|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
25th Sep 2018, 1:33 pm | #1 |
Hexode
Join Date: Jan 2018
Location: Cannock, Staffordshire, UK.
Posts: 268
|
DAC90 replacement waxies
Just started on a DAC90, usual issues;
All the rubber wires hard and cracked. Someone had replaced the reservoir cap - badly. So needed a new one. bulb blown All caps replaced, see below. dropper resistor caused damage to the rear and paxolin - all rewired. Mains switch open-circuit - good cleaning sorted that. V2 EF39 had broken screen wire - ended up covering with tinfoil and re-wired Then came the slightly more anoying; Speaker vibrating and I could not just it - tried for hours. In the end replaced it with my only spare! Had to replace the rubber supports on the tuning cap - it's tricky. WAXIES Anyway I figured after all that I would have a go at replacing the wax caps with something that was a little more sympathetic than the bright yellow poly ones I have. I started with 400v poly caps soldering new wires at 90 degrees to the body - converting them to radials. Then I added two ends to then, consisting of rolled up foam packing, stained at one end (dark brown liquid shoe polish) and then pushed over the new wires. Printed some reproduction art work based on T C C wax originals. wrapped the new assemble in the printed wrapper. Glue in place. And finally "dip" in hot wax, allow to dry clean up with hot soldering iron. And fit! (I must be mad, I did 11 in total!) See photos Derek |
25th Sep 2018, 2:06 pm | #2 |
Heptode
Join Date: Apr 2016
Location: Croxley Green, Hertfordshire, UK.
Posts: 979
|
Re: DAC90 replacement waxies
Wasn't the "vibrating Speaker" just the spider come away on the back?
I've successfully fixed two of these with superglue, it's nice still having the original speakers. BTW great job on those caps.
__________________
Clive |
25th Sep 2018, 6:19 pm | #3 |
Hexode
Join Date: Jan 2018
Location: Cannock, Staffordshire, UK.
Posts: 268
|
Re: DAC90 replacement waxies
Yes about ten minutes after the first post - I remembered about checking the back of the cone. And yes it's come away so my next job is refitting the original speaker !
Thanks for the advice. Derek |
25th Sep 2018, 8:15 pm | #4 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
|
Re: DAC90 replacement waxies
You seem to have converted them from radials to axials. A bit confusing along with the reference to bright yellow (axial?) ones as well.
Nice looking results!
__________________
....__________ ....|____||__|__\_____ .=.| _---\__|__|_---_|. .........O..Chris....O |
25th Sep 2018, 8:22 pm | #5 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
|
Re: DAC90 replacement waxies
Excellent job.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S |
25th Sep 2018, 8:35 pm | #6 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
|
Re: DAC90 replacement waxies
Remember to put a clear note somewhere inside the radio to indicate what you've done!
Some time back I reworked a radio, instinctively ripping out the waxies and a couple of paper-cased cathode-decoupling electrolytics because they were bound to be bad. Nice shiny new yellow 400V-working MKTs and Rubycon electrolytics went in. Only later did I discover that the summarily-junked capacitors had been restuffed by a previous owner. [I was happy to leave it with the MKTs and Rubycons on show: at least that gives a positive indication of the rework!] |
29th Sep 2018, 1:04 am | #7 | |
Hexode
Join Date: Oct 2017
Location: Manchester, UK.
Posts: 361
|
Re: DAC90 replacement waxies
Quote:
|
|
29th Sep 2018, 12:50 pm | #8 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
|
Re: DAC90 replacement waxies
Back in 2009, Colin ('Retired'), who is no longer into radio restoration but remains a member of this forum, set up a 'mini production line' and made quite a lot of reproduction 'waxy' capacitors. The technique he used can be seen at this (closed) thread and might be of interest. As will be seen, they looked very authentic:
https://www.vintage-radio.net/forum/...ad.php?t=46963
__________________
David. BVWS Member. G-QRP Club member 1339. |
29th Sep 2018, 1:01 pm | #9 |
Octode
Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,320
|
Re: DAC90 replacement waxies
A pity we can't do this with resistors...
|
29th Sep 2018, 1:14 pm | #10 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
|
Re: DAC90 replacement waxies
Each to their own, and on that note so long as it's well engineered and to spec, underchassis originality holds no real interest for me. There was a time when I would restuff electrolytics that were mounted above chassis, and I do recognise the amazing work that restorers do in achieving chassis originality.
__________________
A digital radio is the latest thing, but a vintage wireless is forever.. |
29th Sep 2018, 2:27 pm | #11 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
|
Re: DAC90 replacement waxies
Some might argue that paradoxically, re-stuffing capacitors is actually taking authenticity away because during a radio's life, at some point it may break down and if it did, the service engineer would use whatever replacement component was to hand. I guess that the older, rarer and more valuable a set is, the more that conservation and preservation. rather than repair or restoration, comes into play.
Not something I feel strongly about - my priorities have always been safety, functionality, and originality in that order, but I certainly wouldn't dictate to others how they should go about repairing or restoring their own equipment.
__________________
David. BVWS Member. G-QRP Club member 1339. |
29th Sep 2018, 4:29 pm | #12 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
|
Re: DAC90 replacement waxies
I think it depends on the set, to an extent. There are some "showcase" sets for which it is well worth creating original-looking capacitors (2 watt metal film resistors already look sufficiently period), but there are many other "workaday" sets for which a repair using more modern parts than were available when it was built would be entirely authentic.
Even into the late 1970s / early 1980s, there were plenty of older people still listening to MW and LW on 1950s and 1960s-era valve sets; they would have been maintained by the last of the repair shops, who would not have thought twice about fitting a modern polyfilm capacitor in place of a waxed paper original. I'm sure there must even be cases where someone has acquired a pre-war set that had a component replaced in the 1950s, and ended up replicating a 1950s era part to match the original repair as an integral part of the set's history.
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments. |
29th Sep 2018, 4:35 pm | #13 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
|
Re: DAC90 replacement waxies
I wear my 'service engineer's hat' when repairing old/vintage radios -i.e., I do as Julie & David suggest, replace faulty capacitors with the nearest available modern equivalent. Unlike the OP, I have no objection to using the axial yellow poly. types - in fact they are what I usually use. However, as ahas already been said 'each to their own choice' as long as safety and reliability are kept in mind.
|
29th Sep 2018, 6:16 pm | #14 |
Heptode
Join Date: Jan 2009
Location: West Lothian, UK.
Posts: 760
|
Re: DAC90 replacement waxies
I tried - (large 560k with lots of volts across it) but was not happy with result so left the old one in situ with a parallel resistor chain hidden in some heatshrink.
__________________
George |
30th Sep 2018, 3:11 pm | #15 | |
Heptode
Join Date: Apr 2016
Location: Croxley Green, Hertfordshire, UK.
Posts: 979
|
Re: DAC90 replacement waxies
Quote:
But as said "Each to their own."
__________________
Clive |
|