Test Equipment Anonymous (TEA) group therapy thread

[mansaxel]

There's a fall-though if the first named doesn't boot, etc. etc. Obviously add the rest of your config to taste, that's just an extract with some context.

Yes, I've done something similar a few times. Here, I've got enough space on the card that I can scp a new image in as long as I'm removing the old one, so won't mess with TFTP for now.

[mnementh]

...I just did something massive, impulsive and probably stupid which I'm probably going to regret next week (not TE related)

Me too. I am currently attempting to migrate to a new Android pwn. I already regret the decision. 

mnem
Because 3DP wasn't enough misery. 

Ah fuck that. That's more painful than 3DP. I learned that lesson once trying to get Cyanogen working on something Motorola. Actually found a box of phones in the cupboard the other day. There was a Moto G in there. In the fucking bin!

It gets worse. The REASON I'm suffering all this pwn misery... is because I'm giving him my old pwn for his B-day.

mnem

[vk6zgo]

6206B update:

Apparently the neon is supposed to light up when power is applied. This one doesn't. New hole-compatbile one in Mouser shopping cart, together with the full complement of capacitors for a Fluke 8060, and a 100W resistor.

Can you not just remove the old neon lamp from the plastic housing and put a new one in? I've done this with the filament lamp versions before.

David

That is a clever idea! I did toy with it a bit earlier today. It does require digging into the plastic housing a bit, and I did not have the tools right there to do that, but it is possible, if one wants the authentic look.

I must confess that I think of the mods and repairs done to test equipment, if and only if they're done to meet or exceed original specification, and are somewhat in style, as interesting traces of a life spent being useful and cared for.  Thus, I think that fitting new parts that meet requirements is sort of caring about continous relevance.

Further, the neon, specifically, is a safety part, since it carries  (half of if running off 230V) mains voltage. It is not always wise to maintain "vintage" for safety parts. In this case it's probably OK, if one can get the housing separated from the neon without cracking it.

My work life has been pretty much concurrent with that of much of the now "vintage" equipment, & I agree.
Test instruments which have had to "work for a living" will often have modifications, repairs, & other "battle scars", which are all inherent parts of their history.

Those that look "in showroom condition" may have been "lemons" that were never used because of some obscure fault.

[Kosmic]

Got lucky on ebay. I snipped 3 substitution boxes for 20$   



The IET RCS-502 are really nice. They combine resistance (0.1%) and capacitance (1%) decades. The CDE CDB-3 is a lot older and only has only capacitance. Its also less accurate at 3%.

When received the CDB-3 was a bit inconsistent. I decided to open it up to clean the switches. The internal construction is somehow rustic with the piece of wood glued in the middle 



Also I never seen those capacitors before. Look like they are in ceramic. If radiomuseum.org is accurate, they were selling for 16.35 in 1965 (https://www.radiomuseum.org/r/cornel_dub_decade_capacitor_cdb3.html) In pretty good shape for it's age.



As usual I cleaned the switches first with IPA, then Deoxit G5 and finally Deoxit F5, actuating the switch multiple times after each application. After this little maintenance the switch was working fine and measurements were consistent.



AS for the 2 RCS-502 they are working fine excepted 1 resistor on the second decade. Decided to open it up to investigate and found this:



  Luckily those resistors are readily available on digikey.

[Kosmic]

More internal pictures of the RCS-502

[mnementh]

Some progress... and ~$1.50 worth of filament wasted. A clone build-tak that came with a spool of filament resolved my adhesion issues, as well as giving a nice sandstone finish to the front of the piece. However, after successfully printing a nosepiece, I found it had a couple fitment errors that required some severe modification to the design. While I beat Frustion360 into submission, I set the printer to work on another tailpiece.

In the morning, I'll see how my new design behaves.

For those who care... my son's head exploded when he got his two presents from me: the phone and a vintage Bruce Lee-era bone-handled butterfly knife I've been saving for him since he was a toddler. I decided it wouldn't do for him to have a phone before his first pocket knife; especially since I got my first, a honest-to-goodness teak-handled Case pen-knife, when I was 8.

Currently, I'm unpacking a cheap android tablet and adding it to my WiFi whitelist.

mnem

[battlecoder]

Got a new function gen! (and with new I mean old**)
** But not that old
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It's a Minipa Mfg-4220. Definitely not a precision device, and seems to suffer from a bit of frequency drift, but judging from the specs it's apparently to be expected for an instrument in this range.

