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-   -   New build WDPhono 3 Questions; heater voltage/LED (http://www.world-designs.co.uk/forum/showthread.php?t=7729)

G Willis 10th February 2019 07:30 PM

New build WDPhono 3 Questions; heater voltage/LED
 
Hi,

I have just completed a new build of the PSU3 and WDPhono3. This is my first build so I am new to this.

In testing the voltages are all measuring within the stated 15% except the heater voltages which seem off.

I measure a healthy 6.5v across the heater pins (1&4) on the power cable from the PSU. However when plugged into to the phono stage the voltage across HTR+ and HTR- is a fairly anaemic 4,9v. More, the HTR+ to ground reads 54v rather than the specified 49v, and for HTR-/Gnd measures 49v rather than 43v.

Does this indicate a problem?

Also the L.E.D does not light. The instructions say to wire between LED1 and LED2 but LED1 does not seem to go anywhere. I would like to get some confirmation of where the L.E.D should go as its not shown on the circuit diagram. As the LED uses the heater circuit maybe my problems are connected.

Any help gratefully appreciated.

Graham

bikerhifinut 10th February 2019 11:45 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Ok first things first,
remove the PCB in Phono3 and examine your wiring against the images in the instructions, the heaters should be wired in parallel i.e all pin 9 wires connected together and all pin 4+5 wires connected together and thence the heater wires from LH Valve back to the correct pins on the socket i.e pins 1 and 4, polarity is important here to ensure the LED lights up when power applied. Check the dropper resistor and wiring to the indicator LED is correctly wired to the heater pins on V4. It may be theres a short circuit or dry joint here. If all checks out against the diagrams then proceed to the next stage. It doesnt hurt at this point to check continuity with your multimeter.
I don't need to remind you thatthe above checks should be done with the unit disconnected from pSu and mains.

Now then if all checks out visually:

First measure the voltage available at the output of the PSU3, don't worry that the HT will be high without any load on it. Also measure the voltage between the heater - and ground, this should be in the 50V ball park, as per the instructions. the + obviously will be 6.3V higher and 6.3V across pins 1 and 4 of the power plugs. Depending on your home mains voltage it can vary a bit which is why you allow 15% either way. The 6.3V DC will not as its regulated in PSU3.
Assuming that all checks out then plug the umbilical cable into PSU3, then measure the voltages again at the pins of the female plug without having it plugged in to PHono3, this will eleiminate any possibility of a wiring fault in the power cable.
Then plug it in to Phono3 if all measures ok.
WITHOUT any valves plugged in, measure the voltages at the 4 pin socket. We are interested in the voltages around the heaters for now. so you should get 6.3V give or take (you measured 6.5, thats fine) across pin 9 and 4+5 on each valve base.
its worth checking the voltage from heater- to earth but that shouldnt change.
If you are getting this voltage drop without valves plugged in, theres still a wiring fault. My instinct would be to disconnect the LED wiring from the baord and see if that makes a difference.
then plug the valves in, I'd do it one at a time, you won't harm them doing this, and measure the heater volts each time in case its a valve with an internal short pulling the voltage down.

get back to us after these tests, and if you can supply some photos of your build showing how you have wired it up they will be a great help.

Andy.

bikerhifinut 10th February 2019 11:49 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Quote:

Originally Posted by G Willis (Post 89110)
Hi,



Also the L.E.D does not light. The instructions say to wire between LED1 and LED2 but LED1 does not seem to go anywhere. I would like to get some confirmation of where the L.E.D should go as its not shown on the circuit diagram. As the LED uses the heater circuit maybe my problems are connected.

Any help gratefully appreciated.

Graham

My copy of the instructions tells me to wire the LED directly to the base of the output valve under the PCB, maybe you've got it connected across some other part of the circuit causing issues. I'd disconnect the LED wiring altogether at the PCB and measure again. As in the previous post, photos would be a big help.

G Willis 11th February 2019 07:46 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
2 Attachment(s)
Hi Bikerhifinut,

Thanks for responding. :thumbsup:

I followed your instructions and the first thing I found was that I had neglected to fit the LED resistor - R34. This immediately fixed my LED problem.

I proceeded to run the tests with the valves out as you described and I found the heater circuit to be correctly wired using a continuity test and I measure 6.5 volts on all the bases between 4/5 and 9 as expected.

However on fitting the valves I have exactly the same wrong readings in the heater circuit. You suggested this was indicative of a wiring error and I will check through the entire build again. In the meantime I will post some pictures in case there is anything standing out.

