(12-10-2012, 08:52 AM)Joe Wrote: The trouble with both is the price, the 'Icon' effect.
I'd certainly like a B40 as well, tough putting it somewhere would certainly be a challenge.
- Joe
Hi Joe, yes the icon price and also the un got at price, that said you can still pick up a wreck of an R1155 for reasonable money if you look and wait either at auction or local or county amature sales, maybe two of them to make one good one, you can always flog off the surplus bits to get some cash back. The main chassis isn't that bad to work on, the RF box can be a bit of a pig sometimes but not insurmountable, biggest problem is usually the oil filled multi cap capacitor cans and the rubber covered wiring which would need renewing if it's gotten to the crumbly stage, restuffing the cap cans is no problem as they are fixed to the chassis at the base by a nut, if you carefully prise up the ally to get the inards out then prise it back down after then retightening the nut will fold it over the rest of the way and hide any screwdriver/pointed tool marks that might have been made in order to gain access to the can. In many case the slow motion tuning drive will need sorting out, they are quite easy to overhaul and get back to spec, the reduction ratio is excellent, one of the most commnn problems is the cork washer within the tuning drive it has usually "spread" over the steel disc which is part of the same mechanism or come adrift, the cork washer should be trimmed back if it has spread over the edge of the disc, trimmed back to the edge of the disc other wise the taper rollers will not contact the drum properly, full contact at the designated point is vital for differential rotational rate in the tuning drive, I am writing this purely from memory, there is much on the web about these receivers.
The other thing to remember is that the chassis is at a different potential to the HT -ve by approx 25 to 30 volts when the receiver is up to spec, you can earth the chassis if the PSU you use is transformer derived.
As regards the DF section then unless you are going the full restoration route it is not neccesary to get that section working, the receiver will work without it.
As you probably know many of these have been heavily modified over the years, some good some definately not so good so you would need to give it a good visual along with the circuit/layout diagram. Don't be put off by it's condition, it is like any equipement, one stage at a time. As previously said you don't need an added audio stage to use it, the PSU requirements are simple to fullfill.
Forgot to say, don't force any of the dust cores in the IF's or RF box, if they are stuck they will usually loosen up for alignment purposes by using various techniques also be aware that the BFO runs at half IF frequency I seem to recall.
Also forgot to say that the tuning drive as described above is for the original drive, later on they were sometimes fitted with a modified tuning drive, I have not encountered the later type but I guess someone hear has.
Lawrence.
