Variable start - up

Konzentr8

Member
2015-08-05 11:17 pm
Can someone explain what is causing this on my Marantz PM 4200 amp please.
Picked it up on " that auction site " in mint condition and obviously looked after the only issue being the volume tracks were so dirty at anything beyond one o "clock the remote motor was incapable of turning the knob past that point, soon sorted with Deoxit and now smooth and flawless .
However there is an issue ,not really a problem i'd just like to know the cause
The amp is turned off at the wall outlet when not in use and on/off using the front panel button when used and not the remote standby function.
If i use the amp regularly for example with only a 48 hr period between cycling the power upon pushing on theres an instant click followed by the last source used led lighting up then a few seconds later another relay click and the amps good to go.
For longer periods of inactivity start - up works slightly differently , push on and nothing happens for maybe 5 seconds then a click and the power on indicator lights up a few more seconds and the source led lights followed by a second click then a third relay clicks and its ready to play.
Any advice on this would be much appreciated :)
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
The amp has a microprocessor controller which holds the last function settings in memory - as long as there is a source of charging voltage to maintain it with whatever previous use data is needed for a rapid return to previous use status. Often that voltage supply is just that in the electrolytic caps in the remote control circuit and MCU circuit and backup. These will discharge in time though and sooner as they age, losing temporary backup data. However, they need to hold data long enough for power failures, temporary disconnections etc. 48 hours may be too short but I don't know how long it should hold, as the manuals don't specify.

As long is the amplifier is powered in standby mode and the backup circuit operating, this all should work anyway and maintain the status memory etc, as you found.
 

Konzentr8

Member
2015-08-05 11:17 pm
Just discovered another issue ... left channel of the headphone output doesn't work. Suggestions? I've tried a bit of contact cleaner in the jack and the headphones themselves aren't faulty ,channel is completely dead no hiss,static or anything just silence right channel works fine.
 
The stand by circuit is completely independent from the main power circuit.
The first circuit (stand by) only powers the mcu and repective memory and IR circuitry, once turned on by pressing the button or remote a relay connects the power to the main transformer.
About your other problems the best thing to do is to get the service manual and go from there.

PS. using Deoxit on electronics is not a very good idea use only quality contact cleaner.
 

Konzentr8

Member
2015-08-05 11:17 pm
Thanks for the heads up on Deoxit RS , i always assumed that it was the best electronics cleaner especially given how much it costs!
I had a look around the net after reading your comment and theres a lot of none to happy people that wrecked their gear using it . Could have been worse i guess,as in WD 40 worse given how many self proclaimed " experts" advise its use :/
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
The headphone socket doesn't seem to switch anything on this model - you need to turn the main speakers off manually with the speaker selector switches. If both L and R speakers work correctly as a stereo pair but the headphones don't, there is damage to the socket. It may be repairable or may need replacement if, as it seems, it's a sealed assembly.

Even small children have been found "feeding" headphone sockets with pencils, sticks and rubbish. The rubbish may have been removed but the problem could remain. Whether that's the case or not, solvent cleaners are not necessary nor the best means of getting the sliding contacts in headphone sockets to work. Is it possible there's something in there that prevents full insertion?
 

Konzentr8

Member
2015-08-05 11:17 pm
The headphone socket doesn't seem to switch anything on this model - you need to turn the main speakers off manually with the speaker selector switches. If both L and R speakers work correctly as a stereo pair but the headphones don't, there is damage to the socket. It may be repairable or may need replacement if, as it seems, it's a sealed assembly.

Even small children have been found "feeding" headphone sockets with pencils, sticks and rubbish. The rubbish may have been removed but the problem could remain. Whether that's the case or not, solvent cleaners are not necessary nor the best means of getting the sliding contacts in headphone sockets to work. Is it possible there's something in there that prevents full insertion?

Thanks Ian as you say speakers A and B need defeating when using headphones . There are no issues at all with sound through speakers . I noticed since my post though that the plug itself can be inserted further than the point when it clicks until the larger main body of the plug is flush with the socket so i guess theres something broken.
Not to worry it's rare i use headphones so unless any other issues become apparent i'll let it be for now.