Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

That's a tough one... but as it's being used for a shunt, 0.10Ω is a much more reasonable value than 10Ω or even 1Ω. The manual says 0R1 (which is 0.10Ω), the resistor measures 0.10Ω, so I'm inclined to believe it is correct; time to look somewhere else, like maybe a series resistor wrong value against parts list or shifted value higher, causing more voltage dropped across a comparator.

TTi has to get their parts from China just like everybody else; I'm sure they wouldn't send a reel (or more likely 100 or 1000 reels) back just because they printed the value in a non-standard (to us) format.

Good hunting!

mnem
 

[bd139]

I think I have (hopefully) found the culprit on the PL310 that Ice-Tea kindly sent me, the load resistor, a 10W aluminium clad jobbie which has printed on it R10, the manual states it as being 0R1, which unless I’m mistaken, means 1ohm. Looks to be perfect, no discolouration or nothing, seems to give a sensible value in circuit, whip it out and it measures .1ohms WTF?, no wonder it goes into CC mode at 190mA and voltage drops to 1.8V

0R1 = 0.1 ohms. that is correct value as it's the current sense resistor. Is that the one that hangs off the back of the front panel board?

Yes thats the one, as you can see it clearly states R10 5% on it?  The 2.2K below it has been getting hot, this has been replaced, the board has been recapped and the quad amp LM324 has also been replaced and is now in a socket. 

All joints have been reflowed in case they were dry as well.

Edit. I also spoke to engineer in TTi's technical dept and he thought that it should be 1 ohm although, he also claimed that the resistor R51 in the schematic is not fitted on the PL310?? and on the PL320 it is a 1K job, 

You're having your money's worth of repair fun on this one, eh? 

You're not wrong there, I'm not giving up on it though, its a challenge

Did you measure the voltage and current at the terminals or trust the display? Need to work out if it’s a metering or functional problem as the two halves of the supply are separate.

If it’s just the metering replace the cd4052be in it. Those tend to die and cock the metering.

[mnementh]

I just spent half an hour looking for the reason why I have 0.3V on that cap rather than filtered mains.

Go fuck yourself, Rigol.

Ugh that UI is fucking terrible! Took me a minute to parse it.

So... is it running a Min/Max, and it's displaying a Min value?

Sorry... not even a little bit familiar with the UI here; just trying to understand. 

I get annoyed when there is enough of a UI on something like a meter that I have to parse what it's telling me...  IMNSHO, the "UI" of this sort of TE should be so intuitive that it disappears "into the woodwork" of the thing. 

mnem
*poot*

[Ice-Tea]

You're not wrong there, I'm not giving up on it though, its a challenge

As it would seem, I had to go through the trouble of replacing a fuse on my latest "repair" 

[Specmaster]

I think I have (hopefully) found the culprit on the PL310 that Ice-Tea kindly sent me, the load resistor, a 10W aluminium clad jobbie which has printed on it R10, the manual states it as being 0R1, which unless I’m mistaken, means 1ohm. Looks to be perfect, no discolouration or nothing, seems to give a sensible value in circuit, whip it out and it measures .1ohms WTF?, no wonder it goes into CC mode at 190mA and voltage drops to 1.8V

0R1 = 0.1 ohms. that is correct value as it's the current sense resistor. Is that the one that hangs off the back of the front panel board?

Yes thats the one, as you can see it clearly states R10 5% on it?  The 2.2K below it has been getting hot, this has been replaced, the board has been recapped and the quad amp LM324 has also been replaced and is now in a socket. 

All joints have been reflowed in case they were dry as well.

Edit. I also spoke to engineer in TTi's technical dept and he thought that it should be 1 ohm although, he also claimed that the resistor R51 in the schematic is not fitted on the PL310?? and on the PL320 it is a 1K job, 

You're having your money's worth of repair fun on this one, eh? 

You're not wrong there, I'm not giving up on it though, its a challenge

Did you measure the voltage and current at the terminals or trust the display? Need to work out if it’s a metering or functional problem as the two halves of the supply are separate.

