens brand (used)

Spec's:

4700µF / 100V / 85°C / date code 12.88
Height: 80mm
diameter: 50mm
space connectors: ca. 22mm M4 screws
I've measured the capacity and the ESR with my DER EE DE-5000 @ 100Hz
Capacity: 4400 and 4530 µF, ESR ca. 0.05 Ohm

If you want one of them, let me know.

Edit:
added the datasheet

 
Forgot to add the exact type: B41455-P9478-T

[factory]

The HP 6255A delivered by TNT arrived intact. 


As I had bought a cheap step-down transformer when Maplin closed in Crewe, I decided to do a brute force test & reformation of the capacitors.
One half is of the supply is dead and the other side is working fine, voltage controls are 10-turn as well.

A quick check of the fuses revealed they were fine, looking closely the power switch isn't switching both live & neutral but the two lives to the transformers, doing a "Shango066" & shoving an insulated screwdriver across the contacts confirmed the switch is half knackered and the other side of the supply was working fine too. 



Job for Friday afternoon, spend 10 minutes fitting a new switch and 3 hours locating the switch. 

David

[capt bullshot]

1000uF 100V. ~ 21.8mm pitch screw terminals.

Guess these are a bit overspec'd.



Edit: This one at least is in the ballpark of 1mF and should not have any issues with ESR or ripple:

[mansaxel]

Yeah it was checked at low frequency on Peak LCR45, homebrew ESR meter and shitty uni-t meter. The capacitor is completely open circuit

Ho ok

I think the only différance at other frequencies would be in the ESR, not the capacitance.

Would that hold true for an inductance too? I did get wildly fluctuating values as I tested my isolation transformer windings depending on test frequency (using the DE-5000)

[bd139]

The HP 6255A delivered by TNT arrived intact. 


As I had bought a cheap step-down transformer when Maplin closed in Crewe, I decided to do a brute force test & reformation of the capacitors.
One half is of the supply is dead and the other side is working fine, voltage controls are 10-turn as well.

A quick check of the fuses revealed they were fine, looking closely the power switch isn't switching both live & neutral but the two lives to the transformers, doing a "Shango066" & shoving an insulated screwdriver across the contacts confirmed the switch is half knackered and the other side of the supply was working fine too. 



Job for Friday afternoon, spend 10 minutes fitting a new switch and 3 hours locating the switch. 

David

Nice. Glad yours turned out a winner 

[capt bullshot]

Yeah it was checked at low frequency on Peak LCR45, homebrew ESR meter and shitty uni-t meter. The capacitor is completely open circuit

Ho ok

I think the only différance at other frequencies would be in the ESR, not the capacitance.

Would that hold true for an inductance too? I did get wildly fluctuating values as I tested my isolation transformer windings depending on test frequency (using the DE-5000)

At frequencies that are somewhat (typically starting at 1kHz) higher than line frequency, isolation transformers have all kinds of frequency dependent impedances. Core permeability, resonant effects (by interwinding capacitance within the winding), interwinding capacitance between primary and secondary, ...

At a former job, I had knowledge of transformers (100:1 ratio for line frequency, 10kV : 100V, pretty big and heavy iron) that behaved near 1:1 at higher frequencies just by capacitive coupling. So delicate equipment that had to accurately measure voltage at the secondary _must_ survive 10kV transients on a regular basis when some primary side switching was done (yes, you guessed it 10kV power substations were involved). A bit of a learning curve was involved ...

One of these transformers is featured here: http://wunderkis.de/britzel/index.html

And, I guess you just guessed it: Such transformers exist for 400kV primary too ...

[srb1954]

Just got a new motor coupling delivered from China.



You've got the love the way all the burrs have been carefully anodized! 

You gotta appreciate their attention to detail.

They have cut the slit just slightly off-centre to give it that hand-crafted look that is so sought after these days.

[bd139]

If you look closely they overshot the slot cutting as well 

[Kosmic]

Ordered some flux paste on ebay last spring. Just received it today after 5.5 months  A new record for me.

[Cerebus]

You gotta appreciate their attention to detail.

They have cut the slit just slightly off-centre to give it that hand-crafted look that is so sought after these days.

I'd like to be able to say that the offset cut is their careful balance compensation for the off centre effect of the head of the Allen bolt, to keep the thing from wobbling at 3000 rpm, but somehow I suspect not.

[Kosmic]

Yeah it was checked at low frequency on Peak LCR45, homebrew ESR meter and shitty uni-t meter. The capacitor is completely open circuit

Ho ok

I think the only différance at other frequencies would be in the ESR, not the capacitance.

Would that hold true for an inductance too? I did get wildly fluctuating values as I tested my isolation transformer windings depending on test frequency (using the DE-5000)

Yes same principle. With inductor > 1H you get better results at 100Hz and 120Hz.

[vk6zgo]

6294a arrived. Looks good so far.

Firstly I got the shit scared out of me. It arrived in a wet cornered box wrapped in plastic. The wet turned out to be diesel or something similarly nasty based on the smell. Has been disposed of outside as has all packaging.

I've cleaned up poo, & I've cleaned up diesel---------I prefer poo!

Fortunately the power supply was perfectly fine inside it  . And it's in reasonable condition



Need to get rid of this horrid thing off it first



Insides. Date coded around 1989 so this is a VERY late example. This product line ran from 1968 to 1990 approximately which is a hell of a long time.

Tidy up and test later.

Edit: oh win, just seen the voltage pot is a 10 turn one.

Pretty!
I want one! I want one! Wahh! gimme!

