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SteveCG · 17th Jun 2019, 11:05 am

The LM723 order finally turned up.

I fitted one into the IC holder and gently wound the mains voltage up until the unit was just working. This was to minimize any faults taking out the new IC.

I found the unit worked except that the IC holder was one of those cheap ones that does not take lead solder well and that if I gently pressed on pin 6 on the underside of the ic holder with an insulated prod the output voltage went up.

Since because of its cramped construction changing the holder was not really an option, I resoldered all the ic holder pins and really checked that prodding did not produce a voltage change.

According to a DMM the maximum output voltage was about 13 Volts - not the claimed 15 - but 13 seemed quite likely from a study of the LM723's application notes.

The voltage stability under varying load is good.

Finally I reset the analogue meter voltage and current presets to agree with my Fluke DMM. These presets were not the best either - a drop of Servisol 10 helped.

17th Jun 2019, 11:05 am	#11
SteveCG Nonode Join Date: Jun 2009 Location: Herefordshire, UK. Posts: 2,495	Re: Raycom Ltd Bench PSU CB524 The LM723 order finally turned up. I fitted one into the IC holder and gently wound the mains voltage up until the unit was just working. This was to minimize any faults taking out the new IC. I found the unit worked except that the IC holder was one of those cheap ones that does not take lead solder well and that if I gently pressed on pin 6 on the underside of the ic holder with an insulated prod the output voltage went up. Since because of its cramped construction changing the holder was not really an option, I resoldered all the ic holder pins and really checked that prodding did not produce a voltage change. According to a DMM the maximum output voltage was about 13 Volts - not the claimed 15 - but 13 seemed quite likely from a study of the LM723's application notes. The voltage stability under varying load is good. Finally I reset the analogue meter voltage and current presets to agree with my Fluke DMM. These presets were not the best either - a drop of Servisol 10 helped.