[kiwi_steve]

Hi Steve. Typo on my post. The dial number should be 27-5094.

If you can engage the other members to work with you on the rf problem they are top end when it comes to these philcos. I have only done one of em before but I would say this.  

I think you really should be fitting Electrolitics where it says Electrolitics and stay with the Cap values as stated on the service sheets.  The philco engineers determined these values for a reason.  I would also check the routing of the wiring.  

It is important to keep the original routing intact.  A simple thing like moving a wire away from the chassis can cause problems.  Check all  the voltages you have on the service sheets and check that 78 RF tube.

I think you should complete the resistor and cap replacement including the mica.  I dont buy in to the notion that mica seldom goes gaga.  Any radio I have ever fiddled with has had dodgy mica's.

Finally, I have a spare wave trap (again thanks Ron)  Maybe I can email it to you or drop it into your local pub.

Kind Regards Steve.

Will.




I have a spare wave trap

Thanks Will, I'm pretty sure the radio never had the wave trap from factory so unless I can be convinced it needs it I'll just leave that part of the circuit alone... but feel free to drop into the local pub and we can discuss it over a beer or two (or just email me a beer instead)

The cap values are as near to correct as I can get - and I already went through last night and replaced the remaining resistors with modern 1W carbons.  I also replaced the 2 x 110pF caps that are (electrically) beside the volume control because they were a little leaky.  I'd originally left them alone because of their values.  I have no new mica caps in stock, and very rarely change them... only once in fact, and that was because of SMD.  I've put 2 new 3kv 100pF ceramics in there.  I went through my 100pF caps and found 2 that were reading high so they're 107 and 109pF respectively (I don't believe this point in the circuit really needs micas because it doesn't appear to be a critical tuned circuit - again, I am open to advice).  I'm using what I've got there... micas are expensive and my budget is... well, I don't have one because that would imply I have money spare to spend on this

Regarding the polarised / non-polarised nature of the caps in the small can - I did ask about that, but got no feedback.  Unless using electrolytics will provide some important advantage I'll leave that.  I've used 1uF and 2.2uF... better than the 16uF someone had strung up over there in there in the past (not to mention the 40uF they'd wired across the 1uF!)

The voltages are about right everywhere I have checked and the RF 78 got replaced with a spare I had... no change.  I don't have any more, nor does my usual valve guy. 

Re the routing, I have changed very little of that - only around the power supply where I've moved the reservoir cap and smoothing cap on to tag strip just below the originals - otherwise everything is as-was.  I'm aware that certain parts of the circuit need to be kept as they were designed and I've done that pretty much everywhere.

Interestingly, the one band (SW) that I would expect to be the most finicky and potentially the biggest problem is fine, and the ones I would expect to be easier to sort and giving me the biggest headache.  I'm sure I will solve it eventually, and I'm sure it will be something simple, and probably something I did