New build WDPhono 3 Questions; heater voltage/LED

[bob orbell]

I think we should now look at the PSU, it points to the voltage regulator or the two resistors that form the potential divider, more pictures please and bigger if possible, again, please solder both sides of the board if you don't it will end up breaking the tracks as you push the valves in and a new board will be in order. Andy, I think the heater wiring is correct as are all the components, but to be honest the build could be better, please don't take offence Graham it is just that I am very fussy and try to aim at perfection. BOB

[John Caswell]

Guys we are trying to, fix several different things at once so confusion will arise.
The first thing to do is get the heater supply correct in the PSU without anything connected.
I suspect that there is something wrong with the wiring around the regulator itself.
The fact that the heater voltage reads 6.5v without any valve plugged in then drops the moment a valve is plugged in, suggests to me the the regulator is wired incorrectly.
The PSU needs to be checked without the phono3 connected first.

John

[G Willis]

Hi All,

Thanks for all your inputs...

(1) I will solder the bases in from both sides for mechanical strength when removing and inserting the valves as suggested.

(2) No offence taken Bob, the build is not great. Its my first one and I admit I have struggled with some of it not having used a soldering iron for 30 years. In particular I found it difficult to mount the regulator. Also any suggestions on how to solder 4 wires to a single pin would be gratefully received.

(3) Photos of the power supply to follow. Again not great as I mixed up the heater and HT diodes and had to replace them all. The result is not pretty I'm afraid.

Regards, Graham

[G Willis]

There is a very small photo size limit on this bulletin, I've had to resize radically.

[G Willis]

Not good soldering on the regulator. I will redo that.

[bob orbell]

OK Graham, it looks like you have omitted, or fitted the small round black insulator from the regulator chip's heat sink upside down, the larger part should be upper most, the regulator heat sink must be compleatly insulated electrically from the chassis, and it should be quite tight to allow heat transfer, also, not relevant to to the heater problem, but all the large resistors should be well clear of the PCB because they will get quite hot and damage the board, do run over your soldering again with the iron and some flux to remove the blobs and allow the solder to run in the joint's, you are not using enough flux, do not just rely on the flux in the solder. To check the regulator before you start, see if the is any resistance between the earth post and the regulator heat sink, as I have said there should be open circuit. BOB

[John Caswell]

On a further point, you do not need to solder both sides of the component on the current WD PCBs as they are Plated Through Hole (PTH) types, molten solder will "wick through" and make a very good mechanical joint.
You do not need to bend component leads more than 10º, just enough to hold the component in place whilst you solder it in. As Bob says heat producing components ie large voltage dropping resistors should ideally be spaced off the PCB 10-20mm to avoid "cooking" the PCB and solder joints, PTFE sleeving useful here.
When removing multi pinned items, ie valve bases, bite the bullet and cut the pins then remove them one by one, clean up the holes and fit a new item. It will be cheaper both in time and temper than a new PCB.
When fitting a new PCB valve base, solder in just two pins diametrically opposite, check it is seated squarely then solder the rest. If you are paranoid about your valves and spacing you can always fit an old valve to the socket to get the pin alignment correct.
I have to admit even with tagstrip/tagboard construction I have never wrapped wires around tags as I do not think it necessary, but then I have been doing it a long time

John

John

[Greg.]

Yes, indeed. Furthermore, I’ve never found the need to use additional flux except when I fitted a new central heating system

[Phil Y]

I agree Greg, I have never needed liquid flux with proper (leaded) solder.
I have used it many times with lead free solder (like soldering with toothpaste) but no right minded person would ever use that filthy muck at home.

Phil.

[colin.hepburn]

I use flux all the time with lead solder.
I fine it a breezy to work with nice fast clean joints with less heat great for desoldring too cleanes off easy to with isp it can be a bit sticky thou don’t spill it I use this stuff see image