PWS Micropulse 150 TIG welder

[LesWoollam]

I have an old (1985 vintage) PWS Micropulse 150 TIG welder manufactured by Precision Systems Ltd of Cambridge UK. Unfortunately it has recently 'died'. The gas works as it should and you can hear the HF 'clicking' but no welding spark. The voltage meter reads hard over at 30+ volts. Any ideas, or does anyone have any literature (schematics etc.) on this unit?

 

[hotrodder]

HF spark gaps? Talked about briefly here... http://www.millerwelds.com/resources/articles/Tips-to-Improve-TIG-Arc-Starts/
Does it offer a 'lift start' setting? Dunno about microtigs but pretty much universal on 'normal' TIGs for those times when HF is a no, no due to sensitive equipment in the area etc. That'd at least confirm problems are isolated to the HF side

 

[LesWoollam]

Many thanks. Tried the lift start but it's exactly the same, still feels like no amps at tungsten, pedal unresponsive other than to switch on HF and gas. There is a very weak flame maybe hot enough to melt a coke can but thats it! The HF continues to pulse - I suppose waiting for the amps to kick in. Help. . .