TTi TS3021S Power Supply Calibration Issue

Nov 26, 2009 4 Replies

Hi



I have a TTi (Thurlby Thandar) TS3021S Bench Power Supply which works fine but has a slight calibration issue with its voltage display.



According to the specifications, the voltage display should be accurate to



0.2%. Mine always reads low by aboiut 1.5%.

I suspect I can fix this by a simple adjustment of an internal trimmer resistor. But which one? There are approx. 10 on the main circuit board.



Does anybody have a service manual, circuit diagram, or any other information that would help me fix this problem?



Thanks in advance for your help.



Mark


Mark each trimmer and also measure whatever the in circuit resistance of each trimmer is, before speculative adjusting. Perhaps create a WWW repair brief for others while at it

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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fine

to

board.

repair

JIC check the "trimmer" ( in circuit) resistance with probes either way round and note if different

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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I am still hoping someone might be able to tell me which trimmer has the effect I desire. Experimenting with the trimmers is the final option and if it comes to that, I might not bother since the unit basically works as is.

But thanks for your advice. The point about measuring the resistance both ways is a good one - I might not have thought of that.

Is the meter a complete panel meter (separate item) with only a few connections or is it just a display with the A-D on the main PCB? If it is a panel meter then you could look up the model and/or check the voltage at its input connections. If it is just a display then see what chip is driving it and look up the pinout of that to see where the analogue inputs are

Geo

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