Rega Elicit mk1 volume/channel issues

Jonrem

Member
2020-02-09 12:44 pm
My Rega Elicit (MK1) clamshell amp has been acting up poorly the last few months with issues suddenly turning to the worse the last couple of days. Problem is intermittent with one channel falling out occationally. It used to be the right channel and often only after the amp had warmed up properly. On such occations a polite but firm strike with the fist on top of the amp would usually make it behave normally again. The last few weeks however the amp has behaved nicely - until a couple of days ago when the left channel all of a sudden started to distort heavily - to such an extent that I had to inspect more closely my newly installed turntable cart. I then found that the distortion was present also when playing digital files through the aux channel - hence no issue with the turntable then. Now the left channel is more or less dead. If I turn the volume control fast around I may force the left channel into action again for a brief moment, but it will then quite quickly fall out again. I had the master board resolded a few years ago, but I realise that other parts like transistors and capacitators might be deteriorating by now (as the amp is closing in on its 30th anniversary). But intuition tells me that the problem at hand might be related to either the volume potentiometer or possibly the speaker relayes falling apart. Is there anyone out there with actual tech insight into this issue who might point me in the right direction here? Kind regards
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
It's time to check for switching faults, coupling capacitors and more serious problems such as transistor failures. Perhaps that reflow soldering didn't go far enough either. Start simple - just use a multimeter to check for any DC present at the output terminals. Remove the speakers and turn the volume right down or remove the signal input connection, then power on. The DC voltage across the terminals should quickly settle to less than +/- 50mV. That's a very small level. If it's higher, there may be a real problem.

Note that the Elicit models have lots of signal switching relays unlike many other amplifiers. A speaker relay should also engage the output connection (with an audible click) a few seconds after turning on, like most other amplifiers. Does this occur consistently?
 
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Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
I should have suggested that you can download a set of schematics after registering here: Rega Elicit - Manual - Stereo Integrated Amplifier - HiFi Engine. You may have difficulty understanding schematics but you can always share them with others who can assist.

Further to signal relays, these are 5V types, originally designed for reliability in telephony systems and are sealed, probably gold plated contact type but they don't last forever - meaning that replacement of those frequently in use could be a good idea. Use the schematic to identify them and try tapping the particular relay(s) in use with an insulated screwdiver hanldle to see if that affects the problem.

Signal relays seem like a good idea but somehow they have never been popular and some types, such as reed relays, can just spell trouble. If you have the cash, I would replace these with similar 5V DPDT signal relays whether or not they were clearly a problem.
 
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Jonrem

Member
2020-02-09 12:44 pm
Thanks a lot Ian. I will check for DC voltage on the output terminals. As for the relays I don't think I have the required equipement, save for a plain multi meter to check these for function, so for this I will have to hand it in to a service shop I guess. Other than that the relay which engages the output connection seems to be working all right, as it clicks like it always has when I turn the power on.
So basically then to sum it up, it could be any of the output relays or any other relay or a failing capacitor or transistor, but changing the relays - prefeably to 5v dpdt types would be a smart thing to do anyhow...?
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
That amount of DC offset and variation at the output is no problem. As encouragement, testing the signal relays (i.e. the miniature input selector relays - not the power output relay) by tapping them should not be difficult or cost anything, other than needing a solid rod, or piece of insulating material such as even a knife handle, screwdiver handle, large pen etc. They are located on the Relay PCB which is mounted vertically on the main PCB and facing the rear input sockets.

Simply listen to audio playing through them as you test each one, as selected by the input switch. Sharply tapping the plastic case of the relay(s) but take care so as not to touch any unsafe voltages, cause damage etc.

The plan is to listen for any crackle or burst of noise when you tap the plastic relay case. If there is nothing whilst a signal is flowing through that particular relay, it is most likely fine - assuming you correctly identified it as the one selected as the input. They are dual relays so both channels switch simultaneously and it doesn't matter which channel has the problem as you would be treating both.

That is a simple and easy task - there are electronic CMOS signal switches in there too. They would require some expertise to test but it may be cheaper for a professional repairer to just replace them if suspect.
 
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Jonrem

Member
2020-02-09 12:44 pm
I put it back together after not finding anything out of the ordinary by a casual look, other than one of the core transformers had come a bit loose. I tightened it down properly again, but I suppose that would not make much of a difference as it is otherwise solidly grounded to the chassis by a wire. But as I have experienced so often before with electronics - once I've streched the required miles and pulled the equipment out of its location and opened it, the problems I previously experienced disappear like moist under the sun. So now it sounds as good as it ever did - although perhaps the volume is a tad unevenly distributed with one channel sounding slightly (perhaps) louder than the other - but this could also very easily be me looking for problems that actually might not even be there... Anyways I suspect previous problems won't be absent for very long, so it is good to know what to look for and where to go from here. So again, thanks a lot!
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
Your initial problem seemed a bit more obvious if one channel dropped out occasionally. It is most likely a physical contact issue (i.e. a relay, connector plug or the soldering to a front panel control, switch, daughter board mounted on the PCB etc. where movement of the case and controls (that clamshell isn't the most rigid of housings) is transferred to the PCBs, wiring and connectors.

When you stress an assembly by taking it apart and prodding a few things, tightening screws, refitting interconnections and the like, its quite likely you will discover dirty, weak or even corroded contacts and yes, if you prod these about it may well come to life again and work fine - until the root causes like corrosion, loose contacts or bad solder joints simply fall back into their former condition.

Old, as in more than 15 years old commercial audio products become increasingly suspect and unless you practice proper routine maintenance or pay someone to do it professionally, there will almost certainly be problems with mechanical switches and contacts where either lack of use allows corrosion to set in or prolonged use causes wear, stress cracks etc.

As you find, we can pull something down for inspection, only to find that problems have disappeared due the movement of the assembly. That's why we can't assume all is OK if the problem just disappears. A pro. repairer has that issue all the time. Jobs bounce on them and they get a bad rep. if they don't carry out preventative maintenance steps as well as track down specific problems. It's expensive on labour and replacement parts which may not actually be essential but if you elect to do maintenance yourself, better read all you can find about the model and its component parts to make sure you know what the problems are likely to be beforehand.