If it’s just the metering replace the cd4052be in it. Those tend to die and cock the metering.

No, the voltage and current are being measured at the terminals using external meters, which also agree with the fitted displays.

[Specmaster]

You're not wrong there, I'm not giving up on it though, its a challenge

As it would seem, I had to go through the trouble of replacing a fuse on my latest "repair" 

Yep, I've had my share of repairs like that as well, but not lately 

[bd139]

I think I have (hopefully) found the culprit on the PL310 that Ice-Tea kindly sent me, the load resistor, a 10W aluminium clad jobbie which has printed on it R10, the manual states it as being 0R1, which unless I’m mistaken, means 1ohm. Looks to be perfect, no discolouration or nothing, seems to give a sensible value in circuit, whip it out and it measures .1ohms WTF?, no wonder it goes into CC mode at 190mA and voltage drops to 1.8V

0R1 = 0.1 ohms. that is correct value as it's the current sense resistor. Is that the one that hangs off the back of the front panel board?

Yes thats the one, as you can see it clearly states R10 5% on it?  The 2.2K below it has been getting hot, this has been replaced, the board has been recapped and the quad amp LM324 has also been replaced and is now in a socket. 

All joints have been reflowed in case they were dry as well.

Edit. I also spoke to engineer in TTi's technical dept and he thought that it should be 1 ohm although, he also claimed that the resistor R51 in the schematic is not fitted on the PL310?? and on the PL320 it is a 1K job, 

You're having your money's worth of repair fun on this one, eh? 

You're not wrong there, I'm not giving up on it though, its a challenge

Did you measure the voltage and current at the terminals or trust the display? Need to work out if it’s a metering or functional problem as the two halves of the supply are separate.

If it’s just the metering replace the cd4052be in it. Those tend to die and cock the metering.

No, the voltage and current are being measured at the terminals using external meters, which also agree with the fitted displays.

Ok will do some reading when I've eaten dinner. I have seen this before in the distant past somewhere.

[tonyalbus]

Ever seen one of these ??   ..... thank you mailman.....

[mnementh]

https://www.banggood.com/50KHz-3GHz-4-Inch-Display-Antenna-Analyzer-SAA-2N-NanoVNA-V2-50KHz-3GHz-Vector-Network-Analyzer-HF-VHF-UHF-p-1738059.html

https://www.tindie.com/products/hcxqsgroup/4-nanovna-v2-plus4/

Okay guys... think I should cancel the SAA-2N and order the NanoVNA V2 plus4? The price sure has gone up; with shipping it'll cost almost as much as the other 2 pieces put together. If I spring for DHL, will actually be more... plus my butt hurts just thinking about DHL rapism on Duty & brokerage fees...   That 4X scan rate sure sounds tasty tho... *wibble*   No matter which way I go, I'll be lucky to see any of them by Christmas, so... 

mnem

You can upgrade the SAA-2N to a NanoVNA V2 Plus with 2x the scan rate. Edit: I don't really like the form factor of the NanoVNA V2 4 plus but 4G, better sensitivity and scan rate is interesting.

Hmmm... that does make the butt-Hz a little less painful.

Most of the stuff I'm working with at that mega-hurts range is native SMA, as it's RC-related; so there's a consideration. However, more than half the time, I have RP-SMA where I need SMA or vice-versa, so not like I'll ever be able to expect not to need any adapters anyways and the coupling loss with N-connectors (if they're not total shite) is usually much more predictable, and more predictably lower.

Then there's the "early adopter asshole tax"... the nice thing aboot the V2 is it's pretty well established and the major gotchas are already known. Maybe the wisest thing will be to let the SAA-2N come and let Tony take one for the team... err, wait for Tony to tell us what he thinks of the NanoVNA V2 4Plus.

