|
Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
|
Thread Tools |
14th Sep 2020, 4:40 pm | #1 |
Diode
Join Date: Sep 2020
Location: Kingston upon Thames, London, UK.
Posts: 6
|
R1155 Capacitor replacements
Can somebody advise me the following please :
type of capacitor and where to buy to re stuff the big square 2.5 +1.0+2.5 mfd paper wax caps ? 400 volts DC I think. Ditto above for the tubular caps under chassis...mainly 0.1 mfd I think Ditto above for the low capacitance WAX caps all over the place thank you |
15th Sep 2020, 8:23 am | #2 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
For tubular 0.1uF caps, I would buy axial ones, with a voltage rating of 250V or 400V DC. Given the HT is nominally 210V on the R1155, either should be quite adequate for any position in the set.
Radiospares have a 250V offering at £1.29 for 5: https://uk.rs-online.com/web/p/polye...itors/1854151/ Or alternatively a 400V offering at £1.27 for 5: https://uk.rs-online.com/web/p/polye...itors/1854347/ You will need to check physical sizes to see which is most suitable - probably after hollowing one of the originals out to see exactly how much space you really have. Richard |
15th Sep 2020, 8:25 am | #3 |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
Not sure what type of caps are the ones you are calling "low capacitance wax caps". They are probably mica or ceramic. In which case they are very unlikely to have failed - unless its some total failure like a lead falling off. Unless you are quite sure they are faulty, I would leave them well alone.
When I restored a R1155 I didn't touch a single one of those caps - there were plenty of other things to occupy my time!! Richard |
15th Sep 2020, 8:55 am | #4 |
Diode
Join Date: Sep 2020
Location: Kingston upon Thames, London, UK.
Posts: 6
|
Re: R1155 Capacitor replacements
Thanks, I will happily leave all those wax ones alone. I assume you feel Vishay poly caps are also good for the big square cans... I couldn't find 2.5mfd only 2.7 but I assume that will be OK..
|
15th Sep 2020, 10:09 am | #5 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
|
Re: R1155 Capacitor replacements
Capacitors with a paper dielectric will almost certainly need changing. They generally have values from about 0.5uF down to about 0.001uF. Capacitors with lower values that this will be mica or ceramic types and should be left well alone.
Capacitors having values of 1uF or more are generally replaced with electrolytic types assuming they won't reform.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
15th Sep 2020, 10:58 am | #6 |
Diode
Join Date: Sep 2020
Location: Kingston upon Thames, London, UK.
Posts: 6
|
Re: R1155 Capacitor replacements
Thanks... I had assumed the Big 4.5 MFD paper wax ones in the R1155 should be replaced by non polarised type ( like the ones I have taken out.....) But you say I should use electrolytic types......this makes things easier ....is there any reason I shouldn't use film types /polyprop types ? although they do seem much more expensive .
|
15th Sep 2020, 11:14 am | #7 | |
Octode
Join Date: Aug 2008
Location: Rotherham, South Yorkshire, UK.
Posts: 1,724
|
Re: R1155 Capacitor replacements
Quote:
Hope it’s ok to mention but members of the BVWS can buy capacitors at good prices direct from the BVWS. I have no connection to the aforementioned other than being a very satisfied customer and subscriber. Peter |
|
15th Sep 2020, 11:28 am | #8 | |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
|
Re: R1155 Capacitor replacements
Quote:
Where caps are specified as having values in uuF (pF) leave well alone.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
|
15th Sep 2020, 6:12 pm | #9 | ||
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
Quote:
quite right - I should have twigged that the price was suspiciously low!! Particularly when I went to the trouble of buying in such caps from USA some years back to save a small fortune compared to RS/Farnell prices. Sorry for misleading anyone. I guess this shocking price shows how out of fashion leaded axial capacitors now are. Richard |
||
1st Oct 2020, 11:59 pm | #10 |
Hexode
Join Date: Mar 2011
Location: Wilstead, Bedfordshire, UK.
