Wireless Set No. 19 MKIII. PSU arrangements?

[G4YVM David]

Greetings chaps. My lengthy radio silence is due to time pressure and having to be a tad discerning on who I bore...I trust everyone is well.

I am trying to get a Ws19 set Mk iii back to life for a mate but he has no paperwork with it, so I cant even see which pins are for what on the front panel. (I know what the sockets are, its the PINOUTS I can fathom, what gets what voltage etc.) Ive found the WS 19 set group library of manuals, but could someone who already has a manual perhaps tell me which manual shows the front panel pinouts before I start my limited manual download requests please?

The sets previous owner says he fired it op without the PSU by feeding mains voltage into two pins...well I cant see where he did this and without a circuit I cant even say whether he could have.

Any and all help gratefully received

David

[M0FYA Andy]

If he fed mains voltage into two pins there are two options -

1 It's been heavily modified (bodged) with an internal mains psu, which involves ripping parts out to make room.

2. He caused catastrophic damage........

Andy

[ex seismic]

2. He caused catastrophic damage........

Quite likely to himself as well as the set.

gmb

[Vintage Engr]

If you have or can locate a copy of "Wireless For The Warrior", Vol 2 and w/s 19 page 22 is what you require.

This is taken directly from the original Army cct. You will have to trace back each pin from the 12-point connectors, but it's fairly straightforward.

I do have the original Trade Training notes, on which I think I have actually marked which pin is which.
I can't locate the book at present, but will look later on today.

When I was a lad, I managed to work out which pin went to where, just with a multimeter, & no cct diagram so it's not too difficult.

However, as Andy says, if someone has put the mains on it...! Why?, are they still alive?

Hope you manage to sort it out and that not too much damage has been done.

David.

[ex seismic]

OK, so to be helpful now,

The upper 12 pin socket (plug is I suppose more accurate) is power, the lower one is audio.

Upper. (PL2B)
1: earth
2: IC a/f output
3: LT+ (12vdc)
4: HT2+ (540vdc)
5: Signal (driver's buzzer)
6: HT1+ (265vdc)
7: HT2-
8: "A" relay (PTT)
9, 10, 11, 12 all n/c

Lower. (PL2A)
1: A mic
2: B mic
3: IC mic
4: A a/f output
5: B a/f output
6: IC a/f output
7: A PTT
8: B PTT
9: Signal
10: A unattended lamp
11: n/c
12: n/c

Gordon

[G4YVM David]

Fabulous replies, thank you.

I suspect he did NOT feed it from the mains save in his imagination as a ploy to flog the set!

Thank you all.

FWIW the set is a 19 set Mk iii

D

[M0FYA Andy]

Glad to hear that!

Andy

[Orakle42]

Hi David

I am sure removal of the case will immediately reveal if a PSU modification has taken place. From previous experience with my Mk II even after the removal of the "B" set and intercom Amp you would be pushed to fit a mains PSU for HT1 & HT2 in the vacated space. I suspect, as pointed out by M0FYA Andy & ex seismic, it could not have worked simply by the application of mains voltage unless tuning for maximum smoke!

Orakle42

[Sparky67]

If it helps the VMARS web site has a number of WS19 books HERE freely available to download from their manuals listing page.

[G4YVM David]

Thanks guys.
When I looked inside it looks very tidy and clean, I am sure its not been chopped at all. In fact I am very hopeful that it can be reinstated quite safely. If it was a standard mains driven rig I would use a variac to bring it up, but given the rotary inverter will just shoot power at it I'm not at all clear how to do the resurrection in this case. I'm also not happy of just throwing the switch on the PSU and suddenly re-energising those capacitors. I guess the wax ones could have changed and I might end up with a room full of smoke.

[G4YVM David]

Just occurred to me...i could do it pin by pin I guess.

[ex seismic]

I seem to remember there are very few electrolytics in the set, and all quite low values, the biggest is in the power supply.

Gordon
G7KNS

[Keith]

My first question would be is it a MkII or a MarkIII? The former has a 6-point power plug so the quoted pinout would be incorrect. Do I take it that you have the rotary PSU (and the "dog-bone" connecting lead)? Some of these have a large capacitor that tends to explode if energised after a long dormancy. I'd be tempted to start by supplying just the 12V to the set to see if all the heaters light up. Takes me back to my school days...http://www.tibblestone.com/oldradios...arly_years.htm

[HamishBoxer]

It is a MK111 David has stated in an earlier post Keith.

[Keith]

Quite right Hamish - failed to spot that (blame it on the wine!).

[HamishBoxer]

I was not trying be clever Keith as I can miss things too after the Red!

[G4YVM David]

Sorry guys, yes it's a mkiii.

I do have a dog bone but it's too short, which has surprised me...thought they'd all be the same.

You're right, there is a huge cap in the rotary psu...and again right on mynthinking of adding 12v first.

What I haven't fathomed is how to get 12v INTO the psu. My old set had a cable but ibcantbrecall anything about it now. Damn damn tripple damn

D

[ex seismic]

The power into the PSU is the 6 pin connector. PL-1C. Pin 1 is earth/chassis and -12vdc heaters and dynamotors, 2 is IC a/f output, 3 is +12vdc heaters and relay, 4 is +12vdc vibrator and dynamotors, 5 is driver's signal and 6 is -12vdc vibrator.

The Canadian Mk3 PSU has a 12/24v switch inside.

In short, link 3 and 4 to +12v and link 1 and 6 to -12v.

Your dogbone should fit if the PSU is right up against the set.

Gordon

[G6Tanuki]

There are several different designs of PSU: the one I had with my Canadian WS19 used a vibrator for the receive HT and a rotary for the TX; the other one I had [British Mk3] had rotaries for both RX and TX.

The power input is the smaller, 6-pin power socket.

If your WS19 has not been recently reworked, expect all the wax-paper capacitors to be leaky as sieves (metal-cased ones included), and for a number of the resistors to have actual values wildly different to that marked on them! By all means fire it up briefly to see if it does anything but before using it for any sort of significant time it'll need a good going-over.

Remember, it could be nearly 80 years old!

[G4YVM David]

Fabulous info. Thank you

D