I've recently come across three pieces of vintage test equipment; a Precision brand signal tracer, a Heathkit audio analyzer and a Radiometer Copenhaguen model HO-32 beat frequency oscillator. Here are some pics; the ones marked "small" are 60KB on average and the others are roughly 600KB and highly detailed: http://nazas.autonoma.edu.co/heathkit_audioanalyzer-small.jpg http://nazas.autonoma.edu.co/heathkit_audioanalyzer.jpg http://nazas.autonoma.edu.co/heathkit_audioanalyzer_bottom-small.jpg http://nazas.autonoma.edu.co/heathkit_audioanalyzer_bottom.jpg http://nazas.autonoma.edu.co/heathkit_audioanalyzer_top-small.jpg http://nazas.autonoma.edu.co/heathkit_audioanalyzer_top.jpg http://nazas.autonoma.edu.co/precision_tracer_model_st-22.jpg http://nazas.autonoma.edu.co/precision_tracer_model_st-22_small.jpg http://nazas.autonoma.edu.co/radiometer_copenhagen_ho32_BFO-small.jpg http://nazas.autonoma.edu.co/radiometer_copenhagen_ho32_BFO.jpg The Heathkit audio analyzer passed visual inspection (pretty clean and caps looked ok) and I powered it up. It seems to work. The Precision signal tracer is not working; somebody took off the rectifier tube/valve and soldered a couple of diodes; I suspect that at least one filament is open (pins 3 and 4, right? It's been a long time since I last worked with tubes). I certainly want to restore it; I like the "magic eye" indicator tube. The Radiometer Copenhagen gear I haven't powered up because several large electrolitic caps show signs of deterioration. The construction of this last device is outstanding in terms of the quality of the components. The Heathkit is pretty good too; not so the Precision signal tracer. Now the question: can you please take a look and see if 1) you have docs for any of these, 2) might guess what the operating procedures are and what the controls and connectors are for? Some I can guess, others I don't know. regards, carlos. -------------------------------------------------------------- Carlos E. Murillo-Sanchez carlos_murillo(a)nospammers.ieee.org