I'm currently testing its accuracy against a 10Mhz GPSDO, and seems to be off by a bit (as pictured). The manual mentions a "temperature controlled oscillator" so I was hoping that with some warm-up time it would improve a bit, but I've left it ON for like an hour now, and the last two digits are still going back and forth between 22 and 21, sometimes settling on 21 for a while.

While I wasn't expecting this to be SUPER accurate I may open it later to see if the oscillator can be calibrated or replaced by a higher-accuracy part.
It's interesting to notice that it's supposed to be able to measure frequencies of up to 3Ghz (the likes of which I'll probably never need to measure) so this is a pretty solid addition to my collection of devices that go *WELL* beyond the kind of signals I'll ever work with.

[Robert763]

Got a new function gen! (and with new I mean old**)
** But not that old
(Attachment Link) " alt="" class="bbc_img" />

It's a Minipa Mfg-4220. Definitely not a precision device, and seems to suffer from a bit of frequency drift, but judging from the specs it's apparently to be expected for an instrument in this range.

I'm currently testing its accuracy against a 10Mhz GPSDO, and seems to be off by a bit (as pictured). The manual mentions a "temperature controlled oscillator" so I was hoping that with some warm-up time it would improve a bit, but I've left it ON for like an hour now, and the last two digits are still going back and forth between 22 and 21, sometimes settling on 21 for a while.

While I wasn't expecting this to be SUPER accurate I may open it later to see if the oscillator can be calibrated or replaced by a higher-accuracy part.
It's interesting to notice that it's supposed to be able to measure frequencies of up to 3Ghz (the likes of which I'll probably never need to measure) so I this is a pretty solid addition to my collection of devices that go *WELL* beyond the kind of signals I'll ever work with.

Well the counter IS stable if it if flipping between 21 and 22, it's just not accurate.
Just about every digital counter (and other instruments) has an uncertanty of plus or minus one count of the last digit. So the counter is stable within the limits of your measurement. If the TCXO in the generator / counter has an adjustment (it should) then you can remove the 21 Hz offset.

EDIT,
Found a specification for the counter - 5 ppm per year so assuming it's not been adjusted for at least a year it is within specification. 5 ppm at 10 MHz is +_50 Hz. That said you should be able toadjust it to a better accuracy.

[med6753]

Got a new function gen! (and with new I mean old**)
** But not that old
(Attachment Link) " alt="" class="bbc_img" />

It's a Minipa Mfg-4220. Definitely not a precision device, and seems to suffer from a bit of frequency drift, but judging from the specs it's apparently to be expected for an instrument in this range.

I'm currently testing its accuracy against a 10Mhz GPSDO, and seems to be off by a bit (as pictured). The manual mentions a "temperature controlled oscillator" so I was hoping that with some warm-up time it would improve a bit, but I've left it ON for like an hour now, and the last two digits are still going back and forth between 22 and 21, sometimes settling on 21 for a while.

While I wasn't expecting this to be SUPER accurate I may open it later to see if the oscillator can be calibrated or replaced by a higher-accuracy part.
It's interesting to notice that it's supposed to be able to measure frequencies of up to 3Ghz (the likes of which I'll probably never need to measure) so I this is a pretty solid addition to my collection of devices that go *WELL* beyond the kind of signals I'll ever work with.

Well the counter IS stable if it if flipping between 21 and 22, it's just not accurate.
Just about every digital counter (and other instruments) has an uncertanty of plus or minus one count of the last digit. So the counter is stable within the limits of your measurement. If the TCXO in the generator / counter has an adjustment (it should) then you can remove the 21 Hz offset.

EDIT,
Found a specification for the counter - 5 ppm per year so assuming it's not been adjusted for at least a year it is within specification. 5 ppm at 10 MHz is +_50 Hz. That said you should be able toadjust it to a better accuracy.

Agreed. Somewhere in the vicinity of the oscillator crystal there should be a trimmer cap. Using a plastic driver you should be able to set it within +/-1Hz.

Warm up times: 1 hour is an absolute minimum. For critical adjustments as this example I consider 2 plus hours a minimum. Sometimes I'll even leave an instrument idling for as much as 12 hours before a final adjustment.   

[Mr. Scram]

Got lucky on ebay. I snipped 3 substitution boxes for 20$   

Nice catch! I never found a deal I liked but you certainly did.

