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Model 86 Curiosity
#6

Thanks guys.

@Ron - I will definitely try out the 2M value once things are running otherwise.

@Mike - Ah right! I found it: http://philcoradio.com/phorum/showthread.php?tid=17679
I should've looked earlier.

Here's where I'm at so far:

BC Resistor

The 160 ohm and 1K sections of the BC resistor were open. I created a new BC resistor out of 25W resistors. I was lucky in that the three resistors *just barely* fit.

4K resistor w/ tap: 2240 ohm + 1540 ohm sections
160 ohm Philco part
1K resistor

[Image: https://farm2.staticflickr.com/1732/2899...0b81_c.jpg]

I brought it up on the variac and it actually received quite a bit at ~80VAC.

I was fortunate that the RF coils all tested good.

Recap

I replaced the big filter can caps. Boy that was a pain to get out. The tar had previously partially melted - making it stick really well to the sides of the can.
I relied on the trick described elsewhere on the Phorum of driving a screw into the tar block (to pull on) and then heating the sides of the can with a heat gun until I could get the block out.
I also used a small thin pry bar I have to separate it from the edge of the can. It took a little of everything but eventually it came free.

[Image: https://farm2.staticflickr.com/1758/4196...0754_c.jpg]

I also replaced the 0.1uF caps inside the 100 ohm wirewound resistor tubes. Kept the original resistance wire around the tube.

Interstage Transformer

The secondary of part #26 was 1/2 open. I believe that someone long ago someone worked around that problem with this?

[Image: https://farm2.staticflickr.com/1748/4196...f890_c.jpg]

The transformer with the open winding is in the top-right of the picture.

It actually did work reasonably well the way it was (decent volume, but a bit of distortion). I was able to find a replacement transformer on oldradioparts.com so I ordered that.
I'm about to swap that in. I did measure ~6,000 ohm for the secondary. I wonder if I'll get that hum you described now that the two caps / resistors work-around is removed.


Messages In This Thread
Model 86 Curiosity - by Nathan Slingerland - 06-18-2018, 01:00 AM
RE: Model 86 Curiosity - by Radioroslyn - 06-18-2018, 10:04 AM
RE: Model 86 Curiosity - by Nathan Slingerland - 06-18-2018, 10:41 AM
RE: Model 86 Curiosity - by Ron Ramirez - 06-18-2018, 09:49 PM
RE: Model 86 Curiosity - by morzh - 06-18-2018, 10:13 PM
RE: Model 86 Curiosity - by Nathan Slingerland - 06-19-2018, 12:41 AM
RE: Model 86 Curiosity - by morzh - 06-19-2018, 10:27 AM
RE: Model 86 Curiosity - by Nathan Slingerland - 06-19-2018, 11:51 PM
RE: Model 86 Curiosity - by Arran - 06-20-2018, 03:37 AM
RE: Model 86 Curiosity - by Nathan Slingerland - 06-20-2018, 11:37 AM
RE: Model 86 Curiosity - by morzh - 06-20-2018, 08:50 PM



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