[R-390] Re: Collins R-390A restoration

[Graham Baxter]

Hi Brian

I think the Solartron PSU is a good way to kill yourself. I had one of
those and I foolishly gave it away. I dont think I would recommend
your using it as a capacitor tester. In any event, 50k is a bit low. I
would be thinking in terms of megohms in order to protect both
yourself and your AVO.

The Heathkit bridge with leakage detection sounds ideal for this job.
I think you are right, the hand cranked Meggar probably has too much
ripple.

The brown tubulars have been the subject of a vigorous debate in the
past. My view for what its worth is if they measure correctly and they
don't leak using your Heathkit tester then it would be a shame to
spoil the originality of your radio.

Graham

On 27/08/07, Brian McCagherty <bmc at riola.com> wrote:
> Hi Graham
>
> Thanks for the very prompt reply.
> I'm glad to see that not all the BBODs need automatically be condemned!
> I will work my way through your suggestions.
>
> To test the caps I have a choice of:
> a) Heathkit C-3U R-C Bridge with 450V leakage test (EM34 Magic Eye
> indicator), or
> b) Solartron stabilized variable PSU at 450V DC max through (say) 50K and
> metered externally on an Avo.
> I also have a cranked Megger at 625/1250/2500 V but this is rough a.c. so
> not suitable for capacitors I reckon.
> However I don't have anything I would recognise as a "high resistance
> meter"; is (b) above the same thing?
>
> Thanks for the manufrs references, by the way; makes it easier.
>
> 73 de Brian  gi4gnz.
>
> -----Original Message-----
> From: grahambaxterdelphe at googlemail.com
> [mailto:grahambaxterdelphe at googlemail.com] On Behalf Of Graham Baxter
> Sent: 27 August 2007 13:39
> To: Brian McCagherty
> Subject: Re: Collins R-390A restoration
>
> Hi Brian,
>
> I think it is important to establish at the outset that usually there
> are very few faulty resistors and capacitors in an R390A which has
> been kept in a sheltered location.
>
> The only components I would replace as a matter of course, are the
> filter coupling capacitor C553 and then rebuild the main octal based
> smoothing capacitors.
>
> C553 is neatly replaced by
>
> PC/HV/S/WF 10NF 1KV - LCR COMPONENTS - CAPACITOR, 10NF 1000V
>
>
> Manufacturer: LCR COMPONENTS
>
> Farnell Order Code: 9520317
>
> Manufacturer Part No: PC/HV/S/WF 10NF 1KV
>
> The electrolytics can be rebuilt with:
>
> EEUED2V470 - PANASONIC - CAPACITOR, 47UF 350V , 2 off
>
> Manufacturer: PANASONIC
>
> Farnell Order Code: 9696440
>
> Manufacturer Part No: EEUED2V470
>
> RoHS :  Yes
>
>
>
> and
>
>
> EEUED2V330S - PANASONIC - CAPACITOR, 33UF 350V , 3 off
>
> Manufacturer: PANASONIC
>
> Order Code: 9696431
>
> Manufacturer Part No: EEUED2V330S
>
> RoHS :  Yes
>
>
> I would test all the caps with a high resistance meter at 500v. If the
> leakage is not significant, leave them alone. In my view an R390A full
> of unnecessary Orange Drops just arouses suspicion and has less appeal
> to a collector. Clearly if a faulty component is having any effect on
> the performance it should be replaced.
>
> Let me know how you get on.
>
>
> Graham
>
>
>
>
> On 26/08/07, Brian McCagherty <bmc at riola.com> wrote:
> >
> >
> >
> > Hi Graham
> >
> >
> >
> > I have been reading with interest your posts to the R-390 reflector.
> >
> >
> >
> > I have an R-390A which I am planning to restore this winter, and would
> like
> > to start by replacing all the dodgy capacitors.
> >
> > Can you guide me on sources of reliable types please?
> >
> >
> >
> > 73 de Brian  gi4gnz
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>