Hi Barrie, I’m fine thanks. 
As an aid to re-connection I’d stuck little labels on everything identifying what went where. 
But sod’s law determined that the gum on the labels was “dying” and as I moved things I get a cloud of confetti! So out come the handbooks to confirm which output goes to which input via which coloured lead! 
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As my previous posts have explained, I’ve got three 1970s Sony systems, but they are all in separate places (office, dining room and summer house), so the wiring is all pretty straight-forward in each individual case. I’d hate to have everything together, and have to move it, then put it all back again, because all the wiring would confuse the hell out of me.
Good luck !
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The wonderful thing is that all the sockets and plugs are on the REAR of the units so you need a mirror and torch to see them and they have to be connected in situ because the stand with them on is far too heavy to move afterwards! 
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Ooooh - rather you that me !
Good luck.
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Fortunately I was able to leave about 20 plug ends connected but that still leaves about 17 to do, the T/T, CD player, the 4 amps and the speakers.
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Now then. You folk know about hi-fi and wires and things. I know nowt and have a main system with a NAD AV716 receiver, a Technics turntable, Denon Cd etc and huge 40 year old speakers. I also have - or that shoud be had - a mini one-box DENON RCD M39DA system. It was linked to TV and a pair of Monitor Audio speakers. All was fine with 2 separate systems in the same room BUT I tried to link up the 2 speakers from my main system with parallel wiring to the Denon. I connected the 3rd speaker and all was well for about 10 mins. Then had no music (CD) but a buzzing sound. Unplugged the mains lead. Left 60+ mins and then plugged back in. The red power light is flashing rapidly and so I presume that it isn’t a case of the protection circuit kicking in due to overheating which, according to the manual, is a slower flashing cycle.
It advises that a fast flashing light = damaged unit and to contact a service engineer.
The connections were tight e.g. no shorting and the speakers are still fine.
We have opened it up and replaced the visible 1Amp fuse at the rear of the unit as it was blown.
The red light still flashes like mad.
I am not prepared to look any further as I am not qualified to do so.
Is it an almost disposable item? Do you have any ideas on resurrecting the unit and do any of you want it to play with?
I have re-jigged my kit and so will not be repairing it for myself.
Hmm, probably worth a change, the 39 was a downgrade from the 38 as far as build quality is concerned and lost the FM. Did yours have the firmware upgrade to make it work with the later iOS devices and cure the CD problems?
The one I saw a few years ago because of needing the firmware upgrade (always assuming my fractured memory for the Denon micro-box series is correct) used class D switching power amp chips, which in theory are indestructible because of all the on-chip protection systems.
However, if driven into too low a load impedance (eg two 4 Ohm speakers in parallel) then the amp can overheat/over current with quite low signal levels and go into shut-down mode. The processor driving it all learns about this and will keep the protection mode active at next switch on until the unhappy condition is removed.
Try switching it on with just the one pair of original speakers it was happy with. If it works with these, then the load was the problem.
Thanks for the info RichardFX.
Can’t get past the red power light flashing rapidly which, according to the manual = damaged unit and to contact a service engineer!
The official repair firm will look at it - they advise:
We need to inspect it first to give you an estimate for repair.
Our labour charges are £45.00ph+vat plus whatever parts we use.
You can send the unit to us by courier.
Am I right in thinking you have had speakers connected to two separate systems at the same time? If this is the case then the working amplifier is driving both the speakers and also the output stage of the other amp. This is very likely to damage one or both systems.
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Thanks for oyur response Roadie. Both systems were separate.
Then I wanted to try all 4 speakers on the Denon unit and so disconnected from the NAD amp and started to link all 4 speakers up to the Denon. Silly boy me!
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Morning all! I’m interested in a pair of these as monoblock amps.
Not a lot of money TBH. So, how would I connect them? I’m thinking using my Sony STRDH-190 AMP if possible.
Sony STRDH190.CEK 2 Channel Amplifier with Phone Input and Bluetooth - Black https://www.amazon.co.uk/dp/B07C48D98S/ref=cm_sw_r_em_apa_i_cjuiFbB4WW400
I realise this might be a waste of time (and money) but might give it a go as I’ve neglected the hi fi over the last few months 
Barrie
So, re my earlier posts about my deceased DENON RCD M39DA box - does anyone here want it to play with?
Happy to send it to anyone who may wish to tinker with it rather than leave it sitting in a corner doing nowt.
I have replaced it with a reconditioned as new unit direct from Cambridge Audio https://www.cambridgeaudio.com/gbr/en/products/hifi-and-home-cinema/one for TV work and so happy to let the Denon go to give someone some fun.
Cost to be agreed but need to cover postage and maybe a beer or two?
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Don’t want to p*ss on your chips but…
300+300 watts RMS in a home environment? Why? Many moons ago I ran a mobile disco. Biggest power output we ever used was 100+100 watts RMS. Never turned it up to 10 (or 11). Filled some very big venues. Even 100+ inebriated revellers screaming ‘Hi ho silver lining’ couldn’t drown out Jeff Beck.
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Each one is a nice loud stereo amp. So a pair of phono leads…
With a fan they might be noisy.
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Hi Paul/Richard, my chips are dry! 
I’m not sure it would ever reach those figures! I’m just interested to know how to configure them? I presume the Sony would act as a pre amp, feeding right and left speaker outputs into the monoblocks individually, then speaker output as normal from there?
Barrie
That’s how I connected my mono-blocks Barrie. Bi-amping with 4 mono-blocks is more involved.
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Hello Roger, thank you. I shall now proceed and buy all the unnecessary items!
Barrie
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Roger, just read the remainder of your post! 
got me thinking now! 
Barrie
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Just make sure your speakers can handle the additional power Barrie as you’ll be feeding them twice the original amount.
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Just pulled the trigger on a pair of the mono-blocks Also ordered some solderless RCA Phono plugs for the mono-block Input ends of the speaker cables and some IEC 13/14 colour coded socketed mains cables as I’m not sure these amps come with cables supplied
Barrie
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