[Specmaster]

It gets worse. The REASON I'm suffering all this pwn misery... is because I'm giving him my old pwn for his B-day.

mnem


Poor boy, for his birthday he gets Dad's old cast-off while Dad gets the nice shiny new one, don't forget it will him who gets to select what care home you go to when you get old and frail, I suspect that he's already plotting his revenge right now 

[bd139]

Bought another power supply. That's, err 5 now. I think I've got a power supply problem.

Farnell LT30/2 this time. Not HP or TTi for once. Some bugger bid me up £20 in the last 2 seconds of the auction  . Bought it because they are extremely compact, silent and will do 60V@2A, 2x30V@2A or 30V@4A and has analogue metering which I still prefer for power supplies if I'm honest. Watching that current needle bopping around when you're doing things is rather helpful.

Unicorn ending later today. Hope i win this one. I've already managed to diagnose what is wrong with and come up with a test and fix plan and it's not the usual semi-difficult to fix failures in these units. This one is a lot more cash and complexity than I usually throw at broken stuff though so it's a semi-scary . And it may get bounced fairly quickly if it comes out ok to make some cash.

Edit: Will likely need to mod the LT30/2 with a couple of diodes per supply as like the Farnell E-series they blow up if the line power fails and the load drives the power supply. Minor design flaw that is easy to fix though.

[Specmaster]

Talking power supplies, I have been through every part of the current control section of the PL310, no problems founds, everything checked out within 5% tolerance as mentioned in the schematic. Later I'll reconnect it and go through the calibration procedure, failing that its be checking the voltage control section, bit by bit.   

[bd139]

Yeah you're not going to find anything now without running it up. Complete bastard debugging time coming up. At least it's fun 

[Specmaster]

Bought another power supply. That's, err 5 now. I think I've got a power supply problem.

Farnell LT30/2 this time. Not HP or TTi for once. Some bugger bid me up £20 in the last 2 seconds of the auction  . Bought it because they are extremely compact, silent and will do 60V@2A, 2x30V@2A or 30V@4A and has analogue metering which I still prefer for power supplies if I'm honest. Watching that current needle bopping around when you're doing things is rather helpful.

Unicorn ending later today. Hope i win this one. I've already managed to diagnose what is wrong with and come up with a test and fix plan and it's not the usual semi-difficult to fix failures in these units. This one is a lot more cash and complexity than I usually throw at broken stuff though so it's a semi-scary . And it may get bounced fairly quickly if it comes out ok to make some cash.

Edit: Will likely need to mod the LT30/2 with a couple of diodes per supply as like the Farnell E-series they blow up if the line power fails and the load drives the power supply. Minor design flaw that is easy to fix though.

I like the LT30/2 units, nice analogue meters but they are that bit to large for my bench, they won't fit where the PL series will 

[bd139]

They're actually pretty small. I think the total volume is about 1/2 of a PL320QMD for example. Farnell made a point of their later products being fairly small.

The unicorn finishing later is also British manufactured test gear...

[Specmaster]

I meant in the height, they seem to  high to fit under my shelf.

[bd139]

Apparently 226mm high vs 170mm on the PL series.

[battlecoder]

Got a new function gen! (and with new I mean old**)
** But not that old
(Attachment Link) " alt="" class="bbc_img" />

It's a Minipa Mfg-4220. Definitely not a precision device, and seems to suffer from a bit of frequency drift, but judging from the specs it's apparently to be expected for an instrument in this range.

I'm currently testing its accuracy against a 10Mhz GPSDO, and seems to be off by a bit (as pictured). The manual mentions a "temperature controlled oscillator" so I was hoping that with some warm-up time it would improve a bit, but I've left it ON for like an hour now, and the last two digits are still going back and forth between 22 and 21, sometimes settling on 21 for a while.

While I wasn't expecting this to be SUPER accurate I may open it later to see if the oscillator can be calibrated or replaced by a higher-accuracy part.
It's interesting to notice that it's supposed to be able to measure frequencies of up to 3Ghz (the likes of which I'll probably never need to measure) so I this is a pretty solid addition to my collection of devices that go *WELL* beyond the kind of signals I'll ever work with.

Well the counter IS stable if it if flipping between 21 and 22, it's just not accurate.
Just about every digital counter (and other instruments) has an uncertanty of plus or minus one count of the last digit. So the counter is stable within the limits of your measurement. If the TCXO in the generator / counter has an adjustment (it should) then you can remove the 21 Hz offset.