I think by the time this family of gear gets to where it is actually usable in the 6GHz range, where my next RC-related band is busy, I'll probably be ready to spring another $100 on the newest model.

mnem
 

[mnementh]

I think I have (hopefully) found the culprit on the PL310 that Ice-Tea kindly sent me, the load resistor, a 10W aluminium clad jobbie which has printed on it R10, the manual states it as being 0R1, which unless I’m mistaken, means 1ohm. Looks to be perfect, no discolouration or nothing, seems to give a sensible value in circuit, whip it out and it measures .1ohms WTF?, no wonder it goes into CC mode at 190mA and voltage drops to 1.8V

0R1 = 0.1 ohms. that is correct value as it's the current sense resistor. Is that the one that hangs off the back of the front panel board?

Yes thats the one, as you can see it clearly states R10 5% on it?  The 2.2K below it has been getting hot, this has been replaced, the board has been recapped and the quad amp LM324 has also been replaced and is now in a socket. 

All joints have been reflowed in case they were dry as well.

Hmm looks ok. So it goes straight into CC mode as a short?

Check the diode across the front panel terminals isn’t short.

No it doesnt go straight into CC mode, if I only have a high impedance load such as multimeter, analogue or DMM it seems to work OK and the output volts can be adjusted upto 32V and the current display can also be set to any value in the normal way for these supplies if the load switch is OFF. Switch the output ON and the connected multimeter as well as the LED display will go upto 32V if you adjust the knobs, connect say a 15 ohm load, and no matter what you preset the current to, it goes straight into CC mode and volts drop to 1.8V.

EDIT. No the diode across the output terminals is OK.

I'm leaning towards either a hinky input on a comparator in the CC circuit, or maybe a damaged pass transistor that's breaking down and going short under load.

My test for the latter would probably be transistor substitution. Don't stop at the finals, go back up the chain too; finals may have been replaced by some other Magilla. Also, I'd look for a crowbar circuit that may have gone wonky.

mnem
 

[Specmaster]

@mnementh I have already replaced the pass transistor (a single 2N3055 on this) and also rechecked and it is good. I also thought it was the comparator in the CC circuit and this too has been replaced. Currently in the process of removing the resistors associated with the shunt and the comparator to check them open circuit rather than in circuit as they are connected to the shunt and back feeding via it so their values are being distorted by it.

[nixiefreqq]

In little-dumbfuckistan here. Nothing good. All trash. I was hoping to pick up some bits for my eldest’s Christmas present (gaming pc)

Well I managed to pick up this little number https://www.amazon.co.uk/gp/product/B07S34CS24/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 for the princely sum of £5.49 thanks to a £10 voucher that Amazon sent to me when I purchased my recent Dashcam from them, the proper price of the hose kit was £32.19, so I'm a happy bunny.

let me apologize in advance for this.......

but, methinks you got hosed. 

(anything that wiggles around on the ground like that around here gets stomped or whacked with a shovel)

[Specmaster]

I already checked the warranty, its a full 12 month one. I have had one before that split halfway along its length, after 3 years.

[PA0PBZ]

Ever seen one of these ??   ..... thank you mailman.....

It's probably the angle the photo was taken but if not it must be in a lot of pain 

[tonyalbus]

Ever seen one of these ??   ..... thank you mailman.....

It's probably the angle the photo was taken but if not it must be in a lot of pain 

Fluke has its 25... not a beauty per say... so Keithley tried that too 
but this one has 2 turning knobs ...2 is more then 1......
i just liked it, because i had never seen one before and on top of that its a Keithley

[BU508A]

This military 7603N has been sitting under bench 2 and behind the scope cart for nearly a year. When I purchased the 7904 it got kicked off the scope cart and basically forgotten. So today I pulled it out, dusted it off, and powered it up. Came up fine except the left 7A15A plug-in had noisy attenuator switch. IPA to the rescue.

I've not done much to this scope other than knock out the dents in the covers and re-paint. Checked and adjusted the +50V reference and cleaned any noisy pots/switches. Burned it in several times and called it good.

