Author Topic: Repair of Solartron 7081 SN#718  (Read 11886 times)

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Offline meandeev

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Re: Repair of Solartron 7081 SN#718
« Reply #100 on: May 18, 2020, 03:23:08 pm »
Hello branadic,

which LT posts did you use?

 

Offline branadic

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Re: Repair of Solartron 7081 SN#718
« Reply #101 on: May 18, 2020, 05:26:37 pm »
Low Thermal Model 2758 also available at wekomm for the S7081 and Pomona 3770 + 3760 (blue, guard only) for S7061.

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« Last Edit: June 11, 2020, 08:32:34 am by branadic »
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Offline Kosmic

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Re: Repair of Solartron 7081 SN#718
« Reply #102 on: June 11, 2020, 02:16:37 am »
I did a quick print in PLA to test the new front panel. Was done really quickly, so this is not the final quality (and color ...). I will fix the horizontal lines and labels in my next version.

Look like my binding posts are similar to LT post. I had to increase the size of the hole though since the screw part on mine is bigger. Overall i'm pretty happy. Thanks again Branadic!



 

Offline tggzzz

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Re: Repair of Solartron 7081 SN#718
« Reply #103 on: June 11, 2020, 06:54:36 am »
I did a quick print in PLA to test the new front panel. Was done really quickly, so this is not the final quality (and color ...).

I presume you have a daughter, and that you are trying to help her realise that your toys and experience might be valuable to her :)

I must admit, for something as precious as a 7081, once I was satisfied with the design I'd probably want to get this professionally made. Nylon isn't a bad material, being slightly flexible, but a black SLA would be good too.

Are the PLA/ABS materials hygroscopic, or would gaps between layers trap gunk over the years? If so they wouldn't be good w.r.t. high impedance or high voltage.

There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline Kosmic

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Re: Repair of Solartron 7081 SN#718
« Reply #104 on: June 11, 2020, 02:00:57 pm »
I did a quick print in PLA to test the new front panel. Was done really quickly, so this is not the final quality (and color ...).

I presume you have a daughter, and that you are trying to help her realise that your toys and experience might be valuable to her :)

Yep got 2 daughters  :)

I must admit, for something as precious as a 7081, once I was satisfied with the design I'd probably want to get this professionally made. Nylon isn't a bad material, being slightly flexible, but a black SLA would be good too.

Are the PLA/ABS materials hygroscopic, or would gaps between layers trap gunk over the years? If so they wouldn't be good w.r.t. high impedance or high voltage.

My plan is to finalise the form factor and then try different materials (PETG, ABS, PLA). I'm also planning to use paint or epoxy to seal the material. I have a high resistance meter so I should be able to do some interesting tests.
 

Offline branadic

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Re: Repair of Solartron 7081 SN#718
« Reply #105 on: June 17, 2021, 05:43:27 pm »
For some reason my unit started getting Alzheimer, throwing out "NVM Fail". The maintenance manual mentiones to replace the ER3400 by a new one: "NVM FAIL - This could indicate a failure of the NVM circuitry, or of IC804. A spare NVM would prove useful here." which I did, but that didn't change something. I wonder if someone ever had a similar problem and can share experience. I guess it's time to check some power rails.

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Offline branadic

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Re: Repair of Solartron 7081 SN#718
« Reply #106 on: July 10, 2021, 10:11:06 am »
So I think I'm a step further. Turns out replacing the NVRAM requires full calibration. Actually it's a full adjustment instead. Unfortunately, I don't have any AC calibrator or signal source to complete the calibration, which is essential to at least save the calibration constants to the NVRAM.
What's even more weird is, that there is a possibility to dump the calibration constants, which I did in the past, but there seems to be no way of playing them back to the device. I wonder what this CALIBRATE, DUMP option is then for, if you need to fully adjust it in any case. So unless there is no hidden "play your dumped calibration constant back to the unit" command, I guess I need someone helping me out to perform the whole calibration process at once :(

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Offline perdrix

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Re: Repair of Solartron 7081 SN#718
« Reply #107 on: July 10, 2021, 11:18:00 am »
If you happen to be in the UK with your meter, I have a Datron 4808 calibrator :)

PS does anyone have a spare earthy logic board for one of these - I have a bad one I have totally failed to fix :(

David
 

Offline MiDi

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Re: Repair of Solartron 7081 SN#718
« Reply #108 on: July 10, 2021, 03:45:44 pm »
The NVRAM saves the cal constants twice, if only one version is faulty, you can rewrite it by command CALIBRATE, REFRESH.
I guess you know that and the ER3400 had no correct version any more?
You have read the cal constants over the interface, is this a correct cal before the unit got Alzheimer?

If you can read the NVRAM with external programmer, it may be possible to reconstruct a correct cal and write it to a new NVRAM/EEPROM.
Maybe not that easy to find a compatible chip that is supported by programmers today or even make a custom config file for those.

You could ask Adrian, he should be able to calibrate/adjust this units.
« Last Edit: July 10, 2021, 03:53:31 pm by MiDi »
 

Offline branadic

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Re: Repair of Solartron 7081 SN#718
« Reply #109 on: July 10, 2021, 06:08:35 pm »
@ David,

I'm sailing under the german flag ;)

@ MiDi

unfortunately I only have a TL866 II, which seems to not support this ER3400 chippy :(
Already in contact with Adrian, but thanks for the hint anyway.

-branadic-
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Offline picburner

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Re: Repair of Solartron 7081 SN#718
« Reply #110 on: July 10, 2021, 06:55:27 pm »
No commercial programmer, not even my Data I/O 3980, is able to program an EAROM ER3400.
Look what I had to do to be able to program it.
 
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