Test Equipment Anonymous (TEA) group therapy thread

[wkb]

I am using the KE5FX HPIB toolkit, which has a nice Hp plotter emulator. Not as neat as an actual plotter is, but my shack has run out of space..

[factory]

On the repair bench this week, the HP 86290B overclocked edition (aka option H08). 

After giving it a clean, I put it in a known working 8620C sweep oscillator, the power light came on, but none of the other mode lights did, also the cooling fan had gone strangely quiet. 

First thing was to check the many PSU rails in the 8620C sweeper frame, all were OK apart from the +20V (+0.9V), +12.4V (+6V), +5V (0V) on the yellow board and the +9.2V (+7.7V) on the green board.
At this point I should mention I have no manuals to work from (Artek one is too early for the S/N, no point in buying the wrong manual) and decided to work on the faulty +5V rail, this would turn out to be a time consuming mistake.

After checking the +5V rail in the 86290B plug-in, it seemed the low resistance was on somewhere in the RF voodoo section, after removing the ribbon connector from the motherboard. As you can see it's quite cramped with RF plumbing and the various RF modules, YIG oscillator, frequency multiplier, couplers, RF amplifier etc.



Disconnecting the ribbon cable loom from most parts, lead to the RF amp board/module and the rails with the two innocent bead tants.  Which were not faulty in the end, one got terminated in the process, both got replaced with higher rated parts (as it is such a PITA to get to them), they are either side of a -5V regulator IC, this was checked OK along the 6.2V Zener & the axial tants, using with the Peak testers.





Some of the mess from this completely unnecessary plug-in teardown. 



Much reassembly later, I thought maybe the +5V PSU rail needs one of the others to be correct to work. Next I checked the +20V rail, again removed the ribbon connector first, OK not in the RF section this time.  Pulling the boards one at a time lead to the yellow board, a quick check of the axial tants, I found the short circuited 10uF 20V Siemens tant that was causing all the PSU trouble.





This got replaced with a salvaged Hitachi tant of slighty higher rating (25V), I've not verified the actual voltage across this tant, hopefully not 20V  , remember I have no manual to tell me anyway.



After putting it all back together, I now had all PSU rails present & correct, the lights working and a cooling fan making noise.



Finally I could test the special overclocked edition of the HP 5340A (aka option H10), past the 18.6GHz limit of the regular 86290B plug-in I have.  Now I wondering how far the other 5340As I have will count to.



David

[Neomys Sapiens]

Someone here should make this grab:

https://www.ebay.de/itm/126059624913

I have probably every single item in it, but the price is incredible!

[Vince]

Well done David.

As for me, today is fixing day as well, but less fancy : a friend just brought me his old mum's vacuum cleaner 
I already fixed the electronics of it 2.5 years ago, and now it's broken again... There is a triac and 5V MCU in it, IIRC from last time.
I hope it's just a fried triac and I can fix it in a few minutes and move on to more interesting stuff... I don't want to spend my entire sunday on a freaking vaccuum cleaner, especially as I won't make a dime from the repair, of course

[EggertEnjoyer123]

On the repair bench this week, the HP 86290B overclocked edition (aka option H08). 

Nice, I have one of these too (I have the 2-18 and the 0.01 to 2.4 GHz option). Not as good as yours but I got everything for forty bucks so it was worth it. Mine also had a dead capacitor but it was pretty obvious and after replacing it (and a few traces) everything worked.

I’m still trying to figure out how to phase lock them. The biggest issue is that there doesn’t seem to be an easy way to get access to the tuning voltage from the outside.

Anyways I am also thinking about starting a Youtube channel on test equipment. It will probably be focused on explaining how certain circuits inside work. I am probably going to do my first video on that adjustable filter I got, which uses multiplying DACs and op amp integrators to adjust the cutoff. I worked through the math behind it and it’s simple and quite interesting. More on that soon.

[wkb]

For locking you need a combo of a HP 5343A counter (maybe the 5342Α also works) and a HP 5344S source synchroniser.

There is also a non-HP solution, I forgot what exactly

Wilko

On the repair bench this week, the HP 86290B overclocked edition (aka option H08). 

Nice, I have one of these too (I have the 2-18 and the 0.01 to 2.4 GHz option). Not as good as yours but I got everything for forty bucks so it was worth it. Mine also had a dead capacitor but it was pretty obvious and after replacing it (and a few traces) everything worked.

I’m still trying to figure out how to phase lock them. The biggest issue is that there doesn’t seem to be an easy way to get access to the tuning voltage from the outside.

Anyways I am also thinking about starting a Youtube channel on test equipment. It will probably be focused on explaining how certain circuits inside work. I am probably going to do my first video on that adjustable filter I got, which uses multiplying DACs and op amp integrators to adjust the cutoff. I worked through the math behind it and it’s simple and quite interesting. More on that soon.

