Electronics Questions & Answers ← browse Q&As

Philips N2205 Cassette recorder/Player C1972 .Been in store 25 years! Voltage levels OK - Motor deck & keys work OK with new belts Very low level audio output in Play mode Heads cleaned.. All Germanium transistor circuit. All trannys check out OK as in FWD/REV in situ. Audio output transistors removed and checked for transistor action. HFE OK. What level should the head put out from a pre-recorded tape? Is it scope-able? 0.3W rated into 8ohm speaker o/p from Push-Pull AC187/8. Very faint output but no distortion. I have a small schematic but very difficult to interpret. Poorly drawn IMHO. Circuit PCB not lively to hum injection (from body) at head connections? Might be low gain stage? Might be low o/p head. But what sort of gain to expect? Ideas on how to check? I don't have an audio generator but do have a scope with time-base output? Potted down? To what level? Could it serve at say 1KHz? I was an electronics engineer way back in the daze but it's a very long time since I dealt with audio tape. Before transistors ….don't laugh! I cannot recall or otherwise get a handle on the levels to expect / look for etc. Any help gratefully accepted. Favour to a friend repair! Now I need your favour. Best rgds, BerryG

Hi Berry, yes, valves or vacuum tubes in my day too. The simple answer seems to be about a millivolt, more complex answers are given in http://aes-media.org/historical/pdf/morrison_stl-manual.pdf and http://www.jrfmagnetics.com/Nortronics_pro/nortronics_silver/Nortronics_silver_catalog.pdf The signal should be visible on a decent scope.

ps - service manual file:///home/chronos/u-b4967fa0dbdd63c881ca2cf936001741dbfe228e/Downloads/hfe_philips_n2205_service_de.pdf with good quality schematic.

Hello Mike, A million thankyou's for that quick response. Sometimes I feel so alone! It brings on a strange loss of confidence to realise how much one has forgotten. Then I also have to recognise that such items became almost unserviceable throw-away units. Thankyou for the information and the links. In the meantime I have found what I believe to be a confounding issue with intermittent switches! Hey ho on we go! Rgds, Berry

Proprietary switch cleaner is best, but a drop of petrol followed by some three in one oil did the job for me. Thanks for the nostalgia. mike