Murphy B40C

[m1ecy]

Hi all,

For my crimes, which must have been serious, I have a B40c on the bench, my personal favorite Military radio, having played with my first one at about 13 years of age.

I have had several over the years, but have always passed them on due to a lack of space, but now, I want one for the "Core Collection"

Anyway, cutting to the chase, I plan to restore this set to "good out of service" condition, taking it back to a point of good performance, if not immaculate cosmetic condition.

There are a number of parts that are unique to the B40 that I am going to need, so will pop a post down in the relevant section.

Thus far there are several switches that are in poor condition, some of which I have new old stock replacements for, so they have been done. The power supply and audio section has had some checks carried out, most of the coupling caps check out well, and the various resistors all test within tolerance, which is quite surprising, I have changed all of the grid coupling caps as a matter of course, while the B40 is built to last, I see no reason to be mean to the more unobtainable components.

The front panel is in very poor condition, but the rest of the set is certainly salvagable.

More progress reports as I make some....

Cheers
Sean

[pwdrive]

I have a B40D Sean, the front panel etc is well used shall we say.
Very good receivers and not too bad to work on, mines running on all original so far, the only faults on mine are that the tuning gearbox has a bit of backlash and also ocasionally when switched to Xtal marker there is a lot of "squegging" noise before the Xtal marker osc fires up, all components in that stage check out ok and the Xtal has been stripped down and been cleaned but to no avail.

http://golbornevintageradio.co.uk/galler...ategory/28

Lawrence.

[AlanBeckett]

Sean,

A splendid Radio. That range of Valves is getting a bit thin on the ground now and hence they're getting expensive.
Mine works very well. I've also got the SSB Adaptor - Outfit FAZ - plus Plugs and sockets. This year I'll get them connected up.
The other thing I'd like to make is a set of Extension cables for the PSU so that I can spread it out a bit on the Bench, provided I'm brave enough to get it off the shelf.
Keep at it.

Alan

[m1ecy]

I also have the FAZ, one of the reasons I am trying to resurrect this B40

Connectors arent a problem for me been collecting Plessey connectors for years!

[m1ecy]

Project stalled, awaiting parts - perhaps a scrap set will turn up eventually

[pwdrive]

In my experience they are few and far between Sean, might be lucky might be not.
B40's turn up on Ebay if you are prepared to wait, usually 40 to 80 quid for a complete one.

Lawrence.

[Qwenix]

Hello, Sean and other members.

For making your own extended internal cables/wiring.

Heres a link :

http://www.vintage-radio.net/forum/showt...hp?t=70722

http://www.vintage-radio.net/forum/attac...ntid=52523&d=1308170666


Success

Qwenix

[AlanBeckett]

I've long since saved that Thread with the intention of making them.
I just haven't got round to it yet.
It's a splendis idea.

Alan

[Qwenix]

Hello allan, and other members

I didnt have any spare parts for making these. So the only thing i did was asking Roy (@wwwdotelectrojumbledotcouk). If he could give me an offer for 4 plugsand sockets and all the wires including the small coax wire and binding strips. I sorted out all the connections with numbers and pins. So if you try to make these let me know maybe I can help. Lets say if you dont have the tools, take other tools and make them.

best regards Qwenix dutch collector and user of Murphy equipment such as b40 b41 62b FAZ outfit ssb converter.

Any questions alsways willing to answer to my knowledge.

[Qwenix]

I have a very important update about these extended leads. 

http://www.vintage-radio.net/forum/showt...post809574

This is a VERY important update. For those who wish to d.i.y. these leads. I used my extended leads repairing a 62B. I am still convinced that these leads wires are correct. Only one improvement should be taken care of.... To be more specific the extended lead with the 8 way connectors.

I am still troubleshooting this 62B. Attaching both leads between the drawn out power audio plug in and the rest of the receiver I came to the conclusion that in AGC OFF mode there was lots of hum sounding like a broken microphone cable. Bad earth ??. In the AGC ON modus no problem. Touching these leads made me aware that they needed better earthing (shielding) they became sensitive to hand capacity. Pushing the 8 way connector to the chassis or connecting it with a alligator clip to the chassis the problem became very less. So the hum in a 62B turned out to be caused by only these leads. They pick up electromagnetic fields from the transformer/ smoothing coil. Also due to their length. After removing them. I started up the receiver. The hum was gone (except the very quiet hum you an expect from a valve receiver).

So a improvement should be made so that the connector shells themselves are earthened. And the leads should be shielded.

Any comment is welcomed by.
best regards.
Qwenix