[TERRA Operative]

Anyways I am also thinking about starting a Youtube channel on test equipment. It will probably be focused on explaining how certain circuits inside work. I am probably going to do my first video on that adjustable filter I got, which uses multiplying DACs and op amp integrators to adjust the cutoff. I worked through the math behind it and it’s simple and quite interesting. More on that soon.

Dooo eeeettt!

I'm sure you'll get a bunch of us as subscribers to start with.

[tggzzz]

Anyways I am also thinking about starting a Youtube channel on test equipment. It will probably be focused on explaining how certain circuits inside work. I am probably going to do my first video on that adjustable filter I got, which uses multiplying DACs and op amp integrators to adjust the cutoff. I worked through the math behind it and it’s simple and quite interesting. More on that soon.

If you do, please make video is the best medium:

• before starting the video, indicate why it would be worth spending N minutes of my remaining watching it. You have 30s before my attention wanders
• include written "chapter headers", with links to the relevant part of the video
• no waving the cursor over a screen while wittering on about what can be seen in the schematic/photo
• no "talking heads"; I can read >10* faster than you can speak
• no "ums" and "ahs"

There are rare occasions why video is better than a written blog, e.g. showing noise on a scope, or how solder flows in a good joint and a bad joint or when drag soldering. Those cannot be well described on paper.

[AVGresponding]

tggzzz is a tough audience!   

[factory]

He is, the last two videos I've watched on youtube were, about one hour long (CuriousMarc) and nearly two hours long (Shango066). If I want short repair videos where I learn nothing, there is a repair* programme on the Yesterday TV channel in the UK.

*where not everything gets repaired, jukebox cough cough and a motor commutator that gets impaired with sandpaper . 

David

[factory]

On the repair bench this week, the HP 86290B overclocked edition (aka option H08). 

Nice, I have one of these too (I have the 2-18 and the 0.01 to 2.4 GHz option). Not as good as yours but I got everything for forty bucks so it was worth it. Mine also had a dead capacitor but it was pretty obvious and after replacing it (and a few traces) everything worked.

I’m still trying to figure out how to phase lock them. The biggest issue is that there doesn’t seem to be an easy way to get access to the tuning voltage from the outside.

Anyways I am also thinking about starting a Youtube channel on test equipment. It will probably be focused on explaining how certain circuits inside work. I am probably going to do my first video on that adjustable filter I got, which uses multiplying DACs and op amp integrators to adjust the cutoff. I worked through the math behind it and it’s simple and quite interesting. More on that soon.

If you have the HP 8620C, it seems that an external tuning voltage (0 to +10V) can be used with the "programming" connector on the back, front panel "mode" switch needs to be set for "external" sweep to use this. I've no idea if the 8620A/B have this input.

The plug-in came with another 8620C, it has the HPIB programming option board installed, there was also a BCD programming option board can be used instead. This 8620C frame needs a bit of repair, some controls are seized, the band select needs adjustment/fault finding, as some positions bring two plug-in band lamps on at the same time.



Being part of TEA, these are the first two 8620Cs I bought, one of them also has seized controls, plug-ins included were the 86222B (0.01 to 2.4GHz) and 86240B (2.0 to 8.4GHz).



Other plug-ins I've bought in-between are; a very nice condition 86260A (12.4 to 18GHz) plug-in, a 86290C (2.0 to 18.6GHz) with missing/bodged output connector parts and the working 86290B (2.0 to 18.6GHz) I bought recently, I think I might have a problem here....   

86260A





86290B in the working 8620C.



Vince, this fan motor seems familiar. 



David

[Robert763]

Went to the Milton Keynes radio rally (Hamfest) today. It was (almost) a waste of time. There were not a lot of sellers and virtually no TE. The only just about TE Igot was a handful of Greenpar inter-series coaxial adaptors. The only other things that made it not a total failure were a couple of odd connectors I've been looking for for a while, a couple of NOS analog PCBs an a dealer who was giving away a load of NOS components.
The audio boards are for military equipment. They have a bunch of socketed op-amps, NE571 companders and a whole bunch* of Vishay VSR bulk foil precision resistors and 1% film capacitors. Cost £3 for two boards.
Free NOS bits included 6000 1/4W resistors, 3M 0.1" dual row ribbon connectors, XLR plugs and a bunch of variable reluctance speed pick-ups.
*about 140 on each board

[Atomillo]

Hi everyone!!

It's been quite a long time... I've spent the last 6 months outside home doing an internship in Switzerland/France and so my small lab has been almost completely neglected. Now that I'm about to head back home and have some disposable cash, I resumed my continued eBay search for any Spectrum Analyzer under 1k (looking at a 4 figure price for a home figure kind of makes my head spin!).

Low and behold, yesterday I found an Advantest R4131D for 500 euros (shipping included) *in Spain*! I decided to pull the trigger inmediately and now the unit will probably arrive home before I do. The only problem with the unit seems to be that the image of the CRT tube is slightly rotated. I hope it's an easy fix of just tweeaking some pots. Aside from this, the seller has tested the attenuator at all positions and injected signals a both ends of the frequency range succesfully.

