WAD Psu3 replacement Board Build

[colin.hepburn]

Hi All
Oh well that’s life I just rebuilt the PSU 3 board and its working fine with Mains wall voltage of 241v giving an off load H.T voltage of 261v on the phono and 210v for the CF Pre
So now the phono 2 is up and running fine But the CF pre is not running the Valve heaters are lit up but no Led on front panel and no single out from the relay board
I checked the led out of circuit and its fine and I have power to the relay board now after refitting the led but no channel switching happening is there an easy way to test the relays

P.S before I built the new PSU3 Board. The CF Pre was accidently left on over night after last use. and most of the next day as there was no Led lit up. I did not check if the units were power down. on next use is when I realised the CF was not working which is what lead me to believe that the old Psu 2 had failed
Thanks
Colin

[bob orbell]

Colin, make a check on the polarity of the heaters and the relay supply, you may have it reversed. Bob

[colin.hepburn]

Originally Posted by bob orbell

Colin, make a check on the polarity of the heaters and the relay supply, you may have it reversed. Bob

Yes that’s possibly Bob but the CF. Had the same issue before it came to the bench i.e. the led was off? At some point after I last use it as said I had forgot to switch the unit off and did not check it as there was no led light on to remind me that I hadn’t turned it off maybe I had a main surge or something will check PSU heater wiring as well just to verify

I hope it’s not the relays as RS priced them at £3.42 each in packs of 24 only yer right so may have to look for other replacements to make up new switchers as I have couple of original older PCB switcher PCBs I want for another project Pre amp in the wings so if anyone knows of a drop in replacements for this subminiature HF 1A-5Volts relay please let me know
Thanks
Colin

[Greg.]

Colin, once you’ve identified the fault and what you need to do to correct it, always talk first to Matthew to see if he can help you out. It should save you paying RS prices for unwanted multiple items in your order.

[bob orbell]

Colin, even if you had left it switched on for a week or more, no harm should have been done and only one relay would have been energised, it must be something else such as the wiring to the relay PCB or a poor connection on the board, Matthew now dose a much improved rely PCB as the older type were very poor, I had one last year as the track around the resistor had broken giving a intermittent problem. Bob

[bikerhifinut]

Greg's advice is good Colin.
As often as not I buy my parts from the likes of RS etc, but there are times when its not possible to get a good price or even availability of the correct component especially for odd ones and even stuff like odd lengths of wire.
Matthew will sell you what you need and at a fair price.
I bought the WD relay board off Matthew for my KT88 integrated conversion, it was cheaper in the long run than my attempting to make a PCB up and scratch my head as to how I could fit it in.
Mind you, I wish I'd known how awkward it is to get all the sockets lined up, as a retrofit it was not a pleasant experience and I did end up having to perform a bit of remedial surgery.
If you do fit a complete new board I would strongly advise to treat it as a fitment from scratch, meaning removing all the phono sockets and cleaning them up/replacing if not re usable before fitting them back slightly loose. I was very uneasy about all of that but it does seem to work OK now.
I have to say for my own total homebrew projects I build the relay board on a bit of perf board and use very short flying leads to the RCA input sockets. The WD gear is good but I feel its a fit once and get it right first time as you'll never really do a neat job of any repairs if you are as sausage fingered as me these days!
You may of course already know the pitfalls and so I apologise if telling granny to suck eggs.

Andy.

[vinylspinner]

Another useful tip is fit the relays into sockets, it makes life so much easier.

[bob orbell]

Originally Posted by colin.hepburn

Yes that’s possibly Bob but the CF. Had the same issue before it came to the bench i.e. the led was off? At some point after I last use it as said I had forgot to switch the unit off and did not check it as there was no led light on to remind me that I hadn’t turned it off maybe I had a main surge or something will check PSU heater wiring as well just to verify

I hope it’s not the relays as RS priced them at £3.42 each in packs of 24 only yer right so may have to look for other replacements to make up new switchers as I have couple of original older PCB switcher PCBs I want for another project Pre amp in the wings so if anyone knows of a drop in replacements for this subminiature HF 1A-5Volts relay please let me know
Thanks
Colin

Colin, just visited RS and part no. 113-8825 £2.84 plus VAT, you can buy 1 to 24 for that price, you don't have to buy 24 I think you misread it. Bob

[colin.hepburn]

Hi Bob Andy/Greg
Thanks for the reply guys
I know where you are coming from Andy on neat jobs of any repairs and as bob points out old PCBs are a pain
So today I have re touched up all the joints on the CF pre.and did continuity checks on it all seem to check out so far so good?

Next I checked the PSU3s umbilical cables .now as I just built the PSU into a box I did not bother with the sockets on the back I just made up new umbilical’s in the correct colours as per the manual and hard wired them in to the PCB .pins saving on sockets

OK so rechecking for continuity pin 4. Heater +ve checks out with plug pin 4.as dose pin 1 Neg to pin 1 plug. So good all the way to the CF. No wiring changes to CF other than removing the Led to check it was still working as its very bright so thought it may have burned out

So all looks fine to power up ok powered it up. still, no Led valve heaters are up Relay Board tests 6.3v neg on the positive pin? I may have put the led back in backwards not sure

`All other Voltages check out fine
Heaters 6.5v and heater to ground 51.4volts
Cathode HT is bang on 200 volts
OK coffee break time and got to take the Dog out.
Thanks again for the replied help

[colin.hepburn]

Originally Posted by bob orbell

Colin, just visited RS and part no. 113-8825 £2.84 plus VAT, you can buy 1 to 24 for that price, you don't have to buy 24 I think you misread it. Bob

yep i sure misread it didn't i not to bad then for a set of five