I wanted to re-cap it but it looked like getting to the PSU was going to take some major disassembly. So I left it. Well all I had to do was RTFM and discovered that the entire PSU pulls out the back after removing 6 screws. The last pix shows it partially pulled out. There's a bunch of connectors that have to be pulled so I didn't go any further. But yes, I'm going there. It's going to get a PSU re-cap. And we can debate the merits or stupidity of doing that ad nauseam but I'm convinced for long term reliability it's the right thing to do. 

In the meantime it's going up on the torture rack to get some power up time. 

Now I know, why you have chosen this colour for your living room lab: it reminds you of the nice green traces of your Tek-scopes!     

[nixiefreqq]

I already checked the warranty, its a full 12 month one. I have had one before that split halfway along its length, after 3 years.

well ok.  guess if it lasts a year you got fair value back out of it.

gotta' run.  need to prepare for a planning commission meeting that starts in a couple of hours.  not sure how they talked me into sitting on the wrong side of the table.  no matter how you vote you piss someone off.  am seriously considering requesting to not be reappointed, and then go back to attending as "the public".  a much better position for someone who enjoys pissing and moaning.

 

[SilverSolder]

In little-dumbfuckistan here. Nothing good. All trash. I was hoping to pick up some bits for my eldest’s Christmas present (gaming pc)

Well I managed to pick up this little number https://www.amazon.co.uk/gp/product/B07S34CS24/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 for the princely sum of £5.49 thanks to a £10 voucher that Amazon sent to me when I purchased my recent Dashcam from them, the proper price of the hose kit was £32.19, so I'm a happy bunny.

let me apologize in advance for this.......

but, methinks you got hosed. 

(anything that wiggles around on the ground like that around here gets stomped or whacked with a shovel)

I have a shrinkable hose on the deck/patio, to water flower pots etc. -  For this application, it has been good and is still working 6 months later.

The one weirdness with it that I've noticed, is that when you turn the water off, you have to let it run out the other end quite a while to shrink it back down to the smaller size again - but overall, I'm happy with it compared to the much bigger and bulkier normal hose that it replaced.

[factory]

I think I have (hopefully) found the culprit on the PL310 that Ice-Tea kindly sent me, the load resistor, a 10W aluminium clad jobbie which has printed on it R10, the manual states it as being 0R1, which unless I’m mistaken, means 1ohm. Looks to be perfect, no discolouration or nothing, seems to give a sensible value in circuit, whip it out and it measures .1ohms WTF?, no wonder it goes into CC mode at 190mA and voltage drops to 1.8V

0R1 means 0.1Ohm. At least to me... Just like 3V3 means 3.3V..

I suppose that is what the R10 means that is printed on it. The person in TTi I spoke to thought it was 1ohm.

Treat the "R" on those resistors as the decimal point and it makes more sense, so 10R is 10 and R10 is 0.1 .
I've got some R05 & R10 from the stuff I bought from work couple of years ago, see how the label for the R10 got corrected as it clearly confused people when it was as work.

David

[Specmaster]

In little-dumbfuckistan here. Nothing good. All trash. I was hoping to pick up some bits for my eldest’s Christmas present (gaming pc)

Well I managed to pick up this little number https://www.amazon.co.uk/gp/product/B07S34CS24/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 for the princely sum of £5.49 thanks to a £10 voucher that Amazon sent to me when I purchased my recent Dashcam from them, the proper price of the hose kit was £32.19, so I'm a happy bunny.

let me apologize in advance for this.......

but, methinks you got hosed. 

(anything that wiggles around on the ground like that around here gets stomped or whacked with a shovel)

I have a shrinkable hose on the deck/patio, to water flower pots etc. -  For this application, it has been good and is still working 6 months later.

The one weirdness with it that I've noticed, is that when you turn the water off, you have to let it run out the other end quite a while to shrink it back down to the smaller size again - but overall, I'm happy with it compared to the much bigger and bulkier normal hose that it replaced.

