Test Equipment Anonymous (TEA) group therapy thread

[lowimpedance]

Without the specs for the shunts, I can't tell if these things are technically special or easily exceeded via DIY (it's all passive stuff), but it is nice to have the mostly matching enclosure and hardware as the 8100A.

In case you have not looked here,  ko4bb has the manual.

http://www.ko4bb.com/getsimple/index.php?id=download&file=Fluke/Fluke_A90_Current_Shunt_Service_Manual.pdf

[bitseeker]

Adblock Plus, Ghostery, and NoScript (from least to most intrusive) are your friends

I actually have UBlock Origin and Privacy Badger installed but somehow their ad got through.  Maybe it was something hosted on their own server...

Yes, it's possible that it was hosted on their own server. UBlock Origin also has access to many community block lists that can be enabled in the plugin's settings. Some can be quite aggressive, so don't try too many at once or it'll be difficult to tell which one caused an issue.

UBlock Origin also has the ability to selectively block items on a page. Just right-click on the object in the page and select Block Element.

[bitseeker]

But I'm not sure about this one. I probably should return it out of principle. But the shunt resistors measure good and look fine (not fried). The switches should clean up and operate well thereafter. The rest of the enclosure is in good condition. I'm inclined to keep it and post neutral feedback since it was packed well and the seller's response was prompt. But finding a replacement foot for these ancient things is going to be a long journey.

I'm a bit late and you probably decided already but I think you should keep it. Personally the feet, I don't care too much as long as the casing itself is in good shape.

Thanks, Kosmic. All feedback is appreciated. The feet on the old Fluke meters is rather blocky. I started contemplating making one from a small block of wood, then painting it gray like the original.

[bitseeker]

Man, I don't buy unless I see pics of ALL sides of the thing. If I don't - I don't buy. If I really want it bad I'll ask to please take all the pics, or I won't consider it.

Yes there a lot a of marginally honest seller on ebay. Also I noticed after that the guy ony had 40 feedbacks on his account. I guess I'm getting careless since I had only few problems and they were all solved by ebay quickly.

Yep. I usually only buy if I can see everything. Otherwise, I ask for additional photos. Of course, it's when you let your guard down that you get bit. In my case, the price was reasonable and it was BIN or risk it getting bid up higher since they usually sell for more than the BIN price.

Thanks to you guys, I'm OK with what I ended up with.

The only complaint I have is with Fluke's industrial design. There were two similar designs for the 8100A DMM and A90 selectable current shunt. On the earlier one, like my 8100A, the horizontal bar on the handle rotates so that it can lay flat against the enclosure when tucked under or over the meter for stacking as shown below. The feet clear it just fine. Very nice.



However, the newer one, like my A90, was cost-reduced so that the handle is one solid bar that is taller than the instrument's feet. As a result, this can't be stacked without removing the handle altogether. Boo.

[bitseeker]

...

But when I went to send him a message eBay asked why I wanted to contact the seller.  I thought I'd be helpful and click the box that said "Item not as described."  It immediately kicked me into a return case and I had no way to get out of it or cancel it or even contact the seller outside of the return case anymore.  I ended up having to ship them back at his cost and wait for him to get them and send the correct ones.

So don't be "helpful" and check any of the reasons.  Just click the one that says something like "I have a question about the item."

Exactly. You have to select the "I want to ask a question" option. eBay's web UX design is sub-optimal and just gets worse. Their mobile app is horrendous as well, just in different ways than with the site.

[bitseeker]

Without the specs for the shunts, I can't tell if these things are technically special or easily exceeded via DIY (it's all passive stuff), but it is nice to have the mostly matching enclosure and hardware as the 8100A.

In case you have not looked here,  ko4bb has the manual.

http://www.ko4bb.com/getsimple/index.php?id=download&file=Fluke/Fluke_A90_Current_Shunt_Service_Manual.pdf

Thanks! Don't know how I missed that while searching. Usually, PDFs from there come up in general search results.

So, it appears they're rated to be 0.1% resistors except for the 10mΩ, which is 0.2%, for DCA.

[Specmaster]

But I'm not sure about this one. I probably should return it out of principle. But the shunt resistors measure good and look fine (not fried). The switches should clean up and operate well thereafter. The rest of the enclosure is in good condition. I'm inclined to keep it and post neutral feedback since it was packed well and the seller's response was prompt. But finding a replacement foot for these ancient things is going to be a long journey.

I'm a bit late and you probably decided already but I think you should keep it. Personally the feet, I don't care too much as long as the casing itself is in good shape.

