Psu ID

[pwdrive]

Anyone know the type No: of this power supply? it powers and Eddystone 358, in the 358 manual the pictures of the power supply (outlet socket on the side) do not match the layout of the one shown in the picture i have attached, the one in the attatched pic. works fine it contains 4 seleniums in a bridge (temp bridged with silicon rects) It also contains the 7.5k loading resistor from HT + to HT- this loading resistor was fitted also to the PSU pics in the 358 manual.
The PSU shown in my pic is 230 Vac in or 6v Dc in PSU contains 6 v vibrator for the latter operation.
This PSU seems to share certain phyisical traits with a PSU I have that powers a Marconi CR300 (see gallery for that one)
The 5 pin offset outlet socket on the front of the PSU under query takes the PSU input lead from the 358 this lead is original as is the 5 pin offset plug that is fitted to it, I realize that this could be one for the Eddystone User Group but thought I would post it hear first.
Any ideas.

Lawrence.

[Skywave]

. . . . do not match the layout of the one shown in the picture i have attached, the one in the attached pic. works fine . . . .

Lawrence.

What "attached pics."? I see none.

Al.

[pwdrive]

Hello Al, no I coudn't either! Forgot to upload, pic is there now thouigh.

Lawrence

[Skywave]

The power input and power output connectors don't look original to me. They look too modern, compared to the appearance of the rest of that item, and they also look too new 'n' shiny too.
If I had acquired a piece of kit like that and wanted to use it, but found that it had connectors for which I did not have the corresponding plugs and sockets, I'd simply change the ones that are fitted to something that I had. Now I come to think of it, I've done that very thing quite often!

Al.

[pwdrive]

Hello Al, the two input sockets 230 ac and 6v dc appear to be early Bulgin types, it does not look as though they were fitted at a later date, they are shiny because I polished them up. I will see if I can find anything else out, the PSU is matched to the 358 receiver by virtue of the outlet socket and the original receivers input lead and plug, this socket is basically the same type that Eddystone 358 receiveruses to take the plug in coil packs.

Lawrence.

[pwdrive]

Spent quite a while scouring the web and various sites and drawn a blank, the only clue I can think of is the 6 volt input and I am assuming that means it might of been designed for use from a vehicle as well as the normal mains input.
Things that are common to this power supply and one described earlier for the Marconi CR300 in the gallery are that the case is of the same construction and more or less the same dimension, the type of power changeover switches are of very similar construction (ceramic) the power indicater bulb/bezel assy. are the same, inside the rh side of both cabinets is a welded on retainer for storing spare fuse wire, the dimensions of these retainers are approx the same for both. The earth binding posts are the same, both are fitted with slydlock fuse holders, both cabinets have the same vent louvre dimensions, both cabinets are the same colour, my opinion is that these two PSU's were made by the same manufacturer, the question remains by whom and what is the type number for the one in the picture.

lawrence

[Skywave]

I wonder if it is a PSU for a Marconi CR.150?
Just a stab in the dark.

Al.

[pwdrive]

No Al it would not appear to be according to the CR150 book of words.
But thanks anyway.

Lawrence.

[Skywave]

O.K. Lawrence: another line to investigate: I don't give up that easily!

First, although I am fairly familiar with many Eddystone radios, my knowledge gets a bit thin with their early models, such as the S.358. However, it seems that there were two direct variants of the S.358: S.358/1 (low power AF output stage) and the S.358X: crystal filter. Then there were the '358-derived' models: S.400; S.400X and the S.400B, a.k.a. the Air Ministry R.1448. (The S.450B doesn't 'fit' here: required 12-v.d.c.)
Apparently, external PSUs were required with all these receivers: apart from utility a.c. supplies (200 ~ 250-v), 6-v dynamotor or 6-v lead-acid battery and a 175-v dry battery were required. Since all these receivers are so obviously related, but with various differences - and some of those far from 'minor' - it seems likely that the PSUs would have looked - externally and internally - similar, i.e. not quite the same.

Al.

[pwdrive]

Hello Al could be, I know that the receiver version with the low power output stage had it's HT compensated to compensate for less current draw, this was done by shunting a 7.5k across the ht within the PSU, it was only shunted by virtue of the wiring in the PSU lead for those low output receivers, it was done by earthing one of the wires that went to the pin/socket on the PSU that the floating end of the 7.5k was connected to ie:
Standard o/p stage receiver = one end of 7.5k connected to ht in PSU and the other end of 7.5k connected to an unused connection on the PSU o/p socket so therefore 7.5k not in circuit.

Low power output receiver = same as above except that the unused connection on PSU o/p socket is now grounded (HT -ve) via an internal link on that receivers PSU connecting plug, thus dragging down the HT via the 7.5k to the same as it would have been on the high ouput version receiver.
From memory I think the standard receiver was fitted with pentode or tetrode o/p stage and the low output version was fitted with a triode.
The PSU I have has this resistor fitted as an original.
I have since posted on the Eddy user group forum as well.

Lawrence.