WHERE TO PURCHASE REPLACEMENT MULTI SECTION CAPACITORS FOR OS-8E/U

[W2PFY]

Has anyone ever worked on one of these scopes? I fired one up last night and found that the multi sections caps were dried out and heated up.

They are a 3 section one E4C794- 20 uf x 3 @ 450 vdc
and one 4 section one E4d1273-   20 uf x 4 @ 150 vdc

I forgot to measure these caps when I had it all apart but space is a factor so I can't just slap anything in there. I may be able to fit modern single cap types in there since they are made smaller than old buzzard styles.

The scope is only good up to 2 MC but that's fine as a mod scope or to trace things in most of receivers. I wonder what there original purpose was? I guess they were a Navy scopes from the fifties?

 

[N2DTS]

Modern caps are so small, you can fit them anyplace.
Get the 105c rated ones, you can just solder wires to them and stuff them in the old cans for the stock vintage look, or just let them rattle around wherever, tac them on under the chassis, etc.

If you want to pay a lot, tubesandmore.com likely sells the cans.
With filter caps, you can always go bigger without problems, more UF and more voltage...

Brett

[Rob K2CU]

Unless you can bring the vertical defelction plates of the CRT directly out, it will only be good as a mod scope for 160, as you said the vertical amp is only good to 2MHz. OK for audio though.

[W2PFY]

If you want to pay a lot

I think I'll rebuild in the can as suggested.

You know this is where a digital camera really comes in handy. Taking pictures close up and some out about a foot sure helps putting the thing back together again. Save my A** a couple times

[N2DTS]

I really dislike electrolytic caps, they have a finite lifetime.
I have a crap load of new old stock cans, like from 30 years ago.
I likely have what you need, and although they are unused, they are old.
You can have them if you want.

Taking the guts out of the cans seems like it would be real messy, is that stuff toxic?

Brett

[W2PFY]

Well Brett, I appreciate the offer. Here is what I have
C-134 is Aerovox 150 volts (4) section 20 uf each section
size Dia 1 3/8 length 2 1/16

C-135 (3) section  20 uf @ 450 volts. Dia 1 3/8 Length 2 7/16

Let me know if you have something close. Size matters here. can't go bigger. uf is optional.  

 

[N2DTS]

I will look when I get home.

Brett

[N2DTS]

I have:
400 volt, 100, 40, 10, 10, 2.5 inches high.

300 volt, 100uf, 60uf 250v, 20uf 250 v, 2.5 inches high.

450 volt, 35, 35, 10, 5 uf, 3 inches high,

450 volt, 50, 40, 30 uf, 3.5 inches high,

500 volt 40, 40, 8, 8 uf, 3 inches high,

Let me know if any of these will work.

Brett

[W3RSW]

The OSC 8U has all four deflection plates brought out to the rear panel for direct connection if desired.
I use the horiz. sweep on mine to make a pleasant display, either on AM or SSB.  Zero crossings are easily seen. Big difference in just switching the plate caps on the modulator tubes also very easily seen for the positive peaks.  Usually way more than 100%.

  The vertical deflection is done with a UHF tee on the rear coupled with a variable capacitor off the tee to the plates.  Works well but mismatched impedances do cause the display to skew on higher freqs.  Not noticable much on 160, 80 or 40.

[Jim, W5JO]

I don't know if Everett is still doing onseys and twoseys or not but you can try provided you can't find a suitable replacement.  I haven't used him in quite a while but he was honest and did a good job.  His work looks like new.

Frontier Capacitor
403 Mcintosh St S
Lehr, ND 58460
(701) 378-2341

You will have to call him, he doesn't have a website or email address to my knowledge.  For several years he built cans (twist lock) for Antique Electronic Supply, but I think he quit when the present company bought them.  Anyway give him a try if you wish.  I am even not confident he is still rebuilding caps, but if space and operation is problematic then this may be your best answer.  He will have you send the ones you presently have then he returns them when finished.

[KI4ES]

You can also try:

http://www.hayseedhamfest.com/

They are migrating to a new provider today, so the site is being rebuilt.  They do have a fair amount of neat stuff.

[ke7trp]

AES has them..

http://www.tubesandmore.com/

Hold your breath... They are NOT cheap..  This is why I never use them. I just solder in modern caps on the bottom.  20UF is so small now, that you can easily fit them


C