Author Topic: Glitchy Enertec 7150 ( Solartron / Schlumberger )  (Read 6992 times)

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Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #25 on: August 28, 2017, 10:20:42 pm »
PS Scope earth was attached to floating.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #26 on: August 31, 2017, 08:52:49 am »
Now it has been running almost non stop since my last post. What I can see while I'm not away - it does Fail 1 thingy much less with reduced resistors for optocouplers' diodes. Of course, it can be just a coincidence, "a mood". But it definitely does not go against optocouplers hypothesis.

Another question. I poked RX & TX lines further. What I can see is that TX (from the analog) signal is a bit noisy on logic side when it is 1. You can see it in the scope pics I posted before. This noisiness exceeds NAND gate (IC515C). The RX line is not noisy. The power rail is not noisy. Noisiness does not depend on which ground I use for the scope. Can the gate be noisy? Can something beyond the gate be noisy? If yes, I'd like to replace the gate, I could order parts in one order with optocouplers and filter.
 

Online 2N3055

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #27 on: August 31, 2017, 09:37:41 am »
PS Scope earth was attached to floating.

Just a reminder, you must measure against LOCAL ground. On analog board with analog board ground, on floating board, floating board ground.
Boards are isolated from each other, any current and voltage you measure will be parasitic and not good.


 
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Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #28 on: August 31, 2017, 02:10:51 pm »
Another question. I poked RX & TX lines further. What I can see is that TX (from the analog) signal is a bit noisy on logic side when it is 1. You can see it in the scope pics I posted before. This noisiness exceeds NAND gate (IC515C). The RX line is not noisy. The power rail is not noisy. Noisiness does not depend on which ground I use for the scope. Can the gate be noisy? Can something beyond the gate be noisy? If yes, I'd like to replace the gate, I could order parts in one order with optocouplers and filter.

Sorry, I have mixed up some things definitely ::) IC515 is on the input of RX line... Will recheck the noisiness later today.
 

Offline Twoflower

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #29 on: August 31, 2017, 04:58:22 pm »
Nothing related to the problem. But you might consider to make sure that the EPROM-Sticker is fixed. It would be bad if the EPROM start to lose its data.
 
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Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #30 on: August 31, 2017, 05:39:09 pm »
Nothing related to the problem. But you might consider to make sure that the EPROM-Sticker is fixed. It would be bad if the EPROM start to lose its data.

Yes, sticker is not fixed, it has curled. I tried to put it back a few times by simply pushing it down, but it is obvious the glue has died. Any recommendations about how?
 

Offline Twoflower

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #31 on: August 31, 2017, 06:03:41 pm »
I would probably use some good sticking insulation tape to replace the sticker. Eventually with a piece aluminium foil at the area of the window to be sure no UV is passing through the tape. And write the data of the sticker on the tape.

Or just use some glue to glue the sticker back on. But do not super glue as this could have some nasty side-effects to the device.

In the Old Days(TM) the 5 1/4" Floppy Discs came with a sheet of write protection stickers. Some were metallized. That would be a nice replacement.

 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #32 on: August 31, 2017, 07:15:27 pm »
In the Old Days(TM) the 5 1/4" Floppy Discs came with a sheet of write protection stickers. Some were metallized. That would be a nice replacement.

Yeah, I have used those 8) Unfortunately I have none 5 1/4" left. Just a few 3.5" :D
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #33 on: September 05, 2017, 07:07:05 pm »
Sorry, my "later today" or "tomorrow" tends to be overoptimistic...

Finally, I have poked through RX / TX lines with a scope. Two findings:
* I can confirm, that TX line 1 (or "high") is a little bit noisy "after" the optocoupler. After meaning, on logic side. Not much, but still.
* I was surprised to see data line signal :o I start to doubt if I know how to use the scope again :D

I'm attaching two pics here showing abovementioned. Anybody wants to go through all the points I poked? All the pics here https://goo.gl/photos/kj3hLedzVtKwgBf89 and the table here https://docs.google.com/spreadsheets/d/10az8yuaGpXJiQ2TQBqEZ0myO_NRuVFA45nJF3TZ0CoY/edit?usp=sharing

Another observation: I removed extra resistors and Fail 1 seem to happen more often again. No data collected, just a feeling.

Anyway, optocouplers and filter ordered.

PS I tried to buy parts from RSDelivers (for the first time). It was a big fail. They lost my order, but took the money. And told me they do not deliver (under certain circumstances, whatever that means) to Latvia after we started to investigate. So, refund it is. Ordered from DigiKey just a minute ago.

 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #34 on: September 23, 2017, 02:59:57 pm »
I got optocouplers yesterday.

