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Azur Electronics

January 2008

The HP 8601A Generator Sweeper arrived in a fairly messy state. The frequency knob was broken and the gear-driven counter would only count up, not down. The range knob and switch were missing. There were a few dents in the case and the usual collection of old labels.

Front and rear views
The 8601A is fairly straightforward to strip down by unscrewing the covers and side extrusions.

Removing the front panel assembly is a little more difficult. Care must be taken with the black panel in front of the mechanical frequency counter. This has 2 small fibre optic "light pipes" glued to it. These are routed to 2 small indicator lamps which indicate the high or low frequency range. A bit of HP over-engineering, just to indicate the decimal point!

The Meter has 2 wires to be unsoldered and 1 other wire (WH/YL/BL 50Hz Line) needs to be cut. The rest of the wiring loom unplugs from the top assemblies, and the edge connector unplugs from the pcb underneath.

May 2008

Removing various knobs and nuts allows the escutcheon to be separated from the front panel. The missing range switch had been pushed right through the front panel and was jamming the gears, so just required refixing.

Everything required a good clean-up and a few dents straightening out before re-assembly. The sharp edges were sanded-off the end of the broken frequency knob.

The HP Manual downloaded was printed in 1971 and for serial numbers up to 969. The serial number for this unit was much later, circa 1984, so there are several differences to the assemblies.

A thorough inspection of the 8601A did not reveal any other obvious problems.

Powering up on a Variac was ok and the dc voltages from the power supply unit were correct. CAUTION: There are mains voltages exposed when the case covers are removed.

A quick check of RF and VTO outputs showed that they were ok across the frequency range. The more detailed Operators Check and some of the Performance Tests were completed satisfactorily.