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 Help with DFB Styroseal Capacitors
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 Return to top of page · Post #: 1 · Written at 8:55:29 PM on 24 February 2014.
Spottynatty's Gravatar
 Location: Melbourne, VIC
 Member since 23 February 2014
 Member #: 1513
 Postcount: 20

Hi All,
Still in the process or recapping an old Glidomatic RF8.
Member GTC kindly pointed me in the direction of the schematic and on the same site I was able to find the DFB "Engineering Bulletin" which outlines the details of a number of different DFB Capacitors.
I have gone through the schematic and copied all of the required capacitors into an excel spreadsheet and started to source them.
I'm having trouble with the "Styroseal DFB" capacitors.
They are labeled as:
270E
300E
Etc.
I cannot find the exact code in the engineering bulletin.
And sometimes not even close.

Is there anywhere else I can look? Or someone I could email the list of styroseal capacitors to for them to recommend replacements?

Thanks


 
 Return to top of page · Post #: 2 · Written at 9:26:35 PM on 24 February 2014.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1182

Replacing every capacitor in the RF8 is a bit overkill & not necessary. I'd just replace all the electrolytics to start off with.

The polyester capacitors in this unit should be the yellow/mustard Philips types. These capacitors have a reputaton for being very reliable. The only styroseals I'd replace are the ones that have H.T. voltage on them.

From what you described in your other thread it sounds like your left hand output problems could be due to a valve (6GW8) and/or faulty output transformer. The popping in the right channel could be a 6GW8 with a intermittent heater/cathode short. Try swapping the 6GW8's around.

Those styroseal values will be 270 & 300 pf (picofarad)


 
 Return to top of page · Post #: 3 · Written at 9:40:35 PM on 24 February 2014.
Spottynatty's Gravatar
 Location: Melbourne, VIC
 Member since 23 February 2014
 Member #: 1513
 Postcount: 20

That's great news then.
I have already ordered the 2 2x50μF caps and will get onto ordering the electrolytic caps tomorrow.
Much smaller job now!

What is the best way to test the transformers?

While I was having a play around with the radio I did swap the 6GW8's around and it didn't seem to make any difference. I was also able to swap the 2 12AX7s around which I believe are preamps (but could be completely wrong there) and it make no difference.

Thanks


 
 Return to top of page · Post #: 4 · Written at 7:06:47 AM on 25 February 2014.
Scraps's Gravatar
 Location: Blue Mountains, NSW
 Member since 10 March 2013
 Member #: 1312
 Postcount: 401

If there's noise coming out of the speakers, chances are the transformers are okay and the problem is elsewhere. It'd be unusual for the transformers to break down internally without going open circuit. I have found broken leads near the outer layers but again, these were open circuit. If you really want to eliminate them just swap the leads over between channels.


 
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