UPS in my country Latvia really sucks. They did USA->LV in 3 days and then 15 days to get it to my door.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #35 on: September 23, 2017, 03:31:22 pm »
I have replaced the Shaffner filter. A few notes:
* The 1M resistor is shown on the schematic within the filter. In real life the resistor is soldered outside the filter on the contacts. Schaffner filter does not contain the resistor, neither old nor the new one.
* The old one was covered with dregs of some white matter. See pic. What was it I wonder? Does not seem like a factory made.
* Plastic legs holding the old one in place broke during dismount. Crumbled. Because of age, I assume. This is controversial to the previous finding.
* Schematic says fuses should be 100mA. Real life ones were T0.63.
* The funny thing was to discover that the old filter did not make noise :D It was the screws that hold the transformer and the logic board to the enclosure! They vibrated when unscrewed and left in the sockets.

Finally. Changing the filter does not seem to have had any effect on the meter.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #36 on: September 23, 2017, 03:38:59 pm »
I have replaced the TX line optocoupler. Could have done both, but decided to do it one by one in order to catch the guilty one.

I have left the meter on, measuring a resistance, for the test period. Previously it has never survived overnight without resetting itself. It has not done it for 3 hours while I'm writing this post.

Previously it kept changing last 2, sometimes 3 positions of the measurement. Now it stays within a few digits. This gives hope :)
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #37 on: September 23, 2017, 04:05:43 pm »
Btw, replacing the optocoupler did not eliminate small noise on the TX line I mentioned before.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #38 on: September 23, 2017, 04:10:43 pm »
I found out something new before doing abovementioned. IC305, the voltage regulator, gives -24.6V. I think it is as previously. But the IC307 in the cal mode gives -23.6V. Should be -25V, I should revisit my previous records.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #39 on: September 24, 2017, 06:14:18 pm »
It has managed ~30 hours without resetting, still going.

Changing the filter might have been a good idea. By touch it feels that power supply makes less heat now.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #40 on: September 28, 2017, 06:57:33 pm »
Ok, found it with Fail 1 again. It happened overnight between 54 and 64 hours of working.

Must be the other optocoupler.

Changed it and left the meter on. Let's see now.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #41 on: October 06, 2017, 06:42:13 pm »
8 days of non-stop without the Fail 1. To me it is pretty conclusive.

Next steps:
* I'm going to change display lighting diodes and fix some mechanic defects.
* Need to fix that sticker.
* Ordered cheap-ass GP-IB / USB interface from ebay, waiting for it to test.
* I will look for calibration service in Latvia as a last step.
 
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Online 2N3055

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #42 on: October 06, 2017, 06:52:12 pm »
 :-+

Enjoy using your "new" meter  ^-^
 
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Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #43 on: October 08, 2017, 09:24:22 am »
I have replaced LEDs, reglued the flapping aluminium plate on the front panel, cleaned it a bit.

Before and after pics.
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #44 on: October 26, 2017, 07:57:31 pm »
Just received my GPIB-USB interface. Looking forward to when I'll have time to test it.

Normal thing to do would be to install software coming with it in a virtual Windows machine, right? I'm still going to look around if there is any solution to run directly on Mac. Any suggestions?

A little rant.

I bought it off eBay from China of course. Agilent 82357B like this. Less than 100 Eur delivered including tax.

I know, risks of defective, counterfeit, no warranty, etc. I know what I'm doing. Btw, looks original enough to me. Good enough for the hobby anyway.

But then, look at the "original", e.g. here at Farnell. 700+ Eur including tax and delivery. This is crazy difference!

Ok, I could get some counterfeit sh.t. But let's assume it's not. Let's assume it is true that some factory worker got paid his/her salary partly in those devices and has to sell them to get money. That is existing practice, there btw. Is really all the development, branding, warranties, insurances, maybe even better boxing and safer transportation really worth 7-10 times product production value? Ok, this is very specific product. And who needs GPIB nowadays :D But still, this is crazy!

Peace, read Dave's The Economics Of Selling Your Hardware Project ;)
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #45 on: January 12, 2018, 08:18:51 pm »
I still have not managed to set up the GPIB...

But I'm posting because I got weird behaviour of the meter. Sometimes upon turning it on it shows OL and sets to FAIL 1 again... But after trying several times I allways have got it working and stable (for days). Wondering what could be the cause... What could cause overload on data line between floating and earthed boards?
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #46 on: January 15, 2018, 11:01:32 am »
PS One thing I have noticed. Seem that problem occurs more often when leads are attached to the device. Test leads or grounding wire. I wonder if that might point to something? External interference sensitivy changed? How?
 

Online Kleinstein

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #47 on: January 16, 2018, 04:06:11 pm »
The external leads could act as an antenna to catch up some RF crap. Modern DMMs often have a kind of common mode filter for the terminals - something like 2 or 3 turns through a ferrite ring. Even just a clamp on ferrite might have a similar effect, e.g. if the cable is to short.
 
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Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #48 on: February 04, 2018, 03:06:43 am »
Is it only RF?

I noticed that there are fluctuations of the reading when I simply put my arm close to the inputs.

Could it be mains? Would ferite rings help with 50Hz too?
 

Offline jtu

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Re: Glitchy Enertec 7150 ( Solartron / Schlumberger )
« Reply #49 on: March 08, 2018, 12:10:52 pm »
I got my ferrites delivered today. Will try, over this weekend hopefully.
 


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