The unit has no tracking generator, since it was sold a separate item. However since the output of the 1st LO is available it should be in theory possible to make my own. For the moment I'm thinking of just buying a white noise source as a temporary solution. I've found some info in the subject in the forum and online but I need to a bit more research. Black magic RF has never been a strongpoint of mine so I expect a lot of fun ahead of me!

I'm looking at the excellent videos by W2AEW about using and not killing an SA, so far I've understood I need to put a permanent DC blocker and 20dB attenuator at the input to be as safe as possible. Any other advice for this inexperienced explored of the high frequency lands would be very much appreciated!

[wkb]

Could very well be that the deflection yoke has been rotated on the neck of the CRT.
If so: easy fix!

Wilko
(who has this afternoon spent playing with a new to me HP8595E 6.5GHz SA with TG  )

[Martin.M]

Is there no book in the box ?
If not, contact me, I have the original printed  manual/service map in my archive.

greetings
Martin

[Robert763]

If the SA has electrostatic deflection it may have a magnetic rotation coil. This may be just an adjustment.

[PA0PBZ]

If the SA has electrostatic deflection it may have a magnetic rotation coil. This may be just an adjustment.

That, or you simply rotate the tube 

[Martin.M]

look in the bay :-)
https://www.ebay.de/itm/261610468414

that is 100% a simply magnetic CRT. So he can rotate the coilpack, and done.

[Atomillo]

Is there no book in the box ?
If not, contact me, I have the original printed  manual/service map in my archive.

greetings
Martin

There's nothing aside from the SA itself, however I've found the service manual online (https://eetac.upc.edu/ca/lescola/Equipaments/laboratoris/manuals/analitzador-espectres/advantest-spectrum-analyzer-r4131d-operation-manual.pdf). Do you think everything is in there? Thanks for your help!

look in the bay :-)
https://www.ebay.de/itm/261610468414

that is 100% a simply magnetic CRT. So he can rotate the coilpack, and done.

Uhm hopefully it's just that! What leaves me slightly concern is thinking how the coils were moved in the first place. There are some small signs of physical abuse in the frontal cover of the instrument, when I arrive I will check everything else is in order. Either way, that's an outrageous price for a CRT used in just one instrument!

[tggzzz]

tggzzz is a tough audience!   

He is, the last two videos I've watched on youtube were, about one hour long (CuriousMarc) and nearly two hours long (Shango066).

I want videos where the creator demonstrates that they are considering their audience, and aren't just on a lazy ego trip.

I want videos where I can either:

• quickly determine that there's nothing of interest, so I can focus my time on something useful, or
• quickly skip to the part that interests me

and

• has something where moving pictures are important to what I am trying to learn, or
• is information dense

Given those preconditions - which are easily satisfied in written form[1] - then I will watch videos of whatever length.

Examples:

• the Pace soldering videos: terse, information dense, moving pictures needed.
• anything by CGP Gray. Terse, information dense, static pictures that are informative and which need pictures
• some things by Shariar

[1] not moving pictures, obviously

If I want short repair videos where I learn nothing, there is a repair* programme on the Yesterday TV channel in the UK.

*where not everything gets repaired, jukebox cough cough and a motor commutator that gets impaired with sandpaper . 

It is mainstream TV, so I would be worried if you learned much from it! I'm content to see anything that counters the "possibly broke so throw it away" mentality.

[vk6zgo]

He is, the last two videos I've watched on youtube were, about one hour long (CuriousMarc) and nearly two hours long (Shango066). If I want short repair videos where I learn nothing, there is a repair* programme on the Yesterday TV channel in the UK.

*where not everything gets repaired, jukebox cough cough and a motor commutator that gets impaired with sandpaper . 

David

Shango 066 spends most of his time indulging his "F.I.G.J.A.M." fantasies.
I can't stand him!

[vk6zgo]

He is, the last two videos I've watched on youtube were, about one hour long (CuriousMarc) and nearly two hours long (Shango066). If I want short repair videos where I learn nothing, there is a repair* programme on the Yesterday TV channel in the UK.

*where not everything gets repaired, jukebox cough cough and a motor commutator that gets impaired with sandpaper . 

David

A gentle application of sand(not emery) paper can clean up a very lightly scored commutator.

[TERRA Operative]

We used to use fine sandpaper on the genset/welder commutators all the time.
Make sure to blow the dust away properly after, and scrape between the commutator bars with a boxcutter blade to knock the sharp edge off and create clearance by scraping out some of the epoxy potting if needed.

The bars on the stuff I was working on were multiple mm thick, so a good amount of meat to work with.

[Zoli]

BEFORE everything else, try eraser; if it works(and in most cases will), you've spared a life(out of 9 ).

[AVGresponding]

BEFORE everything else, try eraser; if it works(and in most cases will), you've spared a life(out of 9 ).

This is my first port of call for any kind of carbon deposit contamination. It's far less aggressive than an abrasive media.