Have you tried other sources? CDV springs to mind.Or possibly Tape 2 (TP2) My recollection of green displays comes from the very pair I saw when they were introduced. The display was very different from the Mk3. However I see very few Mk1s so am perfectly happy to accept that Mark 1s had an orange display!

They are red LEDs. The manual is on site.

Mark 2 are distinctly orange - much the same as Beolab 3000s. Mark 3s are completely different and are green dot matrix as you say. Best of luck with the refoaming.

And one of the listing.

One bit of diagram - afraid no picture of circuit board - they are no longer provided - just the grid.

I have the correct service manual and the diode ID17 is listed as 8300053 (B&O part number - not useful!) ZPD 15V 5% BZX 79 15V It is in the automatic lowering circuit. In the earlier model, ID17 is not individually given a type - listed as IN4148 SFD184 I do have the circuit diagram if needed. Think I have found some for sale here .

Sound like Mk1s then, though all the ones I have seen had green LED displays. I would replace the mid range units - they are not that expensive though clearly this is made up for by the number of them. You then know you have brand new units with no faults.

Should not make any difference. It sounds as though the Pentas are not recognising the signal from the Powerlink sockets. I suggest it may be the switching signal. Are the Powerlink cables fully wired ones?

And obviously, have all the units switched off when connecting them up. The old adage of switching it all off and then back again is never wasted!

Agree. Sounds as if something is over riding the picture. The curtains, unlike those on the AV9000, are electronic though and I suppose this circuit might be faulty.