Problem with Digimess RLC 100

[tron9000]

Basically its going dolally-tap!

first off the clips on the leads had a broken solder joint, fixed that and now it actually measures components - but they are the wrong values.

it seems to think a 10uH inductor is -2.5uH, a 2.2OHM resistor is -2.5OHMS and constantly says a 100nF cap is out of range.

Needs a recal or has it gone cuckoo?

[airlomba]

Hello tron9000,

I have in hands a RLC100 that works OK except for the C measurement part that also shows me an "Out of range" Message as soon as I connect a capacitor to its leads.

The leads are fine, I checked them on another RLC100 I can access.

Did you manage to solve your issue? Do you have the service manual or some schematics of this instrument?

Sorry I can't be of any help so far.

Best regards,
Emmanuel.

[Fraser]

Please be aware that Digimess are a company that will supply a full service manual and schematics. Sadly it costs around £40 though.

For a unit that starts behaving strange, always check the supply rails for noise and ripple. It causes havoc with the processor.

Fraser

[airlomba]

Hi Fraser,

Thank you for your answer.
I contacted Digimess and they replied very fast. Your are right, they sell the service manual in a DOC format file for GBP 40.

Meanwhile, I found that the capacitor-meter still "works" but only for capacitors with values below 200 nF. Above this value it just shows the "Out of Range" message, despite the instrument being rated to measure up to 1.999 mF (milliFarad).

Inside each instrument (I have access to several units), there is an OpAmp (AD845) that is the only IC mounted on a socket. I had to exchange OpAmps between two units, just to check, but no luck, the OpAmp of the faulty instrument is good.

I guess that either I'll have to reverse engineer the schematics of part of the unit or buy the service manual.

I'll keep this topic updated if I get some evolution (in either direction).

Best regards,
Emmanuel.

[Fraser]

I have baulked at the service manual cost for my Frequency Counter, PSU and Function Generator as well. I happily pay TTi their standard £25 'no profit' price for service manuals but £40 falls into the 'do I really need it?' category. I suppose a co-operative of LCR meter owners could share the cost ?

The Digimess service manuals usually contain useful service information in addition to schematics,  such as passwords to calibration routines and fault finding charts etc. For the relatively expensive LCR meter, the manual could be worth £40 as it will save you much valuable time and is useful for the future.

Fraser

[sorenkir]

On my RLC 100 version 2.01, service password is 640429 (decoded from firmware ROM). It seems to give access to some adjustment functions.
HTH.
Michel.

[airlomba]

On my RLC 100 version 2.01, service password is 640429 (decoded from firmware ROM). It seems to give access to some adjustment functions.
HTH.
Michel.

Hello Michel,

Same firmware version here, and the password you provided is valid for my instrument too. But without a service manual I am not sure of what I am looking at. However I noticed that in the Service menu, one can read the values of the internal trimmers. It seems it provides a default value between rectangular brackets and the real-time reading. This was confirmed by rotating one of the trimmers.

I'll keep in touch.

Best regards,
Emmanuel.