Valhalla 2701C DC calibrator

The front panel

The front panel

Repairing calibrators is always fun. This one had no output. It has the 120mA option but that was dead too. The fuse was blown, a logic-opto and a p-channel jfet were dead. The IC caps had a very high leakage current.  The jfet was obsolete but I found a usable substitute. The only problem was the sot23 package. That was easy solved because it fitted on the through hole pads.

The reference is a LM299 made by LTC. The 120mA option is located after the pushbutton section.

The 120mA option

The 120mA option and LM299

 

The inside

The inside

Bottom view with some modes

Bottom view with some modes

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