WAD Psu3 replacement Board Build

[bob orbell]

Yes Colin, but I always use the LD, low dropout, part no. 686-8837, you have to buy 5. Bob

[Richard]

As far as I can see Colin's number is for the TI make of the reg in singles and Bob's number is for the ST make of the reg in 5's. They're both LDO aren't they?

[John Caswell]

Hi all,
The **1084/5/6 are all Low drop Out (LDO) regulators. Some of them are all plastic casing so do not need insulating kits, cheaper to make I suppose and as no kit needed cheaper for manufacturers
We had to change them when we had instances of customers with low mains causing the 78S05 to start dropping out and causing hum. Tha took a bit of brain power and time to sort

John

[colin.hepburn]

Hi Bob/All
Thanks for the confirmation on the V-Reg part number
My older PSU 2 used the L7805CV with no drop out problems. But I remember is being discussed on the forum at the time
My mains is also up at a constant 246 volts even at peek time it stays
Colin

[colin.hepburn]

Hi all
Ok I have a query on which Diodes to use on the heater side my choices are the following listed below sorry not very good with my understanding of the datasheets
List of the diodes I have in parts box

SB330 30V @3A Diode Check test 0.2165
SB540 40V@5A Diode Check test 0.1658
IN5822 40V @ 3A Diode Check test 0.2012
Which one would you use?
PS the HT Diodes are CQ824G
Thanks
Colin

[Richard]

Hi Col, any of those should be fine, they're all schottkies of suitable rating for 2 small valves in Pre and 3 in Phono

[Richard]

Found the pic of the schottky heater bridge I made up for mine which had the early pcb. I used 1N5822 diodes as attached,

[colin.hepburn]

Originally Posted by Richard

Found the pic of the schottky heater bridge I made up for mine which had the early pcb. I used 1N5822 diodes as attached,

Hi Richard/ALL
OK thanks for the reply Richard

Yes I was looking for that image that’s what I did with the psu2. Back in the day after you posted up that thread Richard. But with a SB330 Diode which know has one Dead diode in it no need to make up a new diode board as the psu3 board will take the diode to the board now

I looked up the HT diodes as well the CQ824G that are still on my old psu2 board and cant remember what they were looks like there discontinued now but I will just swap them over as thay all test ok I think the CQ824G would be in the MUR type now
Thanks
Colin

[colin.hepburn]

Here's the pdf for the WAD psu 2, diode bridge that richard make up and tested back in the day
colin

[Richard]

Hi Col, that's a very neat pdf. SS diodes are usually pretty rugged in use so I wonder if one of yours had been damaged in soldering? They don't like heat and with diodes and transistors I always clip a heat shunt on the leg next to the body. For similar reasons I'd use new HT diodes if you have them rather than un-soldering and re-using the old ones. My HT diodes were TO 220 package as in the pics - but I can't remember which ones - I've not bought any for a while and they change type and numbers quite frequently.