I don't have TE syndrome,-------------how could you think that I do?

[0culus]

Tomorrow's fun will be replacing the A15 board in my 8568B, which is a factory A->B conversion. I scored 2.5 original upgrade kits from fleabay; I don't need all that but it might be useful in the future or I could barter it with someone for another piece of gear. All I really need is the A15 board, which the partial kit comes with. The reason for all this? GPIB is 100% dead on this unit. I've already tried re-seating all the ribbon cables and stuff, but no dice.

So it's time for major surgery. I am clearing off a section of bench to make room and will take pics. 

[bd139]

@bd139

I have here two caps, Siemens brand (used)

Spec's:

4700µF / 100V / 85°C / date code 12.88
Height: 80mm
diameter: 50mm
space connectors: ca. 22mm M4 screws
I've measured the capacity and the ESR with my DER EE DE-5000 @ 100Hz
Capacity: 4400 and 4530 µF, ESR ca. 0.05 Ohm

If you want one of them, let me know.

Edit:
added the datasheet

 
Forgot to add the exact type: B41455-P9478-T

Sorry just seen this. Unfortunately too long. Thanks for offering anyway.

I spent some time last night designing an adapter board. I’m spending some time today considering if I can be bothered to fish out cash for JLC to fab it or doing it myself with toner transfer. The latter requires that I buy some new PCB drills.

[BU508A]

I spent some time last night designing an adapter board. I’m spending some time today considering if I can be bothered to fish out cash for JLC to fab it or doing it myself with toner transfer. The latter requires that I buy some new PCB drills.

I'd suggest this:

- use one of your one-sided pcb
- cut out a rectangular piece of sufficient size
- cut a small slit in it so it will separate the Cu side in two areas
- drill 4 holes in it, two in each Cu area, 2x 4mm 2x 1.3mm
- use two of these "Messing M4 Abstandsbolzen" see picture below
- place the capacitor into the other two holes
- solder them
- assemble it in your device

M4 Messing Abstandsbolzen


capacitor 1000µF / 100V / pitch=7.5mm

[bd139]

That's actually roughly what I have planned. I've got a stack of M4 sized hardware here so I'm going to bolt that through with some spacer washers to raise the bottom of the PCB off the surface and solder another cap on the board first. I've ordered a suitable capacitor and some other stuff from CPC so will inevitably have to wait a few days to see if it works

[BU508A]

Patience, my dear Padawan, is the key.   

[tautech]

I spent some time last night designing an adapter board. I’m spending some time today considering if I can be bothered to fish out cash for JLC to fab it or doing it myself with toner transfer. The latter requires that I buy some new PCB drills.

I'd suggest this:

- use one of your one-sided pcb
- cut out a rectangular piece of sufficient size
- cut a small slit in it so it will separate the Cu side in two areas
- drill 4 holes in it, two in each Cu area, 2x 4mm 2x 1.3mm
- use two of these "Messing M4 Abstandsbolzen" see picture below
- place the capacitor into the other two holes
- solder them
- assemble it in your device

M4 Messing Abstandsbolzen


capacitor 1000µF / 100V / pitch=7.5mm

Ah yes, PC motherboard standoffs, a fine idea ! 

[bd139]

BTW I did some ripple current calculations for this on paper and came across approximately 1.65A at 50Hz for the 100Hz rated ESR for the cap so I picked a Vishay/BC MAL215819102E3 snap in as a replacement. It's 100V which I didn't think had much headroom until I looked at my mains voltage which is running at 255V today and it was just touching 89V across the caps

Had to hit RS in the end for that caps so I'm busy filling the basket with other goodies 

[URI]

I've filled my basket with goodies two days ago at reichelt to build me a T12 soldering station with proper isolation.

This is somehow getting out of control, obviously.   

The isolation transformer and DC/DC converter alone cost more than the DC-Version of a T12-Kit (the one without power supply).   

Nevertheless, this will be fun. Also ordered two 47mF caps for filtering the input DC-voltage for the DC/DC converter.
The isolation transformer is a 160VA toroid and I will add a simple inrush current limiter to it.
The housing will be ...errm a little bit bulkier than the one of the KSGER T12 station with inbuilt power supply.

At the end of the day I'll probably have a really ESD-compliant soldering station with save isolation of the mains.   

[psykok]

Thats Murphy for you, always gets his oar one way or other, bastard.

Talking of Murphy .... that ain't a capacitor any more 

Try at lower frequency just for fun. can you do 100hz?

Did you check at 100Hz or 120Hz ? You should not try to measure high value capacitor like that at 200Khz (my understanding of how your LCR meter is currently setup).

That was also  what I thought , big capa should always  be check at 100 or 120hz (iit's also the industry  standard)

In an other case good with LCR meter doesn’t  mean  good in circuit. I had recently  the case with a 10000u from an old HP instrument.

[Kosmic]

Tomorrow's fun will be replacing the A15 board in my 8568B, which is a factory A->B conversion. I scored 2.5 original upgrade kits from fleabay; I don't need all that but it might be useful in the future or I could barter it with someone for another piece of gear. All I really need is the A15 board, which the partial kit comes with. The reason for all this? GPIB is 100% dead on this unit. I've already tried re-seating all the ribbon cables and stuff, but no dice.

So it's time for major surgery. I am clearing off a section of bench to make room and will take pics. 

The CRT on my 8566B started jittering horizontally. Did you ever had that problem on your 8568 / 8566 ?  I'm procrastinating the maintenance at the moment. That thing is so huge and heavy.