Thanks, Kosmic. All feedback is appreciated. The feet on the old Fluke meters is rather blocky. I started contemplating making one from a small block of wood, then painting it gray like the original.

I have in the past removed feet in situations where one was broken or missing and used the gear without feet. Is a missing foot really that much of deal breaker? It's often far easier to find feet that will do the job then it is finding a meter in good condition.

[bd139]

If it slips around over everything, it’s a problem. This is why it’s really annoying when you get something of HP/Agilent brethren where the feet or bumpers are missing. When you press a button it slides away.

[Specmaster]

Man, I don't buy unless I see pics of ALL sides of the thing. If I don't - I don't buy. If I really want it bad I'll ask to please take all the pics, or I won't consider it.

Yes there a lot a of marginally honest seller on ebay. Also I noticed after that the guy ony had 40 feedbacks on his account. I guess I'm getting careless since I had only few problems and they were all solved by ebay quickly.

Yep. I usually only buy if I can see everything. Otherwise, I ask for additional photos. Of course, it's when you let your guard down that you get bit. In my case, the price was reasonable and it was BIN or risk it getting bid up higher since they usually sell for more than the BIN price.

Thanks to you guys, I'm OK with what I ended up with.

The only complaint I have is with Fluke's industrial design. There were two similar designs for the 8100A DMM and A90 selectable current shunt. On the earlier one, like my 8100A, the horizontal bar on the handle rotates so that it can lay flat against the enclosure when tucked under or over the meter for stacking as shown below. The feet clear it just fine. Very nice.



However, the newer one, like my A90, was cost-reduced so that the handle is one solid bar that is taller than the instrument's feet. As a result, this can't be stacked without removing the handle altogether. Boo.

In situations like that I've gone to the local hardware store and got a packet of felt or silicon stick feet, the ones designed to prevent damage to table tops etc. Stick them on the bottom of the feet of the item you want to stack on top until it clears the handle. It might not look very elegant but it does allow your gear to be fully functional. [emoji106]

[Specmaster]

If it slips around over everything, it’s a problem. This is why it’s really annoying when you get something of HP/Agilent brethren where the feet or bumpers are missing. When you press a button it slides away.

If that happens, I've stuck on some of the furniture protective stick on felt or silicon pads and the work really well to help prevent it from sliding away. Far better to do that and have the equipment in your lab and use than not have it surely?

[Specmaster]

Take a look at the rack & pinion that moves the head, and at the intermediary gears in the reader with a bright flashlight and magnifier. Sometimes there is just a single grain of sand that makes it bind up. The rack gear will have a spring-loaded backlash mechanism; make sure it has no more than one tooth or two of preload, and that it moves smoothly.

Rarely, but sometimes, audio player readers will have a leadscrew mechanism instead of a rack/pinion. Same story as far as looking for grit. If the drive for either type has a belt, remove it and look for it being gummy, hard, or deformed into an egg shape.

As your unit appears to be angle/shock sensitive, odds are one or more of the rubber isolation bobbins has hardened, cracked out, or compressed to the point it is useless. Disassemble the big flat-headed screws that hold the reader to the elevator mechanism and inspect to see if any are bottoming out when in the normal play-mode orientation.

Removing the assembly will also allow you to inspect the head drive mechanism more carefully.

Good hunting!

mnem
*Back to the salt mines*

I've had the deck out and thoroughly checked all cogs and rack and pinion bits for the tracking found nothing wrong there, cleaned them all down to remove all grease and grime looked at them through a powerful bench illuminated magnifier and still found nothing.

Looked at the rubber isolation bobbins and it did seem to me that there was rather a lot of the screw sticking out on top of the whole head assembly so I removed them for closer examination and they did seem to a little flat and stiffer than I'd expected. I have now sourced a similar machine with a far lower spec so I shall be picking that up locally this evening and according to the service manual, the tape and CD decks are the same and given that my tape decks drive belts have turned to sticky goo and fell apart, I'll be looking at the belts on the new donor machine as well.

If the new CD deck is in a similar condition I think a MacGyver fix would be to add a small washer under each of the isolation bobbins to move the head assembly slightly closer to the disc which may help to improve the focussing especially at the starting position which is very close to the transparant bit of the disc which may be letting to much light in and  confusing the head. Moving the head slightly closer to the disc may reduce the amount of light it is seeing.

[mnementh]

Post me a pic of the entire pickup deck mechanism; If I can identify it, I may be able to give some more specific pointers than the generic ones below...

