[MRCA] BC-474 Cap Pack Mystery!

[B. Smith]

This Cap pack discovery was new to me. I am sure that when I worked on 
the sets that I did not bother to investigate each capacitor as I 
changed them. I generally just replace all the caps - value for value 
before working on a set as it saves time. Excellent photos and I have 
placed the info in my BC-474 file.
Jolly good show.
Z


On 7/1/2025 1:56 PM, Ray Fantini via MRCA wrote:
>
> Ok, another project. The BC-474 transmitter receiver. Not my radio 
> just doing it for someone else. Got the radio in and started by 
> removing the Ham radio modifications like a different receiver power 
> cable and the like. Pulled a couple capacitors in the receiver and 
> they were questionable so decided maybe it’s time to replace most, at 
> least the ones associated with RF and AF bypassing, coupling and AVC 
> filtering. The smallest amount of leakage in a AVC filter has a huge 
> effect on the AVC action.
>
> The more I worked on the radio the more it became apparent that I was 
> not able to find a lot of the capacitors, then the discovery! A thing 
> called the CAP Pack, C10, C17 and C18 and a couple of the screen 
> bypass capacitors all live in the cap pack.
>
> Looks like a IF Transformer and located right next to one of the IF cans.
>
> Attached are a couple pictures of the cap pack and what was removed 
> after I melted away some of the wax its sealed in.
>
> Heat gun works for that. Any leaky capacitors in a battery radio are 
> an issue. Remember that all the time the B Battery is connected the B+ 
> bus in the radio is hot and any leakage will kill the battery when not 
> in use.
>
> Somehow the 474 has somewhat of a following so posting this 
> information for anyone who may also work with this radio.
>
> Will be posting more as work progresses, maybe video too. Still have a 
> bucket full of BC-654 video that I have to edit.
>
> Ray F/KA3EKH
>
>
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