Sears 397.19501 C2110 Grinder, need capacitor

[HobbyDad]

Hello, New here. I have a 397.19501 C2110 that was my fathers. I'm troubleshooting it as it just hums and I suspect the motor start capacitor. The motor is free to spin, bearings are good. There's a small rectangular device with the hot and neutral wires (black, white connected and a red, which goes up into the motor. If this is the capacitor, there is no value given, just "RBM" embossed on the top and 3169210 / 83-10111-1220A / FB painted on the side. I'm not concerned about originality, but would like it working again. Anyone know the value of cap or the replacement you're using?

Thank you,

 

[DadsTools]

Welcome to the forum. I have seen other threads in the past discuss this same subject. I recall one thread that talked about this in detail. It's been some time, so I don't recall which threads. But a site search might turn them up. It's not uncommon with these old grinders. Hopefully a member will recall what's what on these caps and post a good answer for you.

 

[HobbyDad]

Thanks. I did find another thread I'm posting to.

 

[exmaxima1]

That relay does not belong in there. And that model is "Split Phase" which has no start capacitor. Before pursuing a replacement relay you need to determine why the grinder is humming. The grinder has a centrifugal switch located inside one of the bell housings which could be burnt and no longer making contact (or the switch cracked). The start winding could also be burnt or open circuit. The insulation on the windings is very old at this point and could be shorted. Basically you will need to take the grinder apart and inspect the guts. Good luck.

 

[HobbyDad]

I'll disassemble and see what I find. If that relay doesn't belong there I don't know when it could have been installed. This has been in my family since about 1965 and dad wasn't one to dig into electrical items. It looks factory though.

I just found this on Ebay. The same model, 397.19501 C2110 with the same relay. See the pictures below. Mine on the left with the date, the one from Ebay on the right. Same mounting rivets, same location.

Not being argumentative, it's a mystery. The relay on mine is coming open so I may attempt to open it completely and see if contacts are burned or stuck before disassembling the rest of the grinder

Thanks,

 

[exmaxima1]

Upon closer inspection I can see that the relay was a factory installation. Though I've never seen that on a Pre-Block, it is possible that Packard (the manufacturer) may have started to use those current sensing relays in the Pre-blocks before they went to the later Block versions. In any case, as TM noted, those relays are generally very reliable and it is rare to replace them. I would still consider stripping the grinder down and looking for possible start coil issues before replacing it. A replacement relay will be around $20-25, and those grinders routinely sell for under $50 so it might not be worth the investment. Take your grinder apart and take some pics. Let us know if the centrifugal switch has been deleted.

 

[torqueman2002]

Here's a thread I posted about a repair on a 1/4-HP Block, you may find helpful.
"CM pre-Block Grinder 115.19500 restore, ver. 2" --> https://www.garagejournal.com/forum/threads/cm-pre-block-grinder-115-19500-restore-ver-2.447537/