The rubber bobbins support the entire CD deck mechanism; altering them won't alter the relationship between laser head and disc, which has to be pretty much dead-on within a few thousandths of an inch for the focusing element to be able to keep up with inevitable disc warpage and runout.

Manufacturing precision of optical media is not that great; the optical pickup has to be able to move up/down +/- 1mm or so in sync with warpage of the disc to be able to function. This means that being off 0.20-0.030" can put the surface of the disc outside that range, and only a few very flat discs will play. I used to keep a stack of discs I'd found and labeled that were "Extra flat" "Average" and "Extra Wavy" for testing.

Another thing you need to watch out for is the magnetic platter clamping disc being mucked up; often they will have a rare-earth magnet doughnut inside, and that rots with age and deforms the flat surface so it doesn't lie flat, or in some cases actual loose flakes of the magnet can cause mayhem the mechanism.

Compressed rubber bobbins are a bit of a PITA to fix; I've had more than a few units that I had to chunk because the bobbins weren't available to buy ANYWHERE and I was unable to scavenge suitable replacements due to some oddball design element. Some other options are: Old PC optical drives, o-ring assortment as spacers (rarely work; usually too thick) and making washers out of craft foam sheet from Wally World (the stuff they sell nowadays instead of craft felt).

These things (and the magnetic platter clamp) are to CD player mechanisms as capacitors are to electronics in general; "the 3¢ part with a finite lifespan that brings everything down eventually". They know this, and as it is a custom-molded part, it is easy to limit production, thereby ensuring turnover. They don't want your favorite CD player becoming an heirloom piece like your favorite Marantz 2xxx or 4xxx series receiver did.   

What is key is to make sure that when the disc and platter are engaged under the magnetic clamp, that there is adequate clearance above the loading tray that it doesn't hit the tray, and that it appears level, and that if you depress the spindle gently, it can move down a couple mm before the disc bottoms out on any edge. If you can get it to that point, you should be golden, and the unit should be fairly vibration tolerant once reassembled. It's usually a lot of trial/error fiddly-bit work though, and often the special shoulder screws go into plastic, which strips out easily and deforms a little with every screw/unscrew cycle, so confounding your efforts.

And sometimes the laser head just gets weak... the diode laser dims or shifts frequency enough that the photodiode doesn't read reliably, or the drive current shifts enough due to aging of electronics that that the laser is over or under driven... or maybe this week solar flares are kicking the ass of everything electronic, and you just drew the short straw on the great circular workbench in the sky.

Point being that if you can't get it to play reliably, even after hours of your tenderest ministrations, don't be too disappointed. Optical drives, especially those made for CD audio, are made absolutely as cheap as possible with the intent of only outliving the warranty. If you get 10 years out of one you're lucky; by which time the deck is often no longer available as spares.

That said... once you DO get a CD player sorted so it works correctly again it can be most satisfying... until the next time it fucks up. 

Good luck!

mnem
You're gonna need it. 

[Specmaster]

Thanks for the tips, the screws that the bobbins are held on with have about 2 to 3 mm of stainless steel shank exposed when they are fully screwed down as far as they will go. This seems to me from looking at other drives I have as being excessive because I think the bellow part under the assembly has over the years aged and become compressed which allows the head to be further away from the disc than would normally be the case and could well explain the track 1 and 2 issue as its at the part of its travel where it drops down to allow the tray to slide out in order to change the disc?

As mentioned, I have another unit arriving tonight so we can see how that one fairs against the existing unit. If I have to junk one system than it going to be the one I just acquired for £10 because it by far the worst in terms of specification and appearance so it might be a good donor for the current one. I have also just acquired another similar unit to the one I'm working but it has the addition of a mini disc recorder/player added in the mix as well as the CD and cassette tape deck and this one is fully working, in fact I'm told both the new units are fully working.

[mnementh]

   

This is a KSM2101ABM/KSS-210A CD Deck & laser pickup; they are one of the few designs that has managed to survive the years (a cockroach component) and can still be found in use more than 20 years after introduction. Most CD decks of any manufacture will be some variant of this basic design.

As you can see, the platter/spindle and the head are both attached to the same piece of steel (or plastic) that are supported by the rubber bobbins; loading and unloading the disc doesn't change the relationship between the spindle/platter surface and the laser head, nor does compression of the bobbins.

The entire mechanism is elevated into place when the CD is loaded; the rubber bobbins support the entire mechanism AND THE DISC, and the magnetic clamping disc once engaged.