I also use mine for the pressure washer as well and it works well on my current 50ft hose. I expect that when the 100ft one gets here that it will suffer from lower water pressure because of its length, but I need the length, because as you already know, until you fill them with water, they are pretty short and the 50ft does not reach from hose tap at the back of the house to the front of of the house, where I need it to wash the car and also to clean our wheelie bins.

[BU508A]

@mnementh I have already replaced the pass transistor (a single 2N3055 on this) and also rechecked and it is good. I also thought it was the comparator in the CC circuit and this too has been replaced. Currently in the process of removing the resistors associated with the shunt and the comparator to check them open circuit rather than in circuit as they are connected to the shunt and back feeding via it so their values are being distorted by it.

This may come as a dumb question: but have you checked the sensing path? Something like a broken trace or a resistor with an increased value?

Btw, I've looked for the schematics of the PL-310 but I only found this (see attachement) and in the schematics I can see four pass transistors in parallel.   

Edit: Source - contains some more useful information.

[bd139]

That’s about right. The thing has different driver board and transistor complement depending on model.

[factory]

Looks like I've won another HP counter to count all the other counters  and a second digital AVO.   

David

Ah so that was you that survived my sniping attempt. I feel no guilt as I was also the first bidder.

Glad it went to someone on here, in all honesty my main purpose in bidding on it was to try and save it from the nixie clock pendejos.

If I had won, I would then have had to bid again on the Dana 5000, which went to the second bidder for £1.20...

No problem I'm okay with that, if I hadn't seen the HP counter I wouldn't have looked at the sellers other items, so it's good that someone else bid that was interested in saving it rather than parting it out. 
Hopefully the AVO will have a different fault to the other one, then I can substitute the boards to narrow down the problem area.
BTW there is no service info as far as I know and the guy that works for Megger (that posts on the UK radio forum) has only seen some adverts for it in the archive.

David

[Robert763]

@mnementh I have already replaced the pass transistor (a single 2N3055 on this) and also rechecked and it is good. I also thought it was the comparator in the CC circuit and this too has been replaced. Currently in the process of removing the resistors associated with the shunt and the comparator to check them open circuit rather than in circuit as they are connected to the shunt and back feeding via it so their values are being distorted by it.

This may come as a dumb question: but have you checked the sensing path? Something like a broken trace or a resistor with an increased value?

Btw, I've looked for the schematics of the PL-310 but I only found this (see attachement) and in the schematics I can see four pass transistors in parallel.   

Edit: Source - contains some more useful information.

Change the CD4052 mux IC(s). These can develop weird faults and inject voltages into the current sensing circuit.

[nixiefreqq]

In little-dumbfuckistan here. Nothing good. All trash. I was hoping to pick up some bits for my eldest’s Christmas present (gaming pc)

Well I managed to pick up this little number https://www.amazon.co.uk/gp/product/B07S34CS24/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 for the princely sum of £5.49 thanks to a £10 voucher that Amazon sent to me when I purchased my recent Dashcam from them, the proper price of the hose kit was £32.19, so I'm a happy bunny.

let me apologize in advance for this.......

but, methinks you got hosed. 

(anything that wiggles around on the ground like that around here gets stomped or whacked with a shovel)

I have a shrinkable hose on the deck/patio, to water flower pots etc. -  For this application, it has been good and is still working 6 months later.

The one weirdness with it that I've noticed, is that when you turn the water off, you have to let it run out the other end quite a while to shrink it back down to the smaller size again - but overall, I'm happy with it compared to the much bigger and bulkier normal hose that it replaced.

I also use mine for the pressure washer as well and it works well on my current 50ft hose. I expect that when the 100ft one gets here that it will suffer from lower water pressure because of its length, but I need the length, because as you already know, until you fill them with water, they are pretty short and the 50ft does not reach from hose tap at the back of the house to the front of of the house, where I need it to wash the car and also to clean our wheelie bins.

make sure it is not employed in a diabolical plan.