EDIT,
Found a specification for the counter - 5 ppm per year so assuming it's not been adjusted for at least a year it is within specification. 5 ppm at 10 MHz is +_50 Hz. That said you should be able toadjust it to a better accuracy.

Agreed. Somewhere in the vicinity of the oscillator crystal there should be a trimmer cap. Using a plastic driver you should be able to set it within +/-1Hz.

Warm up times: 1 hour is an absolute minimum. For critical adjustments as this example I consider 2 plus hours a minimum. Sometimes I'll even leave an instrument idling for as much as 12 hours before a final adjustment.

That's kinda what I thought I was going to find inside. Will try to do this today after work, thanks! It's great to have some confirmation _and_ guidelines for the procedure.
And yes, the counter IS definitely stable. The frequency drift I mentioned is for the signal generation circuitry. That turned out to go away with some warmup time, but still; you can leave it in a set frequency, and it will start moving up and down within a range (it was originally going just in one direction and just kept going and going... but after warmup it stayed within a range, and does no longer try to escape to infinity). It's not dead stable. I think the datasheet mentioned something like 2% FS per range, which is definitely meeting, though. (Although it was listed under "Precision" in the datasheet? I would have expected something like "stability" but that is nowhere to be found in the specs, so whatever)

Anyway, even if the output is not SUPER stable, it still gives a rather clean signal, and the counter seems to be quite decent, so if I can adjust the offset in the frequency measurements I think I'll be more than fine.

Thanks you both for your input!

[Mr. Scram]

Got lucky on ebay. I snipped 3 substitution boxes for 20$   

Nice catch! I never found a deal I liked but you certainly did.

[Specmaster]

Apparently 226mm high vs 170mm on the PL series.

Yep, thats what I deduced when I was looking for replacements for my China made units and the PL fitted that bill very nicely, both in height and depth as my shelf is fixed at 185 high, still like the analogue meters on those Farnell units though.

[mnementh]

It gets worse. The REASON I'm suffering all this pwn misery... is because I'm giving him my old pwn for his B-day.

mnem

https://youtu.be/Ez1XvtyJnvg

Poor boy, for his birthday he gets Dad's old cast-off while Dad gets the nice shiny new one, don't forget it will him who gets to select what care home you go to when you get old and frail, I suspect that he's already plotting his revenge right now 

The boy's lucky he's getting anything at all; he's already on double grounding since before the move for being a Kevin and mouthing off at his daddy over video games... then sneaking off and doing video games on his laptop when he's supposed to be doing homework... then he almost got his birthday taken away for back-talking his momma the night before his birthday.

We actually had the mummeh-daddeh conversation aboot this (but not the knife; I know which of the two is really dangerous ) and decided together; we figured it'll last a week before he gets it taken away for bein' a little ass h'o, so no sense in buying a brand new pwn to sit in a drawer for half the next year.  And since my wife's pwn is the newest in the house by 2 years, it was time for daddeh to get the new shiny: https://bluproducts.com/devices/g90-pro/ 

We also considered getting a new cheapo pwn for him... but I learned my lesson the hard way. My old pwn is still better than 90% of the cheep-cheepies at 3GB/64GB/Snapdragon 425, so it got a fresh screen protector and a new manly-man black hardcase for him.

There has to be something going right here... the boi's current fandoms are Bleach and The Mandalorian. So he is showing some signs of becoming adult-ish. 

mnem

[bd139]

Apparently 226mm high vs 170mm on the PL series.

Yep, thats what I deduced when I was looking for replacements for my China made units and the PL fitted that bill very nicely, both in height and depth as my shelf is fixed at 185 high, still like the analogue meters on those Farnell units though.

Yeah the PL is damn near perfect little supply when they work  . I'm keeping my PL320 as well.

Honestly after this week's events I'm going to focus on populating my living room with cheaper, simpler and easier to maintain bits of kit for the future. I'm hoping the LT30 will be one of them as it's entirely off the shelf cheap as chips parts.

[mnementh]

From the 3DP FTW Dept...


         

It sure is nice when the iterative part of Iterative Design actually works. 

While trimming up this tailpiece, I was struck with an idea for an all-new design which might actually do some muffler-ey action. Currently printing up a new nosepiece; now on Rev5.1.

mnem

[BU508A]

Ungh, that rusty knife scares me.   

And that poor ceramic knife with the missing knife point and the dents in the blade.   

What the heck are you doing with your knives?