Regards, Graham

G Willis 11th February 2019 07:49 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
2 Attachment(s)
Another picture...

bob orbell 11th February 2019 08:18 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
My only comment Graham is, are one of your LED tails contacting the chassis, they need to come out straight, and please solder both sides of the valve bases for mechanical strength. Bob

bikerhifinut 11th February 2019 08:43 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
is it a Phono 3S? if so theres bits you haven't fitted. Like the rest of the interstage coupling capacitors that form the LF filter before the first RIAA correction network.
Those heater connections don't look right to me, I didnt build mine so I've never looked underneath it. However what you could do is solder the heater wiring DIRECTLY to the relevant solder pin pads i.e. pin9 fpr - and pins 4/5 for + to save confusion.
Or take valves out of sockets and with the unit unplugged from power, use a meter on resistance range and check the continuity from the actual valve base pins to all the heater solder points, all should measure zero ohms between their relevant pins and back to the powersocket. That is all pin 9 should measure zero ohms between each other and back to the plug and likewise all pin 4/5 zero and back to the plug. With the LED disconnected the meter should show no circuit between pins 9 and pins 4/5 as the valve heater filament completes the circuit.
I think theres something not right with your heater wiring.
Theres a few others have actually built this circuit who can shed more light on it. My eyes were spinning trying to follow the board tracks. at these times I would have been metering to see where the solder pads were connected.

Andy.

bikerhifinut 11th February 2019 08:54 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Quote:

Originally Posted by bob orbell (Post 89131)
My only comment Graham is, are one of your LED tails contacting the chassis, they need to come out straight, and please solder both sides of the valve bases for mechanical strength. Bob

Aha! Bob do you think because its a double sided board and it looks like the heater tracks cross on both sides of the board maybe theres a dry or solderless joint where a base pin goes through? I realise I was looking at a phono3 not 3S board and now I see the difference. I think you may have spotted the elephant in the room Bob?
Do I take it Mr Willis that you havent bothered with the rest of the LF warp filter capacitors for a reason? or the pics show the board incomplete but screwed down in position?

A.

G Willis 11th February 2019 09:23 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Its a WDPhono3 XL. The instructions state explicitly that C3,4,5 & 6 are not fitted, nor or are they supplied. They do not appear in the circuit diagram or the parts list.

I was aware that the LED was contacting the chassis and have removed it, I will insulate both legs. I intend to go through the whole heater circuit again later in the week but as I say I am measuring 6.5v with no valves in between 4/5 and 9 on all three bases whereas when the valves are in I am only seeing a 4.9v differential. Doubtless I have missed something or made a soldering error but I am curious about these 'missing' capacitors.

Graham

bikerhifinut 11th February 2019 09:39 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
It must be an update.
I take it you don't have the rotary switch on the LHS of the front panel to switch in the LF filters? They are a decoration anyway in my opinion, mine stays on the 10hz setting permanently.
No matter it wont affect the heaters.
Have you considered the possibility of a duff valve?
Also try checking the voltages with just 1 valve in and swap it round the sockets, if theres a wiring fault it might show up?
It'll be something fundamental it usually is.

A

bob orbell 12th February 2019 07:23 AM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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 :D'oh!: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 12th February 2019 09:35 AM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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 12th February 2019 06:29 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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 12th February 2019 06:38 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
1 Attachment(s)
There is a very small photo size limit on this bulletin, I've had to resize radically.

G Willis 12th February 2019 06:46 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
2 Attachment(s)
Not good soldering on the regulator. I will redo that.

bob orbell 12th February 2019 08:24 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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 13th February 2019 09:48 AM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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 10ļ, 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:D

John

John

Greg. 13th February 2019 06:21 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Yes, indeed. Furthermore, Iíve never found the need to use additional flux except when I fitted a new central heating system:D

Phil Y 13th February 2019 11:01 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
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.:eek:

Phil.

colin.hepburn 13th February 2019 11:25 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
1 Attachment(s)
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 donít spill:D'oh!: it I use this stuff see image

G Willis 14th February 2019 08:13 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
I've ordered a new regulator and some power resistors from Matthew. I need to redo some of this. I will let you know how I get on....

Thanks, Graham

G Willis 17th February 2019 06:54 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
I have now done the following:

1. Replaced all the power resistors so that they are well clear of the board
2. Replaced the regulator and fitted as described by Bob. This was much easier second time around as I fitted it to the chassis but only soldered it to the board when all the other wiring was complete.
3. I rewired all the pins in the PSU ensuring good joints. I now have a good technique for doing this.
4. Redid some of the soldering in the Phono3

The good news is that now the heater is at 6.5v as stated.

Thank you all for your help. I can now set up my record deck. :D:D:D

Graham

bob orbell 18th February 2019 07:34 AM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Well done Graham, let us know your thoughts on it, although I am going to say that you may find it a bit bright, if it is I do have a fix :thumbsup:. Bob

G Willis 22nd February 2019 01:44 PM

Re: New build WDPhono 3 Questions; heater voltage/LED
 
Just an update on this: I have set up my deck and it all sounds absolutely fabulous. Very happy. :D:thumbsup:


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