Post a pic of your mechanism and if I can identify it, I may be able to give more specific pointers.

mnem
*tzzt*

[bd139]

I usually look in the service manual at this point and just buy a new transport assembly 

Just snagged a new toy. HP AWG. Lower spec than my Rigol unit but it has some killer features: (1) fully floating output (this is the killer feature really) (2) service manual with schematic (3) keysight still sell bits for it and (4) HP logo  and probably 80 quid back in the bank.  Get rid of that DG1022Z thus leaving me with a "Chinese test gear free lab" 

This Charmanda is representative of my joy at that matter:

[capt bullshot]

Just snagged a new toy. HP AWG. Lower spec than my Rigol unit but it has some killer features: (1) fully floating output (this is the killer feature really) (2) service manual with schematic (3) keysight still sell bits for it and (4) HP logo 

33120 ?

[bd139]

yep.

[capt bullshot]

yep.

Congrats. Still a great instrument. Was really impressive back then, you just dial in "1kHz" , "1 Vss" and it _does_ output 1kHz at 1Vss. What an improvement over your classic function gen.

And makes a nice stack with 34401's. Also matching the 53131 etc. counters.

[bd139]

Yep. Stilll the best user interface as well.

You foiled my HP stack master plan 

34401A is on the shopping list already.

[mnementh]

I usually look in the service manual at this point and just buy a new transport assembly 

Just snagged a new toy. HP AWG. Lower spec than my Rigol unit but it has some killer features: (1) fully floating output (this is the killer feature really) (2) service manual with schematic (3) keysight still sell bits for it and (4) HP logo  and probably 80 quid back in the bank.  Get rid of that DG1022Z thus leaving me with a "Chinese test gear free lab" 

This Charmanda is representative of my joy at that matter:

   
Option 001? Or "Dunno, waiting for delivery like it's Christmas!" ? 

mnem
Which, actually, it is... close enough. 

[Specmaster]

   

This is a KSM2101ABM/KSS-210A CD Deck & laser pickup; they are one of the few designs that has managed to survive the years (a cockroach component) and can still be found in use more than 20 years after introduction. Most CD decks of any manufacture will be some variant of this basic design.

As you can see, the platter/spindle and the head are both attached to the same piece of steel (or plastic) that are supported by the rubber bobbins; loading and unloading the disc doesn't change the relationship between the spindle/platter surface and the laser head, nor does compression of the bobbins.

The entire mechanism is elevated into place when the CD is loaded; the rubber bobbins support the entire mechanism AND THE DISC, and the magnetic clamping disc once engaged.

Post a pic of your mechanism and if I can identify it, I may be able to give more specific pointers.

mnem
*tzzt*

That looks exactly the same as mine. Can't be 100% certain because I have put it all together again while I crack on with something else. When I take it apart again later I'll check it against your photo.

If the bobbins are compressed therefore shallower than they should be, when the plastic frame that this drive is attached to is raised to meet the disc, then the head assembly should be lower as a result no?

[Specmaster]

I usually look in the service manual at this point and just buy a new transport assembly 

Just snagged a new toy. HP AWG. Lower spec than my Rigol unit but it has some killer features: (1) fully floating output (this is the killer feature really) (2) service manual with schematic (3) keysight still sell bits for it and (4) HP logo  and probably 80 quid back in the bank.  Get rid of that DG1022Z thus leaving me with a "Chinese test gear free lab" 

This Charmanda is representative of my joy at that matter:

Congrats on the HP, but you've a long way to go yet before you Chinese free in your lab totally. What about all your power blocks, LEDS, etc etc.

Haha, like to be a fly on your wall now watching you getting a groove on [emoji6]

[mnementh]

   

This is a KSM2101ABM/KSS-210A CD Deck & laser pickup; they are one of the few designs that has managed to survive the years (a cockroach component) and can still be found in use more than 20 years after introduction. Most CD decks of any manufacture will be some variant of this basic design.

As you can see, the platter/spindle and the head are both attached to the same piece of steel (or plastic) that are supported by the rubber bobbins; loading and unloading the disc doesn't change the relationship between the spindle/platter surface and the laser head, nor does compression of the bobbins.

The entire mechanism is elevated into place when the CD is loaded; the rubber bobbins support the entire mechanism AND THE DISC, and the magnetic clamping disc once engaged. Post a pic of your mechanism and if I can identify it, I may be able to give more specific pointers.

mnem
*tzzt*

That looks exactly the same as mine. Can't be 100% certain because I have put it all together again while I crack on with something else. When I take it apart again later I'll check it against your photo.

