Phono11 - Brain Damage

[Black Stuart]

Hi all,
two summers ago, Angela took delivery in the UK of a new PCB for Phono11, at the time I thought it strange that Mark & Phil had not charged VAT on the board.When Angela returned naturally I had a look, I saw that it said issue 1 (same as I had) so thought no more about it.

Today I dismantled all the components from the old board. Afterwards I saw that some of the cap nos. had been changed - no worries, it all looked the same and various people have mentioned cock-ups with numbering on different PCBs' from WAD.

So soldered the 3 valve bases and some of the caps, stopped to cook merluza a la plancha (wonderful with white wine). Sat down to resume work, in a very positive frame of mind - shock/horror - I now see that there are 4 more caps marked to the right of V3 & V2. They are marked C10/11 & C18/19.

Unfortunately I don't have a scanner, otherwise I would be able to show what I mean. The rest of the PCB is identical and these extra cap positions are 'extra legs from R17/18 & R27/28 which then go to ground.

There seems to be 2 ways to deal with these anomolies:

(1) wire link them.

(2) break the connection after the resistor positions.

I was hoping to be listening to my 'new' Phono11 later tonight but will wait for the wise ones to pontificate and come up with the answer.

Not best pleased of Guadix.

Black Stuart

[NickG]

I would "guess" they may be cathode resistor bipass caps, where do the ends go?

If they are across the four cathode resistors, you should be able to just ignore them and leave there positions unpopulated.

[Black Stuart]

I think that all I have to do is break the connection, otherwise the resistors are connected to ground twice - and I really don't know what that would do?

Black Stuart

[buddam]

Hi Stuart

I have the same empty spaces on my pcb. No problem. Do you want me to look at the instructions?

Adrian

[buddam]

Silly me, the instructions are right in front of me. There's a page headed 'alterations to Ph II instructions'. Due to communication error with pcb manfacturer the pcb supplied was for the mark I kit. It goes on to refer to those 4 cap positions and says 'pls ignore these and do not put anything in there place'. Enjoy your evening's listening.

Adrian

[Black Stuart]

Hi Adrian,
that would be a real help friend. I'm glad this has happend now and not a few years ago. By holding the two PCBs' to the light I can clearly see that this is the only difference and that if I ignore the cap positions, it's just one more route to earth but yes please have a look.

Black Stuart

[buddam]

And for the 3rd time. Since I think stuart likes this sort of thing. I'm just reading a book about the Brit Raj in India. Apparently when the E India Co was running amok, government letters from London took c.150 days to arrive n the 1750s. Meant the EIC could basically carry on as it wished.

Today, you can get your problem sorted in 11 mins!

Just a random thought

Adrian

[Black Stuart]

Great Adrian,
I would still like one of the 'wise ones' to come back with an answer to - 'what happens if resistors have (2) paths to ground.

Black Stuart

[buddam]

Stuart, don't miss my 2nd message posted as you were writing your reply to my 1st

[Black Stuart]

Hi Adrian & NickG,
I'm sitting here marvelling at the www.Just 20 years ago if someone had said that in a few years from now bla bla bla everyone would have said - is he out on day release.

Adrian - all empires are evil, rapacious and totally negative. What the Brits did in India was loot and if any of the indigenous people dared to do anything they were called rebels and if caught blown to pieces in front of cannons.

I applaud you reading such a book. After a few chapters may I suggest some music and a glass or two of wine, to take away the bad taste in the mouth.

If only more people would listen to good music.

Black Stuart