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Old 14th Oct 2018, 12:29 am   #1
Nymrod121's Avatar
Join Date: Apr 2012
Location: Worcestershire, UK.
Posts: 1,688
Default Marantz SR4200 soak testing (!)

This item formed part of a recent 'bereavement-related equipment uplift & dispersal' project.

Applying power brought it to standby, after which I selected the built-in tuner's FM band as a source. The display briefly showed 87.50 MHz, followed by the word 'PROTECT' which flashed several times, after which a relay clicked and the unit reverted to standby.

After taking the top (ventilated) cover off, I found evidence of liquid spillage ... what looked like tea or coffee had got onto two of the three major PCBs. Not good news ... so on the basis of 'nothing ventured, nothing gained' - and bearing in mind some previous conversations with Craig Sawyers regarding Tektronix procedure on overhauls - I removed the affected boards and ran them through a dishwasher cycle (no tablet/salt) then put them in a fan-assisted oven at 50℃ for two hours, then overnight in the airing cupboard to dry out.

After re-assembly, I applied power via a variac having set the Marantz' power button to 'out of standby'. I heard very faint / intermittent fizzing at the 40% variac setting, so I left it at this value (whilst listening *very* intently) for ten minutes. The effect had ceased by that time so I increased the variac setting in 5% steps every ten minutes - listening/watching all the while for any signs of distress - then left it at 100% for half an hour. Nothing further untoward was noted (phew!) so I selected 'tuner' - the display again came up showing 87.50 MHz but now it stayed on. I attached a simple wire antenna and tuned to 88.30 MHz. I advanced the volume control and there was Sutton Coldfield's Radio 2 service ...

So now after two hours of further careful testing, the audio side of things seems to be working as it should but I need to check its ability to route analogue video before putting it up for disposal.

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