Posts: 367
|
Re: R1155 Capacitor replacements
Hi
I would suggest that you try to get a copy of Pete Holkham's book on R1155 it is a most informative book. If you cannot borrow one then you will have to buy a copy from Pete Holkham unfortunately he lives in Australia and the postage costs as much as the book itself but as I said it's well worth it Regards Bill |
2nd Oct 2020, 8:15 am | #11 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
Quote:
Richard |
|
2nd Oct 2020, 8:45 am | #12 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,386
|
Re: R1155 Capacitor replacements
You'll need to open the swear box when replacing the metal can paper 0.1uF caps underneath the coil box. You can do it without dismantling the whole assembly, but it's very fiddly. Good luck - I never want to do another one, once was enough. It was also extremely frustrating trying to get the slow-motion dial to work properly. Cheers, Jerry
|
2nd Oct 2020, 9:13 am | #13 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,578
|
Re: R1155 Capacitor replacements
Just thinking about these radio's and their original use in Lancaster bombers. Were they ever designed to be serviced? Their construction suggests probably not since failures would normally be expected to be fixed fairly quickly. I heard somewhere that their expected life was only months since Lancasters themselves were heavy casualties of the war.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman..... |
2nd Oct 2020, 9:16 am | #14 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
|
Re: R1155 Capacitor replacements
The caps can be replaced by re stuffing with 0.1uF SMD's rated at 500 Volts or at least one person has done. Slip in the tube very easily.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S |
2nd Oct 2020, 10:37 am | #15 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
Quote:
Richard |
|
2nd Oct 2020, 10:44 am | #16 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
Posts: 1,654
|
Re: R1155 Capacitor replacements
Quote:
Strangely, few documents on RAF servicing of equipment have survived. I do have the odd one in APs, listing things like "spare parts" and so on. The occasional modification instruction turns up too. Many T1154s have a notice on the front panel saying "modification xyz carried out" for instance. So we know such work did take place. Its in severe contrast to the Army kit, for which very extensive document survives in the form of EMERs, telling you just everything including how to rewind transformers! That's possibly due to the fact that Army kit could turn up just about anywhere, a zillion miles from the nearest "service centre", but planes tend not to - they land normally fairly often in a location where all the service kit etc is available. Richard |
|
2nd Oct 2020, 2:46 pm | #17 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,386
|
Re: R1155 Capacitor replacements
In the RAF we used to do certain levels of modification, depending on depth of maintenance; at first line (at the aircraft) very rarely - merely black box replacement whereas at second line (workshop level) I recall mods to Tornado main computers being carried out to upgrade memory from 128k to 224k RAM (wow!). Usually the line-replaceable unit (black box) had a mod strike-off plate with instructions as to how to annotate it in the relevant mod leaflet. Deeper levels of mod were done at 3rd Line (30MU Sealand, I think it's still going) or 4th Line (manufacturer). Cheers, Jerry
|
3rd Oct 2020, 12:58 am | #18 |
Hexode
Join Date: Mar 2011
Location: Wilstead, Bedfordshire, UK.
Posts: 367
|
Re: R1155 Capacitor replacements
Hi
I agree that the wiring can be absolutely awful, just looking at can make it crumble if you are unlucky. I have restuffed many of the 3 X .1uf caps in the cans and all are quite easy apart from the one in the middle of the coil can but with a lot of patience it can be done. there are also, i think 3 x .1uf in metal cans that are singular that are again quite easy to restuff but one is a right pig, it is in the BFO can and if it goes faulty will only show when you select BFO, to get to that one the can has to come out, with regard to the 4uf capacitor in the rectangular can, I unsolder the base, take all the innards and fit a 4uf electrolytic inside and then resolder the can up Cleanup and maybe spray the capacitor can and refit. There are many more things that go wrong with the R1155 and they can be time consuming but very rewarding in the end. Good luck Bill |