Wilcox-Gay Recordette 3 Problems

[RecordOrr]

Hello all,
I have recently purchased a Wilcox-Gay Recordette Model IJ11. I turned it on and surprisingly the crystal cartridge has sound coming through it, however it is a really bad hum (Same thing happens when on play mode, a constant, LOUD hum that is loud regardless of what the volume is at). As someone who is just starting to do electronic repair, I haven't a clue where to begin! I cannot find any schematics for this specific model.

[emorritt]

More than likely you need to re-cap the unit; e.g. replace all capacitors. Over time, the old paper and oil caps absorb moisture and stop working. You can use modern "orange drop" capacitors for the interstage caps, just make sure the values are identical (or with better voltage rating) as the originals. I usually mark which end was negative on the new cap (black stripe around the original on the end) in case someone in the future starts making electrolytics for tube electronics again, so you'll know which way to install them. For the filter stack (usually the cause of 'hum') just use modern electrolytic equivalents of the values indicated on the original and tie all negative ends together. These HAVE to be electrolytics. I usually use a bakelite terminal block and tie all negative leads to the terminal that screws to the chassis. If you hide it under the chassis and leave the original in place for appearance, I usually use one of the mounting screws to mount the new block assembly. Here's an article on filter cap replacement in this manner:

http://rayz.com/ham-radio/hallicrafters-s38c-restoration/s-38c-restoration-filter-capacitors/

And here's a link to obtain tube value capacitors:

https://www.justradios.com/

Hope this helps.

[RecordOrr]

Hello,
How exactly do you determine the voltage of the cap? Several are labeled with 100 and such, however a good majority of them have no label at all.

[emorritt]

If the labels have been pulled off or otherwise are not there, you will have to have a schematic of the unit which will list the values. You should see on all of them some value like .05 followed by what looks like 'uf' which means microfarad then followed by the voltage. It is also possible that the values are printed on the caps, they just aren't turned so you can see the labels. A typical cap would read .1uf 200v. Some values will be different, some similar; just depends on where in the circuit they are used and for what purpose. If you see a black stripe, but nothing else, the cap is just turned where you can't see the brand and the value.

Also, some older molded caps have dots rather than numbers. These are typically OK because the molded casing provides protection from moisture. Also, some units have ceramic disc caps; these values are printed on one side of the component, sometimes a value with voltage, sometimes a code number. There are resources online that provide information on reading colored dots or component codes on older capacitors. Ceramics are also usually OK.

Just remember that the interstage electrolytics can be replaced with newer molded caps, but the filter caps (in a can with several values on the side) HAVE to be replaced with new electrolytics. It's unlikely you will find a newly made exact replacement for a filter stack, but you can build the same thing on a terminal strip.

Also, be careful if you handle the caps with your fingers. Even though an old electronic device may have been unplugged and not used for decades, some caps can retain a charge which can give you quite a shock if you aren't careful. The workaround is to bend a heavy paperclip in a "U" shape and hold it with something non-conductive, then touch both ends on the leads of the capacitor. If there is a charge, it will discharge when shorting it, making it safe to handle.