If the bobbins are compressed therefore shallower than they should be, when the plastic frame that this drive is attached to is raised to meet the disc, then the head assembly should be lower as a result no?

No, what happens is that the entire mechanism rides lower... head, spindle/platter, disc, magnetic clamping disc all ride lower... until you have problems with vibration sensitivity because the CD deck mechanism is resting on something solid in the elevator mechanism, or the clamping disc bottoms out, and/or the laser pickup hits something in the elevator mechanism in the normal course of its travel, or the ribbon cable to the laser pickup binds or "pushes back" or upward due to almost binding. The entire mechanism... clamping disc, CD deck, laser pickup, ribbon cables, and whatever elevator/CD tray mechanism they're attached to... all work together with clearances of a few millimeters when the disc is loaded. Any deviation from that (such as are caused by droopy rubber bobbins) can allow something to interfere.

Used to be when you bought the deck, you got the generic Sony-design rubber bobbins as well, which can be made to work with almost any elevator mechanism... but I suspect they stopped doing that because skeevball shops and dickwads were ordering the deck, swapping the old bobbins out, and sending the part back as defective. Either that, or the planned obsolescence I suggested earlier. 

What's the model of your little unit? I may be able to track down what you need from some of my old suppliers, if they still exist. Donberg will probably have what you need; but they've always been sky-high.

mnem

[Specmaster]

   

This is a KSM2101ABM/KSS-210A CD Deck & laser pickup; they are one of the few designs that has managed to survive the years (a cockroach component) and can still be found in use more than 20 years after introduction. Most CD decks of any manufacture will be some variant of this basic design.

As you can see, the platter/spindle and the head are both attached to the same piece of steel (or plastic) that are supported by the rubber bobbins; loading and unloading the disc doesn't change the relationship between the spindle/platter surface and the laser head, nor does compression of the bobbins.

The entire mechanism is elevated into place when the CD is loaded; the rubber bobbins support the entire mechanism AND THE DISC, and the magnetic clamping disc once engaged. Post a pic of your mechanism and if I can identify it, I may be able to give more specific pointers.

mnem
*tzzt*

That looks exactly the same as mine. Can't be 100% certain because I have put it all together again while I crack on with something else. When I take it apart again later I'll check it against your photo.

If the bobbins are compressed therefore shallower than they should be, when the plastic frame that this drive is attached to is raised to meet the disc, then the head assembly should be lower as a result no?

No, what happens is that the entire mechanism rides lower... head, spindle/platter, disc, magnetic clamping disc all ride lower... until you have problems with vibration sensitivity because the CD deck mechanism is resting on something solid in the elevator mechanism, or the clamping disc bottoms out, and/or the laser pickup hits something in the elevator mechanism in the normal course of its travel, or the ribbon cable to the laser pickup binds or "pushes back" or upward due to almost binding. The entire mechanism... clamping disc, CD deck, laser pickup, ribbon cables, and whatever elevator/CD tray mechanism they're attached to... all work together with clearances of a few millimeters when the disc is loaded. Any deviation from that (such as are caused by droopy rubber bobbins) can allow something to interfere.

Used to be when you bought the deck, you got the generic Sony-design rubber bobbins as well, which can be made to work with almost any elevator mechanism... but I suspect they stopped doing that because skeevball shops and dickwads were ordering the deck, swapping the old bobbins out, and sending the part back as defective. Either that, or the planned obsolescence I suggested earlier. 

What's the model of your little unit? I may be able to track down what you need from some of my old suppliers, if they still exist. Donberg will probably have what you need; but they've always been sky-high.

mnem

The model of the unit us Aiwa XR-M500  and its not worth anything really. I got it cheap to rob speakers from it really to go with the TEAC units.

[grizewald]

eBay's contact system does seem to be biased towards making things hard for the seller. I've nearly been caught out by clicking the wrong reason for contact before. Now I always select "Other" as I know it'll let me just send the seller a message.

As it goes, the guy has replied and offered that I could return it or get a 'small refund'. I've just replied and suggested that returning 10Kg from Sweden to the UK isn't likely to be financially advantageous to anyone except the courier and instead suggested that he refunds me 50% of what I paid for the meter.

I also managed to find a NOS Panaflex display unit for 15 GBP, so that particular problem is solved at least. I was quite surprised to find one, but there is a German seller who appears to still have 'more than 10 available' despite having sold two already.

Now to start stripping the entire meter down. There's certainly more than just the display that's FUBAR as the self test gave all zero on every test. Hopefully it's just the connection between the display logic and the rest of the meter. Until I've got all the boards out though it's hard to tell.