CVRS Photo Challenge

[Don]

Back in the April, 2018, edition of CVR, the editor published a Photo Contest submitted by Ivan E Geleye. The challenge was to find the differences between a picture of the original chassis and the same chassis after it had been restored. Apparently there are five differences between the pix, but I can only find two. (Two of the paper capacitors have been reinstalled backwards with their outer foil lead reversed from the original positions.)

So to everyone out there: help in completing the challenge is requested. Can anyone spot the other 3? And – maybe even more of a challenge, Gerry O’Hara offered bonus marks to anyone who could identify the manufacturer and model of the radio. (Is he kidding? Like this is even possible?)

I’m passing this challenge over to all CVRS Forum members.

Attachments:

1. 

   Chassis1_original.jpg
   

2. 

   Chassis1_restored-.jpg
   

[Rick]

It looks like a painstakingly detailed and faithful restoration to the original. I do notice, however that there are at least 3 capacitors installed in reverse:

• the 0.1 µF capacitor near the bottom left of the photo
• the capacitor just above the 0.1
• the capacitor at an angle near the on/off switch

[John Greenland]

1 — 2.2 mega-ohm resistor near/connected to volume control

2 —- also the main filter cap at upper left corner.

It looks like a Philco as it uses a loctal tube.

[ivan]

Rick – yeah, I screwed up the orientation of these three caps. (the new yellow poly caps inside don’t have an outer foil marking!)
John – right on with the 2.2M resistor being replaced the other way around, and noticing that the filter cap was restuffed. But it’s not a Philco.
And there are still a few more differences in the photos.
ivan

[Anonymous]

– Additional piece of black insulation added to component lead beneath 47k resistor attached to volume pot.
– 470 ohm(?) resistor below cap and above coil/choke(?) in top right hand quadrant of chassis is physically much smaller in restoration.

[ivan]

Nice catch on the extra piece of black insulation, Ed! I thought it was needed because of the resistor directly above it.

Yes, both the old resistor and it’s replacement directly above the oscillator coil are 1/2 watt 470 ohm. Interesting how components changed during the period shortly after WWII.

Another interesting note is that this resistor and the .02uF cap above it are not in the schematic for this radio. This is a US model. But, there is a Canadian model of this same radio which contains both the resistor and the capacitor on the schematic.

So, was this a US model built in Canada, or was it built in the US using the Canadian schematic?

And there are still a couple more differences in the photos.

ivan

[Anonymous]

Hmmm – not sure how persnickety we are expected to be(!) – for example, there are several lead dress differences, such as the upper lead from the large cap to the centre-right of the chassis, and the wire from the volume pot switch to the tube base to its left… but after that I think I am stumped!

[phil]

rivets in the IF can or whatever it is , replaced with little bolts.

[ivan]

Phil – yes, that’s the second IF transformer that’s located under the chassis, but I didn’t replace the rivets. They are still the originals.
Hint – check the orientation of all the resistors.

And as for the make and model of this radio here’s a hint: It’s a 1945-47 produced both in the US and in Canada under different model numbers for different colours. Based on the chassis you can see that it’s a basic AA5 table model but a bit unusual because it has an RF amplifier stage (6 tubes). And if you could see the top of the chassis before restoration, you would notice that the plastic dial on the tuning capacitor is warped.

Ivan

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