I understand your position - and I admire people wanting to have a go at fixing things themselves, but I am
not sure if I understand the working methods used here - or the advice you were given.
My recommendation would always be to diagnose any present faults before eventually upgrading and replacing a lot of things that "could potentially make the thing even better".
There's a huge risk that you will introduce new faults which could make it much more difficult to diagnose the original problem.
Faults due to "natural" causes are always far easier to diagnose than it is to take as much as a qualified guess at what could possibly have
gone wrong when somebody fiddled with everything and/or replaced a lot of things more or less on sight.

Repair first. Do upgrades later. And when doing upgrades, do only a few things at a time and then test. That'd make eventual fault-finding
so much easier. Particularly for a "kitchen-table" repairer. 

Beocord 5000 has a number of standard faults, all of which are fairly easy to remedy.
I have lost count of the ones I have repaired - but it's a three-digit number.
They are superb decks and they rarely need a lot of components replaced. I certainly never had to replace more than about a handful - and that being only in severe cases.

Voltage readings depend greatly upon the instrument you use and the circuit you measure in. Keep in mind, that the instrument takes
place as a part of the circuit when connected, so its internal impedance and capacitance etc. affects the circuit - and the reading. 
Resistors and voltages a bit out of spec will typically not cause a major malfunction, whereas shorted transistors definitely could.
Voltages a bit off is quite common (ref. to the explanation above) - but shorted transistors are not common sights in Beocord 5000.
They shorted for a reason. That reason will have to be found and corrected before replacing the shorted transistors and powering up again.

Anyway, I suggest you turn to the experts who gave you the initial advice and let them guide you on.
And do let us know how it goes.

In the mean time, will you let us know what the initial problem was? 

Martin

Thanks Martin for your reply, as wrote on first post my Beocord had display with no sign of life,  so thought about a PSU problem 

During these weeks checked and replaced  BD533/534 and LM317, all shorted, 10 ohm fusible resistor, browning, and the 2 ribbon cables.

On connectors P6  and P7, power up on 230V , I've tensions that exceeded more or less of 30% as describe on SM, for this reason I try to power up on 125V.

Have a nice Friday.

MArco

Sounds like a severe case of overvoltage.
Lightning strike perhaps.

With all those components burned - also blackened cables! - I'm afraid that it's safe to say that this Beocord will never
run again unless all internals are replaced (in one go).
Too many semiconductors will be bad and many more will have internal scars that will show up sooner or later, so even if you find
and replace all bad components now, you'll face problems again before long.

If cables have blackened, some of the copper traces on the circuit boards will also have experienced overloads (that's where the cables come from and go to).
In my opinion this Beocord has reached a dead end.
I suggest you grab another one.
They are plentyful, so choose one with "only" standard faults.
That would also be the cheaper solution.
Finding f.e. a replacement processor would not be easy and there's a good chance it could only come from a donor Beocord anyways.

If your cabinet is nice, you could find another with a bad cabinet to make it even cheaper.

Martin

Hello Martin

yes you are probably right about lightning strike, I would just check copper traces on the circuit boards after all  my cabinet is nice, so search another one with a bad cabinet.

Have a nice Monday

MArco

Now we know that your machine has suffered some sort of flashover or voltage surge,it seems pointless to struggle on trying to fault find.

As Martin suggests,there will be damage in all sorts of places,and although you are keen to fault find,it will be an interminable job!!!

As the machine is in good condition otherwise,and you have repaired the power supply,why not swap out the main board?

I have a spare one that I think is working.It will certainly be better then the one you have?

You are welcome to it gratis if you'd like to have it?

Just reimburse me for postage?

Regards,

Nick

And the Dolby board.
And the display board.

Martin 

Hello Nick

thank you for your offer, frankly think problem are still located in power supply board, let me time to check  pcb another time and after I'll be glad to pay postage for motherboard.

Have a nice day

MArco

Hello Nick

thank you for your offer, frankly think problem are still located in power supply board, let me time to check  pcb another time and after I'll be glad to pay postage for motherboard.

Have a nice day

MArco

Hello 

I I want to publicly thank Nick for providing me spares pcb for my Beocord that now return to be a functioning deck, all function play well, still remain minor issues that may solve in next days.

Many thanks again Nick all the best

MArco